Search

Lactic acid bacteria (LAB) are known to exhibit various beneficial roles in fermentation, serving as probiotics, and producing a plethora of valuable compounds including antimicrobial activity such as bacteriocin-like inhibitory substance (BLIS) that can be used as biopreservative to improve food safety and quality. However, the yield of BLIS is often limited, which poses a challenge to be commercially competitive with the current preservation practice. Therefore, the present work aimed to establish an optimised two-plasmid CRISPR/Cas9 system to redirect the carbon flux away from lactate towards compounds with antimicrobial activity by disrupting lactate dehydrogenase gene (ldh) on various strains of LAB. The lactic acid-deficient (ldhΔ) strains caused a metabolic shift resulting in increased inhibitory activity against selected foodborne pathogens up to 78 % than the wild-type (WT) strain. The most significant effect was depicted by Enterococcus faecalis-ldh∆ which displayed prominent bactericidal effects against all foodborne pathogens as compared to the WT that showed no antimicrobial activity. The present work provided a framework model for economically important LAB and other beneficial bacteria to synthesise and increase the yield of valuable food and industrial compounds. The present work reported for the first time that the metabolism of selected LAB can be manipulated by modifying ldh to attain metabolites with higher antimicrobial activity. • The development of a new mutant lactic acid bacteria (LAB) strains was attained by genetically disrupt lactate dehydrogenase (ldh) gene, to eliminate the production of lactic acid. • The deletion of the ldh was achieved by introducing an efficient two-plasmid CRISPR system. • The growth rate of the mutant LAB strains show significant changes due to the deletion of ldh. • The effects of metabolic alteration on Bacteriocin-Like Inhibitory Substance (BLIS) was significantly increase up to two-fold resulted from re-routing of the carbon flow towards BLIS pathway. [ABSTRACT FROM AUTHOR]

Food-borne pathogens and antimicrobial resistance (AMR) represent the significant public health challenges in the 21st century. Increased emergence of AMR in major zoonotic food-borne pathogens (Salmonella, Campylobacter) and in commensal bacteria (E. coli, enterococci), its presence in agro-food (meat) chain and environment, including control/prevention of AMR transfer from food-producing animals to humans via food consumption, is of utmost importance for public health. This review highlights the most relevant risk mitigation strategies for AMR in the meat production chain within One Health context. The monitoring and surveillance systems for AMR in meat chain are presented and briefly discussed, including sampling schemes, susceptibility testing, clinical resistance and epidemiological cut-off values. The most effective approaches to track and manage AMR in farm-abattoir-meat processing-retail continuum have been recommended, including aspects of international harmonization of critically important antimicrobials for human and veterinary use. The successful AMR monitoring and control in the meat chain can be achieved by evidence-based and integrated approach within One Health context. The application of state-of-the-art technologies and methods for detection and tracking of zoonotic food borne pathogens and AMR, such as Whole Genome Sequencing supported with data processing using Artificial Intelligence (machine learning), can contribute to achieving this goal. [ABSTRACT FROM AUTHOR]

Human bocavirus (HBoV) is an emerging pathogen causing gastroenteritis/respiratory tract infection. Shellfish has been implicated in foodborne HBoV dissemination. The present investigation aimed at synthesising shellfish-associated HBoV data. Shellfish-HBoV data were mined from public repositories using topic-specific algorithm. A total of 30 data sources was identified of which 5 were synthesised. The average HBoV positivity and sample-size was 12 ± 9.2 and 134.2 ± 113.6, respectively. HBoV was studied in mollusc with 3.7–83.3% crude prevalence. The pooled HBoV prevalence in shellfish was 9.2% (7.2–11.8; 5 studies) and 12.9% (1.8–53.9; 5 studies) in common-effects and random-effects model respectively, with 0.12–94.89% prediction interval (PI). Sensitivity analysis yielded 8.7% (6.7–11.2; PI = 1.99–29.48%) prevalence. HBoV1 and HBoV2 pooled prevalence in shellfish was 7.91% (1.61–31.09; 3 studies) and 12.52% (0.01–99.60; 3 studies), respectively. HBoV3 prevalence was reported in one single study as 6.96% (4.41–10.35). In conclusion, the present study revealed high HBoV prevalence in shellfish, signifying the need to characterise HBoV and subtypes circulating in non-mollusc shellfish. Furthermore, there is an urgent need to mitigate the food safety risk that may result from HBoV contaminated shellfish since shellfish-borne HBoV is not routinely assessed and might be underestimated at present. [ABSTRACT FROM AUTHOR]

Bacillus cereus is a foodborne opportunistic pathogen commonly found in humans and animals. It produces various toxins, causing frequent food safety incidents. Therefore, establishing a fast and accurate method for detecting B. cereus enterotoxin is crucial for disease diagnosis and food safety. In this study, Haemolysin BL comprising Hbl B and L2 was obtained from a prokaryotic expression system and then used to immunize mice for antibody preparation. Paired antibodies 2A10–5C7 against Hbl B and 1E2–10A4 against Hbl L2 were screened using the chessboard method and then used to construct a double-antibody sandwich detection method and a lateral flow immunochromatographic assay (LFIA) to quantify the concentrations of Hbl B and L2 in PBS and milk. The limits of detection for Hbl B and L2 in milk were 0.74 ng mL−1 and 1 ng mL−1 with detection ranges of 1.48–645.5 ng mL−1 and 2.33–391.5 ng mL−1. The spiked recoveries ranged from 82.2% to 105.67% and there was no cross-reactivity with common microbial toxins. The established LFIA was low in cost and rapid and was comparable with commercially available detection kits for food samples. [ABSTRACT FROM AUTHOR]

The pathogenic bacterium Campylobacter jejuni is a major food safety concern as it can form biofilms that increase its survival and infective potential. Biofilms consist of microbial cells and extracellular matrix (ECM), which is made of water and extracellular polymeric substances (EPS), which are critical for structural integrity and pathogenicity. The aim of this study was to optimize a protocol for the isolation of C. jejuni ECM. We employed eight physical and chemical isolation methods to extract and purify ECM, followed by different qualitative and quantitative analyses using gel electrophoresis and spectroscopy. This comprehensive approach enabled the evaluation of ECM composition in terms of polysaccharides, proteins, and extracellular DNA. The isolation methods resulted in different yields and purities of the extracted ECM components. Centrifugation in combination with chemical treatments proved to be most effective, isolating higher concentrations of polysaccharides and proteins. Additionally, extraction with ether solution facilitated the recovery of high-molecular-weight extracellular DNA. Overall, we provide a refined methodology for ECM extraction from C. jejuni. As polysaccharides and proteins participate in biofilm stability and microbial communication, and extracellular DNA participates in genetic exchange and virulence, our study contributes towards a better understanding of the persistence of this pathogen in the food industry. [ABSTRACT FROM AUTHOR]

The genus Salmonella contains the most common foodborne pathogens frequently isolated from food-producing animals and is responsible for zoonotic infections in humans and animals. Salmonella infection in humans and animals can cause intestinal damage, resulting in intestinal inflammation and disruption of intestinal homeostasis more severe cases can lead to bacteremia. Pyroptosis, a proinflammatory form of programmed cell death, is involved in many disease processes. Inflammasomes, pyroptosis, along with their respective signaling cascades, are instrumental in the preservation of intestinal homeostasis. In recent years, with the in-depth study of pyroptosis, our comprehension of the virulence factors and effector proteins in Salmonella has reached an extensive level, a deficit persists in our knowledge regarding the intrinsic pathogenic mechanisms about pyroptosis, necessitating a continued pursuit of understanding and investigation. In this review, we discuss the occurrence of pyroptosis induced by Salmonella effectors to provide new ideas for elucidating the regulatory mechanisms through which Salmonella virulence factors and effector proteins trigger pyroptosis could pave the way for novel concepts and strategies in the clinical prevention of Salmonella infections and the treatment of associated diseases. [ABSTRACT FROM AUTHOR]

The antibacterial and antibiofilm effects of rosehip vinegar and propolis extract, separately and as a mixture, were investigated on Staphylococcus aureus and Escherichia coli O157:H7. The organoleptic properties and tissue integrity of sardine fish treated with this mixture were evaluated. The propolis extract was found to have a higher inhibitory effect (>80%) on S. aureus (up to the 5th dilution) than on E. coli O157:H7 (only at the first dilution). A potential synergistic antibacterial and antibiofilm effect of the mixture was observed with an inhibition ratio of ≥50%. This mixture may extend the shelf life of sardines as a natural antibacterial/antibiofilm preservative. [ABSTRACT FROM AUTHOR]

The research aimed to produce microemulsions loaded with garlic essential oil (5, 10, and 15% w/w) to improve the mechanical and antimicrobial properties of Persian gum and k-carrageenan-based microemulgels against food pathogens. Microemulsions loaded with 10% garlic essential oil had an average particle size of 88.59 ± 2.59 mm and an encapsulation efficiency of 95.61 ± 1.38%. Microemulsions loaded with 10% garlic essential oil with levels of 3, 5, and 7% were used in the structure of hydrogels. Using garlic essential oil microemulsion (up to 50%) in microemulgels structure led to an increase in viscosity and consistency index. The rheological data were well-fitted by the power law model, and all samples had pseudoplastic (shear-thinning) behavior. The mechanical properties of microemulgels were improved by using microemulsions, and a 5% microemulsion of garlic essential oil was associated with an increase in hardness, cohesiveness, and chewiness indices. FTIR analysis confirmed that garlic essential oil is well placed in the microemulsion structure, and microemulsions containing garlic essential oil will strengthen the mechanical properties of microemulgels by establishing hydrogen bonds with the hydrogel matrix. The modeling of the release of garlic essential oil in food simulants showed that the highest amount of release occurs in aqueous media, and the Peleg model is the best description of the release behavior of the essential oil from the structure of microemulgels. The dominant mechanism involved in the garlic essential oil release in the food simulants was the Fickian release mechanism. Staphylococcus aureus showed the highest sensitivity against microemulgels loaded with garlic essential oil. [ABSTRACT FROM AUTHOR]

In this study, the antimicrobial activity of silver nanoparticles (AgNPs L21, AgNPs L22) produced using aqueous extracts of the Laser trilobum harvested in 2021 and 2022 was optimized. The experimental design and optimization of antimicrobial activity were performed using the response surface method (RSM). Using RSM, independent variables, such as silver concentration, extraction time, and synthesis temperature, were optimized as a result of the inhibition zone diameter against Staphylococcus aureus, Escherichia coli, Salmonella Typhimurium, and Listeria monocytogenes. Based on the optimization results, the extraction time, silver concentration, and temperature for AgNP L21 and L22 synthesis were determined to be 60 min, 5 mM, and 25 °C, respectively. When the XRD and TEM results of the nanoparticles synthesized under optimal conditions were evaluated, it was determined that the AgNPs were spherical in shape and had an average size of 30 ± 12 nm. Our study revealed that the year of harvest is unimportant for nanoparticles synthesized from L. trilobum, using a cheap and simple method that does not require toxic substances. Owing to the antimicrobial activity of nanoparticles produced under optimal conditions, it is possible to biocontrol and prevent contamination by these bacteria in food science and industry. [ABSTRACT FROM AUTHOR]

Summary: Pork cutlets are susceptible to cross‐contamination with foodborne pathogens during processing. Food irradiation effectively improves food hygiene by eliminating microbes. We investigated the application of X‐ray irradiation (0.5–10 kGy) on pathogen inactivation (D10 value), quality changes [total aerobic bacteria (TAB), yeast and mould (Y&M), total coliform (TC), colour, thiobarbituric acid reactive substance (TBARS), and pH], and the hydrocarbon profile of pork cutlets. D10 values of Escherichia coli O157:H7, Salmonella typhimurium, Listeria monocytogenes, and Staphylococcus aureus were 0.37, 0.62, 0.52, and 0.36 kGy, respectively. At least 3.10 kGy (5‐D10 values) is required to ensure the microbiological safety of pork cutlets. X‐ray irradiation dose‐dependently reduced all microbial counts, and up to 7 kGy had no adverse effects on colour, TBARS, and pH. Furthermore, 1,7‐hexadecadiene and 8‐heptadecene were potential markers for irradiated pork cutlets. X‐ray irradiation of up to 7 kGy is effective in improving hygiene levels while maintaining pork cutlet quality. [ABSTRACT FROM AUTHOR]

The consumption of organic food has increased in recent years. In organic rearing animals are exposed to outdoor conditions, which may increase their risk of infection from various pathogens. In the present study the occurrence of the most significant foodborne pathogenic bacteria in organic meat and ready-to-eat organic meat products was assessed. Out of 100 raw organic meat samples tested, 72 were contaminated with bacterial pathogens. The highest percentage of contaminated samples was observed in poultry meat (92.5%) followed by pork meat (66.7%). Furthermore, 50.0% of beef origin samples were positive for the bacteria tested. L. monocytogenes was found in 39.0% of samples, S. aureus was identified in 37.0%, Campylobacter in 20.0%, Salmonella in 8.0% and Shigatoxin-producing E. coli in 4.0% of raw meat samples. In 31.0% of samples a co-occurrence of two (83.9%) or three (16.1%) pathogens was observed. Among 100 samples of organic meat products tested, only L. monocytogenes was found in 5.0% of samples. The result of the present study indicated that organic food may be a source of harmful microorganisms that may pose foodborne infections to consumers. [ABSTRACT FROM AUTHOR]

High incidences of the foodborne pathogen Listeria monocytogenes have been reported on smear cheeses, and despite increased hygiene efforts, this incidence has remained stable in recent years. Applying antilisterial strains may increase the safety of smear cheeses. To find and test antilisterial strains, we inoculated fresh soft cheeses from nine dairies with the surrogate species Listeria innocua and assessed its growth under standardized ripening conditions. Acetic acid at day 23 (r = −0.66), lactose in fresh cheese (r = −0.63), and glucose at day 10 (r = −0.62), as well as seven amplicon sequence variants (ASVs), were negatively correlated with L. innocua growth. Two of these ASVs were assigned to the genus Leuconostoc of Lactobacillaceae (r = −0.82 and −0.71). Isolates from this family, from Aerococcaceae, and Carnobacteriaceae were characterized according to their inhibitory properties, and those showing antilisterial properties were applied as protective cultures in challenge tests. The combined application of strains of Leuconostoc mesenteroides, Aerococcaceae, and Carnobacteriaceae successfully eliminated low levels of L. innocua in the final products. This is likely explained by antimicrobial compounds, including mesentericin Y105 and acetate, and competition for carbon sources and iron. This study shows a promising way to improve the safety of soft smear cheeses by applying defined protective cultures. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes is a foodborne pathogen that causes listeriosis in humans, the severity of which depends on multiple factors, including intrinsic characteristics of the affected individuals and the pathogen itself. Additionally, emerging evidence suggests that epigenetic modifications may also modulate host susceptibility to infection. Therefore, different clinical outcomes can be expected, ranging from self-limiting gastroenteritis to severe central nervous system and maternal-neonatal infections, and bacteremia. Furthermore, L. monocytogenes is a genetically and phenotypically diverse species, resulting in a large variation in virulence potential between strains. Multilocus sequence typing (MLST) has been widely used to categorize the clonal structure of bacterial species and to define clonal complexes (CCs) of genetically related isolates. The combination of MLST and epidemiological data allows to distinguish hypervirulent CCs, which are notably more prevalent in clinical cases and typically associated with severe forms of the disease. Conversely, other CCs, termed hypovirulent, are predominantly isolated from food and food processing environments and are associated with the occurrence of listeriosis in immunosuppressed individuals. Reports of genetic traits associated with this diversity have been described. The Food and Agriculture Organization (FAO) is encouraging the search for virulence biomarkers to rapidly identify the main strains of concern to reduce food waste and economical losses. The aim of this review is to comprehensively collect, describe and discuss the methodologies used to discriminate the virulence potential of L. monocytogenes CCs. From the exploration of in vitro and in vivo models to the study of expression of virulence genes, each approach is critically explored to better understand its applicability and efficiency in distinguishing the virulence potential of the pathogen. [ABSTRACT FROM AUTHOR]

Globally, the significant risk to food safety and public health posed by antimicrobial-resistant foodborne Salmonella pathogens is driven by the utilization of in-feed antibiotics, with variations in usage across poultry production systems. The current study investigated the occurrence of virulence, antimicrobial resistant profiles, and biofilm-forming potentials of Salmonella isolates sourced from different chicken types. A total of 75 cloacal faecal samples were collected using sterile swabs from layer, broiler, and indigenous chickens across 15 poultry farms (five farms per chicken type). The samples were analysed for the presence of Salmonella spp. using species-specific PCR analysis. Out of the 150 presumptive isolates, a large proportion (82; 55%) were confirmed as Salmonella species, comprising the serovars S. typhimurium (49%) and S. enteritidis (30%) while 21% were uncategorised. Based on phenotypic antibiotic susceptibility test, the Salmonella isolates were most often resistant to erythromycin (62%), tetracycline (59%), and trimethoprim (32%). The dominant multiple antibiotic resistance phenotypes were SXT-W-TE (16%), E-W-TE (10%), AML-E-TE (10%), E-SXT-W-TE (13%), and AMP-AML-E-SXT-W-TE (10%). Genotypic assessment of antibiotic resistance genes revealed that isolates harboured the ant (52%), tet (A) (46%), sui1 (13%), sui2 (14%), and tet (B) (9%) determinants. Major virulence genes comprising the invasion gene spiC, the SPI-3 encoded protein (misL) that is associated with the establishment of chronic infections and host specificity as well as the SPI-4 encoded orfL that facilitates adhesion, autotransportation and colonisation were detected in 26%, 16%, and 14% of the isolates respectively. There was no significant difference on the proportion of Salmonella species and the occurrence of virulence and antimicrobial resistance determinants among Salmonella isolates obtained from different chicken types. In addition, neither the chicken type nor incubation temperature influenced the potential of the Salmonella isolates to form biofilms, although a large proportion (62%) exhibited weak to strong biofilm-forming potentials. Moderate to high proportions of antimicrobial resistant pathogenic Salmonella serovars were detected in the study but these did not vary with poultry production systems. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is a prevalent foodborne pathogen, and its resistance has become more pronounced due to antibiotic overuse. In this paper, we constructed a 3D‐QSAR model using 47 naphthalimidopropanediols derivatives (NIOLs). The results indicate that the CoMFA model (q2 = 0.771, r2 = 0.998) and CoMSIA‐ASH model (q2 = 0.638, r2 = 0.995) exhibit favorable predictive capabilities, leading to the design of 11 novel NIOLs as antibacterial agents. ADMET was used to validate their pharmacokinetic characteristics, molecular docking was performed to validate the binding capability of the designed molecules, dynamics simulations, and binding free energy were employed to verify the accuracy of docking results. The results demonstrate excellent performance of the designed novel molecules, which may provide significant references for the development of novel and effective antibacterial agents against S. aureus. [ABSTRACT FROM AUTHOR]

Background: Salmonella, a foodborne pathogen, possesses a type I-E clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated (Cas) system. We investigated the system's role in regulating Salmonella virulence by deleting the CRISPR arrays and Cas operon. Results: Our study demonstrates invasion and proliferation defects of CRISPR-Cas knockout strains in intestinal epithelial cells and macrophages owing to the repression of invasion and virulence genes. However, proliferation defects were not observed in the Gp91phox−/− macrophages, suggesting the system's role in the pathogens' antioxidant defense. We deduced that the CRISPR-Cas system positively regulates H2O2 importer (OmpW), catalase (katG), peroxidase (ahpC), and superoxide dismutase (soda and sodCI), thereby protecting the cells from oxidative radicals. The knockout strains were attenuated in in-vivo infection models (Caenorhabditis elegans and BALB/c mice) due to hypersensitivity against antimicrobial peptides, complement proteins, and oxidative stress. The attenuation in virulence was attributed to the suppression of LPS modifying (pmr) genes, antioxidant genes, master regulators, and effectors of the SPI-1 (invasion) and SPI-2 (proliferation) islands in knockout strains. The regulation could be attributed to the partial complementarity of the CRISPR spacers with these genes. Conclusions: Overall, our study extends our understanding of the role of the CRISPR-Cas system in Salmonella pathogenesis and its virulence determinants. [ABSTRACT FROM AUTHOR]

The detrimental impact of foodborne pathogens on human health makes food safety a major concern at all levels of production. Conventional methods to detect foodborne pathogens, such as live culture, high-performance liquid chromatography, and molecular techniques, are relatively tedious, time-consuming, laborious, and expensive, which hinders their use for on-site applications. Recurrent outbreaks of foodborne illness have heightened the demand for rapid and simple technologies for detection of foodborne pathogens. Recently, Lateral flow assays (LFA) have drawn attention because of their ability to detect pathogens rapidly, cheaply, and on-site. Here, we reviewed the latest developments in LFAs to detect various foodborne pathogens in food samples, giving special attention to how reporters and labels have improved LFA performance. We also discussed different approaches to improve LFA sensitivity and specificity. Most importantly, due to the lack of studies on LFAs for the detection of viral foodborne pathogens in food samples, we summarized our recent research on developing LFAs for the detection of viral foodborne pathogens. Finally, we highlighted the main challenges for further development of LFA platforms. In summary, with continuing improvements, LFAs may soon offer excellent performance at point-of-care that is competitive with laboratory techniques while retaining a rapid format. [ABSTRACT FROM AUTHOR]

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Salmonella enterica, a prominent foodborne pathogen, contributes significantly to global foodborne illnesses annually. This species exhibits significant genetic diversity, potentially impacting its infectivity, disease severity, and antimicrobial resistance. Whole genome sequencing (WGS) offers comprehensive genetic insights that can be utilized for virulence assessment. However, existing bioinformatic tools for studying Salmonella virulence have notable limitations. To address this gap, a Salmonella Virulence Database with a non-redundant, comprehensive list of putative virulence factors was constructed. Two bioinformatic analysis tools, Virulence Factor Profile Assessment and Virulence Factor Profile Comparison tools, were developed. The former provides data on similarity to the reference genes, e-value, and bite score, while the latter assesses the presence/absence of virulence genes in Salmonella isolates and facilitates comparison of virulence profiles across multiple sequences. To validate the database and associated bioinformatic tools, WGS data from 43,853 Salmonella isolates spanning 14 serovars was extracted from GenBank, and WGS data previously generated in our lab was used. Overall, the Salmonella Virulence database and our bioinformatic tools effectively facilitated virulence assessment, enhancing our understanding of virulence profiles among Salmonella isolates and serovars. The public availability of these resources will empower researchers to assess Salmonella virulence comprehensively, which could inform strategies for pathogen control and risk evaluations associated with human illnesses. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bacillus cereus, a foodborne pathogen, produces resilient endospores that are challenging to detect with conventional methods. This study presents a novel Flower-Shaped PCR Scaffold-based Lateral Flow Biosensor (FSPCRS-LFB), which employs an aptamer-integrated PCR scaffold as capture probes, replacing the traditional streptavidin-biotin (SA-Bio) approach. The FSPCRS-LFB demonstrates high sensitivity and cost-efficiency in detecting B. cereus endospores, with a limit of detection (LOD) of 4.57 endospores/mL a visual LOD of 102 endospores/mL, and a LOD of 6.78 CFU/mL for endospore-cell mixtures. In chicken and tea samples, the platform achieved LODs of 74.5 and 52.8 endospores/mL, respectively, with recovery rates of 82.19% to 97.88%. Compared to existing methods, the FSPCRS-LFB offers a 3.7-fold increase in sensitivity while reducing costs by 26% over the SA-Bio strategy and 87.5% over rolling circle amplification (RCA). This biosensor provides a rapid, sensitive and cost-effective solution for point-of-care testing (POCT) of B. cereus endospores, expanding detection capabilities and offering novel approaches for pathogen detection. [ABSTRACT FROM AUTHOR]

Salmonella Enteritidis is a major foodborne pathogen throughout the world and the increase in antibiotic resistance of Salmonella poses a significant threat to public safety. Natural nanobodies exhibit high affinity, thermal stability, ease of production, and notably higher diversity, making them widely applicable for the treatment of viral and bacterial infections. Recombinant expression using Lactococcus lactis leverages both acid resistance and mucosal colonization properties of these bacteria, allowing the effective expression of exogenous proteins for therapeutic effects. In this study, nine specific nanobodies against the flagellar protein FliC were identified and expressed. In vitro experiments demonstrated that FliC-Nb-76 effectively inhibited the motility of S. Enteritidis and inhibited its adhesion to and invasion of HIEC-6, RAW264.7, and chicken intestinal epithelial cells. Additionally, a recombinant L. lactis strain secreting the nanobody, L. lactis-Nb76, was obtained. Animal experiments confirmed that it could significantly reduce the mortality rates of chickens infected with S. Enteritidis, together with alleviating the inflammatory response caused by the pathogen. These results provide a novel strategy for the treatment of antibiotic-resistant S. Enteritidis infection in the intestinal tract. [ABSTRACT FROM AUTHOR]

AbstractListeria monocytogenes, a resilient bacterium in diverse food conditions, such as refrigeration, reduced water activity and low pH, poses a significant threat to the food industry and public health. In recent years, it has been documented an increase in the antibiotic resistance of zoonotic pathogens, including L. monocytogenes. This review provides new insight into the molecular mechanisms involved in both intrinsic and acquired antibiotic resistance of L. monocytogenes with an emphasis on the effect of different environmental and food-related factors. It also explores the relationship of these resistance mechanisms with virulence factors. An analysis of literature data (2009–2021) was conducted to investigate statistically and graphically potential associations between specific antibiotic resistance patterns in the pathogen and food categories using an unbiased variance analysis. The results evidenced that food type had an influence on the antibiotic resistance profiles of L. monocytogenes, with meat and vegetables being the food categories exhibiting the most prevalent profiles. The frequent detection of resistance to ampicillin, penicillin, and tetracycline (non-intrinsic resistances) indicates that specific processing conditions along the food chain may induce them. Many questions remain about the impact of food chain factors (e.g. thermal treatments, cold chain, preservatives, etc.) and food type (low pH, reduced water activity, etc.) on the antibiotic resistance patterns of the pathogen, particularly concerning food-related sources, the resistance mechanisms involved (e.g. cross-protection, horizontal gene transfer, etc.), and the evolutionary processes of antibiotic-resistant microbial populations. Metagenomics, in addition to other –omics technologies (metabolomics and transcriptomics), allows a better understanding of the processes involved in the acquisition of resistance. [ABSTRACT FROM AUTHOR]

The growth of bacteria and fungi may cause disease inf human or spoilage of food. New antimicrobial substances need to be discovered. Lactoferricin (LFcin) is a group of antimicrobial peptides derived from the N-terminal region of the milk protein lactoferrin (LF). LFcin has antimicrobial ability against a variety of microorganisms, which is significantly better than that of its parent version. Here, we review the sequences, structures, and antimicrobial activities of this family and elucidated the motifs of structural and functional significance, as well as its application in food. Using sequence and structural similarity searches, we identified 43 new LFcins from the mammalian LFs deposited in the protein databases, which are grouped into six families according to their origins (Primates, Rodentia, Artiodactyla, Perissodactyla, Pholidota, and Carnivora). This work expands the LFcin family and will facilitate further characterization of novel peptides with antimicrobial potential. Considering the antimicrobial effect of LFcin on foodborne pathogens, we describe the application of these peptides from the prospective of food preservation. [ABSTRACT FROM AUTHOR]

AbstractSalmonella is a pathogenic bacterium, being the second most commonly reported foodborne pathogen in Europe, due to the ability of its different serovars to contaminate a wide variety of foods, with differences among countries. Common chemical or physical control methods are not always effective, eco-sustainable and adapted to the diversity of Salmonella serovars. Thus, great attention is given to developing complementary or alternative control methods that can be tailor made for specific situations. One of these methods is biopreservation using lactic acid bacteria, with most studies on their antagonistic activity focused on the production of antimicrobials. Less attention has been given to competition by exploitation of nutrients. This review is thus set to investigate and highlight limiting resources that may be involved in the competitive exclusion of Salmonella in food matrices. To do this the needs for nutrients and microelements and the known homeostatic pathways of Salmonella and lactic acid bacteria are examined. Finally, milk, intended for the manufacture of fermented dairy foods, is pointed out as an example of food to investigate the bioavailable macronutrients, metals and vitamins that could be involved in competition between the different species and serovars, and could be exploited for targeted biopreservation. [ABSTRACT FROM AUTHOR]

Introduction: Although Campylobacter spp., including Campylobacter coli, have emerged as important zoonotic foodborne pathogens globally, the understanding of the genomic epidemiology of C. coli of porcine origin is limited. Methods: As pigs are an important reservoir of C. coli, we analyzed C. coli genomes that were isolated (n = 3) from pigs and sequenced (this study) them along with all other C. coli genomes for which pig intestines, pig feces, and pigs were mentioned as sources in the NCBI database up to January 6, 2023. In this paper, we report the pan-genomic features, the multi-locus sequence types, the resistome, virulome, and mobilome, and the phylogenomic analysis of these organisms that were obtained from pigs. Results and discussion: Our analysis revealed that, in addition to having an open pan-genome, majority (63%) of the typeable isolates of C. coli of pig origin belonged to a single clonal complex, ST-828. The resistome of these C. coli isolates was predominated by the genes tetO (53%), blaOXA-193 (49%), and APH (3')-IIIa (21%); however, the virulome analysis revealed a core set of 37 virulence genes. Analysis of the mobile genetic elements in the genomes revealed wide diversity of the plasmids and bacteriophages, while 30 transposons were common to all genomes of C. coli of porcine origin. Phylogenomic analysis showed two discernible clusters comprising isolates originating from Japan and another set of isolates comprising mostly copies of a type strain stored in three different culture collections. [ABSTRACT FROM AUTHOR]

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High-pressure processing (HPP) is a promising technology for increasing the shelf life of food, with minimal effects on the nutritional or sensory quality. However, there has been a concern that high-oil-content foods may protect food pathogens in HPP, and that HPP can affect the quality of lipids. We inoculated Listeria monocytogenes and Salmonella Typhimurium into 34% and 54% oil-content pesto sauce, processed them either with HPP (600 MPa, 4 min) or thermal processing (82 °C, 5 min), and analyzed bacteria counts, pH, GC-MS (Terpene compounds), the time–kill kinetic study, and lipid oxidation value for 60 days in refrigerating storage (5 ± 2 °C). Our findings show that HPP significantly reduced the number of bacteria (more than 4-log) compared to thermal processing or non-processing. Additionally, we discovered terpene compounds (highest-level terpene: L-linalool, eugenol, and 1,8-cineol) in pesto oil that exhibit antimicrobial activity. Different oil content did not have any significant effect on bacteria levels. Regarding chemical results, all samples were of acceptable quality, and the processes did not show any negative effect on lipid oxidation (Peroxide and P-Anisidine value under 10 meq per kilogram of oil). In conclusion, our study indicates that HPP is a suitable method for high-oil-content pesto sauce. In addition, functional compounds naturally present in pesto may contribute to maintaining its microbial and chemical quality. [ABSTRACT FROM AUTHOR]

Six hundred million cases of disease and roughly 420,000 deaths occur globally each year due to foodborne pathogens. Current methods to screen and identify pathogens in swine, poultry, and cattle products include immuno-based techniques (e.g., immunoassay integrated biosensors), molecular methods (e.g., DNA hybridization and PCR assays), and traditional culturing. These methods are often used in tandem to screen, quantify, and characterize samples, prolonging real-time comprehensive analysis. Next-generation sequencing (NGS) is a relatively new technology that combines DNA-sequencing chemistry and bioinformatics to generate and analyze large amounts of short- or long-read DNA sequences and whole genomes. The goal of this project was to evaluate the quantitative capabilities of the real-time NGS Oxford Nanopore Technologies' MinION sequencer through a shotgun-based sequencing approach. This investigation explored the correlation between known amounts of the analyte (lambda DNA as a pathogenic bacterial surrogate) with data output, in both the presence and absence of a background matrix (Bos taurus DNA). A positive linear correlation was observed between the concentration of analyte and the amount of data produced, number of bases sequenced, and number of reads generated in both the presence and absence of a background matrix. In the presence of bovine DNA, the sequenced data were successfully mapped to the NCBI lambda reference genome. Furthermore, the workflow from pre-extracted DNA to target identification took less than 3 h, demonstrating the potential of long-read sequencing in food safety as a rapid method for screening, identification, and quantification. [ABSTRACT FROM AUTHOR]

Postbiotics are the non-viable bacterial products or the low molecular weight metabolites produced by probiotics that have received considerable attention owing to their health promoting effects. The present study aimed to investigate the safety and antibacterial properties of postbiotic components of Lacticaseibacillus rhamnosus (Lra) and Limosilactobacillus reuteri (Lre) for their potential applications in food products. The freeze dried postbiotic metabolites (FD-P) from Lra and Lre were extensively analyzed for their physico-chemical properties and antibacterial actions against common food borne pathogens. Higher levels of total flavonoids (1971.79 ± 20 mg Qu/ g), total short-chain fatty acid (23 µg/g), sugar contents, CAT, and SOD anti-oxidative enzymes were detected in the Lra postbiotic, while GSH-px levels and riboflavin were higher in Lre postbiotics (P < 0.01). No significant differences were recorded in the total phenolic (2501 and 2518 mg GAE/ L) and crude protein contents (305. 58 and 296.23 µg/g) of the postbiotics (p ≥ 0.05), respectively. Both FD-P samples showed enhanced activities against Gram-Positive pathogens compared to Gram-Negative pathogens (p < 0.05), while combining the two postbiotics further potentiated the antibacterial actions. Both FD-P samples were non-hemolytic to human erythrocyte cells, and exhibited low cytotoxicity in MRC 5 and IPEC-J2 cell lines at the highest used concentrations (150 mg/ml). In summary, the postbiotics derived from Lra and Lre are safe bioactive ingredients with enhanced antibacterial and antioxidant capabilities, having potential applications as a natural preservatives in food system, potentially enhancing safety and extending the shelf life of food products. [ABSTRACT FROM AUTHOR]

Escherichia coli O157:H7 is a major foodborne pathogen that poses a significant threat to food safety and human health. Rapid and sensitive detection of viable Escherichia coli O157:H7 can effectively prevent food poisoning. Here, we developed a microwell-confined and propidium monoazide-assisted digital CRISPR microfluidic platform for rapid and sensitive detection of viable Escherichia coli O157:H7 in food samples. The reaction time is significantly reduced by minimizing the microwell volume, yielding qualitative results in 5 min and absolute quantitative results in 15 min. With the assistance of propidium monoazide, this platform can eliminate the interference from 99% of dead Escherichia coli O157:H7. The direct lysis method obviates the need for a complex nucleic acid extraction process, offering a limit of detection of 3.6 × 101 CFU mL−1 within 30 min. Our results demonstrated that the platform provides a powerful tool for rapid detection of Escherichia coli O157:H7 and provides reliable guidance for food safety testing. [ABSTRACT FROM AUTHOR]

The red swamp crayfish (Procambarus clarkii) is a widely distributed invasive species that is listed in the Delivering Alien Invasive Species Inventory for Europe. Native to North America, it has been introduced to numerous regions, such as the Canary Islands, Spain. Previous studies have confirmed the role of this crayfish in the maintenance of several foodborne pathogenic bacteria. Therefore, the aim of this study was to analyze the main zoonotic bacterial and parasitic pathogens present in a P. clarkii population introduced to the island of Tenerife, Canary Islands, and to assess the potential risk to public health and native fauna. A total of 22 crayfish from Tenerife were analyzed using Biofire FilmArray Gastrointestinal Panels and culture–PCR methods. The results show the presence of Plesiomonas shigelloides, Shigella/enteroinvasive Escherichia coli, enteropathogenic Escherichia coli, Salmonella ser. Enteritidis, Salmonella ser. Typhimurium, and Salmonella ser. Typhi. These results demonstrate the presence of a variety of pathogenic bacteria in the red swamp crayfish in Tenerife that represent a significant concern in terms of public health and conservation. Implementing educational campaigns to inform the community about the risks associated with handling and consuming contaminated crayfish, as well as initiatives for the restoration of the contaminated ecosystem, are necessary to prevent the transmission of the foodborne pathogens. [ABSTRACT FROM AUTHOR]

Dish sponges are known to support the proliferation of human bacterial pathogens, yet they are commonly used by consumers. Exposure to foodborne pathogens via sponge use may lead to illness, a serious concern among susceptible populations. The extent of exposure risks from sponge use has been limited by constraints associated with culture‐independent or dependent methods for bacterial community characterization. Therefore, five used dish sponges were characterized to evaluate the presence of viable bacterial foodborne pathogens using the novel application of propidium monoazide (PMA) treatment and targeted 16S rRNA gene amplicon sequencing. Select pathogen viability was confirmed using targeted selective enrichment. The taxonomic abundance profiles of total and viable sponge microbiomes did not vary significantly. The numbers of unique bacterial species (p = 0.0465) and foodborne pathogens (p = 0.0102) identified were significantly lower in viable sponge microbiomes. Twenty unique bacterial foodborne pathogens were detected across total and viable sponge microbiomes, and three to six viable foodborne pathogens were identified in each sponge. Escherichia coli and Staphylococcus aureus were identified in each viable sponge microbiome, and viable E. coli were recovered from two sponges via targeted selective enrichment. These findings suggest that sponge‐associated bacterial communities are primarily viable and contain multiple viable bacterial foodborne pathogens. [ABSTRACT FROM AUTHOR]

Theaflavin 3,3′‐digallate (TF3), a major polyphenolic component of black tea, exhibits antibacterial effects against many foodborne pathogens. However, the antibacterial mechanisms of TF3 against Listeria monocytogenes remain unclear. In this study, we investigated the effects of TF3 on viability, biofilm, and membrane function of L. monocytogenes by the conventional plating method, crystal violet staining, and microscopy using fluorescent dyes JC‐1 and Laurdan, respectively. It was found that TF3 showed excellent antibacterial activity against L. monocytogenes with the minimum inhibitory concentration of 62.5 mg/L. The viable count determined on TSA decreased by 3 log after the treatment for 2 h with TF3 at 62.5 mg/L. The viable count determined on TSA containing 4% NaCl decreased by more than 4 log after the treatment for 30 min with TF3 at the same concentration, suggesting that TF3 gave damage on the cells, enhancing the antibacterial action of 4% NaCl, but the damage was recoverable in the absence of 4% NaCl. To explore the antibacterial mechanisms of TF3, the effects of TF3 on membrane potential and membrane fluidity were investigated. TF3 reduced both membrane potential and fluidity of L. monocytogenes at 62.5 mg/L, suggesting that TF3 damaged the structural integrity of the cell membrane. TF3 reduced biofilm mass of mature biofilm of L. monocytogenes. Moreover, THEAFLAVIN TF40, a commercially available Camellia sinensis leaf extract containing TF3, reduced viable count of L. monocytogenes by 2 log on apple skin. These results suggest the potential of theaflavins as a natural anti‐Listeria disinfectant. [ABSTRACT FROM AUTHOR]

Background: The urgent need for affordable and rapid detection methodologies for foodborne pathogens, particularly Escherichia coli (E. coli), highlights the importance of developing efficient and widely accessible diagnostic systems. Dark field microscopy, although effective, requires specific isolation of the target bacteria which can be hindered by the high cost of producing specialized antibodies. Alternatively, M13 bacteriophage, which naturally targets E. coli, offers a cost-efficient option with well-established techniques for its display and modification. Nevertheless, its filamentous structure with a large length-diameter ratio contributes to nonspecific binding and low separation efficiency, posing significant challenges. Consequently, refining M13 phage methodologies and their integration with advanced microscopy techniques stands as a critical pathway to improve detection specificity and efficiency in food safety diagnostics. Methods: We employed a dual-plasmid strategy to generate a truncated M13 phage (tM13). This engineered tM13 incorporates two key genetic modifications: a partial mutation at the N-terminus of pIII and biotinylation at the hydrophobic end of pVIII. These alterations enable efficient attachment of tM13 to diverse E. coli strains, facilitating rapid magnetic separation. For detection, we additionally implemented a convolutional neural network (CNN)-based algorithm for precise identification and quantification of bacterial cells using dark field microscopy. Results: The results obtained from spike-in and clinical sample analyses demonstrated the accuracy, high sensitivity (with a detection limit of 10 CFU/μL), and time-saving nature (30 min) of our tM13-based immunomagnetic enrichment approach combined with AI-enabled analytics, thereby supporting its potential to facilitate the identification of diverse E. coli strains in complex samples. Conclusion: The study established a rapid and accurate detection strategy for E. coli utilizing truncated M13 phages as capture probes, along with a dark field microscopy detection platform that integrates an image processing model and convolutional neural network. [ABSTRACT FROM AUTHOR]

Summary: The increased consumption of minimally processed vegetables (MPV) in various countries is related to the continued interest of consumers in seeking practical and healthy food items. Due to multiple processing steps, MPV can be contaminated by several foodborne pathogens that pose significant health risks to consumers. The use of rapid techniques to detect pathogens in ready‐to‐eat (RTE) foods such as MPV is therefore essential to provide high quality and safe products. This review aims to provide a comprehensive description of molecular‐based techniques for rapid detection of pathogenic bacteria in MPV, and their occurrence reported in studies published in the last 10 years. The main pathogens detected using rapid methods were Salmonella spp., Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, Shigella spp., and Campylobacter jejuni. Molecular‐based techniques included real‐time polymerase chain reaction (PCR), multiplex PCR, matrix‐assisted laser desorption ionisation time of flight mass spectrometry (MALDI‐TOF MS), and denaturing gradient gel electrophoresis (DGGE). The data indicate high incidences of pathogenic bacteria in MPV, stressing the need for their rapid detection in these products to prevent associated health risks. Further studies should be carried out to increase the sensitivity of molecular‐based techniques and prevent false positives due to undesirable non‐specific PCR amplifications. [ABSTRACT FROM AUTHOR]

Summary: This article reviews available evidence on food safety and foodborne illness in Laos, especially as it relates to human nutrition. There is a distinct lack of research in Laos surrounding bacterial, viral, parasitic and chemical foodborne contaminants, which contribute to significant yet avoidable public health problems. Viral and chemical foodborne contaminants are especially under researched. Major challenges include undeveloped reporting systems for outbreaks, zoonotic foodborne pathogens, antimicrobial resistance, resource constraints and communicating food safety risks to diverse ethnic groups. Evidence‐based food safety policy in Laos requires improved surveillance and reporting, identification of evidence gaps within food value chains, assessments of risks and cost‐effective approaches, and supporting partnerships with neighbouring countries. Specific suggestions for targeted research involve conducting longitudinal studies to ascertain long‐term public health impacts, continuing to identify foodborne etiologic agents and transmission routes in Laos and implementing interdisciplinary, One Health approaches to address complex problems more sustainably. [ABSTRACT FROM AUTHOR]

Foodborne pathogens may cause foodborne illness, which is among the major health problems worldwide. Since the therapeutic options for the treatment of the disease are becoming limited as a result of antibacterial resistance, there is an increasing interest to search for new alternatives of antibacterial. Bioactive essential oils from Curcuma sp become potential sources of novel antibacterial substances. The antibacterial activity of Curcuma heyneana essential oil (CHEO) was evaluated against Escherichia coli, Salmonella typhi, Shigella sonnei, and Bacillus cereus. The principal constituents of CHEO are ar-turmerone, β-turmerone, α-zingiberene, α-terpinolene, 1,8-cineole, and camphor. CHEO exhibited the strongest antibacterial activity against E. coli with a MIC of 3.9 µg/mL, which is comparable to that of tetracycline. The combination of CHEO (0.97 µg/mL) and tetracycline (0.48 µg/mL) produced a synergistic effect with a FICI of 0.37. Time-kill assay confirmed that CHEO enhanced the activity of tetracycline. The mixture disrupted membrane permeability of E. coli and induced cell death. CHEO at MIC of 3.9 and 6.8 µg/mL significantly reduced the formation of biofilm in E. coli. The findings suggest that CHEO has the potential to be an alternative source of antibacterial agents against foodborne pathogens, particularly E. coli. [ABSTRACT FROM AUTHOR]

Shiga toxin-producing and Enteropathogenic Escherichiacoli are foodborne pathogens commonly associated with diarrheal disease in humans. This study investigated the presence of STEC and EPEC in 771 dairy cattle fecal samples which were collected from 5 abattoirs and 9 dairy farms in South Africa. STEC and EPEC were detected, isolated and identified using culture and PCR. Furthermore, 339 STEC and 136 EPEC isolates were characterized by serotype and major virulence genes including stx1, stx2, eaeA and hlyA and the presence of eaeA and bfpA in EPEC. PCR screening of bacterial sweeps which were grown from fecal samples revealed that 42.2% and 23.3% were STEC and EPEC positive, respectively. PCR serotyping of 339 STEC and 136 EPEC isolates revealed 53 different STEC and 19 EPEC serotypes, respectively. The three most frequent STEC serotypes were O82:H8, OgX18:H2, and O157:H7. Only 10% of the isolates were classified as "Top 7" STEC serotypes: O26:H2, 0.3%; O26:H11, 3.2%; O103:H8, 0.6%; and O157:H7, 5.9%. The three most frequent EPEC serotypes were O10:H2, OgN9:H28, and O26:H11. The distribution of major virulence genes among the 339 STEC isolates was as follows: stx1, 72.9%; stx2, 85.7%; eaeA, 13.6% and hlyA, 69.9%. All the 136 EPEC isolates were eaeA-positive but bfpA-negative, while 46.5% carried hlyA. This study revealed that dairy cattle are a major reservoir of STEC and EPEC in South Africa. Further comparative studies of cattle and human STEC and EPEC isolates will be needed to determine the role played by dairy cattle STEC and EPEC in the occurrence of foodborne disease in humans.Please kindly check and confirm the country and city name in affiliation [6].This affiliation is correct.Please kindly check and confirm the affiliationsConfirmed. All Affiliations are accurate [ABSTRACT FROM AUTHOR]

Listeria monocytogenes is an important foodborne pathogen. It can adhere to food or food contact surface for a long time and form biofilm, which will lead to equipment damage, food deterioration, and even human diseases. As the main form of bacteria to survive, the mixed biofilms often exhibit higher resistance to disinfectants and antibiotics, including the mixed biofilms formed by L. monocytogenes and other bacteria. However, the structure and interspecific interaction of the mixed biofilms are very complex. It remains to be explored what role the mixed biofilm could play in the food industry. In this review, we summarized the formation and influence factors of the mixed biofilm developed by L. monocytogenes and other bacteria, as well as the interspecific interactions and the novel control measures in recent years. Moreover, the future control strategies are prospected, in order to provide theoretical basis and reference for the research of the mixed biofilms and the targeted control measures. [ABSTRACT FROM AUTHOR]

This paper describes a unique, extremely sensitive biophotonic sensor with a three-tier S-tapered (3S) structure. It is designed for the real-time detection of Shigella flexneri (S. flexneri), a common foodborne pathogen that causes severe gastrointestinal diseases. The sensor development includes three distinct diameters of S-tapered structures. The performance of tapered sections was improved by using molybdenum disulfide nanosheets (MoS2-NSs), zinc oxide nanowires (ZnO-NWs), and photoluminescent bimetallic gold–copper nanoclusters (AuCu–NCs). These nanoparticles greatly improve the sensor's performance. The sensor is further functionalized using anti-S. flexneri antibodies, allowing for the precise detection and capture of the target bacterium. The results show that the sensor can detect S. flexneri rapidly and accurately, with a linear detection range of 1–108 colony-forming units per milliliter (CFU/ml) and a low detection limit of 4.412 CFU/ml. In addition, the sensor's ability to identify S. flexneri biofilms is demonstrated. Biofilm detection allows us to better understand and control biofilm concerns in the environment, equipment, and biomedical devices. Aptamer examines confirm the sensor's ability to detect S. flexneri from the lateral direction. This study makes a significant contribution to the field of biosensing because no biophotonic sensor has previously been developed specifically for the detection of S. flexneri, fulfilling a critical gap in the arena of food safety and pathogen detection. The 3S sensor's performance, robustness, and potential for practical applications make it an important addition to the field of photonics. [ABSTRACT FROM AUTHOR]

Background: Extended-spectrum-β-lactamase (ESBL) and carbapenemase-producing Enterobacterales and Acinetobacter spp. pose significant challenges as nosocomial pathogens, demonstrating resistance against various antimicrobials. Their presence in food suggests that hospital kitchens could serve as antibiotic resistance reservoirs leading to patients' infection. Objectives: The aim of this study was to assess the prevalence and characteristics of β-lactam-resistant strains of Escherichia coli, Klebsiella pneumoniae, and Acinetobacter spp. isolated from the kitchen environment and from the staff of two Greek hospitals. Methods: Strains were recovered after selective isolation with β-lactams and were identified with MALDI–TOF MS. Antimicrobial susceptibility and presence of common β-lactamase genes were evaluated. Protein profiles were examined to analyze potential relationships of the strain with those from hospital patients. E. coli strains were further categorized into phylogenetic groups. Results: The overall prevalence in the kitchen environment was 4.5%, 1.5%, and 15.0% for E. coli, K. pneumoniae, and Acinetobacter spp., respectively, whereas the prevalence of Acinetobacter spp. in human skin was 4.0%. Almost all strains were multidrug-resistant. All E. coli strains were ESBL producers and belonged to phylogroups A and B1. All K. pneumoniae and seven Acinetobacter strains were carbapenemase-producers. A protein profile analysis showed relatedness between chicken and kitchen environment strains, as well as between kitchen environment and patient strains originated either from the same or from different hospitals. Conclusions: The results suggest that hospital kitchens may act as important pathogen hotspots contributing to the circulation of resistant strains in the hospital environment. [ABSTRACT FROM AUTHOR]

The current study aimed to evaluate the antibacterial efficacy of black seed oil (BSO) and its nanoemulsion (BSO-NE) against two foodborne pathogens, Listeria monocytogenes and Salmonella Typhimurium, during the processing and storage of yoghurt. Additionally, the sensory properties of the resulting yoghurt were assessed. Firstly, BSO-NE was prepared and characterized using zeta-sizer and Transmission electron microscopy (TEM). Then, the antibacterial activity and minimum inhibitory concentration (MIC) were determined via a resazurin-based microtiter dilution assay. Fresh buffalo's milk was inoculated with L. monocytogenes and Salmonella Typhimurium (1×105 CFU/ml) with the addition of either BSO or BSO-NE. The inoculated milk was then used for yoghurt making. The organoleptic properties and bacterial load of the obtained yoghurt were evaluated during storage in comparison to a control group. This study elucidated that BSO can be successfully produced in a nanoemulsion form, exhibiting acceptable particle size, stability, and morphology. The results demonstrated a strong antibacterial activity of BSO-NE (3.125 mg/mL) against both L. monocytogenes and Salmonella Typhimurium compared to the control and pure oil groups. Notably, complete eradication of L. monocytogenes and Salmonella Typhimurium was observed in yoghurt formulated with BSO-NE on the 8th day of storage. Interestingly, the antibacterial effect of BSO and BSO-NE on Salmonella Typhimurium was approximately similar throughout the experiment. Moreover, the results indicated that the addition of BSO-NE to yoghurt enhanced its organoleptic properties. Overall, these findings suggest that yoghurt can be fortified with BSO-NE to prevent bacterial contamination by L. monocytogenes and Salmonella Typhimurium in the dairy industry. [ABSTRACT FROM AUTHOR]

Sous vide cooking implies cooking foods, packed under vacuum conditions, at controlled temperatures (<80 °C). Although this method opens a new window of culinary possibilities, it also involves a series of risks, mainly microbiologically related, that must be assessed. The aim of this work was to evaluate the effectiveness of SV processes to inactivate three important foodborne pathogens (Campylobacter, Salmonella, and Clostridium spores) in chicken breast and eggs (omelet). For this purpose, two levels of inoculation (102 and 106 CFU/g), two different recipes, and two distinct treatments (with and without storage) for each food were studied. After treatments and storage, the corresponding microbiological counts were performed with standard methods. Average inactivation rates observed were 1.70, 4.82, and 4.34 log for Clostridium spores, Campylobacter, and Salmonella, respectively. No significant differences in microbial inactivation were perceived between the different recipes (food composition) or treatments, except for Clostridium spores, which showed a higher inactivation rate (2.30 log) when samples were stored. In general, preliminary results showed that, although appropriate levels of inactivation are reached for vegetative pathogenic cells, in some cases (spores in breast and Salmonella in eggs), the remaining microbiological risks should be considered and further studied, especially if long-term storage is planned. [ABSTRACT FROM AUTHOR]

Foodborne pathogens, such as Salmonella, are major factors that pose significant threats to global food safety and public health. Salmonella typhimurium is a prominent serotype contributing to non-typhoidal salmonellosis, which is a prevalent foodborne illness affecting humans and animals. Bacteriophages are considered one of the most environmentally friendly biocontrol agents, particularly in the food industry, owing to their high specificity and high safety. However, the emergency of phage-resistant mutants limits the biocontrol effect of phage treatment, leading to the requirement for a high diversity of lytic phages. Therefore, the study isolated and characterized two novel lytic Salmonella bacteriophages (SPYS_1 and SPYS_2) targeting S. typhimurium ATCC14028 and evaluated their effectiveness in reducing the contamination rates for milk and chicken tenders. Morphological and genomic analyses indicated that Salmonella phages SPYS_1 and SPYS_2 are novel species classified under the genus Skatevirus and the genus Berlinvirus, respectively. Both phages exhibited high stability across a broad range of thermal and pH conditions. The one-step growth curve result suggested that both phages had a short adsorption time and a large burst size in a single lytic cycle. The phage SPYS_1 demonstrated a noteworthy inhibition effect on the growth of S. typhimurium ATCC14028 in milk, resulting in a ~2-log reduction within the 2 to 4 h range. Overall, both phages have shown significant potential for application in food safety in the future. [ABSTRACT FROM AUTHOR]

Salmonella typhimurium and Listeria monocytogenes are relevant foodborne bacterial pathogens which may cause serious intoxications and infectious diseases in humans. In this study, a sensitive immunochromatographic analysis (ICA) for the simultaneous detection of these two pathogens was developed. For this, test strips containing two test zones with specific monoclonal antibodies (MAb) against lipopolysaccharides of S. typhimurium and L. monocytogenes and one control zone with secondary antibodies were designed, and the double-assay conditions were optimized to ensure high analytical parameters. Prussian blue nanoparticles (PBNPs) were used as nanozyme labels and were conjugated with specific MAbs to perform a sandwich format of the ICA. Peroxidase-mimic properties of PBNPs allowed for the catalytic amplification of the colorimetric signal on test strips, enhancing the assay sensitivity. The limits of detection (LODs) of Salmonella and Listeria cells were 2 × 102 and 7 × 103 cells/mL, respectively. LODs were 100-fold less than those achieved due to the ICA based on the traditional gold label. The developed double ICA was approbated for the detection of bacteria in cow milk samples, which were processed by simple dilution by buffer before the assay. For S. typhimurium and L. monocytogenes, the recoveries from milk were 86.3 ± 9.8 and 118.2 ± 10.5% and correlated well with those estimated by the enzyme-linked immunosorbent assay as a reference method. The proposed approach was characterized by high specificity: no cross-reactivity with other bacteria strains was observed. The assay satisfies the requirements for rapid tests: a full cycle from sample acquisition to result assessment in less than half an hour. The developed ICA has a high application potential for the multiplex detection of other foodborne pathogens. [ABSTRACT FROM AUTHOR]

Bacterial resistance and persistence in food environments are major concerns for the industry, which constantly seeks new strategies to reduce microbial contamination. Rhamnolipids (RL) biosurfactants are considered sustainable and green alternatives to synthetics; furthermore, they have demonstrated potential for controlling various foodborne pathogens. Food environments are typically exposed to diverse pH, solutes, temperatures, and water activity (aw) levels that may favor the survival of pathogens. Therefore, it is crucial to consider these factors in evaluating the performance of novel antimicrobials. Our study examined the influence of pH and sucrose on the antimicrobial activity of RL against both planktonic and biofilm of Listeria monocytogenes. We found that the presence of sucrose can enhance the antimicrobial effectiveness of RL against both planktonic and sessile bacteria. The addition of sugar particularly improved RL action at pH 6 and 7. Moreover, we observed that the type and size of RL self-assembly structures depend on the pH and sucrose concentration. These findings suggest potential for developing RL-based innovative methods to control L. monocytogenes in sugar-rich or -low aw foods and environments. [ABSTRACT FROM AUTHOR]

AbstractListeria monocytogenes (L. monocytogenes), a gram-positive foodborne pathogen that can easily cause listeriosis. It secretes extracellular polymers and forms biofilms that are highly resistant to disinfection methods, such as UV light and germicides, posing risks to food processing equipment and food quality. Dispersion of biofilm is the cycle of its formation in which the bacteria return to planktonic state and become susceptible to antimicrobials, the strategic manipulation of biofilm dispersion is thus heralded as a novel and promising approach for the effective control of biofilm-related infections. Compared to the traditional methods, it is more effective to start with the composition of biofilms, cut off the production of their constituent substances, and genetically reduce the probability of biofilm formation. Meanwhile, the dispersion of bacteria can be supplemented with exogenous substances, making long-term control possible. This paper provides a brief but comprehensive overview of the mechanisms of L. monocytogenes biofilms or cross-contamination and their resistance properties, and facilitates our understanding and control of the prevention and containment of L. monocytogenes biofilm contamination based on the biofilm's active and passive diffusion strategies. This work provides practical guidelines for the food industry to guard against the enduring threat to food safety due to L. monocytogenes biofilms. [ABSTRACT FROM AUTHOR]

Good hygienic milking practices including the disinfection of the cow teat skin before and after milking aimed at preventing the occurrence of new intramammary infections (IMI) in dairy cows. This practice is generally performed using disinfectants, and in the current context of attention to the emergence of resistances, it is of greatest interest to evaluate alternative solutions that can expand treatment options. We assessed the efficacy of a pre-dipping and a post-dipping product based on the bacteriocin-containing culture of Lactococcus cremoris strain FT27, as compared to commercial disinfectants. FT27 was selected for the bactericidal activity in vitro against food pathogens. In the present study, it also revealed a high bactericidal activity against the main mastitis pathogens, most likely related to Nisin A production, according to genomic and proteomic analysis. The lactococcus-based preparations were applied in two commercial dairy farms in Northern Italy. Overall, 298 dairy cows were enrolled, 141 in the treated group (TR), and 157 in the control group (CTR). The cows were sampled at quarter level every two weeks for 3 months. During the trial, all cows showed a good health status. The hygiene level for udder, flanks and legs was generally good (on average < 3 score); the udder hygiene was significantly worse (P < 0.01) in the CTR group. The teat apex hyperkeratosis was overall low (on average < 2 score). We recorded no significant differences between the two experimental groups in the Somatic Cell Count (SCC) values and the bacteriological results. The overall frequency of new IMI was low, ranging 0.6 − 0.5% for S. aureus in the TR or CTR group respectively, to 2.6–4.4% for NASM. Regarding Str. spp., the new IMI accounted for 1.7% or 1.9% in the TR or CTR group, respectively. Notably, the incidence of S. aureus new IMI did not increase during the study, even though neither of the two herds segregated the positive cows. The non-inferiority test showed that the Lactococcus-based pre- and post-dipping products had an efficacy comparable to proven commercial disinfectants in maintaining udder health and preventing new IMI, thus representing a possible alternative to current teat dip products. [ABSTRACT FROM AUTHOR]

The Pss exopolysaccharide (EPS) enhances the ability of the foodborne pathogen Listeria monocytogenes to colonize and persist on surfaces of fresh fruits and vegetables. Eradicating listeria within EPS-rich biofilms is challenging due to their increased tolerance to disinfectants, desiccation, and other stressors. Recently, we discovered that extracts of maple wood, including maple sap, are a potent source of antibiofilm agents. Maple lignans, such as nortrachelogenin- 8'-O-β-D-glucopyranoside and lariciresinol, were found to inhibit the formation of, and promote the dispersion of pre-formed L. monocytogenes EPS biofilms. However, the mechanism remained unknown. Here, we report that these lignans do not affect Pss EPS synthesis or degradation. Instead, they promote EPS detachment, likely by interfering with an unidentified lectin that keeps EPS attached to the cell surfaces. Furthermore, the maple lignans inhibit the activity of L. monocytogenes sortase A (SrtA) in vitro. SrtA is a transpeptidase that covalently anchors surface proteins, including the Pss-specific lectin, to the cell wall peptidoglycan. Consistent with this, deletion of the srtA gene results in Pss EPS detachment from listerial cells. We also identified several additional maple compounds, including epicatechin gallate, isoscopoletin, scopoletin, and abscisic acid, which inhibit L. monocytogenes SrtA activity in vitro and prevent biofilm formation. Molecular modelling indicates that, despite their structural diversity, these compounds preferentially bind to the SrtA active site. Since maple products are abundant and safe for consumption, our finding that they prevent biofilm formation in L. monocytogenes offers a viable source for protecting fresh produce from this foodborne pathogen. [ABSTRACT FROM AUTHOR]