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Foodborne pathogens pose a significant risk to human health via the food chain. Here, we evaluated the antibacterial effects of cell-free supernatant (CFS) of Pediococcus acidilactici (P. acidilactici) LWX 401 isolated from food-grade Chinese traditional pickles and found that it exhibited broad antibacterial activity against multidrug-resistant gram-negative Escherichia coli (E. coli) O157:H7 and yogurt-derived gram-positive Staphylococcus aureus (S. aureus), with inhibition zone sizes of 23.10 ± 0.80 and 20.53 ± 0.07 mm, respectively (all P < 0.001 compared with the controls). Moreover, the CFS exhibited strong thermostability and pH tolerance and was capable of inhibiting the formation of biofilms of these foodborne pathogens. Notably, the LWX 401 CFS inhibited both E. coli O157:H7 and S. aureus contamination in milk samples under different storage temperatures (4 °C, 25 °C, and 35 °C), with considerable bacterial reduction by 1–7 log CFU/mL compared with untreated controls. Additionally, the potential antibacterial metabolites (VIP >1, adjusted P < 0.05, and fold-change >2; n = 56) were identified in the LWX 401 CFS by UHPLC-QE-MS metabolomic analysis, and these metabolites were mostly lipids (25.73%) and organic acids (23.30%). Our results provide insights for the development of bio-preservatives against foodborne pathogens in the milk industry. • P. acidilactici LWX 401 was isolated from food-grade traditional Chinese pickles. • LWX 401 CFS showed a broad antimicrobial spectrum against foodborne pathogens. • Pathogenic biofilm formation was inhibited upon LWX 401 CFS treatment. • Antibacterial efficacy was validated in the milk ecosystem. • The potential antibacterial compounds were identified by metabolomic analysis. [ABSTRACT FROM AUTHOR]

Abstract In this study, antimicrobial, anti-quorum sensing and anti-biofilm forming activities of phenolic-enriched extracts produced by enzyme-assisted extraction from oven-dried and lyophilized black grape (Vitis vinifera x (Vitis labrusca x Vitis riparia)), apple (Malus domestica cv. Jonagold) and yellow pitahaya (Hylocereus megalanthus) residues were investigated. Both disk-diffusion and minimal inhibitory concentration (MIC) assays showed increased antimicrobial capacity for many extracts after the carbohydrase treatments. The lowest MIC (12.5 mg/mL) was found for black grape samples against Bacillus cereus and Bacillus subtilis , and for apple and pitahaya samples against Pseudomonas putida. The percent quorum sensing inhibition effect on Chromobacterium violaceum has varied between 9 and 36%, 15 and 24% and 6 and 23% for black grape, apple and pitahaya extracts, respectively, depending on the enzyme treatment. Pseudomonas aeruginosa , P. putida and Staphylococcus aureus biofilms were the most sensitive to the extracts, while the Salmonella enterica , Listeria monocytogenes and Escherichia coli biofilms were modulated by certain enzyme-free and treated samples. The extracts can be good candidates for the development of natural preservatives. Highlights • Carbohydrase-assisted extraction of antimicrobial compounds from fruit residues. • Extracts subjected to antibiofilm and anti-quorum sensing activity assays. • The antimicrobial activity correlated with the total phenolic content of samples. • Phenolic products inhibited the growth and biofilms of food-related bacteria. • Extracts and phenolics suppressed the violacein production in Chromobacterium. [ABSTRACT FROM AUTHOR]

Food safety detection is developing rapidly and with high throughput. Nanoparticles have obvious advantages in foodborne pathogens detection, among which gold nanoparticles (AuNPs) are widely used due to their stable chemical and optical properties. In this study, two kinds of aptasensors based on AuNPs were established. The first one was a visual detection method based on AuNPs lateral flow aptasensor, and the other one was a surface-enhanced Raman spectroscopy (SERS) aptasensor detection based on silver-core gold-shell nanoparticles (Ag@Au). The former allowed for visual readings, eliminated the need for machines, which achieved an initial diagnosis of three common pathogenic bacteria with a detection limit of 20–30 CFU/mL. The sensitivity of the latter can be improved by Ag@Au and the detection limit reached 2 CFU/mL, which can achieve high sensitivity and high-throughput detection. We systematically studied the structure, function and optical signal characteristics of AuNPs in detection, which can provide a favorable reference for the detection of foodborne pathogens in the future. [Display omitted] • The lateral flow aptasensor achieved visual and rapid detection of pathogens. • The Ag@Au SERS aptasensor with high sensitivity provide high through detection. • The multiple application scenario of AuNPs aptasensors is extended. • Rapid testing and batch screening realized by dual mode aptasensors. [ABSTRACT FROM AUTHOR]

Honey is a natural food with functional properties such as antioxidant and antimicrobial activities. These properties vary greatly depending on floral source, climate, and environmental and processing conditions. In this work, we characterized honeys on the basis of their botanical composition and clustered them according to their physicochemical parameters in order to find similarities, and assess their antibacterial action against microorganisms isolated from contaminated food. All honeys studied complied with international quality standards. The data showed differences between multifloral and unifloral honeys in their physicochemical parameters, as well as a direct correlation between colour, phenolic compounds, and antioxidant activity. -Antimicrobial activity resulted from hydrogen peroxide effect. Multifloral honeys with similar phenolic compounds and a botanical composition of eucalyptus and blueweed had greater inhibitory power against E. coli, P. aeruginosa, Salmonella spp., S. aureus and B. cereus . [ABSTRACT FROM AUTHOR]

Antibacterial effects of unripe grape products (verjuice and sour grape sauce) which are particularly rich in antioxidants and organic acids were evaluated. Survival of Escherichia coli , Listeria monocytogenes, Salmonella Typhimurium and Staphylococcus aureus which were inoculated in unripe grape products at different inoculum doses (2 and 6 log CFU/mL) was determined. All the samples were kept at room temperature (approximately 25 °C) for 0, 5, 15 and 30 min after inoculation with pathogens, separately. The unripe grape products which were inoculated at low inoculum dose inhibited all tested pathogens in 5 min, while it took 15 min for high inoculum dose. The pH, titratable acidity (tartaric acid %) and total sugar content values of the samples were between 2.14–2.74, 2.29–7.10% and 1.19–17.65 g/L, respectively. It was concluded that unripe grape products are microbiologically safe products and they have self-protection systems even when they were contaminated with pathogens at high levels. [ABSTRACT FROM AUTHOR]

Recently, the attention of researchers regarding Artemisia annua has been focused on the antimicrobial activity of the essential oil. This oil, rich in mono- and sesquiterpenes, has a strong activity against some Gram-negative and Gram-positive bacteria. The aim of our study is to further contribute to the knowledge of the antibacterial activity of an Artemisia annua essential oil collected in Tuscany and its three most represented compounds (artemisia ketone, 1,8-cineole and camphor). The essential oil obtained by hydrodistillation gave a yield of 0.37% (w/w fresh plant material). The composition of the essential oil extracted from flowering aerial parts was determined by gas chromatography (GC/FID and GC/MS). The essential oil and compounds were tested for activity against Escherichia coli O157, Salmonella Enteritidis, Salmonella Typhi, Yersinia enterocolitica and Listeria monocytogenes , all of which have great significance in foodborne infections. The antibacterial activity was tested using disk diffusion method and broth microdilution assay. The microorganisms tested were all sensitive to the A. annua essential oil in toto and to all its components, which often have lower activity than oil in toto . [ABSTRACT FROM AUTHOR]

The effect of carvacrol at different doses (0.1, 0.5 and 1 ml/100 ml) on ammonia (AMN) and biogenic amines (BAs) production by 8 food-borne pathogens (FBP), which are Staphylococcus aureus , Escherichia coli , Klebsiella pneumoniae , Enterococcus faecalis , Pseudomonas aeruginosa , Listeria monocytogenes , Aeromonas hydrophila and Salmonella enterica serovar Paratyphi A was investigated in histidine decarboxylase broth (HDB) using HPLC method. Significance differences were found in histamine (HIS), AMN and other BAs production (P < 0.05). The highest HIS production was obtained by K. pneumoniae (2.5 mg L −1 ) and the lowest by E. faecalis (1.6 mg L −1 ). Almost all other BAs such as PUT, CAD, SPD and PHEN were formed by pathogens. The highest concentration of dopamine (DOP) was given by K. pneumoniae which produced 1004.8 mg L −1 while agmatine (AGM) was 72.5 mg L −1 for L. monocytogenes . The most significant amounts of AMN were noticed for E. coli and E. faecalis with a value of 908.19 mg L −1 and 685.46 mg L −1 respectively. Consequently, the results of this current study shows that all FBPs tested are capable of decarboxylating more than one amino acid and the effect of carvacrol on AMN and BAs formation by FBPs depends on bacterial strains as well as on carvacrol doses. [ABSTRACT FROM AUTHOR]

Chicken breast is prone to Listeria monocytogenes , Salmonella spp., and E. coli O157:H7 contaminations. Therefore, a quantitative method for the rapid detection of these pathogens simultaneously in chicken breast is highly desirable for food safety control. This study reports a flow cytometry (FCM)-based method for rapid and multiplexed quantification of the above-stated three pathogens without enrichment. Using the developed method, the complete detection process, including a sample pretreatment procedure, the multiplex staining, and the FCM analysis, could be realized within 1 h, rendering this method more efficient than the plate counting method. The bacterial recovery rates were 96.24% for Listeria monocytogenes , 96.74% for Salmonella , and 96.42% for E. coli O157:H7. A good linear correlation was realized between the FCM-based method and the plate counting method for all three pathogens. The relative standard deviations were 3.0%, 2.7%, and 2.9% for Listeria monocytogenes , Salmonella , and E. coli O157:H7, which indicated excellent reproducibility of the method. This study is the first one to report the rapid and simultaneous quantification of foodborne pathogens in chicken breast using FCM. Moreover, the developed method was also applied successfully to the multiplexed detection of bacteria, which indicated that the method has great potential in food contamination monitoring. [Display omitted] • We first report a method for rapid multi-quantification of pathogens in chicken. • The developed method proved frozen storage can inhibit bacterial growth in chicken. • This method exhibited an excellent specificity towards three pathogens. • A pretreatment protocol was developed to ensure a higher bacterial recovery rate. • The as-developed method can be accomplished within 1 h. [ABSTRACT FROM AUTHOR]

This study determined the desiccation resistance of 37 Salmonella strains belonging to 16 serotypes isolated from the soybean meal production chain. Besides, the survival of strains from three Salmonella enterica serovars (S. Typhimurium , S. Schwarzengrund, and S. Havana) on dry- and wet-inoculated soybean meal through storage at 25 °C and 37 °C was evaluated. Desiccation resistance varied within strains of the same serotype and amongst strains of different serotypes. On the other hand, the isolation source did not affect desiccation resistance. The inoculation method did not influence the survival of the three Salmonella enterica strains in soybean meal, but the effects of serovars and temperature were statistically significant (p < 0.05). The Weibull model was fitted to Salmonella survival in this matrix data, with the time for the first decimal reduction (δ) ranging from 21.1 to 50.8 days at 25 °C and from 2.7 to 7.9 days at 37 °C, respectively. The increase in storage temperature led to a decrease in survival regardless of the variability among the three isolates. The ability of Salmonella enterica to resist desiccation and to survive long-term on soybean meal reinforces the need for strategies to control this pathogen in the soybean production chain. • Desiccation resistance of 37 Salmonella isolated from soybean bran was evaluated. • Large differences in desiccation resistance inter- and intra-serotypes were found. • Wet or dry inoculation did not influence the survival of Salmonella in soybean bran. • The time for the first decimal reduction varied from 21.1 to 50.8 days at 25 °C. • The time for the first decimal reduction varied from 2.7 to 7.9 days at 37 °C. [ABSTRACT FROM AUTHOR]

The survival of Salmonella , Escherichia coli O157:H7, and Listeria monocytogenes was assessed on low- and high-moisture Medjool dates, sundried tomatoes and dried pluots. Dates were inoculated using a dry (sand) carrier, while dried pluots and tomatoes were inoculated using a wet (phosphate-buffered saline) carrier to ensure even distribution of the inoculum on dried fruit surfaces while minimizing the impact on their physiochemical properties. Inoculated dried fruits were stored at ambient and refrigerated temperatures for 180 days. No significant change was observed in pH and water activity of dried fruits during storage. In general, pathogens survived at higher levels for longer time on dates (pH 5.59–5.83) than sundried tomatoes (pH 3.80) and pluots (pH 3.45) and better at refrigerated temperature than ambient temperature. Salmonella survived better than the other two pathogens. When inoculated on dates, up to 5.31 log CFU/g of Salmonella was recovered after 180 days of refrigerated storage. Results of this study prove that common foodborne pathogens can survive on dried fruits, particularly at refrigerated temperature. Factors such as pH, water activity, and inoculation levels impact bacterial behavior during storage. Control measures need to be validated to minimize pathogen contamination of dried fruits and ensure their microbial safety. • Common foodborne pathogens can survive on dried fruits for an extended period. • Pathogens survived better at refrigerated temperature than ambient temperature. • Salmonella survived better than E. coli O157:H7 and L. monocytogenes. • Pathogens survived better on dates than sundried tomatoes and dried pluots. • pH, a w , and inoculation levels impact the bacterial behavior during storage. [ABSTRACT FROM AUTHOR]

A simple, precise, and highly sensitive detection method is urgently needed for diagnosis and monitoring of foodborne pathogens. To meet these requirements, we designed a micro-propulsion reactor based on the trans -cleavage activity of Cas12a and recombinase polymerase amplification (RPA) for simultaneous amplification and detection and named it "Cas12a-MPR". This method can provide a contamination- and instrument-free nucleic acid rapid detection platform with precision and ultrasensitivity using CRISPR-Cas12a combined with RPA in the same vessel. For improved performance, the interaction between the CRISPR detection system and the RPA reagent was explored. Our data showed that the impact of CRISPR reagents on RPA was negligible, but magnesium ions played a vital role in the functioning of the CRISPR/Cas12a system. After exploring the interaction between the CRISPR detection system and the RPA reagent, the method was further optimized to specifically detect target DNA at the attomolar level and achieved a limit of detection of 10 CFU mL-1 at 37 °C. Compared to qPCR, our detection results exhibited 100 % accuracy for detection of Listeria monocytogenes contamination. All the results demonstrated that Cas12a-MPR has great promise for the detection of foodborne pathogens. • We propose a CRISPR/Cas12a-based method named "Cas12a-MPR" for rapid nucleic acid detection. • Cas12a-MPR can realize contamination-free, instrument-free, and one-step nucleic acid detection in a syringe reaction vessel. • Cas12a-MPR can be used for the detection of L. monocytogenes with high sensitivity and specificity. • Cas12a-MPR can be used to detect other foodborne pathogens. [ABSTRACT FROM AUTHOR]

Abstract: Antibacterial effects of American cranberry (Vaccinium macrocarpon) concentrate on foodborne pathogens, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium, and Staphylococcus aureus in vitro were investigated. Cranberry concentrate at various concentrations was prepared in distilled water (DW) or Brain Heart Infusion (BHI) broth. Pathogens were inoculated in each sample and incubated at 21 and 4°C for 0, 1, 5, 7, and 24h (DW samples) and 0, 1, 3, and 5 days (BHI samples). Transmission electron microscopy (TEM) was used to study the effects of cranberry concentrate on cellular structure of pathogens. DW results showed that S. Typhimurium and L. monocytogenes were reduced to non-detectable levels at 5h in 100μl/ml treatment at 21 and 4°C. At 24h, no target pathogens were detected from the 100μl/ml treatment. BHI data indicated that the 100μl/ml treatment reduced the four pathogens by 3–8logCFU/ml compared with the control on Day 5 at 21 and 4°C. TEM revealed damage to the bacterial cell walls and membranes. Cranberry concentrate has antibacterial effects on the four foodborne pathogens. Based on potential health benefits and proven antimicrobial effects, American cranberry concentrate may have dual applications as a food preservative. [Copyright &y& Elsevier]

This work evaluated the effect of slightly acidic electrolyzed water (SAEW), fumaric acid (FA) and antioxidant solution treatments on the quality of red and yellow fresh-cut bell pepper (FCBP) challenged with foodborne pathogens (Listeria monocytogenes and Salmonella sp.). The quality of the FCBP was determined in terms of the microbial contamination, and sensory properties. The sanitizer treatment such as (T1-T6) significantly inhibited the microbial colonization comparing to the untreated control (T0) group of R-FCBP and Y-FCBP. Total bacterial count (TBC) was reduced by 4.1 and 76.8 fold for Y-FCBP and R-FCBP respectively when treated with T6 during the 15 day of storage. The treatment of T6 significantly reduced the total fungal (TF) counts by 7.9 fold for Y-FCBP and 7.7 fold for R-FCBP comparing to T0 at 15 day of interval. Also, this treatment inhibited the total Salmonella sp., (TSC) by 4.93 fold for Y-FCBP and 4.23 fold for R-FCBP when comparing to T0 at 15 day of interval. These results proved the efficiency of T6 (FA, SAEW, and antioxidant solution) treatment compared to untreated control (T0) expands the quality of FCBP up to 9 days when preserved at 4 °C through inhibiting the microbial colonization. [Display omitted] • Effect of SAEW and organic acids treatments on quality fresh-cut bell pepper (FCBP). • The FCBP quality was determined by microfloral nutritional and sensory properties. • SAEW and organic acids treatments inhibited microfloral colonization in FCBP. • Newly composed sanitizer treatments were promising in expanding the shelf life of FCBP. [ABSTRACT FROM AUTHOR]

Kimchi seasoning is manufactured non-thermally without any additional decontamination step, resulting in possible microbiological growth and food safety issues. This study examines the effects of gamma irradiation on the microbiological and physicochemical characteristics of kimchi seasoning mixture during storage. Foodborne pathogens, i.e. , Escherichia coli O157:H7 and Salmonella Typhimurium were inoculated into the seasoning mixture and irradiated at doses ranging from 0 to 10 kGy. Regardless of the microbial species, the number of microorganisms was adversely correlated with increasing gamma irradiation. The levels of E. coli O157:H7 and S. Typhimurium were reduced to below the detection limit (1 log CFU/g) after exposure to 5 kGy of gamma irradiation. The number of total aerobic and lactic acid bacteria decreased by 3.29 and 4.78 log CFU/g, respectively, after 10 kGy of gamma irradiation exposure. Changes in pH, acidity, reducing sugar content, and headspace gas concentrations were significantly delayed in irradiated kimchi seasoning mixtures (P < 0.05), whereas no significant difference was observed in color values between the irradiated and non-irradiated kimchi seasoning mixtures (P > 0.05). These results imply that gamma irradiation can enhance the microbiological safety and shelf-life of kimchi seasoning mixture, and decrease the initial concentration of microorganisms without adverse effects on quality. • Effects of gamma irradiation on kimchi seasoning mixture were examined. • The microbial population decreased proportionally to the radiation doses. • Irradiation delayed the changes in pH, acidity, reducing sugar, and headspace gas. • Irradiation did not change the color values of the kimchi seasoning mixture. [ABSTRACT FROM AUTHOR]

Based on the Minamata convention, prohibiting the use of mercury, UVC LED technology has been researched as a putative replacement for mercury lamps. In this study, the possibility of inactivating Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on selective media and sliced deli meat and spinach surfaces by a simple UVC LED irradiation system was evaluated and inactivation rate constants of the bacteria were analyzed in survival curves with highly accurate modeling equations. The UVC LED irradiation system fulfilled 3 log reductions of E. coli O157:H7 and S. Typhimurium on their corresponding selective media within 1.35 s and 3.60 s, respectively. Log linear and Weibull model equations described the survival of bacteria on selective media very well based on the parameters of goodness of fit kinetic models, and 2–15 mJ/cm2 D 3d and D 5d values were calculated. Pathogens inoculated onto sliced deli meat and spinach surfaces were reduced by 1.5–3 log reductions within 34 s of UVC LED irradiation. Significant differences in k values were observed in pathogens on selective media (P < 0.05), while relatively similar k values were obtained from food surfaces even though there were significant differences in some points (P < 0.05). • An optimal UVC irradiation system considering light angle and distance was built. • Effective inactivation was achieved within short time for 3 major foodborne pathogens. • Pathogens on sliced deli meat and spinach surfaces were treated by UVC LED. • UV sensitivity was evaluated for the pathogens on selective media and food surfaces. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes is a significant foodborne pathogen with numerous serogroups which vary in their virulence and distribution across countries. This study aimed to determine the serogroups and virulence genes of L. monocytogenes isolated from bulk tank milk, dairy cow feces and imported beef in Jordan. To achieve this aim, multiplex PCR assays were utilized to serogroup and determine the virulence genes of 70 L. monocytogenes isolates from dairy ruminants (n = 28) and imported beef (n = 42). Results identified that the L. monocytogenes isolates from these sources were in five serogroups. The majority of isolates (55.7%) belonged to serogroup 1/2a (3a), followed by serogroup 1/2b (22.9%), serogroup 4b (d, e) (14.3%), serogroup IV (serotypes 1/2c and 3c) (5.7%), and serogroup 4a/c (1.4%). Forty-six (65.7%) of the isolates carried both the InlA and InlC genes, specifically 53.6% of dairy and 73.8% of beef isolates. Four isolates also carried the inlC gene, specifically, two dairy isolates and two beef isolates. These findings recommend the implementation of improved sanitation procedures at slaughterhouses and dairy operations in Jordan to reduce the public health risk of L. monocytogenes. • L. monocytogenes isolates from dairy ruminants and imported beef were studied. • Majority of isolates (55.7%) belonged to serogroup 1/2a. • 65.7% of the isolates carried both the InlA and InlC virulence genes. [ABSTRACT FROM AUTHOR]

Synthetic lipid membranes are considered as promising food-grade nano vesicles (NVs), but their functionalization is required to empower them as active-nano vesicle systems. In this study, rhamnosomes (RS) were developed by engineering the membrane of nano-liposomes with antimicrobial surfactant i.e. rhamnolipids (RL). Intrinsically active rhamnosome nano-vesicles (RSNVs) were loaded with bacteriocin (nisin Z) to acquire broad-spectrum antimicrobial activity. Addition of rhamnolipids into the lipid bilayer exhibited an increase in the encapsulation efficiency of nisin from 47 ± 4% to 88 ± 7%. Scanning electron microscope (SEM) and Zeta-sizer revealed that the surface functionalization with RL increased the size of vesicles from 145 ± 2 nm to 209 ± 4 nm. Whereas, the zeta potential of nisin-loaded RSNVs was −20 ± 0.25 mV as compared to −3.47 ± 0.13 mV for loaded nano-liposomes, indicating higher physical stability of RSNVs. RSNVs not only demonstrated higher antimicrobial activity than liposomes but also enhanced the activity of nisin against Gram-positive and Gram-negative resistant foodborne pathogens including L. monocytogenes, S. aureus, E. coli and P. aeruginosa. Almost 80% reduction in biofilm biomass was observed when treated with nisin-loaded RSNVs due to its improved binding with bacterial surface. Thus, surface-active nanoliposomes (intrinsically active) with higher stability can provide an innovative strategy to control the biofilm-forming food associated pathogens. • Food grade nano-antimicrobials: Effective control against MDR foodborne pathogens. • Rhamnosomes (RSNVs) demonstrated intrinsic antimicrobial and antibiofilm activity. • Nisin loaded RSNVs: Extended release with improved bioavailability. • EE of nisin increased from 47% to 88% by functionalization with rhamnolipids (RLs). • RLs and nisin: Synergistic action against Gram (+) and Gram (−) bacterial pathogens. [ABSTRACT FROM AUTHOR]