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[Display omitted] • Discover the latest trends in rapid detection through a review of recent breakthroughs in identifying foodborne pathogens. • The innovation and limitations of different detection methods and their relationship were summarized. • CRISPR/Cas applications in rapid detection are summarized, showing innovation in food safety. • Molecular biology techniques offer high specificity, sensitivity, and rapidity for improved foodborne pathogens detection. In recent years, foodborne diseases have posed a serious threat to human health, and rapid detection of foodborne pathogens is particularly crucial for the prevention and control of such diseases. This article offers a detailed overview of the development of detection techniques for foodborne pathogens, transitioning from traditional microbiological culture methods to the current array of techniques, including immunological, molecular biological, and biosensor-based methods. It summarizes the technical principles, advantages, disadvantages, and research progress of these diverse methods. Furthermore, the article demonstrates that the combination of different methods enhances the efficiency and accuracy of pathogens detection. Specifically, the article focuses on the application and advantages of combining CRISPR/Cas systems with other detection methods in the detection of foodborne pathogens. CRISPR/Cas systems, with their high specificity, sensitivity, and ease of operation, show great potential in the field of foodborne pathogens detection. When integrated with other detection techniques such as immunological detection techniques, molecular biology detection techniques, and biosensors, the accuracy and efficiency of detection can be further improved. By fully utilizing these tools, early detection and control of foodborne diseases can be achieved, enhancing public health and preventing disease outbreaks. This article serves as a valuable reference for exploring more convenient, accurate, and sensitive field detection methods for foodborne pathogens, promoting the application of rapid detection techniques, and ensuring food safety and human health. [ABSTRACT FROM AUTHOR]

[Display omitted] • Detection of Yersinia enterocolitica in bivalve mollusks by a reference test (ISO 10273:2017). • Validation "in house" of the molecular method employed to detect pathogenic Yersinia enterocolitica in bivalve mollusks. • Detection of Yersinia enterocolitica in real samples of bivalve mollusks. Yersinia enterocolitica (Ye) is a foodborne pathogen isolated from humans, food, animals, and the environment. Yersiniosis is the third most frequently reported foodborne zoonosis in the European Union. Ye species are divided into six biotypes 1A, 1B, 2, 3, 4, and 5, based on biochemical reactions and about 70 serotypes. Biotype 1A is non-pathogenic, 1B is highly pathogenic, and biotypes 2–5 have moderate or low pathogenicity. The reference analysis method for detecting pathogenic Ye species underestimates the presence of the pathogen due to similarities between Yersinia enterocolitica -like species and other Yersiniaceae and/or Enterobacteriaceae , low concentrations of distribution pathogenic strains and the heterogeneity of Yersinia enterocolitica species. In this study, the real-time PCR method ISO/TS 18867 to identify pathogenic biovars of Ye in bivalve molluscs was validated. The sensitivity, specificity and accuracy of the molecular method were evaluated using molluscs experimentally contaminated. The results fully agree with those obtained with the ISO 10273 method. Finally, we evaluated the presence of Ye in seventy commercial samples of bivalve molluscs collected in the Gulf of Naples using ISO/TS 18867. Only one sample tested resulted positive for the ail gene, which is considered the target gene for detection of pathogenic Ye according to ISO/TS 18867. Additionally, the presence of the ystB gene, used as target for Ye biotype 1A, was assessed in all samples using a real-time PCR SYBR Green platform. The results showed amplification ystB gene aim two samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Survival of L. monocytogenes in minced pork to single or sequential environmental stresses after cold stress was explored. • Thermal and gastric fluid resistance of L. monocytogenes was evaluated after sequential stress. • NaCl adaptation reduced the resistance of L. monocytogenes to LA and Nisin stress, whereas LA induced the opposite trend. • Sequential pressure reduces the effect of a single pressure on the thermal resistance of L. monocytogenes. • Sequential stress of LA 1.25-NaCl 50 renders thermal-treated L. monocytogenes insensitive to simulated gastric fluid. In this study, Listeria monocytogenes from minced pork was evaluated for changes in resistance to thermal treatment and gastric fluid following environmental stresses during food processing. Bacteria were exposed to cold stress, followed by successive exposures to different stressors (lactic acid (LA), NaCl, or Nisin), followed by thermal treatments, and finally, their gastrointestinal tolerance was determined. Adaptation to NaCl stress reduced the tolerance of L. monocytogenes to subsequent LA and Nisin stress. Adaptation to LA stress increased bacterial survival in NaCl and Nisin-stressed environments. Bacteria adapted to Nisin stress showed no change in tolerance to subsequent stress conditions. In addition, treatment with NaCl and LA enhanced the thermal tolerance of L. monocytogenes , but treatment with Nisin decreased the thermal tolerance of the bacteria. Almost all of the sequential stresses reduced the effect of a single stress on bacterial thermal tolerance. The addition of LA and Nisin as a second step of stress reduced the tolerance of L. monocytogenes to gastric fluid, whereas the addition of NaCl enhanced its tolerance. The results of this study are expected to inform processing conditions and sequences for meat preservation and processing and reduce uncertainty in risk assessment of foodborne pathogens due to stress adaptation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biofilm and planktonic L. monocytogenes are sensitive to rhamnolipids. • pH and NaCl influence antimicrobial action of rhamnolipids. • Rhamnolipids are more effective at pH 5.0. • NaCl enhances rhamnolipid action mainly at pH above 6.0. • Rhamnolipid self-assembly is associated with antimicrobial activity. The use of natural and sustainable additives, that are less aggressive to the environment, is a trend in the food industry. Rhamnolipids (RL) biosurfactants have shown potential for controlling food pathogens however, due to the presence of free carboxyl groups, the pH and ionic strength may influence the properties of such surfactants. In this study, we describe the antimicrobial activity of RL under different pH values and NaCl concentrations, towards both planktonic and biofilms of Listeria monocytogenes. RL were effective at pH 5.0 and the addition of 5 % NaCl improved the bactericidal efficacy for planktonic and sessile cells. The effect of NaCl was more pronounced at pH above 6 showing a significant increase in RL antimicrobial activity. At pH 7.0 planktonic population was eradicated by RL only when salt was present whereas biofilm viability was decreased by 5 log with MBIC varying from > 2500.0 mg/L (RL) to 39.0 mg/L (RL + 5 % NaCl). Larger vesicular and lamellar RL self-assembly structures were predominant when NaCl was present, suggesting their association with the antimicrobial activity observed. The pH and ionic strength of the medium are important parameters to be considered for the development of RL-based strategies to control L. monocytogenes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Foodborne pathogens' response in the simulated GIT when subjected to antibiotics. • Minimum inhibitory concentration assays. • Representative in vitro simulation of the harsh GIT environment. Minimum inhibitory concentrations (MIC) assays are often questioned for their representativeness. Especially when foodborne pathogens are tested, it is of crucial importance to also consider parameters of the human digestive system. Hence, the current study aimed to assess the inhibitory capacity of two antibiotics, ciprofloxacin and tetracycline, against Salmonella enterica and Listeria monocytogenes , under representative environmental conditions. More specifically, aspects of the harsh environment of the human gastrointestinal tract (GIT) were gradually added to the experimental conditions starting from simple aerobic lab conditions into an in vitro simulation of the GIT. In this way, the effects of parameters including the anoxic environment, physicochemical conditions of the GIT (low gastric pH, digestive enzymes, bile acids) and the gut microbiota were evaluated. The latter was simulated by including a representative consortium of selected gut bacteria species. In this study, the MIC of the two antibiotics against the relevant foodborne pathogens were established, under the previously mentioned environmental conditions. The results of S. enterica highlighted the importance of the anaerobic environment when conducting such studies, since the pathogen thrived under such conditions. Inclusion of physicochemical barriers led to exactly opposite results for S. enterica and L. monocytogenes since the former became more susceptible to ciprofloxacin while the latter showed lower susceptibility towards tetracycline. Finally, the inclusion of gut bacteria had a bactericidal effect against L. monocytogenes even in the absence of antibiotics , while gut bacteria protected S. enterica from the effect of ciprofloxacin. [ABSTRACT FROM AUTHOR]

[Display omitted] • The process and influencing factors of Listeria monocytogenes biofilm formation have been described. • Qualitative and quantitative techniques to detect L. monocytogenes biofilm have been presented. • This study elaborates the possible mechanisms of biofilm resistance: extracellular polymers, specific physiological adaptations, high genetic variability, and regulation of signaling molecules. • Various strategies and associated challenges in managing L. monocytogenes biofilm along with future prospects for controlling L. monocytogenes biofilm using hurdle techniques have been discussed. Listeria monocytogenes is an important foodborne pathogen that causes listeriosis, a severe and fatal condition. Biofilms are communities of microorganisms nested within a self-secreted extracellular polymeric substance, and they protect L. monocytogenes from environmental stresses. Biofilms, once formed, can lead to the persistence of L. monocytogenes in processing equipment and are therefore considered to be a major concern for the food industry. This paper briefly introduces the recent advancements on biofilm formation characteristics and detection methods, and focuses on analysis of the mechanism of L. monocytogenes biofilm resistance; Moreover, this paper also summarizes and discusses the existing different techniques of L. monocytogenes biofilm control according to the physical, chemical, biological, and combined strategies, to provide a theoretical reference to aid the choice of effective control technology in the food industry. [ABSTRACT FROM AUTHOR]

[Display omitted] • An overview of Raman spectroscopy-based microfluidic platforms is provided. • Summary of cell trapping mechanisms compatible with microfluidic platform. • Recent applications of technique in foodborne pathogen analysis are discussed. • Advances and challenges of the technique in microbial detection are summarized. Rapid and sensitive detection of foodborne pathogens in food products is paramount for ensuring food safety and public health. In the ongoing effort to tackle this issue, detection methods are continually researched and upgraded to achieve rapidity, sensitivity, portability, and cost-effectiveness. This review addresses the critical need for improved technique by focusing on Raman spectroscopy-based microfluidic platforms, which have shown potential in revolutionizing the field of foodborne pathogen analysis offering point-of-care diagnosis and multiplex detection. The key problem lies in the persistent threat of compromised food quality and public health due to inadequate pathogen detection. The review elucidates the various trapping strategies employed in a microfluidic platform, including optical trapping, electrical trapping, mechanical trapping, and acoustic trapping for the capture of microbial cells. Subsequently, the review delves into the key aspects of the application of microbial detection in food products, highlighting recent advances and challenges in the field. The integrated technique allows point-of-care application assessment, which is an attractive quality for in-line and real-time detection of foodborne pathogens. However, the application of the technique in food products is limited and requires further research to combat the complexity of the food matrix, reduced costs of production, and ensure real-time use for diverse pathogens. Ultimately, this review aims to propel advancements in microbial detection, thus promoting enhanced food safety through state-of-the-art technologies. [ABSTRACT FROM AUTHOR]

[Display omitted] • The ultrasound-assisted pulsed ohmic heating (POH) system was developed and its bactericidal effect was investigated. • Ultrasound-assisted POH inactivated pathogens in phosphate buffered saline and milk with 0–3.6% fat by more than 1 log unit compared to each treatment alone. • Bacterial cell membrane damage and leakage of intracellular materials were intensified by ultrasound-assisted POH. • Milk fat decreased the heating rate and bactericidal effect of ultrasound-assisted POH system. • There were no significant differences in pH, color, and viscosity of milk between before and after the ultrasound-assisted POH treatment. The central objective of this research was to develop an ultrasound-assisted pulsed ohmic heating (POH) system for inactivation of food-borne pathogens in phosphate buffered saline (PBS) and milk with 0–3.6% fat and investigate its bactericidal effect. Combining ultrasound with POH did not significantly affect the temperature profile of samples. Both POH alone and ultrasound-assisted POH took 120 s to heat PBS 60℃. Milk with 0, 1, and 3.6% fat was heated to 60℃ by POH alone and ultrasound-assisted POH after 335, 475, and 525 s, respectively. This is because the electrical conductivity of the samples was the same for POH alone and ultrasound-assisted POH. Despite identical temperature profiles, ultrasound-assisted POH exerted a synergistic effect on the reduction of Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes , and Staphylococcus aureus. In particular, the inactivation level of S. Typhimurium in PBS subjected to ultrasound-assisted POH treatment for 120 s corresponding to a treatment temperature of 60℃ was 3.73 log units higher than the sum of each treatment alone. A propidium iodide assay, intracellular protein measurements, and scanning electron microscopy revealed that ultrasound-assisted POH treatment provoked lethal cell membrane damage and leakage of intracellular proteins. Meanwhile, fat in milk reduced the efficacy of the bacterial inactivation of the ultrasound-assisted POH system due to its low electrical conductivity and sonoprotective effect. After ultrasound-assisted POH treatment at 60℃, there were no significant differences (P > 0.05) in the pH, color, and apparent viscosity of milk between the untreated and treated group. [ABSTRACT FROM AUTHOR]

[Display omitted] • Glabridin treatment causes membrane permeabilization and cell-envelope disruption. • Glabridin induces cell envelope stress response orchestrated by LiaSR and VirRS. • SigB-controlled stress defence proteins regulon was upregulated. • Sub-lethal treatment of glabridin may induce (cross)protection. Glabridin is a prenylated isoflavan which can be extracted from liquorice roots and has shown antimicrobial activity against foodborne pathogens and spoilage microorganisms. However, its application may be hindered due to limited information about its mode of action. In this study, we aimed to investigate the mode of action of glabridin using a combined phenotypic and proteomic approach on Listeria monocytogenes. Fluorescence and transmission electron microscopy of cells exposed to glabridin showed membrane permeabilization upon treatment with lethal concentrations of glabridin. Comparative proteomics analysis of control cells and cells exposed to sub-lethal concentrations of glabridin showed upregulation of proteins related to the two-component systems LiaSR and VirRS, confirming cell envelope damage during glabridin treatment. Additional upregulation of SigmaB regulon members signified activation of the general stress response in L. monocytogenes during this treatment. In line with the observed upregulation of cell envelope and general stress response proteins, sub-lethal treatment of glabridin induced (cross)protection against lethal heat and low pH stress and against antimicrobials such as nisin and glabridin itself. Overall, this study sheds light on the mode of action of glabridin and activation of the main stress responses to this antimicrobial isoflavan and highlights possible implications of its use as a naturally derived antimicrobial compound. [ABSTRACT FROM AUTHOR]

[Display omitted] • Proteomics changes lead to a better understanding of L. monocytogenes lag. • Half-Fraser broth does not lack critical substrates for L. monocytogenes recovery. • Supplementation does not lead to biologically relevant shortening of lag. The dynamics of the enrichment-based detection procedure of the foodborne pathogen Listeria monocytogenes from food still remains poorly understood. This enrichment is crucial in the reliable detection of this pathogen and more insight into the recovery mechanism during this step is important to advance our understanding of lag phase behaviour during enrichment. In this study we combined transcriptomic and proteomic analyses to better understand the physiological processes within the lag phase of L. monocytogenes during enrichment. Upon transfer of BHI-cultured stationary phase L. monocytogenes cells to half-Fraser enrichment broth (HFB), motility-associated genes and proteins were downregulated, while expression of metal uptake transporters, resuscitation-promoting factors that stimulate growth from dormancy, antibiotic efflux pumps and oxidative stress proteins were upregulated. Next to this, when cells with a heat stress history were cultured in enrichment broth, proteins necessary for recovery were upregulated with functions in DNA-damage repair, protein refolding, cell-wall repair, and zinc transport. Proteomic results pointed to possible factors that support shortening the lag duration, including the addition of 10 µM zinc and the addition of spent HFB containing presumed concentrations of resuscitation-promoting factors. However, these interventions did not lead to biologically relevant reduction of lag phase. Also, when cells were enriched in spent HFB, final cell concentrations were similar to enrichments in fresh HFB, indicating that the enrichment broth seems not to lack critical substrates. Concludingly, this study gives insight into the proteomic changes in the lag phase during enrichment and shows that supplementation of HFB is not the best strategy to optimize the current enrichment method. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effect of refrigerated temperatures was assessed for Salmonella in liquid egg. • pH and color presented minor changes in liquid egg at 7 °C and 10 °C for 31 days. • Nisin and EDTA, plus 7 °C inhibited the growth of Salmonella in liquid egg. • Salmonella grew quickly at 10 °C regardless of the presence of antimicrobials. • Weibull and logistic models fitted well the decay and growth of cells, respectively. Salmonella spp. can be present in pasteurized liquid egg products because of its heat resistance or post-processing contamination, thereby representing a food safety risk. The effect of 1000 IU nisin/ml plus 20 mM disodium ethylenediaminetetraacetic acid (EDTA), two refrigerated temperatures (7 °C and 10 °C), and two inoculation levels (103 and 105 cfu/ml) were studied in the growth of S. Typhimurium in pasteurized liquid whole egg (LWE). Two mathematical models were used to fit the microbial curves. Physicochemical characteristics of LWE, such as pH and color, were assessed for 31 days at the two storage temperatures, and no significant changes (p < 0.05) were observed for most of the samples. Results showed the significant impact of temperature on microbial growth. Samples kept at 7 °C showed the decay of microbial cells during storage; meanwhile, the effect at 10 °C was shown as fast growth. The combination of nisin plus EDTA and 7 °C accelerated the decay of microbial cells during the storage showing a synergistic effect. The Weibull model described the decline of cells during the shelf-life. Meanwhile, the logistic model fitted the growth of Salmonella in LWE at 10 °C. Adding these additives to LWE, combined with the correct temperature during pasteurization and adequate conditions during the cold chain, can minimize the food safety risk related to Salmonella. [ABSTRACT FROM AUTHOR]

Lactic acid bacteria (LAB) exert a strong antagonistic activity against many microorganisms including food spoilage organisms and may be used as an alternative to control biofilm formation of pathogens in food industries. The objective of this work was to investigate the ability of fifteen Salmonella strains isolated from poultry environment to form biofilms on different surfaces. In addition, the effect of Lactobacillus kefiri strains 8321 and 83113 and Lactobacillus plantarum 83114 and their surface proteins on biofilm development of Salmonella Enteritidis 115 was studied. The relationship between surface properties of bacteria (hydrophobicity, autoaggregation and coaggregation with lactobacilli) and biofilm formation was also investigated. Most of Salmonella strains were hydrophilic and five strains were moderately hydrophobic. In general, Salmonella strains showed high aggregation abilities (27–54%). S. Enteritidis 106 and S. Typhimurium 102 and 108 showed the highest percentages of autoaggregation. All Salmonella strains tested showed aggregation abilities with the three lactobacilli studied, but the percentage of coaggregation proved to be strain-specific. When comparing stainless steel, glass and polystyrene surfaces, higher levels of biofilm formation occurred on polystyrene plate than on glass surfaces or stainless steel. S. Enteritidis 115 exhibited the greatest attachment to polyestyrene surface. The preincubation or coincubation with the three lactobacilli strains significantly reduced (about 1 log CFU/ml of reduction) the ability of S. Enteritidis 115 to form biofilm compared to the control without lactobacilli. These results were confirmed by confocal microscopy. In the same way, when surface proteins extracted from lactobacilli strains were preincubated or coincubated with S. Enteritidis 115, biofilm formation of this strain was significantly decreased compared to the control. The results obtained showed that these Lactobacillus strains and their surface proteins can be used as alternatives for control of biofilm formation by Salmonella in the poultry industry. Unlabelled Image • Biofilm formation of Salmonella isolated from poultry was investigated under different conditions. • Three Lactobacillus strains can be excellent candidates to prevent Salmonella biofilm formation. • Surface proteins extracted from lactobacilli strains contribute to the Salmonella biofilm inhibition. [ABSTRACT FROM AUTHOR]

Foodborne pathogens such as Listeria spp. contain the ability to survive and multiply in poultry farming environments, which provides a route of contamination for poultry processing environments and final poultry products. An understanding of the effect of meteorological variables on the prevalence of Listeria spp. in the farming environment is lacking. Soil and feces samples were collected from 11 pastured poultry farms from 2014 to 2017. Random forest (RF) and gradient boosting machine (GBM) predictive models were generated to describe and predict Listeria spp. prevalence in feces and soil samples based on meteorological factors at the farming location. This study attempted to demonstrate the use of GBM models in a food safety context and compare their use to RF models. Both feces models performed very well, with area under the curve (AUC) values of 0.905 and 0.855 for the RF and GBM models, respectively. The soil GBM model outperformed the RF model with AUCs of 0.873 and 0.700, respectively. The developed models can be used to predict the prevalence of Listeria spp. in pastured poultry farm environments and should be of great use to poultry farmers, producers, and risk managers. Unlabelled Image • Environmental samples were evaluated from poultry farms for Listeria prevalence. • Listeria prevalence can be predicted by machine learning models based on weather. • Wind speed, temperature, and humidity affect Listeria spp. prevalence. • This study provides a framework for future use of machine learning in food safety. [ABSTRACT FROM AUTHOR]

Activated persulfate, a relatively new advanced oxidation process, has gained attention for its potential to ensure fresh produce safety. One of the major advantages is to avoid the formation of toxic chlorinated disinfection byproducts which are concerns for chlorine-based sanitizers. This study was aimed to investigate the efficacy of ferrous and alkaline activated persulfate in inactivating Escherichia coli O157:H7 and Listeria monocytogenes , with the primary focus on the effect of initial persulfate concentration, the effect of gradual addition of ferrous ion, and the stability of activated persulfate. The prepared 5-strain pathogen cocktails were treated by activated persulfate for 60 or 120 s. Sodium thiosulfate combined with phosphate buffer was used to quench the reaction. Both pathogens were plated onto non-selective agars for colony enumeration. The steady-state concentrations of sulfate and hydroxyl radicals were quantified in each activation conditions. The results showed higher initial persulfate concentration can lead to more pathogen reductions. About 8.50 log CFU/mL reduction was observed in 120 s after the initial persulfate concentration was increased to 80 mmol/L (ferrous activation on both pathogens) or 600 mmol/L (alkaline activation on L. monocytogenes). Gradual addition of ferrous ion into persulfate solution achieved more pathogen reductions than adding all ferrous ion at once. However, only the increases of reductions achieved by four sequential addition were significant (P < 0.05). In addition, the steady-state concentrations of both sulfate and hydroxyl radicals were found to be positively correlated with microbial reductions at all conditions. Furthermore, the pathogen inactivation efficacy of both ferrous and alkaline activated persulfate can be maintained for a relatively long period (up to 3 h). Unlabelled Image • Activated persulfate was effective in inactivating foodborne pathogens. • Higher initial persulfate level can lead to more pathogen reductions. • Gradual addition of ferrous ion can improve pathogen inactivation efficacy. • The inactivation efficacy of activated persulfate can be stable for hours. [ABSTRACT FROM AUTHOR]

Abstract Rhamnolipid (RL) biosurfactants have been studied as agents to control the growth of food pathogens however, to be successful applied as antimicrobial agent in food, is important to determine the effect of environmental conditions on RL activity. Once pH is a determinant factor to the development of microorganisms in food, we investigated the antimicrobial activity of RL under different pH values. The antimicrobial activity of RL against the Gram-positive pathogens L. monocytogenes , B. cereus and S. aureus was pH dependent and favored at more acidic conditions while the Gram-negative Salmonella enterica and E. coli (EHEC) showed resistance at all pH levels studied. Bacillus cereus was the most sensitive bacteria showing MIC of 19.5 μg/mL and eradication of the population was observed after 30 min with 39.1 μg/mL of RL. The sensitivity to RL was associated with reduction on cell surface hydrophobicity and cytoplasmic membrane damage. Scanning Electron Microscopy images evidenced the cell damage promoted by RL on sensitive strains. The pH is an important factor to be considered on developing RL-based strategies to the control of food pathogens. Graphical abstract Unlabelled Image Highlights • Antimicrobial activity of rhamnolipid is pH dependent. • Rhamnolipid action is favored at more acidic conditions. • B. cereus is very sensitive to rhamnolipids. • Rhamnolipid changes cell surface hydrophobicity and composition. [ABSTRACT FROM AUTHOR]

[Display omitted] • Diet influenced the gut microbiota colonization resistance mechanisms. • The healthy diet caused a greater inactivation of L. monocytogenes. • The healthy diet inferred the induction of stress tolerance for S. Typhimurium. • Competitive responses were the main mechanism of colonization resistance. • E. coli and B. thetaiotaomicron were the most prevalent gut microbiota species. The human gastrointestinal tract employs an assortment of chemical, enzymatic and immune barriers to impede pathogen colonization. An essential component of these barriers is the gut microbiota, which infers protection against ingested pathogens through its colonization resistance mechanisms. Specifically, the gut microbiota of the distal small intestine (ileum) renders a crucial line of defense, given that this location is regarded as an important interaction site. This study aimed to evaluate the impact of the ileal microbiota on the survival of the foodborne pathogens Salmonella enterica serotype Typhimurium and Listeria monocytogenes , utilizing an in vitro digestion model system. Moreover, the effect of diet on the gut microbiota colonization resistance mechanisms was assessed, by comparing a healthy (high fiber/low sugar) and a western diet (low fiber/high sugar). For S. Typhimurium, the results revealed that the digestion of a healthy diet led to a similar inactivation compared to the western diet, with the values of total log reduction being 0.83 and 0.82 log(CFU), respectively; yet the lack of readily accessible nutrients in the healthy diet combined with the acidic shock during gastric digestion caused the induction of stress tolerance to the pathogen. This resulted in increased pathogen survival in the presence of gut microbiota, with S. Typhimurium proliferating during the ileal phase with a maximum specific growth rate of 0.16 1/h. On the contrary, for L. monocytogenes , the healthy diet was associated with a greater inactivation than the western diet (total log reduction values: 3.08 and 1.30 log(CFU), respectively), which appeared strongly influenced by the encounter of the pathogen with the gut microbiota. Regarding the latter, the species Escherichia coli and Bacteroides thetaiotaomicron appeared to be the most prevalent in most cases. Finally, it was also demonstrated that the ileal microbiota colonization resistance mechanisms largely relied on competitive responses. The obtained knowledge of this research can contribute to the development and/or complementation of defensive strategies against pathogen infection, while also underlining the value of in vitro approaches. [ABSTRACT FROM AUTHOR]

[Display omitted] • This study investigated the effects of the power level of 915 MHz microwave heating at the same holding time on the bacterial inactivation efficacy. • A holding time of 15 s after 100℃ resulted in a > 5 log reduction with 3–5 kW microwave heating. • Microwave heating led to a significant change in transmembrane potential by increasing power level and caused damage to>86% of the DNA at power levels of 2–5 kW. • Severe cell membrane damage in Listeria monocytogenes due to non-thermal effects was observed at 5 kW through transmission electron microscope images. • An increase of the power level influenced the moisture content, cooking loss and texture properties. The main purpose of this research was to investigate the effect of power level of 915 MHz microwave heating on the inactivation of foodborne pathogens in ground pork and its bactericidal mechanism. It was demonstrated that the heating rate was proportional to the power level. For instance, the heating rates observed at microwave heating powers of 2, 3, 4, and 5 kW were 1.70, 2.77, 3.35, and 4.03℃/s, respectively. The bactericidal effect of microwave heating also significantly (P < 0.05) increased with increasing power level. In particular, when ground pork was subjected to microwave heating at 5 kW, the reduction level of pathogens was>2 log units higher than at 2 kW. To determine the bactericidal mechanism of microwave heating depending on power level, changes in transmembrane potential and DNA damage were determined using fluorescence. The extent of depolarization in membrane potential of pathogens significantly (P < 0.05) increased as power level increased. There was no significant difference in degree of DNA damage at different power levels. However, the percentage of DNA damage was>86% at all power levels. The transmembrane potential assay indicates that the bacteria exhibited dramatic pore formation on the membrane at 5 kW. Through transmission electron microscopy, the electroporation effect was enhanced as power level increased. Moreover, the quality of ground pork subjected to microwave heating at 2–5 kW was determined by measuring the moisture content, cooking loss, and texture profile. [ABSTRACT FROM AUTHOR]

Application of bacteriophages to eliminate foodborne pathogens in food matrices is an emerging research field. In this study, a promising phage candidate specific for Salmonella strains was screened and its ability to decrease Salmonella counts in some food, such as milk, sausage, and lettuce, was investigated. A total of 58 Salmonella phages were isolated from a wastewater treatment plant, sewage near a river, farm ditch near a lake, and poultry house. Among them, phages LPST10, LPST18, and LPST23 were highly efficient in infecting Salmonella Typhimurium ATCC 14028. In particular, phage LPST10 could infect all the tested Salmonella Typhimurium and Salmonella Enteritidis strains with high efficiency. Bacterial challenge tests revealed that phage LPST10 and its combination with phages LPST18 and LPST23 could consistently inhibit the growth of multiple strains. Phage LPST10 presented a lysis time of about 50 min with a burst size of 101 PFU/CFU, exhibited two distinct phases in the one-step growth curve, and was stable at a pH range of 3–13 that corresponds to the pH of most of the foods (pH 3.5–7.5) and at temperatures between 30 °C and 60 °C. Transmission electron microscopy demonstrated that phage LPST10 belongs to the Siphoviridae family, with an icosahedral head with a diameter of 83.26 nm and tail length and width of approximately 144.89 nm and 10.9 nm, respectively. A significant decrease in the bacterial counts (0.92–5.12 log 10 CFU/sample) and an increase in phage titers (0–2.96 log 10 PFU/sample) were observed in different food matrices tested. These results demonstrated that phage LPST10 is a promising candidate for controlling Salmonella contamination in foods owing to its safety and effectiveness. [ABSTRACT FROM AUTHOR]

Foodborne pathogens cause serious health issues and have a strong impact on the economy of the country. In this context, quality testing of royal delicious apple by detecting pathogen contamination using an electronic nose, which contains an array of six ready-made sensors, has been proposed. To estimate the types of pathogens, fresh, half and completely contaminated apple samples were considered for bacterial studies. This study revealed the presence of Staphylococcus, Salmonella and Shigella bacteria, which were in the order of zero, 10 2 , 10 3 −10 4  CFU/mL. Further, the recorded headspace GC–MS spectra of contaminated samples confirmed the presence of bacterial spoilage markers namely acetone, ethyl acetate, ethyl alcohol and acetaldehyde. Voltage swing of 0.2 and 0.5 V was observed for half and completely contaminated apple samples respectively with reference to the fresh sample. Voltage responses of the sensors fed to Principal component analysis and Ward's method of hierarchical cluster algorithms helped to assess the quality of apple samples. By correlating the results of tri-layers namely bacterial count, GCMS data and classification results, reference table was developed and embedded in the ATmega processor of the electronic nose for real-time quality estimation of apple samples. [ABSTRACT FROM AUTHOR]

The object of this study was to elucidate the bactericidal mechanism of a 222 nm Krypton Chlorine (KrCl) excilamp compared with that of a 254 nm Low Pressure mercury (LP Hg) lamp. The KrCl excilamp had higher bactericidal capacity against Gram-positive pathogenic bacteria ( Staphylococcus aureus and L. monocytogenes ) and Gram-negative pathogenic bacteria ( S . Typhimurium and E. coli O157:H7) than did the LP Hg lamp when cell suspensions in PBS were irradiated with each type of UV lamp. It was found out that the KrCl excilamp induced cell membrane damage as a form of depolarization. From the study of respiratory chain dehydrogenase activity and the lipid peroxidation assay, it was revealed that cell membrane damage was attributed to inactivation of enzymes related to generation of membrane potential and occurrence of lipid peroxidation. Direct absorption of UV radiation which led to photoreaction through formation of an excited state was one of the causes inducing cell damage. Additionally, generation of ROS and thus occurrence of secondary damage can be another cause. The LP Hg lamp only induced damage to DNA but not to other components such as lipids or proteins. This difference was derived from differences of UV radiation absorption by cellular materials. [ABSTRACT FROM AUTHOR]

Salmonella enterica is a major foodborne bacterial pathogen. This forms biofilms on surfaces and persists, depending on the strain and the environment. The integrative interaction of temperature (T; 13–39 °C), pH (5–8) and sodium chloride (NaCl) concentration (0.5–8.5%) on biofilm formation by two S. enterica strains (ser. Enteritidis and Typhimurium) was here evaluated under low nutrient conditions. This was achieved using response surface methodology to model the combined effect of each factor on the response, through mathematical quadratic fitting of the outcomes of a sequence of designed experiments. These last were executed by incubating stainless steel coupons carrying sessile bacteria, for 24 h, in 1:10 diluted tryptone soya broth, under 15 different combinations of three independent factors (T, pH and NaCl). For each strain, a second order polynomial model, describing the relationship between biofilm formation (log CFU/cm 2 ) and the factors (T, pH and NaCl), was developed using least square regression analysis. Both derived models predicted the combined influences of these factors on biofilm formation, with agreement between predictions and experimental observations (R 2  ≥ 0.96, P  ≤ 0.0001). For both strains, the increase of NaCl content restricted their sessile growth, while under low salinity conditions (NaCl < 4%) biofilm formation was favored as pH increased, regardless of T. Interestingly, under low salt content, and depending on the strain, biofilm formation was either favored or hindered by increasing T. Thus, 34.5 and 13 °C were the T predicted to maximize biofilm formation by strains Enteritidis and Typhimurium, respectively, something which was also experimentally verified. To sum, these models can predict the interactive influences of crucial food-related factors on biofilm growth of a significant foodborne pathogen towards the efforts to limit its persistence in food industry. [ABSTRACT FROM AUTHOR]

Highly prevalent in poultry, Campylobacter is a foodborne pathogen which remains the primary cause of enteritis in humans. Several studies have determined prevalence and contamination level of this pathogen throughout the food chain. However it is generally performed in a deterministic way without considering heterogeneity of contamination level. The purpose of this study was to quantify, using probabilistic tools, the contamination level of Campylobacter spp. on chicken carcasses after air-chilling step in several slaughterhouses in France. From a dataset (530 data) containing censored data (concentration < 10 CFU/g), several factors were considered, including the month of sampling, the farming method (standard vs certified) and the sampling area (neck vs leg). All probabilistic analyses were performed in R using fitdistrplus, mc2d and nada packages. The uncertainty (i.e. error) generated by the presence of censored data was small (ca 1 log 10 ) in comparison to the variability (i.e. heterogeneity) of contamination level (3 log 10 or more), strengthening the probabilistic analysis and facilitating result interpretation. The sampling period and sampling area (neck/leg) had a significant effect on Campylobacter contamination level. More precisely, two “seasons” were distinguished: one from January to May, another one from June to December. During the June-to-December season, the mean Campylobacter concentration was estimated to 2.6 [2.4; 2.8] log 10 (CFU/g) and 1.8 [1.5; 2.0] log 10 (CFU/g) for neck and leg, respectively. The probability of having > 1000 CFU/g (higher limit of European microbial criterion) was estimated to 35.3% and 12.6%, for neck and leg, respectively. In contrast, during January-to-May season, the mean contamination level was estimated to 1.0 [0.6; 1.3] log 10 (CFU/g) and 0.6 [0.3; 0.9] log 10 (CFU/g) for neck and leg, respectively. The probability of having > 1000 CFU/g was estimated to 13.5% and 2.0% for neck and leg, respectively. An accurate quantification of contamination level enables industrials to better adapt their processing and hygiene practices. These results will also help in refining exposure assessment models. [ABSTRACT FROM AUTHOR]

The use of nisin producers in foods is considered a mitigation strategy to control foodborne pathogens growth, such as Listeria monocytogenes , due to the production of this bacteriocin in situ . However, when the bacteriocin does not reach an adequate concentration, the target bacteria can develop a cross-response to different stress conditions in food, such as acid, thermal and osmotic. This study aimed to evaluate the interaction of a nisin-producing strain of Lactococcus lactis DY-13 and L. monocytogenes in BHI and skim milk, and its influence on general ( sigB ), acid ( gadD2 ), thermal ( groEL ) and osmotic ( gbu ) stress-related genes of the pathogen. L. monocytogenes populations decreased approximately 2 log in BHI and 1 log in milk after 24 h in co-culture with the nisin producer L. lactis , coherent with the increasing expression of nisK . Expression of stress-related genes by L. monocytogenes presented lower oscillation in BHI than in milk, indicating its better ability to survive in milk, despite the higher nisin production. Stress-related genes presented a varied expression by L. monocytogenes in the tested conditions: sigB expression remained stable or reduced over time; gadD2 presented high expression in milk; groEL presented low expression in BHI when compared to milk, trending to decrease overtime; gbu expression in milk after 24 h was lower than in BHI. The presented study demonstrated the growth of a nisin producer L. lactis can affect the expression of stress-related genes by L. monocytogenes , and understating these mechanisms is crucial to enhance the conservation methods employed in foods. [ABSTRACT FROM AUTHOR]

A continuous-flow UV reactor operating at 254 nm wave-length was used to investigate inactivation of microorganisms including bacteriophage in coconut water, a highly opaque liquid food. UV-C inactivation kinetics of two surrogate viruses (MS2, T1UV) and three bacteria ( E . coli ATCC 25922, Salmonella Typhimurium ATCC 13311, Listeria monocytogenes ATCC 19115) in buffer and coconut water were investigated (D 10 values ranging from 2.82 to 4.54 mJ·cm − 2 ). A series of known UV-C doses were delivered to the samples. Inactivation levels of all organisms were linearly proportional to UV-C dose (r 2 > 0.97). At the highest dose of 30 mJ·cm − 2 , the three pathogenic organisms were inactivated by > 5 log 10 (p < 0.05). Results clearly demonstrated that UV-C irradiation effectively inactivated bacteriophage and pathogenic microbes in coconut water. The inactivation kinetics of microorganisms were best described by log linear model with a low root mean square error (RMSE) and high coefficient of determination (r 2 > 0.97). Models for predicting log reduction as a function of UV-C irradiation dose were found to be significant (p < 0.05) with low RMSE and high r 2 . The irradiated coconut water showed no cytotoxic effects on normal human intestinal cells and normal mouse liver cells. Overall, these results indicated that UV-C treatment did not generate cytotoxic compounds in the coconut water. This study clearly demonstrated that high levels of inactivation of pathogens can be achieved in coconut water, and suggested potential method for UV-C treatment of other liquid foods. Industrial relevance This research paper provides scientific evidence of the potential benefits of UV-C irradiation in inactivating bacterial and viral surrogates at commercially relevant doses of 0–120 mJ·cm − 2 . The irradiated coconut water showed no cytotoxic effects on normal intestinal and healthy mice liver cells. UV-C irradiation is an attractive food preservation technology and offers opportunities for horticultural and food processing industries to meet the growing demand from consumers for healthier and safe food products. This study would provide technical support for commercialization of UV-C treatment of beverages. [ABSTRACT FROM AUTHOR]

Naturally fermented meat sausages have a long tradition in Mediterranean countries and are one of the most important groups of traditional foods consumed throughout Europe. Despite all the advances in food science and technology and increased regulatory requirements and concerns for safety and quality during the last decades, the challenge to control important foodborne pathogens in this type of meat products still persists. Simultaneously, growing consumer interest in safe, high quality and minimal processed products, with less additives/preservatives have driven the food industry and scientists in a crusade for innovative technologies to maintain the safety of these products by natural means. Biological control (biocontrol) fits well within this tendency. This review summarizes the latest achievements on biocontrol strategies applied to Mediterranean-style fermented sausages, namely: (i) bioprotective cultures; (ii) bacteriocins; and, (iii) essential oils (EOs). [ABSTRACT FROM AUTHOR]

[Display omitted] • Lyophilized paraprobiotic (LP) of P. acidilactici showed antimicrobial effects against E. coli O157:H7, L. monocytogenes , and S. Typhimurium. • LP has a high level of free amino acids, phenolic and organic acid contents. • LP contained different levels of fatty acids, polyphenols and volatile compounds. • Use of LP in food matrices provided pronounced reductions in the viable microorganisms. It was aimed to assess the antimicrobial potential of lyophilized/freeze-dried paraprobiotic (LP) of P. acidilactici against some food-borne pathogens under in-vitro conditions and food model, and determination of bioactive compounds that contribute to the antimicrobial activity of LP. For this purpose, minimum inhibitory concentration (MIC), inhibition zones were determined against Listeria monocytogenes , Salmonella Typhimurium and Escherichia coli O157:H7. The MIC value was 6.25 mg/mL and a 20 µL LP displayed 8.78 to 10.0 mm inhibition zones against these pathogens. In the food matrice challenge, two concentrations of LP (3% and 6%) alone or in combination with EDTA (0.02 M) were added to pathogenic bacteria spiked meatballs, and antimicrobial activity of LP was also determined during refrigerated storage. 6% LP + 0.02 M EDTA treatment provided 1.32 to 3.11 log 10 CFU/g reductions in the numbers of these pathogens (P < 0.05). Furthermore, this treatment provided significant reductions on psychrotrophs, TVC, LAB, mold-yeast, and Pseudomonas spp. over the storage (P < 0.05). Regarding characterization results, LP contained contained a wide variety of bioactive compounds, including 5 organic acids (2.15 to 30.64 g/100 g), 19 free amino acids (6.97 to 699.15 mg/100 g), free fatty acids (short-, medium-, and long-chain fatty acids), 15 polyphenols (0.03 to 383.78 mg/100 g), and some volatile compounds such as pyrazines, pyranone and pyrrole derivatives. These bioactive compounds are not only involved in antimicrobial activity but also contribute to the free radical scavenging activity according to the DPPH, ABTS and FRAP assays. In conclusion, the result revealed that the LP improved the chemical and microbiological quality of foods due to containing biologically-active metabolites involved in antimicrobial and antioxidant capacity. [ABSTRACT FROM AUTHOR]

Cronobacter sakazakii is a foodborne pathogen throughout the world and survives extremely desiccation stress. However, the molecular basis involved in desiccation resistance of C. sakazakii is still unknown. In this study, the potential desiccation resistance factors of C. sakazakii ATCC 29544 were determined using iTRAQ-based quantitative proteomic analysis. A total of 2775 proteins were identified by iTRAQ, of which 233 showed a different protein expression between control group and desiccation stress group. Among these 233 proteins identified as desiccation resistance proteins, there were 146 proteins downregulated and 87 proteins upregulated. According to the comprehensive proteome coverage analysis, C. sakazakii increased its resistance to desiccation by reducing the gene involved with unnecessary survival functions such as those used for virulence, adhesion, invasion and flagella assembly, while increasing gene expression of genes used in withstanding osmotic stress such as those genes involved in trehalose and betaine uptake. However, the mechanism involved in amino acid metabolism in an osmotic stress response, including the producing of γ-aminobutyric acid in C. sakazakii is still uncertain. This is the first report to determine the potential desiccation resistant factors of C. sakazakii at the proteomic levels. [ABSTRACT FROM AUTHOR]

Due to the ability of foodborne pathogens to survive in low moisture foods, the decontamination of these products is an important issue in food hygiene. Up to now, such decontamination has mostly been achieved through empirical methods. The intention of this work is to establish a more rational use of heat treatment cycles. The effects of thermal treatment cycles on the inactivation of dried Salmonella Typhimurium, Salmonella Senftenberg, Cronobacter sakazakii and Escherichia coli were assessed. Bacteria were mixed with whole milk powder and dried down to different water activity levels (0.11, 0.25, 0.44 and 0.58). The rate of inactivated bacteria was determined after thermal treatment at 85 °C, 90 °C, 95 °C and 100 °C, from 0 s to 180 s in closed vessels, in order to maintain a w during treatment. In a first step, logarithmic bacterial inactivation was fitted by means of a classical loglinear model in which temperature and a w have a significant effect (p < 0.05). D T, aw values were estimated for each T, a w condition and the results clearly showed that a w is a major parameter in the thermal decontamination of dried foods, a lower a w involving greater thermal resistance. In a second step, Bigelow's law was used to determine z T , a classical parameter relative to temperature, and y aw values, a new parameter relative to a w resistance. The values obtained for z T and y aw showed that the bacterium most resistant to temperature variations is Salmonella Typhimurium, while the one most resistant to a w variations is Escherichia coli . These data will help design decontamination protocols or processes in closed batches for low moisture foods. [ABSTRACT FROM AUTHOR]

The aim of this study was to develop a quantitative microbial risk assessment (QMRA) model to estimate the risk of illness caused by Salmonella in ready-to-eat (RTE) leafy greens, based on common practices in Brazilian processing plants. The risk assessment model considered five modules: in field, washing step, retail storage, home storage and dose-response. Fifty thousand iterations of a @Risk model built in Excel were run for each of sixty scenarios. These scenarios considered different initial pathogen concentrations, fractions of contaminated produce and chlorine concentrations. For chlorine, seven pre-set concentrations (0, 5, 10, 25, 50, 150 and 250 mg/L) and three triangular distributions were considered [RiskTriang(0,5,10 mg/L), RiskTriang(0,80,250 mg/L) and RiskTriang(10,120,250 mg/L)]. The outputs were risk of infection, estimated number of illnesses and estimated percent of illnesses arising from cross-contamination. The QMRA model indicated quantitatively that higher chlorine concentrations resulted in lower risk of illness. When simulation was done with < 5 mg/L of chlorine, most (> 96%) of the illnesses arose from cross-contamination, but when a triangular distribution with 10, 120 and 250 mg/L of chlorine was simulated, no illnesses arising from cross-contamination were predicted. Proper control of the sanitizer in the washing step is essential to reduce initial contamination and avoid cross-contamination. [ABSTRACT FROM AUTHOR]

[Display omitted] • Filter-sterilized mushroom medium is a suitable nutrient source for L. monocytogenes. • Variability in growth performance between L. monocytogenes mushroom isolates is low. • L. monocytogenes mushroom isolates and non-mushroom isolates have comparable growth. • Mushroom products support grow of L. monocytogenes despite high background microbiota. Foods and food production environments can be contaminated with Listeria monocytogenes and may support growth of this foodborne pathogen. This study aims to characterize the growth and biofilm formation of sixteen L. monocytogenes strains, isolated from mushroom production and processing environments, in filter-sterilized mushroom medium. Strain performance was compared to twelve L. monocytogenes strains isolated from other sources including food and human isolates. All twenty-eight L. monocytogenes strains showed rather similar growth performance at 20 °C in mushroom medium, and also significant biofilm formation was observed for all strains. HPLC analysis revealed the presence of mannitol, trehalose, glucose, fructose and glycerol, that were all metabolized by L. monocytogenes , except mannitol, in line with the inability of L. monocytogenes to metabolize this carbohydrate. Additionally, the growing behavior of L. monocytogenes was tested on whole, sliced and smashed mushroom products to quantify performance in the presence of product-associated microbiota. A significant increase of L. monocytogenes was observed with higher increase of counts when the mushroom products were more damaged, even with the presence of high background microbiota counts. This study demonstrated that L. monocytogenes grows well in mushroom products, even when the background microbiota is high, highlighting the importance to control (re)contamination of mushrooms. [ABSTRACT FROM AUTHOR]

[Display omitted] • First systematic study of food composition on pathogens during in vitro digestion. • Protein has higher buffering effect than fat during simulated gastric digestion. • Protective effects of protein towards pathogens were stronger than those of fat. • Low fat was associated with the development of stress resistance for pathogens. • Both pathogens survive passage through the simulated gastrointestinal tract. Even though a plethora of barriers are employed by the human gastrointestinal tract (GIT) to cope with invading pathogens, foodborne diseases are still a common problem. The survival of food pathogens in the GIT is known to depend on food carrier properties. The aim of this study was to investigate the influence of food buffering capacity and food structure on the survival of Salmonella Typhimurium and Listeria monocytogenes during simulated digestion, following contamination of different food model systems that had different combinations of fat and protein content. The results illustrated the strong protective properties of proteins, acting either as a strong buffering agent or as a physical barrier against gastric acidity, for both pathogens. In comparison, fat manifested a lower buffering capacity and weaker protective effects against the two pathogens. Intriguingly, a low fat content was often linked with increased microbial resistance. Nonetheless, both pathogens survived their transit through the simulated GIT in all cases, with S. Typhimurium exhibiting growth during intestinal digestion and L. monocytogenes demonstrating a healthy residual population at the end of the intestinal phase. These results corroborate the need for a deeper understanding regarding the mechanisms with which food affects bacterial survival in the human GIT. [ABSTRACT FROM AUTHOR]

[Display omitted] • Paper chromogenic array (PCA) integrated with machine learning (ML) was developed. • PCA exhibit distinguishable pattern shifts when reacting volatile metabolites. • PCA pattern recognition achieved using a cross-validated neural network. • PCA accurately identify multiplexed pathogens from indigenous microflora. • The nondestructive PCA-ML holds great potential as a smart food safety system. Non-destructive detection of human foodborne pathogens is critical to ensuring food safety and public health. Here, we report a new method using a paper chromogenic array coupled with a machine learning neural network (PCA-NN) to detect viable pathogens in the presence of background microflora and spoilage microbe in seafood via volatile organic compounds sensing. Morganella morganii and Shewanella putrefaciens were used as the model pathogen and spoilage bacteria. The study evaluated microbial detection in monoculture and cocktail multiplex detection. The accuracy of PCA-NN detection was first assessed on standard media and later validated on cod and salmon as real seafood models with pathogenic and spoilage bacteria, as well as background microflora. In this study PCA-NN method successfully identified pathogenic microorganisms from microflora with or without the prevalent spoilage microbe, Shewanella putrefaciens in seafood, with accuracies ranging from 90% to 99%. This approach has the potential to advance smart packaging by achieving nondestructive pathogen surveillance on food without enrichment, incubation, or other sample preparation. [ABSTRACT FROM AUTHOR]

[Display omitted] • This study reviews the evidence on the prevalence of pathogenic microorganisms in vegetables. • The prevalence of bacteria, parasites and viruses in vegetables was relatively low. • The type of vegetables did not influence the prevalence of the pathogens analyzed. • An association between continent of origin and prevalence of pathogens was noted. This meta -analysis aims to summarize the available information on the prevalence of the main human pathogenic microorganisms in vegetables, with emphasis on lettuce (Lactuca sativa). The database searches included scientific papers from 1980 to 2019, without language restrictions. Inclusion criteria were prevalence or incidence studies published in peer-reviewed journals reporting the total number of vegetable samples studied and the number of samples positive for the presence of the studied pathogens. The target pathogens were grouped into the following categories: bacteria, parasites and viruses. Results of different vegetable types, years of sampling, analyzed regions or species of microorganisms reported in the same article were considered as different studies. Therefore, each scientific article may contain several studies. Multilevel random‐effect meta‐analysis models were fitted to estimate the mean occurrence rate of pathogenic microorganisms and to compare them with different factors potentially associated with the outcome. Overall, the prevalence of bacterial, parasitic and viral pathogens in vegetables was relatively low. The mean prevalence of bacterial hazards was < 0.023, with the exception of S. aureus , whose prevalence was estimated at 0.096. The mean occurrence rates of parasites and viruses were 0.067 (95 % CI: 0.056–0.080) and 0.079 (95 % CI: 0.054–0.113), respectively. The prevalence of pathogenic E. coli and parasites increased as the year of publication of the scientific articles progressed, whereas the prevalence of the other bacterial pathogens and enteric viruses was steady. The types of vegetables evaluated did not affect pathogen prevalence. The prevalence of pathogenic microorganisms differed according to the continent of origin, except for E. coli O157:H7 and parasites. The prevalence of pathogens in vegetables is of public health importance, especially in vegetable types that are eaten raw, without thermal treatment to inactivate pathogens. This meta -analysis results show the need to apply proper sanitation methods to treat raw vegetables in order to avoid foodborne infections. [ABSTRACT FROM AUTHOR]

In this study, we developed a novel and sensitive AgNPs self-assembled solid-phase (AgNPs@SASP) SERS substrate platform using seed-mediated and liquid interface self-assembly methods and applied the platform for the detection of three bacterial spores. Multivariate statistical analysis (HCA and LDA) were employed for identification and categorization of the obtained data, providing an effective tool for food safety risk control and detection. [Display omitted] • The foodborne pathogens spores were quickly identified based on optical tweezers SERS; • An novel and sensitive SERS substrate platform (AgNPs@SASP) was preparated by a seed-mediated growth process using liquid interfacial self-assembly method to fabricate AgNPs self-assembled solid-phase. • Food-borne pathogens were rapidly identified by SERS chip and chemometrics. In this study, we developed a novel and sensitive AgNPs self-assembled solid-phase (AgNPs-SASP) SERS substrate platform using seed-mediated and liquid interface self-assembly methods and applied the platform for the detection of three bacterial spores. Multivariate statistical analysis (HCA and LDA) were employed for identification and categorization of the obtained data. The results illustrated that AgNPs-SASP exhibited high reproducibility and Raman enhancement effect (1.43 × 104). The Raman shift bands of the three bacterial spores ranged from 400 to 1800 cm−1 demonstrating the difference in reigon and intensity. And the intensities of their Ca2+-DPA Raman bands are significantly different. HCA results revealed that the spectra for the three bacterial spores were statistically different while LDA completely differentiated the spectra for the three bacterial spores with 100 % sensitivity and specificity. Overall, the novel SERS platform based on AgNPs-SASP provides an effective tool for food safety risk control and detection. [ABSTRACT FROM AUTHOR]

While there are many (potentially) foodborne parasites, these are often neglected infections, with relatively little attention devoted to their surveillance, prevention, and/or treatment, and policy makers are unclear as to where interventions should be targeted. Different parasite–food matrix combinations have different implications for public health in different global regions. We conducted a risk ranking of foodborne parasites in India as part of a One Health workshop held in Chandigarh, India for postgraduate medical and biomedical students. This exercise followed a similar procedure to an analogous exercise conducted by the Food and Agriculture Organization of the United Nations (FAO) and World Health Organization (WHO) in 2012 when foodborne parasites were ranked from a global perspective according to various criteria with different weightings. Although both the Indian and global ranking exercises placed Taenia solium as the most important foodborne parasite, probably due to the severe disease associated with cysticercosis, other parasites were ranked differently in the two ranking exercises. In particular Cryptosporidium and Ascaris were ranked more highly in the Indian risk ranking. These differences probably reflect parasite occurrence in India, eating habits (lack of consumption of raw meat and fish), and potential severity of infection. Risk ranking also assists in highlighting data gaps; in this exercise some data gaps, particularly on the prevalence of different foodborne parasites in India, were found to be very large and should be filled in order to provide a more solid basis for such an exercise that will enable understanding of where control should be targeted. [ABSTRACT FROM AUTHOR]

In this study, silver–stearate nanoparticles (AgStNPs) have been produced from silver nitrate solutions by replacing the nitrate by stearate ions and then reducing by thermal treatment. AgStNPs were characterized by particle size, zeta-potential, ATR-FTIR, contact angle and SEM (scanning electron microscopy) analyses. The mean particle size and zeta potential of AgStNPs were determined to be 69.22 ± 7.30 nm and + 8.02 ± 0.88 mV. ATR-FTIR analysis showed characteristic IR bands of stearate, revealing the two strong peaks at 2848 and 2915 cm − 1 associated to symmetric (ν s (CH 2 )) and asymmetric (ν as (CH 2 )) stretching vibrations of methylene groups, respectively. On the other hand, the scissoring and rocking modes of methylene group were observed at 1470 and 718 cm − 1 , respectively. Nanomorphological characterization by SEM revealed a layered morphology of AgStNPs. Contact angle measurements demonstrated that a contact angle of water drop on glass coated with AgStNPs was found to be 108.76°, which proved the strong hydrophobic properties of AgStNPs. AgStNPs seemed to be very effective in inhibiting foodborne pathogens ( Salmonella Typhimurium, Escherichia coli O157:H7, Staphylococcus aureus , Listeria monocytogenes and Candida albicans ). The results suggest the use of AgStNPs as a coating material to reduce biofilm or biofouling formation in terms of achieving appropriate food contact surfaces and higher hygiene/easier sanitation due to their strong hydrophobic and antimicrobial properties. [ABSTRACT FROM AUTHOR]

High pressure processing (HPP) is a promising food preservation technology as an alternative to thermal processing for microbial inactivation. The technological parameters, the type of microorganism, and the food composition can greatly affect the microbicidal potential of HPP against spoilage and pathogenic microorganisms. Presently, the number of available models quantifying the influence of food characteristics on the pathogen inactivation is scarce. The aim of this study was to model the inactivation of Listeria monocytogenes CTC1034 in dry-cured ham, as a function of pressure (347–852 MPa, 5 min/15 °C), water activity (a w , 0.86–0.96) and fat content (10–50%) according to a Central Composite Design. The response surface methodology, based on the equation obtained with a stepwise multivariate linear regression, was used to describe the relationship between bacterial inactivation and the studied variables. According to the best fitting polynomial equation, besides pressure intensity, both a w and fat content exerted a significant influence on HP-inactivation of L. monocytogenes . A clear linear piezoprotection trend was found lowering the a w of the substrate within the whole range of tested pressure. Fat content was included in the model through the quadratic term and as interaction term with pressure, resulting in a particular behavior. A protective effect due to the presence of high fat content was identified for pressure treatments above ca. 700 MPa. At lower pressure, higher inactivation of L. monocytogenes occurred by increasing the fat content above 30%. The results emphasize the relevant influence of intrinsic factors on the L. monocytogenes inactivation by HPP, making necessary to assess and validate the effectiveness of HPP on specific food products and consequently set process criteria adjusted to each particular food product. [ABSTRACT FROM AUTHOR]

[Display omitted] • Direct/Cross-resistances were induced in Salmonella treated by essential oil (EO). • 161–324 differentially expressed genes were screened by a transcriptomics analysis. • Metabolomics analysis revealed changes of 47 significant metabolites and pathways. • Thyme oil induced a more conservative strategy compared with cinnamon oil. Essential oils (EOs), such as thyme (Thy) and cinnamon (Cin) oils, present promising antibacterial properties against foodborne pathogens (e.g., Salmonella enterica serovar Typhimurium). However, the food matrix might result in sublethal EO stress, and little information about direct and/or cross-resistance development after sublethal EO exposure is available. This study revealed that S. Typhimurium under sublethal Thy and Cin (50% minimum inhibitory concentration, MIC 50) treatments exhibited a lower growth rate and an extended lag phase. EO adapted cells showed direct-resistance to subsequent lethal EO treatment, and cross-resistance to thermal (58 °C) and oxidative (hydrogen peroxide, 50 mmol/L) stresses. Metabolomics analysis revealed changes of 47 significant metabolites (variable importance in projection > 1, false discovery rate (FDR) < 0.05), including lipids, oligopeptides, amino acids, nucleotide related compounds, and organic acids. Metabolic pathways, such as aminoacyl-tRNA biosynthesis, were shown to be involved in EO adaptation. Furthermore, a transcriptomics study identified 161 differentially expressed genes (DEGs, fold change > 2, FDR < 0.05) in MIC 50 Thy treated cells, while more DEGs (3 2 4) were screened from the MIC 50 Cin group. The integrated omics analysis allowed us to speculate on the molecular mechanisms. Under harsher Thy stress, S. Typhimurium cells adopted a conservative strategy to survive. By contrast, more radical responses were observed during Cin adaptation. In conclusion, the food industry should be more cautious in the use of EOs because sublethal EO stress might result in the development of resistance. [ABSTRACT FROM AUTHOR]

The effect of the microstructure of the medium on the growth of the food-borne pathogen Listeria monocytogenes was studied. The pathogen's growth kinetics was evaluated using liquid substrates and gels formed from different concentrations of sodium alginate (3.0% w/w) and gelatin (0–30.0% w/w). These results were further verified using a model dairy product with solid concentrations varying from 10.0 to 40.0% w/w. The pathogen's growth was faster in the liquid media than in the gels regardless of the gelling agent employed. The substrate's microstructure, apart from altering the growth pattern from planktonic to colonial, resulted in microbial growth suppression; however, each system affected the microorganism's growth in a different way. The suppressing effect of the substrate's microstructure on microbial growth was also dependent on temperature, while the presence of glucose in the solid medium accelerated microbial growth, thus reducing substantially the difference in growth kinetics between the gels and the liquid media. Any increase in the hydrocolloid concentration, which was also reflected in the rheological properties of the structured samples, resulted in a reduction of growth rate and in an increase of the lag phase of the pathogen. Overall, the gelation of the medium was found to exert a stress on the microorganism since the sol–gel transition, when the pathogen was already at the exponential growth phase, resulted in an additional lag phase or a decrease in the growth rate. The relationship between maximum specific growth rate and loss tangent of the gels ( tanδ = G ″/ G ′) was explored, pointing to the possible use of a single structural parameter to describe food matrix effects on microbial growth kinetics. [ABSTRACT FROM AUTHOR]

Salmonella spp. is an important foodborne pathogen, often associated with meat products. This pathogen presents a complex tolerance mechanism in the presence of organic acids, which is regulated by a diversity of genes, including rpo S, nlp D and clp P. The present study aimed to measure the expression of such genes by Salmonella strains subjected to acid stress conditions, and associate these data with microbial growth. A culture collection composed of 79 strains of Salmonella spp. obtained from bovine and swine production chains was subjected to PFGE using Xba I, and 3 strains (serovars Derby, Typhimurium and Meleagridis) were selected for acid tolerance trials. The selected strains were inoculated in meat extract broth (MEB) added to lactic or acetic acids at a final pH of 4.0, 5.0 or 6.0, and incubated at 37 °C for 6, 12, 24 and 48 h. As controls, Salmonella strains were inoculated in MEB at pH 7.0, and incubated in the same conditions. Bacterial populations were monitored by direct plating and gene expression using qPCR. Salmonella presented similar populations to controls and evident expression of rpo S at pH 5.0 and 6.0. However, Salmonella populations were not detectable after 6 h at pH 4.0. The adaptability of Salmonella to pH 5.0 and 6.0 emphasizes the importance of adequate monitoring of pH reduction during cleaning procedures in food industries, such as organic acid spraying in bovine carcasses. The data obtained demonstrated the relevance of rpo S in the acid tolerance mechanism of Salmonella strains, prompting further studies to investigate its expression in meat systems. [ABSTRACT FROM AUTHOR]

Abstract: Meat and meat products are the main vehicles of foodborne diseases in humans caused by pathogens such as Salmonella spp., Campylobacter spp., Listeria monocytogenes, Yersinia enterocolitica, verotoxigenic Escherichia coli (VTEC) and Staphylococcus aureus. In order to prioritise research on those microbial hazards, a meta-analysis study was conducted to summarise available information on the presence of such pathogens in meats produced in Portugal. By using a logit-transformed proportion as effect size parameterisation, a number of multilevel random-effect meta-analysis models were fitted to estimate mean occurrence rates of pathogens, and to compare them among meat categories (i.e., bovine meat, broiler meat, pork, minced beef and minced pork), and among meat product categories (i.e., intended to be eaten cooked, to be eaten raw and cured meats). The mean occurrence rate of Campylobacter in Portuguese broiler meat (40%; 95% CI: 22.0–61.4%) was about ten times higher than that of Salmonella (4.0%; 95% CI: 1.4–10.8%); although these levels were comparable to current EU ranges. Nevertheless, in the other meat categories, the meta-analysed incidences of Salmonella were slightly to moderately higher than EU averages. A semi-quantitative risk ranking of pathogens in Portuguese-produced pork pointed Salmonella spp. as critical (with a mean occurrence of 12.6%; 95% CI: 8.0–19.3%), and Y. enterocolitica as high (6.8%; 95% CI: 2.2–19.3%). In the case of the Portuguese meat products, the non-compliance to EU microbiological criteria for L. monocytogenes (8.8%; 95% CI: 6.5–11.8%) and Salmonella spp. (9.7%; 95% CI: 7.0–13.4%) at sample units level, in the categories ‘intended to be eaten cooked’ and ‘to be eaten raw’, were considerably higher than EU levels for ready-to-eat products in comparable categories. S. aureus was the pathogen of greatest concern given its high occurrence (22.6%; 95% CI: 15.4–31.8%) in meat products. These results emphasised the necessity of Portuguese food safety agencies to take monitoring, and training actions for the maintenance of good hygiene practices during the production of the great variety of traditional meat products. This meta-analysis study also highlighted important gaps of knowledge, and may assist food safety authorities in the prioritisation of microbiological hazards, and the implementation of essential food safety assurance systems at primary production. [Copyright &y& Elsevier]

Abstract: Chilean tinamou (Nothoprocta perdicaria) egg white ovotransferrin was purified with anion-exchange Fast Protein Liquid Chromatography and identified by peptide mass fingerprinting. Tinamou egg white ovotransferrin was compared to chicken (Gallus gallus) and emu (Dromaius novaehollandiae) ovotransferrin by SDS-PAGE analysis. Though all three species contained similar molecular weight ovotransferrins, tinamou egg white contained 20% more ovotransferrin than chicken, but 30% less than emu. The effectiveness of tinamou ovotransferrin as a natural antimicrobial agent was compared to chicken ovotransferrin against two food related pathogens, Escherichia coli O157:H7 and Staphylococcus aureus. The bacteriostatic and bactericidal activities of the native, apo and holo forms of the proteins were dependent on the presence of 50mM bicarbonate and protein iron saturation. Native ovotransferrins were the most effective at a concentration of 10mg/ml with 50mM bicarbonate, exhibiting bacteriostatic and bactericidal activities against both pathogens. Holo ovotransferrins exhibited moderate antimicrobial activity in the presence of bicarbonate. Different antimicrobial activities were observed between chicken and tinamou ovotransferrins, suggesting tinamou ovotransferrin may possess unique antimicrobial motifs that warrant further investigation of its amino acids composition. Further, our results suggest that tinamou ovotransferrin may represent a natural antimicrobial agent suitable for use in food matrices or on food preparation surfaces. [Copyright &y& Elsevier]

[Display omitted] • Survival curves of Salmonella in tahini at 70 °C, 80 °C and 90 °C fit a biphasic logarithmic inactivation model. • The second thermal treatment of tahini is less effective against Salmonella than the first. • A w has a significant effect on Salmonella 's survival in tahini during thermal treatment. • Adding sesame oil to tahini enhances the sensitivity of bacterial to heat when they are pre-acclimatized to oil. • The tahini heterogeneity probably leads to differences in the thermal resistance of subpopulations. Salmonella enterica is a leading human pathogen responsible for foodborne outbreaks worldwide. In the last decade, foods with low water activity (a w) and high-fat content have been involved in an increased occurrence of foodborne outbreaks. This research focuses on the foodstuff tahini, which is often linked to Salmonella infection outbreaks and recalls. Thermal treatments are suggested to reduce microbial populations in tahini, but little is known about its effectiveness against Salmonella. Our major objectives were to study the survival of Salmonella Typhimurium in tahini treated at temperatures ≥ 70 °C, and to identify food related factors that could influence its survival. Based on our experimental results the thermal treatments at 70 °C, 80 °C and 90 °C are suitable to inactivate only a partial population of Salmonella. The death of Salmonella in tahini matches a biphasic logarithmic inactivation model, with a maximal 3-log reduction after 1 h at 90 °C. Moreover, we observed that a second thermal treatment the day after the first treatment, is significantly less effective compared with the first thermal treatment. The inactivation rates of Salmonella in 100% tahini are almost 4-log lower than in water/tahini emulsions at 70 °C, with negative linear correlation between D-value and a w , and the Salmonella susceptibility to heat in sesame oil/tahini emulsions is affected by the matrix of pre-acclimation. Bacteria that had been acclimated in tahini kept their heat resistance, while acclimation in sesame oil before mixing in the preheated oil/tahini emulsions resulted in a sharp decline within 2 min at 70 °C. According to these findings, tahini producers' current pasteurization processes are not sufficient to achieve the required 5-log reduction. Furthermore, we suggest that due to the tahini heterogenicity, the a w in the micro-environment of each bacterium, which is shaped by the tahini substances, plays an essential role in Salmonella' s survival in tahini at temperatures ≥ 70 °C. [ABSTRACT FROM AUTHOR]

[Display omitted] • LED and citral inactivated C. sakazakii in reconstituted powdered infant formula synergistically. • The combination of LED and citral prolonged lag phase of sublethally-injured C. sakazakii. • LED combined with citral damaged cell morphology and disrupted the cell membrane integrity. • LED combined with citral induced the lipid peroxidation and caused no breakage to genomic DNA. Cronobacter sakazakii , a foodborne opportunistic pathogen, mainly affects neonates and infants, with mortality rates of 26.9%. Most outbreaks arise from powdered infant formula (PIF). The aim of this study was to investigate the efficacy and mechanism of 405-nm light-emitting diode (LED) and citral treatment used in combination against C. sakazakii in reconstituted PIF. LED-illumination combined with citral showed better antimicrobial effects than either treatment alone. In reconstituted PIF, the abundance of C. sakazakii cells was reduced by 6.5 log 10 CFU/mL following combined LED and 9 µL/mL citral treatment for 90 min compared with untreated controls, respectively. Combined LED and 6 µL/mL citral treatment destroyed C. sakazakii cellular morphology and membrane integrity, prolonged the recovery time of sublethally-injured cells, and induced lipid peroxidation. Besides, LED treatment decreased the amount of lipid peroxidation caused by citral treatment alone. Neither LED illumination nor citral treatment resulted in breakdown of C. sakazakii genomic DNA. Because of its safe, environmentally-friendly, economical, and high-performance characteristics, the combination of LED-illumination and citral treatment has the potential to be developed into a strategy to control C. sakazakii contamination in stored and reconstituted PIF. [ABSTRACT FROM AUTHOR]

Abstract: Arcobacter spp. is an emerging foodborne pathogen due to increasing association with foods of animal origin. A number of Arcobacter selective broths and agars are available for the enrichment, isolation and detection of Arcobacter spp. from food, fecal and environmental sources. However, studies have not examined the specificity of different Arcobacter selective agars for selective enumeration of Arcobacter spp. in beef. The purpose of this study is to determine which of the three published Arcobacter selective agars (Houf, JM and AC agar) can provide acceptable counts while inhibiting the growth of selected indigenous meat microflora during direct plating. Houf and AC agar were able to supress the growth of all selected indigenous meat microflora tested while JM agar supported the growth of Leuconostoc carnosum. In the Arcobacter butzleri recovery efficiency trial, Houf, JM and AC agar achieved recovery rates between 81–98%, 12–52% and 77–97%, respectively, in comparison to TSA. JM and AC agar were unable to supress the growth of indigenous beef microflora from temperature abused retail ground beef even at dilutions as high as 10−6. Houf agar was able to effectively suppress indigenous beef microflora at dilutions as low as 10−1. This study showed that Houf agar is more suitable compared to JM or AC agar for use in meat challenge studies as a direct plating agar for enumeration of A. butzleri. [Copyright &y& Elsevier]

Salmonella spp. is one of the major causes of foodborne diseases and a problem for the poultry industry. Bacteriophages have emerged as a promising agent to reduce pathogens in foods. Here, we compared bacteriophages and the classically used chemical agents for reducing S. enteritidis counts in chicken skin. Five phages were isolated from chicken feces, characterized and selected to be used as biosanitizer. Bacteriophages were assigned to the family Podoviridae and revealed identical RFLP profiles, although they showed a different host range and replication dynamics. Bacteriophages were found to be effective at a multiplicity of infection (MOI) of 10 at both 37°C and 25°C in liquid medium, with no significant reductions taking place when MOI was less than 10. When samples of chicken skin experimentally contaminated with 1×105 CFU/cm2 S. enteritidis were treated with phage cocktail or chemical agents, similar reductions of about 1logCFU/cm2 were observed. These data suggest that bacteriophages can be employed as an alternative agent to reduce S. enteritidis contamination of poultry carcasses in industrial conditions. [ABSTRACT FROM AUTHOR]

Abstract: The antimicrobial activity of quaternary ammonium salts of pyridinium oxime against four food pathogenic bacteria, the Gram positive Bacillus subtilis and Listeria monocytogenes, as well as the Gram negative Escherichia coli and Yersinia enterocolitica, were evaluated. Changes of proteome in these bacteria grown under stress conditions were identified. By the application of a new method for sample preparation, followed by both in-gel and in-solution digestion and LC–MS/MS, both characterization and comparison of proteomes of these food pathogens were achieved. It was shown in all investigated bacteria that some of the proteins of key importance for protein turnover and bacterial metabolism are down regulated. Some stress proteins involved in protein folding and degradation were up regulated. Most of both up- and down-regulated proteins belong to the group of proteins with high abundance. Flagellin is the only protein of lower abundance that was found to be down regulated in two strains, B. subtilis and E. coli. The presented results give the better view into the proteome of food pathogens, and pave the way for further investigation of their virulence, pathogenicity and detection of biomarkers for tracing the ways and sources of food contamination. [Copyright &y& Elsevier]

Abstract: This study was achieved in order to determine the antimicrobial potential of six essential oils (EOs) (Origanum vulgare, Cinnamomum cassia, Brassica hirta, Thymus vulgaris, Satureja montagna, and Cymbopogon nardus) and four bacteriocins (nisin, pediocin, and two bacteriocins produced from our isolated Enterococcus faecium MT 104 and MT 162) against five pathogenic bacteria and two spoilage bacteria. The synergistic effect of combined antimicrobial agents on pathogenic bacteria was also evaluated. The antimicrobial activity was determined by evaluation of minimum inhibitory concentration (MIC) of the tested antimicrobial agents. Each agent was tested against seven bacterial foodborne pathogens (Bacillus cereus, Escherichia coli, Listeria monocytogenes, Salmonella typhimurium and Staphylococcus aureus) and food spoilage (Lactobacillus sakei and Pseudomonas putida) in 96-well microplate. The checkerboard technique was used to evaluate the possible synergistic effects between antimicrobial agents against each bacterium. The MIC value of 500ppm was obtained when C. cassia and O. vulgare EOs were tested against B. cereus, E. coli O157:H7, and L. sakei and when B. hirta EO was tested against P. putida and S. aureus. The combination of nisin with O. vulgare EO induced a synergistic effect against L. monocytogenes whereas the combination of nisin with T. vulgaris EO caused a synergistic effect against S. typhimurium. Pediocin caused a synergistic effect against E. coli O157: H7 when combined with the S. montagna EO. The combinations of EOs and bacteriocins can act synergistically or additionally to eliminate important foodborne pathogens and spoilage bacteria. This study demonstrated the potential of using different combinations of natural antimicrobial compounds to control foodborne pathogens effectively. [Copyright &y& Elsevier]

Abstract: Listeria monocytogenes, an important foodborne pathogen, is of great concern especially for the ready-to-eat (RTE) food industry. The purpose of the study was to determine the number of L. monocytogenes in 300 RTE poultry products at their shelf-life expiry date. The samples were examined following the ISO 11290-2:2005 protocol. Overall, 6% and 3% of the analyzed products were positive for Listeria spp. and L. monocytogenes, respectively. The occurrence of L. monocytogenes was significantly (p<0.05) higher in raw RTE poultry products than in heat treated RTE poultry products. The contamination level of L. monocytogenes was <10cfu/g in 94%, between 10 and 100cfu/g in 3% and >100cfu/g in 1% of the samples. L. monocytogenes were isolated from products of various lots from 3 out of 7 manufacturers. All 18 L. monocytogenes belonged to serotype 1/2a and among the isolates only two PFGE patterns were obtained, indicating a common contamination source. This is the first study that surveyed the number of L. monocytogenes in RTE poultry products at the end of their shelf-life. The high frequency of L. monocytogenes found in frankfurters and raw spreadable sausages underlines the need for food manufacturers to regularly control L. monocytogenes in the food processing environment. Consumers should nevertheless be cautious when handling these products. Since poultry products are becoming more and more popular for consumers, regular monitoring is necessary to track the occurrence of the pathogen in RTE poultry products. [Copyright &y& Elsevier]

Abstract: The objective of this study was to evaluate physicochemical properties and bactericidal activities of acidic electrolyzed water (AEW) used or stored at different temperatures on shrimp. Three independent experiments were carried out. The first experiment was to evaluate the physicochemical properties and bactericidal activities of AEW used at three different temperatures (4, 20, 50°C) against food-borne pathogens (Listeria monocytogenes and Vibrio parahaemolyticus) contamination on cooked shrimp at 1 or 5min; the second one was to monitor the bactericidal activity of AEW used at two temperatures (20, 50°C) against total aerobic bacteria on raw shrimp at 5min by conventional plate count method and PCR–DGGE method; the last one was to examine the physicochemical properties and bactericidal activities of AEW (AEW1, AEW2) stored at two temperatures (−18, 25°C) for 30d against total aerobic bacteria on raw shrimp at 2min. Results showed that AEW used at 50°C showed the best bactericidal activity, leading to a log reduction of 3.11 for V. parahaemolyticus, 1.96 for L. monocytogenes and 1.44 for total aerobic bacteria at 5min, respectively. Conventional plate count and PCR–DGGE (denaturing gradient gel electrophoresis) study further suggested that the bactericidal activity of AEW used at 50°C was higher than at 20°C. The loss of bactericidal activity of AEW stored at −18°C was less than that of stored at 25°C, and the ORP and ACC decreased more slowly than those of stored at 25°C. However, the ORP and ACC of AEW used at 50°C showed a remarkably faster decrease than that of used at 20°C. We suggest using AEW at 50°C to enhance bactericidal activity and storing at −18°C to keep the content of ACC and the bactericidal activity. [Copyright &y& Elsevier]