A point-source staphylococcal foodborne outbreak occurred in a corporate canteen in Shenzhen, China, in April 2024, affecting 16 of 107 exposed employees (attack rate, 15.0%). A retrospective cohort study identified a hand-shredded chicken dish as the vehicle of transmission (relative risk = 5.91; 95% confidence interval, 1.41 to 24.76). Staphylococcus aureus and its enterotoxin A were recovered from patient specimens and from the implicated chicken, whereas three other retained dishes yielded the organism without detectable toxin; S. aureus was also isolated from an asymptomatic food handler. Approximately 15 kg of cooked chicken was shredded by hand and held overnight in a covered basin filled to a depth of roughly 15 cm, in a crowded refrigerator, giving an interval of about 20 hours between the estimated point of contamination and consumption. A one-dimensional cooling estimate suggests that the interior of such a mass would have remained above 20°C for 10-14 hours, conditions under which published data for cooked chicken are compatible with the accumulation of enterotoxin A to an illness-inducing level. Brief steaming before service would not have removed preformed toxin. This outbreak illustrates two preventable failures common in mass catering: bare-hand contact with cooked, ready-to-eat food, and inadequate cooling of large batches during storage.
Ensuring the microbial safety of raw milk cheeses demands a robust, quantitative understanding of contamination pathways and risk mitigation strategies. In this study, we developed an innovative agent-based Quantitative Microbial Risk Assessment (QMRA) model that explicitly represents farms, animals, cheese batches, and consumers as individual agents. This approach enables a realistic simulation of microbial transmission throughout the entire production chain and facilitates the assessment of the effectiveness of control measures. Grounded in extensive knowledge of the French raw milk cheese sector, the model simultaneously addresses three major pathogens of concern: Shiga toxin-producing Escherichia coli (STEC), Salmonella, and Listeria monocytogenes. By incorporating stochastic Monte Carlo simulations, the model captures variability in microbial shedding at the farm level, contamination dynamics during milk collection and cheese processing, as well as exposure scenarios at the consumer level. This multi-agent framework provides a structured approach that enhances the interpretation of risk scenarios and facilitates risk communication, particularly for risk managers aiming to implement evidence-based food safety policies or consumer guidelines. By explicitly modeling each component of the system, this methodology bridges the gap between theoretical risk assessment and practical decision-making. The approach presented in this article serves as a flexible and transparent tool for assessing microbial risks associated with STEC, Salmonella, and L. monocytogenes in bovine raw milk cheeses, and can be adapted to other foodborne hazards and production systems.
Antimicrobial resistance (AMR) is a significant threat to poultry production and food safety. In laying hens, commensal Escherichia coli can serve as a reservoir of AMR and virulence genes. Although omega-3 fatty acids (N-3 FA), yeast bioactives (YB), and spacing allowance (SA) influence gut health and immunity, their combined effects on AMR profiles of gut bacteria remain unclear. A total of 2,832 chicks were raised in enriched cages under high (HSA, 348 cm2/bird) or low (LSA, 284 cm2/bird) SA and fed a control diet (C), C+3% N-3 FA, or C+0.05% YB. At 4, 16, and 35 weeks of age (woa), cecal contents were cultured on ChromoCult agar to isolate E. coli. Susceptibilities of isolates to 14 antibiotics were determined. Of the 428 isolates, 35.7% were resistant to at least one antimicrobial, and overall AMR prevalence decreased with age (P < 0.05). At each of 4 and 16 woa, N-3 FA-fed birds showed the lowest ampicillin resistance (P < 0.05). Streptomycin resistance was higher in N-3 FA than in YB-fed birds at 16 woa (P = 0.02) but lower than in control-fed birds. Whole-genome sequencing and analysis of 237 selected isolates identified 19 antimicrobial resistance genes (ARGs) and 29 plasmids, with 15 (78.9%) ARGs and 19 (65.5%) plasmid replicons affected by either diet, SA, or age (P < 0.05). Several virulence genes were identified in sequenced E. coli isolates, with those encoding fimbriae, pili, protectin, and toxins being higher in younger pullets (P < 0.05). Overall, isolates from phylogroups A and B1 were predominant; however, at 4 woa, phylogroup D isolates were most prevalent, depending on diet and SA (P < 0.05). Isolates of serotype O23:H16, ST2 were the most prevalent. Of the 237 sequenced isolates, 13 were related to human ExPEC strains. Overall, these findings suggest that N-3 FA YB and SA modulate AMR and virulence genotypes in laying hens, highlighting their potential in mitigating AMR in the poultry production system.
Salmonella is common in cattle without clinical signs, persisting in feces, peripheral lymph nodes, and occasionally liver abscesses. While the association with this pathogen has been studied extensively, knowledge gaps remain regarding its relationship with beef × dairy crossbred cattle. Given the high prevalence of liver abscesses in beef × dairy crosses and their potential link to gastrointestinal disruption and subsequent pathogen translocation, this study investigated Salmonella contamination in lymph nodes, liver abscesses, and carcasses of beef × dairy cross cattle. Lymph nodes (LN; subiliac, superficial inguinal, mesenteric, and prescapular) and liver samples were collected from case (n = 124; liver abscess), and control (n = 124; no liver abscess) beef × dairy cross cattle carcasses. Samples were analyzed for Salmonella using the BAX®-System Real-Time Salmonella Assay, and isolates recovered from the original enrichment were serotyped. Prevalence ranged from 4.4% for livers to 8.5% for mesenteric LNs. Salmonella prevalence did not vary by sample type (P = 0.5574), carcass category (case vs. control; P = 0.4326), or sample type × carcass category (P = 0.4745). When analyzed on a carcass level (one or more LNs positive in a single carcass), prevalence did not vary (P = 0.3575), with 19.4% and 24.2% (not model-adjusted) in control and case carcasses, respectively. Salmonella Montevideo was the most frequently recovered serotype (19.1%), followed by Muenchen (10.0%) and Typhimurium (9.1%). Salmonella was detected across all sample types with no differences detected in prevalence by sample type or carcass category, and the presence of liver abscesses was not associated with an increased risk of Salmonella contamination of LNs. Although these data suggest that no relationship exists between Salmonella and liver abscesses in beef × dairy crossbred cattle, the findings are based on a limited sample size and should be validated in larger, more comprehensive studies.
In the United States, the N60 excision sampling method for beef trim products used by FSIS collects 60 thin slices of raw meat which are then analyzed for bacteria. This destructive sampling method is time-consuming, results in inconsistent sample mass, and has a risk of worker injury. To address these limitations, FSIS conducted a series of laboratory and field studies to determine if a surface sampling method could achieve equal or better bacterial recovery compared to N60 excision for sampling beef trim products. The first study compared, under laboratory conditions, sponge and cloth surface sampling methods against N60 excision using Salmonella and three strains of Shiga toxin-producing Escherichia coli (STEC), which led to the selection of the cloth-based method. An extensive field trial comparing the cloth and N60 excision sampling methods found that the dry cloth method was inferior for the detection of Salmonella and aerobic bacteria counts (p = 0.05). FSIS hypothesized bacterial die-off during sample shipping to the laboratory may have reduced dry cloth recovery. FSIS completed two additional laboratory studies to compare cloth with the addition of two types of Buffered Peptone Water to the dry cloth and found statistically significant improvements (p=0.012 and 0.039) in all measures of bacterial recovery with added buffer. The final study repeated the original field trial, except that sample collectors added 25 mL of neutralizing Buffered Peptone Water (nBPW) to the cloth prior to shipping. This study found that the cloth, with buffer recovered significantly higher counts of aerobic bacteria compared to the N60 excision sampling method and there was no significant difference in the recovery of Salmonella (p = 0.41). FSIS concluded that the cloth sampling method is the regulatory equivalent to the N60 excision sampling method and replaced N60 excision sampling with the cloth sampling method with nBPW for domestic raw beef trim products on February 1, 2023.
This study investigated the thermal inactivation kinetics of three pathogens, Salmonella, Escherichia coli, Listeria monocytogenes, and a surrogate microorganism Enterococcus faecium during oil frying of potato pellets at varying moisture contents of 5.4, 10.0, and 14.4%. Thermal treatments were conducted across temperatures ranging from 80 to 108 °C to establish comparative heat resistance profiles. Experimental results demonstrated that Salmonella exhibited superior thermal resistance compared to both E. coli and L. monocytogenes. At 14.4% moisture content, Salmonella D-values were determined to be 1.93, 0.85, and 0.45 min at 88 ,92 , and 96 °C, respectively. When moisture content was reduced to 5.4%, Salmonella displayed increased thermal resistance, with D-values of 2.38, 1.2, and 0.72 min at 89, 92, and 98 °C. Notably, E. faecium emerged as the most heat-resistant microorganism among all tested species, exhibiting D-values of 1.06, 0.65, and 0.31 min at 98, 103, and 108 °C in 5.4% moisture samples. Comparative analysis revealed that E. faecium demonstrated 1.6-fold greater heat resistance than Salmonella at 5.4% moisture, and 2.8- to 5.4-fold greater resistance at 14.4% moisture across 90-110 °C. Verification testing at 129 °C with 10.6% moisture content resulted in population reductions of 4.73 and 5.6 log CFU/g for E. faecium and Salmonella, respectively, after 6 seconds of treatment. These findings provide a scientific foundation for validation protocols in similar fried, low-moisture food products and substantiate the potential application of E. faecium as a suitable surrogate organism for in-plant validation studies of fried, low-moisture products such as potato pellets.
Rendered fats are highly susceptible to species mislabeling because processing removes visual markers, threatening Halal/Kosher compliance and food safety management. We developed a precalibrated droplet digital PCR (ddPCR) screening method using operational quantification coefficients K, eliminating routine dependence on scarce matrix-matched certified reference materials for fresh or once-frozen-thawed fats. Species-specific biological coefficients ti were established from pure fats (n = 23), and interspecies signal conversion factors CF from aqueous-phase recovery experiments. Validated across five laboratories and four ddPCR platforms, the method achieved interlaboratory RSDR of 2.88-8.58% at 5-50% (w/w) mass fractions and mean recoveries of 99.45-101.71% at validated levels (H2-H5). Near the limit of quantification (LOQ), porcine at 5% and equine at 10% showed systematic positive bias (recoveries 140.64% and 121.22%), requiring semi-quantitative reporting; ovine at 10% showed negative bias (85.02%) and requires confirmatory testing in interlaboratory application. In-house LOQs were 5% (porcine) and 10% (bovine, equine, ovine); interlaboratory reporting limits were 5% (porcine), 10% (equine), and 20% (bovine, ovine). Analysis takes 2.5 h per sample. In blind testing of six samples, species were correctly detected and quantified in all five commercial fats; a plant-based control yielded no signal, falling outside the validated scope. This screening-level approach supports HACCP (Hazard Analysis and Critical Control Points)-based monitoring at critical control points (CCPs) in rendering facilities and customs inspection stations.
The development and application of novel rapid detection technologies are critical for advancing food safety regulation. In recent years, immunology-based methods have played a pivotal role in food safety supervision due to their speed, operational simplicity, and cost-effectiveness. However, conventional colloidal gold techniques exhibit limited sensitivity for trace analytes (e.g., early-stage microbial contamination) and are primarily qualitative, thus failing to meet the quantitative detection requirements for pesticides, veterinary drugs, and food additives, which restricts their practical applicability. Additionally, the difficulty and high cost of obtaining high-quality monoclonal antibodies increase the technical barriers and commercialization costs of immunochromatographic assays. Consequently, modern immunological techniques and novel alternative biotechnologies have emerged as focal points in rapid detection research. This review examines the principles and technical characteristics of advanced immunological methods, including immunofluorescence quantitative chromatography (IF-QCT) and flow cytometry-based immunophenotyping (FCI), as well as emerging antibody-alternative technologies such as aptamers, CRISPR/Cas systems, and phage-based technologies. This review further summarizes the latest research advances of the above-mentioned technologies in the rapid detection of food safety risk factors, including pathogenic microorganisms, biotoxins, residues of pesticides and veterinary drugs, heavy metals, and other chemical contaminants. It critically analyzes their technical advantages and practical limitations, and discusses potential future directions. This review aims to provide insights and a theoretical basis for developing and applying technologies to rapidly detect food safety hazards.
Lactic acid bacteria (LAB) are recognized as candidates for biopreservation because of their antagonistic activities. For industrial applications, however, the performance of individual LAB strains in specific food matrices must be carefully evaluated. This study investigated the biopreservative potential of four LAB strains (Carnobacterium maltaromaticum 35, C. maltaromaticum 55, C. divergens 468, and Leuconostoc gelidum 406) in vacuum-packed fresh ready-to-eat salmon portions stored at 4 ℃ for 22 days. Strain performance was assessed based on their growth properties, effects on the microbial community, inhibition of an inoculated Listeria innocua strain (CCUG 15531), and impacts on chemical (ATP‑degradation products, biogenic amines) and physicochemical (pH, color, water holding properties) quality of the salmon portions. LAB counts increased in the LAB-inoculated groups from 4.2 to 4.6 log CFU/g to 7.2-8.6 log CFU/g, and inoculated samples were associated with a lower relative abundance of Photobacterium spp., which dominated the microbial community in control samples. None of the strains adversely affected chemical or physicochemical quality. In the absence of inoculated LAB, L. innocua increased significantly from 3.4 ± 0.1 to 5.0 ± 0.3 log CFU/g, whereas in the presence of C. maltaromaticum 35, no significant proliferation was observed (p = 0.19). These findings indicate that C. maltaromaticum 35 is a promising candidate for improving the safety and microbial stability of ready-to-eat vacuum-packed salmon portions.
Electrolyzed water (EW) has emerged as an effective, eco-friendly alternative to traditional chemical disinfectants in the food industry, offering low toxicity, adaptability across commodities, and strong antimicrobial properties while preserving food quality. This review explores various types of EW, including slightly acidic electrolyzed water (SAEW) and alkaline electrolyzed water (ALEW), and their application in food safety, particularly for fresh produce, meat, poultry, and seafood. SAEW’s ability to reduce microbial contamination, delay food spoilage, and preserve sensory qualities like texture and color is highlighted, along with its synergistic effects when combined with non-thermal technologies such as ultrasound. Its compatibility with hurdle technologies enhances efficiency. The review also delves into the mechanisms behind EW’s antimicrobial activity, focusing on its ability to disrupt cell membranes and effectively eradicate biofilms of foodborne pathogens like E. coli, Listeria, and Vibrio, offering sustainable solutions for microbial control in food processing. EW effectively removes residues and reduces microbial contamination on surfaces and in dairy products, achieving significant reductions in pathogenic and spoilage microorganisms while supporting low-chemical sanitation practices. Challenges such as organic matter interference, optimal treatment conditions, and scalability are discussed. This review highlighted intelligent CIP systems integrating EW with AI-driven digital technologies for adaptive, efficient sanitation. It also examined EW applications in biofilm control, pathogen inactivation, and shelf-life extension. The paper concludes by outlining future research directions, particularly for large-scale industrial implementation and improving the efficacy and cost-effectiveness of EW technologies across the food industry. Overall, EW represents a promising strategy for improving food safety and sustainability in food production systems.
Biogenic amines (BAs) are low-molecular-weight organic bases that occur naturally in various foods, particularly those undergoing fermentation or spoilage. Although they play essential physiological roles in the human body, excessive intake through food can have adverse health effects. Due to their accumulation in food products, including fish, cheese, and fermented foods, BAs are considered chemical hazards in food safety and can cause toxicological effects. Consumption of foods, especially aquatic products, with elevated BA levels can lead to symptoms ranging from headaches and hypertension to severe allergic reactions, depending on individual sensitivity and the specific amines present. Aquatic foods, including fish and other seafood, represent a critical component of human nutrition due to their high-quality protein, essential fatty acids, and micronutrient content. However, their susceptibility to spoilage and BA formation poses significant challenges to food safety and quality. Therefore, controlling BA levels in these products is of paramount importance to ensure consumer health and preserve the nutritional and sensory attributes of seafood. This review provides an in-depth overview of emerging strategies to control BA formation in fishery products, categorizing them into three primary approaches: physical (e.g., high hydrostatic pressure, modified atmosphere packaging, irradiation), chemical (e.g., natural extracts, essential oils), and microbial (e.g., probiotic strains, starter cultures). The combined application of these methods often offers synergistic benefits, resulting in more efficient BA mitigation while preserving desirable qualities such as flavor, aroma, texture, and color. Consequently, integrating these innovative techniques can significantly enhance seafood safety, extend shelf life, and improve consumer acceptance.
Listeria monocytogenes is a major food safety concern, notably because of its ability to grow in a wide range of environmental conditions. Since this pathogen generally requires high infectious doses to cause illness, reliable models describing its growth boundaries as a function of temperature, pH, water activity (aw), and preservatives (e.g., organic acids) are essential for accurate risk assessment. This study proposes a growth/no growth model, based on an 'interaction term', for the effects of eight environmental factors (temperature, pH, aw, lactic, acetic, sorbic, propionic and citric acids). In that model, single values for strain-dependent model parameters were replaced, wherever possible, with statistical distributions, making it possible to describe the intraspecies variability in the growth capabilities of L. monocytogenes. The distributions of the Minimum Inhibitory Concentrations (MIC) of lactic, acetic, propionic, and citric acids are based on values for 33, 14, 9, and 8 different Listeria strains, respectively. The information available on sorbic acid is limited, and the distribution has been derived from two MIC values retrieved from the literature. For model evaluation, a literature review was conducted to compile growth/no growth data for L. monocytogenes primarily in culture media, but also in model food matrices and food products (dairy, seafood, and meat-based products). In total, 3,060 growth/no growth data were compiled in culture media and 622 in model foods and food products. The model predictions for the transition from "no growth" to "possible growth" usually provided correct or fail-safe predictions. Some "fail-safe" predictions in food products are associated with curing or the presence of high concentrations of lactic acid bacteria. Further model validation will be necessary, especially for citric and propionic acids, where data gaps have been acknowledged.
BACKGROUND:Incidence of vibriosis infections caused by several emerging Vibrio species has increased in the United States, including V. alginolyticus (Va), V. cholerae (Vc), V. fluvialis (Vf), and V. mimicus (Vm), which contribute substantially to overall vibriosis burden. The objective of this analysis was to characterize the epidemiology of these emerging Vibrio species using US national surveillance data. METHODS:We conducted an analysis of national Cholera and Other Vibrio Illness Surveillance (COVIS) data from 1988 to 2024. Spline regression was used to estimate trends. Counterfactual random forests were used to compare epidemiologic and clinical profiles across species. RESULTS:During 1988-2024, 4,350 Va, 2,856 Vc, 1,722 Vf, and 582 Vm infections were reported, and incidence increased for all species and varied by region. The largest relative increases were for Vf (+101%), Vc (+79%), and Va (+67%). Va had an epidemiologic profile distinct from Vc, Vf, and Vm; Va infections were associated with persons aged 1-17 years, waterborne transmission, and wound and ear infections. Vc, Vf, and Vm infections were more often foodborne and associated with gastrointestinal illness. Hospitalization was more common for Vc, Vf, and Vm (37-42%) compared with Va infections (13%). CONCLUSIONS:Va, Vc, Vf, and Vm infections represent a growing component of vibriosis infections in the United States and exhibited distinct epidemiologic profiles with substantial morbidity. Vibriosis prevention efforts should be tailored to include both foodborne and non-foodborne transmission in regions and populations at higher risk, and clinicians should have increased awareness of emerging Vibrio species. Plain Language:Vibrio are naturally occurring bacteria that can cause illnesses ranging from gastroenteritis to serious wound infections. Infections caused by four emerging Vibrio species of concern, namely V. alginolyticus (Va), V. cholerae (Vc), V. fluvialis (Vf), and V. mimicus (Vm), have been increasing in the United States. During 1988-2024, the incidence of infections caused by these species increased. Va infections were distinct from the Vc, Vf, and Vm infections. Va infections were more often associated with waterborne transmission, people aged 1-17 years, and ear and wound infections. Vc, Vf, and Vm infections were more often foodborne and linked to gastroenteritis and hospitalization. These species represent a growing component of vibriosis in the United States and have distinct clinical and epidemiologic profiles. Prevention efforts should be tailored to address foodborne and non-foodborne transmission in populations at higher risk for specific infection types.
Older adults are at increased risk of foodborne illness due to age-related changes in immune function. Previous research has identified discrepancies between food safety knowledge, attitudes, self-reported practices, and observed behaviors among older adults; however, why potentially unsafe food safety practices occur is unknown. The Health Belief Model identifies modifying factors as influences on health behaviors, yet these factors are seldom considered in consumer food safety research. This study aimed to explore the modifying factors influencing domestic food safety beliefs and behaviors among older adults. A retrospective qualitative analysis was undertaken using interview transcripts from a completed doctoral study involving adults aged ≥60 years living in Wales (n = 100). The original study identified discrepancies between food safety cognition and behavior, but the factors contributing to these differences were not explored. Interview transcripts were analyzed using the Dimensions of Wellness (physical, intellectual, emotional, social, spiritual, vocational, financial, and environmental) as an analytical framework to examine the modifying factors of the Health Belief Model. Factors influencing food safety beliefs and behaviors included health changes, sensory decline, household transitions, social circumstances, access to food, financial resources, and changing food environments. Findings indicate that food safety behaviors are shaped by wider life circumstances rather than knowledge and perceptions alone. Although the eight dimensions provided a useful exploratory framework, considerable overlap indicated the need for refinement into five broader determinants: biological, physical, psychological, economic, and social. This revised framework provides a more structured approach for understanding the modifying factors of food safety behaviors among older adults. It may also support future research and the development of targeted food safety interventions.
Fresh-cut produce operations often generate work-in-process (WIP) ingredients that have undergone peeling, cutting, washing, etc., and are then subjected to temporary holding, prior to packaging, creating conditions that may favor pathogen survival and growth. The objective of this study was to evaluate the survival of Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica, and native microbiota on WIP fresh-cut carrot and yellow onion treated with deionized water, sodium hypochlorite (NaOCl, >10 ppm free chlorine), or peracetic acid (PAA, 80 ppm) and held at 4, 8, or 12 °C for up to seven days. Pathogen behavior was strongly influenced by storage temperature and commodity matrix. At 4 °C, E. coli O157:H7 and S. enterica populations generally declined or remained stable. Conversely, at 8 °C and 12 °C, which were evaluated to simulate potential temperature-abuse scenarios, E. coli O157:H7 and S. enterica proliferated in unwashed samples but were often suppressed by chlorine and PAA. L. monocytogenes on carrot did not grow under any treatment or temperature, likely due to intrinsic antimicrobial compounds, while it persisted on onion and grew by 0.5-1.6 logs under temperature abuse. PAA often provided the greatest pathogen reductions on onion, although chlorine was more effective against E. coli O157:H7 on carrot. Native mesophilic or psychrotrophic bacteria, and yeast and mold populations, increased rapidly across all treatments and storage conditions, with PAA-washed samples often having the greatest growth rates. Overall, while sanitizer efficacy was commodity-dependent, strict temperature and holding time management emerged as the most critical factor in limiting pathogen growth. These findings underscore the necessity of an integrated management approach for WIP produce, although further validation under dynamic industrial conditions and mechanisms for the rapid regrowth of microbiota in PAA-washed samples warrant further investigations.
Salmonella remains a major foodborne zoonotic hazard, yet long-term data on the distribution of serovars in foods of animal origin in South-Eastern Europe are limited. This study describes the temporal dynamics and food-category distribution of Salmonella enterica serovars isolated from foods of animal origin in Bulgaria between 2007 and 2023. A total of 1,906 confirmed Salmonella isolates submitted by public and private laboratories to the National Reference Laboratory were analyzed by classical biochemical identification and serotyping according to the White-Kauffmann-Le Minor scheme. Salmonella was most frequently recovered from poultry meat (39.8%), poultry by-products (13.1%), meat preparations (16.9%), minced meat (11.7%), and pork meat (6.9%). Temporal serovar composition differed significantly (Monte Carlo χ2 = 763.0, P < 0.0001; Cramer's V = 0.258). Binomial generalized linear models showed a significant annual increase in S. Infantis (OR/year = 1.095, 95% CI 1.056-1.136; FDR q < 0.001) and decrease in S. Typhimurium (OR/year = 0.929, 95% CI 0.873-0.989; q = 0.030), whereas S. Enteritidis showed no significant linear trend. Food category and major serovar were strongly associated (Monte Carlo χ2 = 827.0, P < 0.0001; Cramer's V = 0.339). S. Infantis, S. Enteritidis and S. Kottbus were concentrated in poultry-derived products, whereas S. Typhimurium, its monophasic variant, and S. Derby were associated with pork, minced meat, and meat preparations. These findings support continuous serovar-level surveillance and targeted control measures in poultry and pork chains.
Salmonella enterica, a foodborne pathogen, poses a significant public health risk, particularly multidrug-resistant strains. Because antimicrobial resistance (AMR) is often linked to specific serotypes or clones, factors that shift Salmonella populations in feedlots can indirectly drive resistance. The study aimed to characterize the genomic diversity and clonal composition of Salmonella across cattle and the pen environment from a feedlot trial involving crossbred steers fed a high-starch or control diet combined with erratic or regular feeding management until harvest (168 to 222 days; hereafter 168+). A total of 509 isolates recovered from feces, pen surfaces, hide swabs, and lymph nodes were whole-genome sequenced for in silico prediction of serotype, 7-gene multilocus sequence type (ST), core-genome ST (cgST), AMR genes, and plasmids, as well as single-nucleotide polymorphism-based phylogenetic inference. The population was dominated by four serotypes (Anatum, Montevideo, Kentucky, and Lubbock), each associated with a dominant ST, though Kentucky and Lubbock each comprised two STs. Only two isolates, both from pen surface, carried multiple AMR genes: 1 Montevideo harbored floR, tet(A), aph(6)-Id, aph(3'')-Ib, sul2, and 1 Anatum carried these plus blaTEM-1A. Serotype populations were clonal within sampling day and pen; no clear treatment-related patterns emerged. Serotype and clonal patterns were assessed through genomic characterization and descriptive visualization. Clonal clustering within pens suggests that environmental persistence and reinoculation from pen surfaces may play a larger role in shaping Salmonella populations than dietary or management factors. The sporadic nature of AMR under limited antibiotic use underscores the need for targeted preharvest interventions focused on the pen environment.
The purpose of this study was to determine the fate and growth kinetics of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes on the surface of whole cantaloupe and watermelon. Athena cantaloupes and mini seedless watermelons were spot inoculated (ca. 103 CFU/3.14 cm2) on the sun-side of the melons with pathogen-specific cocktails of rifampicin-resistant strains of E. coli O157:H7, Salmonella, or L. monocytogenes. To simulate postharvest handling conditions, inoculated melons were stored at 4, 10, 15, 20, or 25 °C for up to 21 days. On cantaloupe surfaces, E. coli O157:H7 increased by 2.40 log CFU/3.14 cm2 at 25 ℃ after 3 days and L. monocytogenes increased by 2.14 log CFU/3.14 cm2 at 25 ℃ after 7 days. Salmonella did not grow on cantaloupes but persisted at 25 ℃ for 7 days before cantaloupes deteriorated. On watermelon surfaces, pathogens did not grow with the exception of L. monocytogenes at 20 ℃ and 25 ℃. Growth rates of both pathogens generally increased at higher temperatures, and the lag phase shortened at higher temperatures for L. monocytogenes, except at 25 ℃. Collectively, temperature control for storage of whole melons reduces the risk of foodborne pathogen growth and persistence on whole cantaloupes and watermelons.
This comparative review explores the physicochemical and microbiological profiles of Ethiopian honey produced by A. mellifera and stingless bees, synthesizing data on quality and safety. Across both bee species, key parameters including moisture, reducing sugars, free acidity, pH, and hydroxymethylfurfural (HMF) generally conform to National, European Union, and FAO/WHO standards. Distinct profiles emerge between the two types: stingless bee honey exhibits significantly higher moisture content, whereas A. mellifera honey scores superior in total reducing sugars. Crucially, despite honey's inherent antimicrobial properties, localized microbial contamination including yeasts, molds, and Staphylococcus was detected, highlighting risks from primary ecological inputs and secondary post-harvest handling. These findings underscore an urgent need for advanced research into the microbial safety of indigenous honeys and argue for the establishment of mandatory, species-specific national quality standards to safeguard public health and boost international marketability.
Untreated manure is commonly used as a biological soil amendment of animal origin in organic production but may introduce foodborne pathogens into the farm environment. In this multiregional study, generic E. coli was used as an indicator of fecal contamination to identify factors associated with its concentration in manure-amended soils. The analysis included samples from 19 certified organic farms in California, Maine, Minnesota, and Maryland collected over two growing seasons. A zero-inflated linear mixed model was used to assess the association between generic E. coli concentration in soil, and farm-related practices, soil and environmental factors. Generic E. coli concentration in the soil declined in the first 60 days after manure application (β: -1.00, CI95: -1.17, -0.83) before a secondary increase through Day 180. Manure management practices, including use of different types of animal manure and manure application rates, were significantly associated with generic E. coli concentration in soil. Soil nutrients (phosphorus (β: 0.22, CI95: 0.15, 0.30)) and micronutrients (zinc (β: 0.03, CI95: 0.01, 0.04) and manganese (β: 0.02, CI95: 0.01, 0.02)), elevated moisture content (β: 0.13, CI95: 0.07, 0.19), and Salmonella (β: 1.79, CI95: 1.31,2.23) or Listeria monocytogenes (β: 0.24, CI95: 0.03, 0.44) also showed positive association with generic E. coli concentration in soil. Lower wind speed (β: -0.12, CI95: -0.19, -0.06), increased precipitation (β: 0.03, CI95: 0.01, 0.05), and increased UV index (β: 0.24, CI95: 0.15, 0.34) were found to be associated with higher E. coli concentration in manured soil. Overall, the persistence of generic E. coli in manure-amended soil was multifactorial. Effective microbial risk management should incorporate considerations for animal origin of manure, management, environmental, and meteorological factors alongside current USDA National Organic Program standards (90-120 days) regarding the interval of application of raw manure to harvest of the edible portion of food crops.
