Global health actionHimadri Pal, Judy Bettridge, Paula Dominguez-Salas, Delia Grace
BACKGROUND: Over the past two decades, food safety training interventions in LMICs have increased significantly, yet improvements in food hygiene and safety outcomes remain inconsistent. This limited effectiveness may reflect a lack of contextual adaptation and a failure to align training materials with the socio-economic constraints of participants. OBJECTIVE: To evaluate LMIC food safety training interventions and their educational materials on a novel framework, and to propose a checklist for the efficacy of future programs. METHODS: Relevant literature on training interventions was systematically identified, and only studies with accessible training materials were included. Interventions were evaluated using a novel qualitative framework, encompassing image-text ratios, readability grade, training design, incentives, and outcome parameters. Novel concepts, 'Engagement features' and 'Contextual-fit factors' were also developed, and the correlations between them were tested. RESULTS: A total of 28 studies met the inclusion criteria with available training materials. Infographics from 13 studies demonstrated a satisfactory balance of images and text. The readability assessment revealed an average result comparable to the US grade 6 level (5.90 ± 1.74), potentially hindering comprehension for low-literacy populations. Incentives were commonly used (n = 18), most frequently as non-cash economic incentives. Change in knowledge was the most measured outcome, and studies reporting null or negative results lacked several engagement and contextual-fit elements. CONCLUSIONS: This study uses innovative methods to identify and shed light on the existing gaps in food safety trainings. Based on these findings, it proposes a 35-point checklist to support the development of more engaging, comprehensible, and contextually appropriate programs.
Food microbiologyHisaya K Ono, Tamako Kimura, Oku Okamoto, Yasunori Suzuki, Yusuke Sato'o, Taishi Tanabe, Dong-Liang Hu
Staphylococcus aureus in poultry is a potential source of food contamination and staphylococcal food poisoning. However, its carriage patterns and toxigenic potential at the slaughterhouse stage remain insufficiently characterized in Japan. This study investigated the prevalence and molecular characteristics of S. aureus in spent laying hens entering the processing line over a one-year period. Three anatomical sites (head, wing, and leg) were sampled per carcass (n = 800). S. aureus was detected in 649 of 800 birds (81.1%), and 995 isolates were obtained. Virulence gene profiling showed that 503 of 995 isolates (50.6%) carried one or more staphylococcal enterotoxin (SE) genes, with seh being the most prevalent, followed by sed and ser. se gene carriage was strongly site-dependent: isolates from the head and wing were predominantly se gene-positive, whereas most leg-derived isolates lacked these genes. Multilocus sequence typing of representative isolates revealed clonal heterogeneity, including newly registered sequence types with site-associated distributions. To assess toxigenic potential beyond gene carriage, we quantified production of selected enterotoxins in culture supernatants from broth cultures by enzyme-linked immunosorbent assay (ELISA) under different temperature conditions and further examined enterotoxin accumulation in chicken minced meat as a food-relevant matrix. In addition, SE accumulation above the detection limit was confirmed in chicken minced meat inoculated with a representative isolate under permissive temperature conditions (25 °C and 37 °C). These findings indicate that spent laying hens entering the processing line harbor S. aureus isolates from different anatomical sites with distinct virulence and toxigenic characteristics. The results provide baseline information on the microbiological status of birds at slaughterhouse entry and support the importance of temperature management during subsequent handling and processing to limit enterotoxin accumulation.
Food microbiologyFrancesca Rigano, Alessia Tropea, Giuseppe Micalizzi, Tania Maria Grazia Salerno, Cassamo U Mussagy, Angie V Caicedo Paz, Anja Poehlein, Thorsten Brinkhoff, La…
Bacterioruberin is a C50 carotenoid gaining more interest because of its important biological properties. This study aimed to the identification and characterization of a bacterial strain producing this attracting carotenoid, Arthrobacter sp. strain CP30. Phylogenetic analysis based on 16S rRNA gene sequences and whole genome comparison showed that strain CP30 belongs to the Arthrobacter agilis group with Arthrobacter bussei being the closest relative. Sequence similarity of the 16S rRNA gene of CP30 to described Arthrobacter species as well as average nucleotide identity values indicate that CP30 represents a new species within the genus Arthrobacter. The strain has been cultivated under controlled fermentation parameters, and the obtained biomass was investigated for carotenoids and lipids quali-quantitative profiles characterization. The biomass extracts enriched in bacterioruberin have been evaluated for antimicrobial and antioxidant properties. The bacterioruberin produced by the strain reached up a carotenoid titer of 1.28 mg L-1 in 72 h, with a yield of 327.67 ± 6.6 μg g-1 of dry biomass, a productivity of 0.02 mg/L/h, and showed an IC50 value of 3.87 μg/mL. The most abundant fatty acids were 12-methyltetradecanoic, 14-methylpentadecanoic and 13-methyltetradecanoic. Whereas, among the intact lipids, glycolipids, phospholipids, diacylglycerols, and triacylglycerols have been identified in the investigated strain. This study allowed pointing out the potential of strain CP30 as a promising bacterioruberin producer, representing an interesting natural carotenoids source to be further investigated as suitable candidate for feed and food application. Comparison of key protein sequences involved in bacterioruberin biosynthesis of CP30 and A. bussei showed sequence similarities of >90%.
Food microbiologyNicholas A Bokulich, Lena Flörl, Eve Beauchemin, Chad Masarweh, Irnayuli R Sitepu, Karen Kalanetra, Roger Boulton, David A Mills, Kyria Boundy-Mills
The microbial communities inhabiting food production environments are distinguished from those of other built environments in their capacity to influence food quality and safety, impacting consumer health. However, the degree to which indoor environmental conditions influence the composition of the bacterial and fungal communities throughout food production facilities remains insufficiently explored. In this study of five commercial food production facilities, we employed remote wireless sensors paired with marker-gene amplicon sequencing (bacterial 16S rRNA genes and fungal internal transcribed spacer sequences) of processing equipment and non-processing built environment surfaces (N = 2329) to profile spatial and longitudinal changes in bacterial and fungal communities, and their association with indoor climate. Indoor sensor data only explained a small proportion of overall variance in microbiota composition, suggesting that other latent and stochastic factors predominate. Nevertheless, we identify multiple associations between indoor environmental conditions and microbial community structure, including CO2 levels with overall microbial diversity in creameries, and higher temperature and relative humidity with lower bacterial diversity in wineries, demonstrating the possible role of the indoor environment in shaping microbial communities on food processing and non-processing surfaces. This highlights indoor climate as a modifiable factor for manipulating microbial surface communities to enhance food quality and safety.
Food microbiologyClaire Yvon, Pierre-Emmanuel Douarre, Delphine Fert, Vincent Leclerc, Jean-Charles Leblanc, Déborah Merda, Laetitia Bonifait, Núria Ferrer-Bustins, Maria Pardo…
Salmonella enterica serotype Agona (S. Agona) is a globally distributed foodborne pathogen associated with diverse hosts, environments, and foodborne outbreaks. We investigated its population structure, global dissemination, and the genetic determinants underlying the ecological adaptation and epidemiological success of strains implicated in nationwide alerts in France in 2005 and 2017. A total of 4202 genomes from isolates collected worldwide between 1952 and 2025 were analyzed, including 141 newly sequenced genomes representative of agri-food sectors in France. Whole-genome analyses confirmed the polyphyletic nature of S. Agona, while cgMLST hierarchical clustering at the HC900 level identified two major genomic lineages differing in type VI secretion system (T6SS) patterns and the presence of Salmonella pathogenicity island 17 (SPI-17). The dominant lineage (ST13) accounted for approximately 99% of genomes and displayed broad distribution across hosts and ecological niches worldwide. Despite core genome conservation, fine-scale HC5 clustering revealed substantial microdiversity with 1771 clusters, including 229 identified among isolates from France, 183 of which were unique to the country. Phylogenetic analysis of 233 human and agri-food isolates from France suggested complex transmission pathways between environmental, food, and human reservoirs and demonstrated that the 2017 infant formula outbreak in France originated from direct descendants of the 2005 outbreak clone. Accessory genome analysis revealed genes associated with tolerance to metals, biocides, and antimicrobials, two independently acquired Salmonella genomic island-4-like elements, and 133 predicted plasmids, collectively encoding 26 carrying antimicrobial resistance genes. These findings provide new insights into the evolution, ecological versatility, and public health significance of S. Agona.
Gut microbesPeter Suenaert, Anneleen Segers, Leen Rymenans, Hélène Devroye, Janne Marie Moll, Patrice D Cani, Willem M de Vos
Pasteurized Akkermansia muciniphila MucT was found to improve barrier function in preclinical models and a proof-of-concept study in obese and prediabetic adults. Here, we describe the results of a double-blind placebo-controlled multicenter (Ireland and Germany) trial in 142 adults with metabolic syndrome, with or without prediabetes. The primary endpoint of whole-body insulin sensitivity (Matsuda index) did not differ after 4-months of daily administration of capsules containing 30 billion cells of pasteurized A. muciniphila MucT compared to placebo in the intention-to-treat subjects. Subsequent exploratory analyses showed that 3-months intake of pasteurized A. muciniphila MucT already improved HOMA-based hepatic insulin sensitivity in prediabetic (12%; p = 0.05) and 63-y-or-older-age subgroups (p = 0.05) while increasing post-OGTT excursion of the insulinotropic hormone glucagon-like peptide 1 (GLP-1) over placebo (p < 0.01). Further analysis of the gut microbiota by deep metagenomic analysis showed minor effects of the intervention but revealed that the baseline microbial composition differed from that in matched healthy adults. We found that participants with low baseline Akkermansia gene counts experienced significant health improvements and GLP-1 excursion after 3-months of treatment with pasteurized A. muciniphila MucT over the placebo. These benefits included improved insulin sensitivity (as shown by Matsuda and HOMA-S indices) and GLP-1 excursion (post-OGTT) (p < 0.05), reductions in body weight (p = 0.06) and decreased trunk fat (p < 0.05). In conclusion, daily supplementation with pasteurized A. muciniphila MucT has the potential to improve health markers in overweight or obese normo- or dysglycemic adults with the most significant improvements in subjects with low baseline intestinal Akkermansia levels, who are apparently truly in need of this intervention. Clinical trial registration no.: NCT05114018 clinicaltrials.gov.
Bongkrekic acid (BA) poisoning is a rare but highly lethal foodborne intoxication caused by Burkholderia gladioli pathovar cocovenenans. This heat-stable mitochondrial toxin irreversibly inhibits the adenine nucleotide translocator, leading to abrupt energy failure, metabolic collapse, and high case fatality rates. Although historically confined to specific regions and traditional fermented foods, recent outbreaks, particularly in Asia, suggest an expanding and underrecognized global risk. The first documented outbreak in Taiwan in 2024 highlights a shift from household fermentation to modern food service settings, indicating evolving exposure pathways. Detection remains a major challenge due to the toxin's organoleptic invisibility and the lack of rapid, field-deployable diagnostic tools. Meanwhile, globalization of food systems, increased consumption of fermented products, and climate-driven environmental changes may broaden the ecological conditions favorable for toxin production. In the absence of an effective antidote, prevention remains the primary strategy, requiring targeted food safety interventions and culturally informed risk communication. We argue that bongkrekic acid poisoning should be reframed as an emerging global food safety threat, warranting enhanced surveillance, improved detection technologies, and greater clinical and public health awareness.
Fungal spoilage is a leading cause of postharvest losses in fruit, resulting in quality deterioration, economic losses, and food waste throughout the supply chain. Conventional control using synthetic fungicides faces increasing challenges from resistance development, environmental concerns, and regulatory restrictions. Biological control agents (BCAs) offer a sustainable alternative, but their commercial adoption requires deeper understanding of their mechanisms and reliable integration into postharvest systems. This review synthesizes recent advances in next-generation BCAs, emphasizing the science-based selection of antagonistic yeasts, bacteria, and microbiome-derived isolates. Beyond nutrient and space competition, we examine complementary mechanisms including antibiosis mediated by antimicrobial metabolites and volatile organic compounds, mycoparasitism involving cell wall-degrading enzymes, and host defense priming through jasmonate, salicylate, and ethylene signaling pathways. To address performance variability in commercial settings, we evaluate integrated strategies combining BCAs with physical treatments (heat, UV-C, modified atmospheres), food-grade additives, and advanced formulation technologies such as microencapsulation and nanotechnology-enabled delivery that enhance viability, stress tolerance, and controlled release. Finally, we discuss the need for validation under supply-chain conditions, microbiome-informed design of stable bioactive consortia, and integration of BCAs into a preharvest-to-postharvest management framework. By connecting fundamental microbial mechanisms to practical applications, this review provides a framework for developing sustainable, residue-free strategies to reduce postharvest spoilage and maintain fruit quality.
Food microbiologyMuftau Adeniyi Moshood, Eugénio da Piedade Edmundo Sitoe, Anderson S Sant'Ana
Biofilms are microbial communities embedded in a matrix of extracellular polymeric substances (EPS) that protect cells and spores from heat, acidity, and sanitizing agents. In the food and beverage industry, thermophilic spore-forming bacteria, such as Bacillus, Geobacillus, and Alicyclobacillus, represent a significant challenge because their spores survive pasteurization, adhere to industrial surfaces, and form persistent biofilms. This ability promotes microbial persistence, product recontamination, and food spoilage, often leading to the production of undesirable compounds such as guaiacol in fruit juices and enzymatic degradation in dairy products. Modern molecular and analytical techniques have increasingly replaced traditional culture-based methods for detecting these microorganisms in food systems. However, knowledge regarding biofilm formation by thermophilic spore-forming bacteria remains limited compared with that of pathogenic biofilm producers, such as Salmonella and Listeria monocytogenes. This review synthesizes current knowledge on the ecology, physiology, and biofilm-forming mechanisms of thermophilic spore-forming bacteria in foods and beverages. It also examines their occurrence in food processing environments, available detection approaches, and emerging prevention and control strategies. Furthermore, this review identifies critical knowledge gaps regarding the persistence of thermophilic spore-former biofilms in industrial environments and highlights promising research directions for their effective control. By integrating current evidence and emerging concerns, this work provides a scientific framework to guide future research and improve biofilm management strategies in the food and beverage industry.
Ethyl carbamate (EC), a carcinogenic contaminant widely found in fermented foods, poses significant public health risks. Here, EC formation and degradation during fermentation using two types of Daqu, screened for high-efficiency EC-degrading strains, characterized their degradation mechanisms, and evaluated their enzymatic and fermentation applications were investigated. Sichuan Baijiu Daqu produced substantially less EC than Putong Daqu under both urea-present and urea-absent conditions, supported by more favorable pH, organic acid profiles, and microbial functional diversity, and it generated richer flavor compounds such as higher alcohols and esters. A fungal isolate, designated EC-2 and identified as Lichtheimia ramosa through morphology and ITS sequencing, degraded 42.29% of EC (5 g·L-1, pH 7) within 7 days and up to 59.98% under optimized conditions. Integrated transcriptomic and metabolomic analyses demonstrated that EC-2 enhanced stress tolerance via antioxidant enzyme induction and redirected carbon metabolism toward acetyl-CoA synthesis by upregulating pathways including β-alanine metabolism, fatty acid degradation, and tryptophan metabolism. These shifts coordinated a dynamic, acetyl-CoA-centered carbon flux and regulated the function of microbial community by strengthening carbon and nitrogen cycling while suppressing arginine-derived EC precursor formation, establishing a positive feedback loop of "EC degradation-functional enhancement." EC-2 also secreted a novel amidase, TR3551 (Kcat/Km = 79.6 mM-1 min-1), which degraded 18.95% of EC within 6 h and remained stable at 50 °C with tolerance to 20% ethanol. These findings provided promising fermentation additives and enzymatic tools for mitigating EC in Baijiu production.
Food microbiologySwapnika Medikonda, Miriam Ruiz-Cuadra, Claire M Murphy
Recent recalls for tree fruit due to possible contamination with Listeria monocytogenes have highlighted the importance of understanding the high-risk food contact surfaces (FCS) in commercial packinghouses in order to manage the risk of cross-contamination within the packing environment. The objectives of this study were to determine the prevalence of Listeria spp. on FCS in Washington State and California cherry packinghouses and to identify locations with the greatest likelihood to harbor Listeria spp. Four commercial cherry packinghouses were visited three times each during two consecutive packing seasons in Washington, and four commercial packinghouses were visited up to three times during one packing season in California. A total of 40 FCS were swabbed for Listeria spp. at each facility during each visit at two intra-day sampling timepoints: (i) post-sanitation but pre-packing and (ii) during packing. Swabs were processed following a modified protocol of the FDA's Bacteriological Analytical Manual method. In Washington, 2.0% (38/1920) of FCS were positive, while 2.4% (15/636) were positive in California for Listeria spp. Across both states, the FCSs that showed the greatest prevalence of Listeria spp. were bristle flaps, solid conveyor belts, and singulators, with combined prevalence of 5.7% (12/209), 4.7% (9/192), and 3.8% (6/154), respectively. The prevalence of Listeria spp. also varied depending on processing stage (i.e., receiving vs. sorting vs. packing) and intra-day timepoints (i.e., post-sanitation/pre-packing vs during packing). Study findings will help cherry packinghouses in mitigating the risk of cross-contamination and harborage of Listeria spp. in packing environments.
Food microbiologyNatoavina T Faliarizao, Teresa M Bergholz, Kirk D Dolan
Dried chilies, although widely used as food ingredients such as paprika, present food safety risks across the production chain due to bacterial contamination, including Salmonella. This study assesses the fate of Salmonella Montevideo on red peppers during microwave drying and compares predictive models incorporating the effects of dynamic temperature and water activity (aw). Fresh red chilies (aw = 0.98) were sliced lengthwise, inoculated with Salmonella Montevideo, then dried at two power levels in a microwave oven for 45 min (120W) and 18 min (240W) to achieve aw<0.60. Temperature dynamics (24.5-87.6°C) were captured using an infrared camera, then the aw and Salmonella counts were measured at each sampling point. Salmonella survival parameters were estimated with four primary models (Weibull, log-linear, Geeraerd, and Cerf models), and then the Bigelow-type model was incorporated into the selected primary model to characterize the effects of temperature and aw on Salmonella inactivation. All models were assessed using the corrected Akaike information criterion (AICc). Higher microwave power resulted in lower Salmonella survival over time (p < 0.05) with a reduction range of 2.3-3.2 log. The log-linear/Bigelow (zT) yielded the lowest AICc value (11.94), which was the best-fitted model with D77°C-value of 4.24 min and a zT-value of 9.15°C. Temperature changes are determinant to describe Salmonella survival during chili drying, as the log-linear/Bigelow (zT) model better described the nonlinear reduction of Salmonella during the process. These findings serve as a basis to develop and refine spice drying conditions to improve Salmonella control while maintaining quality.
Food microbiologyMengru Wang, Huanhuan Li, Meng Chen, Teng Hang, Shaofeng Yuan, Weirong Yao, Hang Yu
Ultrasound is an emerging technology for cleaning produce and surface sterilization in the food industry; however, inappropriate intensity of ultrasound treatment may induce stress responses in food spoilage bacteria and enhance their stress resistance. This study systematically evaluated roles of mechanosensitive (MS) channel proteins: MscL and MscS on ultrasonic stress responses in Pseudomonas fluorescens as a typical bacterium leading to food spoilage. The MS channel proteins deletion mutants of P. fluorescens ATCC 13525 were initially constructed, including ΔmscL, ΔmscS, and ΔmscL ΔmscS. MscL was more sensitive to mechanical stimulation of ultrasound which rapidly released intracellular osmotic pressure to alleviate membrane tension damage; however, MscS only provided complementary protection under the ultrasound treatment as proved by Ca2+ fluorescence labeling and antibacterial activity assays. Acoustic pressure distribution and thresholds of MscL (289.45 kPa) and MscS (334.21 kPa) initiating acoustic stress response were determined by COMSOL Multiphysics. Phenotypic assays showed that ultrasound induced membrane potential disruption, ATP depletion, leakage of intracellular components, and oxidative stress response in an intensity-dependent manner with the strongest disturbance observed in the ΔmscL ΔmscS mutant. Ten stress-related genes expression at different ultrasonic intensities further indicated that MscL primarily governed the initial response to ultrasound stimulation, whereas MscS acted as a regulatory factor during sustained and amplified signaling. Both MscL and MscS maintained membrane integrity and cellular homeostasis which jointly regulated the initial transcriptional response including oxidative stress, biofilm formation, and DNA repair. Results of this study would provide theoretical evidences for ultrasound-activation of MS proteins to achieve efficient antibacterial activity.
White brined cheeses can provide a suitable environment for the persistence of spore-forming bacteria such as Clostridioides difficile. This study examined the behaviour of C. difficile during the controlled manufacture and 90-day ripening of laboratory-scale white brined cheeses and assessed the inhibitory effects of two probiotic combinations. After pasteurization, C. difficile spores were inoculated into designated batches, while two formulations previously shown to suppress the pathogen in vitro (commercial probiotic + isolate 43; YF-L901 + isolate 33) were added to separate groups. Physicochemical and microbiological parameters were monitored throughout ripening. Six experimental white-brined cheese groups were produced, consisting of rennet-only control cheeses with and without Clostridioides difficile inoculation, as well as probiotic-containing cheeses prepared with two different culture combinations under both inoculated and non-inoculated conditions. In the rennet-only batch containing C. difficile, counts decreased from 6.54 to 5.00 log CFU/g by day 90. C. difficile counts declined from 5.61 to 4.20 log CFU/g in cheeses containing the commercial probiotic + isolate 43, and from 5.54 to 4.38 log CFU/g in those with YF-L901 + isolate 33. Probiotic-supplemented cheeses also showed stronger lactic acid bacteria development, confirming successful colonisation of the cheese matrix. Although typical ripening changes in pH, moisture and salt were observed, these factors alone did not account for the reductions in C. difficile. Overall, probiotic-containing cheeses exhibited a more pronounced decline in C. difficile than the non-probiotic control. These results indicate that inhibition may be influenced not only by acidification but also by broader microbial interactions associated with the added cultures.
Jiangshui, a traditional fermented vegetable food in Northwest China, suffers from unstable quality and difficulty in industrialization due to undefined natural fermentation. To address this, a synthetic microbial community (SynCom) via manual combination was constructed for standardized Jiangshui fermentation by combining screened LAB strains from traditional Jiangshui at ratios empirically optimized through evaluation of acidity, sensory quality, total phenols, and flavonoids. In this study, LAB were isolated and purified from 53 traditional Jiangshui samples collected from Gansu Province, and 5 dominant strains (Y-5-3, Y-6-2, HN, HX, CB) were screened via morphological, molecular and physiological characterization. These strains were systematically evaluated for growth performance, acid production capacity, stress tolerance, gastrointestinal tolerance, adhesion properties, antimicrobial activity, and biosafety (hemolytic activity, antibiotic susceptibility, virulence gene detection). On this basis, 3 high-performance strains (Y-5-3, Y-6-2, HN) were selected and manually combined in 20 ratios to construct SynComs, and fermentation effects were assessed by acidity, sensory quality, total phenol, and flavonoid contents. All 5 strains exhibited γ-hemolysis, no virulence genes, and good antibiotic susceptibility, confirming biosafety. Strain Y-5-3 showed optimal performance. The optimal fermentation scheme was Y-5-3: Y-6-2: HN = 2:3:1, achieving the highest sensory score (89.38 ± 4.10 points) and significantly increasing total phenols (72.20% higher, P < 0.01) and flavonoids (61.13% higher, P < 0.01) compared with natural Jiangshui, while reducing off-odors and improving stability. This study provides a scientific basis for industrialization and standardization of traditional Jiangshui production.
Bacillus cereus is a major foodborne pathogen characterized by robust biofilm formation and increasing antimicrobial resistance. This study identified 2-Methoxycinnamaldehyde (MCA) from Toona sinensis as the principal antibacterial compound and evaluated its inhibitory mechanisms and preservation potential. MCA exhibited potent activity against B. cereus ATCC 11778 (MIC = 150 μg/mL; MBC = 200 μg/mL) and resistant strains. In vitro assays demonstrated that MCA induced concentration-dependent membrane disruption, DNA damage, and intracellular protein leakage. Furthermore, treatment at 1 MIC and 2 MIC significantly impeded biofilm maturation; the secretion of extracellular proteins was reduced by 45.3% and 54.5%, polysaccharides by approximately 93%, and extracellular DNA (eDNA) by over 99%. Correspondingly, biofilm metabolic activity declined by 85.9% and 90.3%, and initial cellular adhesion was reduced by up to 88.1%. Untargeted metabolomic analysis revealed that these phenotypic defects stem from profound disturbances in amino acid biosynthesis, the TCA cycle, and nucleotide metabolism. Molecular docking revealed that MCA targets multiple essential bacterial enzymes, including ribonucleotide reductase, lysyl-tRNA synthetase, pyruvate kinase, betaine aldehyde dehydrogenase, and 5'-nucleotidase, through stable hydrogen bonding and π-interactions. In a refrigerated pork model, MCA completely eliminated B. cereus by day 7 while significantly delaying pH increases and color deterioration. These findings provide the first evidence for MCA as an antibacterial and antibiofilm agent against B. cereus, highlighting its potential in food preservation.
Recombinase polymerase amplification (RPA) is a promising technology for amplifying nucleic acids at a constant temperature; its simple procedure, minimal equipment requirements, and fast detection times make it highly suitable for food safety applications. This study develops two rapid and sensitive assays for detecting Yersinia pseudotuberculosis in food based on RPA technology. The first assay combines RPA with a lateral flow stick (RPA-LFS) for visual readouts. The method showed high specificity against common food-borne bacteria and could detect Y. pseudotuberculosis at temperatures between 30 and 45 °C. High concentrations of templates were detected within 10 min, whereas low concentrations required 20-30 min. The limit of detection (LOD) with 95% probability by probit analysis was determined to be 206 CFU/mL. The second assay integrates RPA with real-time fluorescence detection (RT-RPA), allowing continuous monitoring of amplification products. RT-RPA detected as few as 47.5 copies/μL for pure DNA templates and 103 CFU/mL for bacteria suspensions. Amplification occurred in 3-14 min for 106-102 copies/μL of DNA template and 3-10 min for 107-103 CFU/mL of boiled bacterial suspensions. Both methods showed 100% accuracy in artificially contaminated pork samples and produced results consistent with qPCR. The RPA-LFS and RT-RPA assays constructed in this study can rapidly and accurately detect Y. pseudotuberculosis, which is crucial for food safety emergencies.
Food microbiologyJincheng Ma, Yingwen Tang, Shaojin Wang, Byron D Chaves, Long Chen
A major cause of Salmonella spp. foodborne outbreaks in milk powder is cross-contamination in production environments. Transfer experiments under different conditions were performed between different donors and acceptors (stainless steel coupon, paper towel, and milk powder). A Monte Carlo simulation was developed to model the cross-contamination of Salmonella Enteritidis PT 30 (S. PT 30) and dry cleaning interventions in milk powder production environments under 8 scenarios. Inputs to the model included the initial level of S. PT 30, the proportion of milk powder in contact with the surface, the normal force for dry wiping, the log transfer coefficient (log TC) under various conditions, and the reduction proportion on the surface with inoculated milk powder residues after dry cleaning. The model's outputs mainly included the quantity and the concentration (log CFU/g) of contaminated milk powder. Initial level, normal force, inoculation method, and transfer direction significantly affected the log TC (p < 0.05). After a contamination breach on the contact surface in scenario 1, milk powder was contaminated. Milk powder could still be contaminated with a low concentration even after multiple S. PT 30 transfer steps from different contamination sources to the contact surface in scenarios 2-5. Dry wiping effectively reduced the quantity and the concentration of contaminated milk powder in scenarios 6-7. But multiple dry wipes were needed to remove all S. PT 30 from the surface in scenario 8. The developed model can be used to evaluate the risk of cross-contamination in various scenarios in milk powder production environments and provide guidance for hygiene intervention strategies.
Hepatitis E virus (HEV) belongs to the Paslahepevirus balayani species (Hepeviridae family) and harbours a positive-sense, single-stranded RNA genome. HEV genotypes 3 and 4 (HEV-3 and-4) are mainly transmitted from animal reservoirs (primarily domestic pig), either through direct contact or by consuming meat from infected animals. Heat treatment is the main food technological process used to inactivate HEV in pork products. It is crucial to implement robust methods for assessing HEV infectivity to ensure the effectiveness of such inactivation processing. Even if several cell lines are permissive to HEV, cell culture-based methods still present several drawbacks (high technical expertise, time-consuming, low throughput). The aims of this study were to optimize a capsid-integrity-RT-qPCR assay to study the thermal resistance of HEV in simple matrix (PBS, cell culture medium), to validate its application to deli meat products (cooked ham and emulsified sausage), and to compare its performance to a cell culture assay using HepaRG cells. Among several candidates, PtCl4 was identified as the most effective capsid-integrity marker to bind viral RNA, and a concentration of 2.5 mM PtCl4 provided the highest reduction in genomic titre for both heat-inactivated strains of HEV-3 tested (HEV-3c and HEV-3f) without affecting the viral genomes from intact viral particles. The capsid-integrity-RT-qPCR was successfully validated in food matrices (cooked ham and emulsified sausage), with reductions >4 log10 achieved for heat-inactivated HEV whatever the strain tested. Sensitivity analysis showed reliable detection of infectious HEV in both suspensions and food matrices down to 2 log10 genome equivalents/mL. When applied to assess the effectiveness of thermal inactivation of ≥63°C for ≥5 min or ≥75°C for 5 min, our results showed effective inactivation of HEV, with both molecular and cell culture detection methods showing parallel trends. Capsid-integrity-RT-qPCR showed a time- and temperature-dependent reduction in HEV genomic titres that correlated with the loss of infectivity observed in cell culture assays. These findings support the use of capsid-integrity-RT-qPCR as a useful first-line screening tool for evaluating HEV thermal inactivation, to be complemented by cell culture assays when feasible, particularly in complex food matrices. This complementary use of both methods is intended to be further assessed for validating viral inactivation processes in the food industry.