The soybean plant (Glycine max L.) is an important crop for valuable food source because of its high levels of protein and oil, thus contributing greatly to a sustainable system for producing food through biological nitrogen fixation. Recent research supports the theory that the soybean-associated microbiome located in the rhizosphere is a crucial regulatory mechanism governing plant growth, nutrient acquisition, and stress tolerance. Additionally, advances in metagenomics, metatranscriptomics, metabolomics, and root exudate profiling via LC‒MS have shown that soybean roots alter the microbial communities found in their rhizosphere by utilizing dynamic chemical signaling and targeted microbial recruitment, thereby enhancing the ecological interpretation of the processes that drive microbiome assembly. Microbial consortia (AMF & PGPR) assess cycling through nutrients, phytohormones, suppressing diseases, as well as having a legacy effects on the productivity of agroecosystems. Factors such as plant genotype, physical and chemical soil properties, and environmental conditions greatly affect the assembly and functioning of the soybean microbiome, thus this is difficult to transfer this information to field applications. Unlike previous reviews focused primarily on biological nitrogen fixation, this review integrates recent advances in multi-omics technologies, species-level microbiome characterization, root exudate chemistry, microbiome-assisted breeding, and translational microbiome engineering approaches to provide a systems-level perspective of soybean-microbiome interactions. while also identifying significant knowledge gaps and future areas of research within this aspect of agriculture.
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.
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.
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.
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.
Current quality control measures for thermally processed foods predominantly rely on reactive post-spoilage analyses rather than proactive monitoring of specific spoilage organisms. In this study, 64 gas-producing strains were isolated from swollen bagged soy sauce and identified as Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus velezensis, and Bacillus licheniformis. Notably, B. velezensis was associated with gas spoilage in soy sauce for the first time. Inoculation experiments conducted directly in soy sauce confirmed species-specific gas production within 1-3 days. Among the tested species, B. licheniformis posed the highest risk due to the earliest onset (1 day). To trace contamination, critical control points in soy sauce processing were analyzed. High-throughput sequencing showed elevated levels of Bacillus spp. Under high-heat conditions, primarily B. velezensis (38.11%), B. subtilis (6.13%), and B. amyloliquefaciens (4.83%) in group JY100, whereas B. licheniformis was primarily detected in equipment pipelines. For proactive monitoring, a multiplex qPCR assay was developed. A degenerate gyrB primer set enabled simultaneous detection of B. subtilis, B. amyloliquefaciens, and B. velezensis, while B. licheniformis was specifically detected using an adk-based set. The method showed no cross-reactivity with 15 non-target strains. The limits of detection (LOD) were 110, 105, 108, and 102 CFU/mL for each species in pure culture and soy sauce, with amplification efficiencies between 92.71% and 100.92%. When applied to 84 commercial samples, the positive detection rate was 15.48%. This integrated approach enables a transition from reactive post-spoilage analysis to proactive surveillance, providing a replicable framework for managing microbial spoilage risks in thermally processed foods.
Kombucha tea, a fermented beverage, is widely consumed and gaining global popularity for its perceived functional properties. The kombucha microbial community comprises bacteria and yeast that can produce antimicrobial metabolites during fermentation, thereby suppressing foodborne pathogens. However, this aspect of kombucha's functionality remains only partially characterized under controlled conditions. This study, therefore investigated the survival of Salmonella Enteritidis (S. Enteritidis) and the associated physicochemical parameters during 14 days of black-tea kombucha fermentation. The study also assessed changes in the indigenous microbiota responsible for fermentation over the 14-day fermentation period. Kombucha was prepared using 1.6% (w/v) black tea, 10% (w/v) sucrose, and a commercially available starter culture. The kombucha was inoculated with 7.2 log CFU/mL of S. Enteritidis and fermented at room temperature for 14 days. Pathogen populations, lactic acid bacteria (LAB), total yeast and mold (TYM) counts, pH, titratable acidity, and total phenolic content were monitored over 14 days. The initial S. Enteritidis population (7.24 ± 0.44 log CFU/mL) decreased significantly (p < 0.05) by 5 log on day 10 (2.01 ± 0.1 log CFU/mL) and continued to reduce to 1.4 ± 0.3 log CFU/mL by day 14, whereas the S. Enteritidis population in the black tea increased and remained stable throughout the incubation. The inactivation of S. Enteritidis coincided with increased titratable acidity, reduced pH, and increased total phenolic content. Growth in the populations of LAB and TYM increased, corresponding to acidification and associated with the inhibition of pathogens. Results from this study demonstrate that kombucha fermentation can suppress S. Enteritidis, thereby substantially reducing pathogen growth and the risk of foodborne illness.
Antimicrobials are used in aquaculture to treat bacterial infections, and their use could promote the emergence of antimicrobial-resistant bacteria. Monitoring the antimicrobial resistance profiles of fish-derived bacteria, especially those pathogenic to fish and humans, such as Lactococcus petauri, L. formosensis, and L. garvieae, can be essential for assessing the risk of antimicrobial-resistant bacteria. Therefore, we conducted a pilot study to continuously monitor the contamination and antimicrobial resistance of these bacterial species in retail fish in Japan. We purchased domestic seafood fish samples (n = 490), including wild-caught and farm-raised fish, from supermarkets in Japan between 2023 and 2024. We isolated bacteria from 16.1% of the samples, with L. petauri (8.8%) being the most prevalent species, followed by L. formosensis (5.5%) and L. garvieae (2.2%). Oxytetracycline, erythromycin, and lincomycin resistance rates were 11.6%, 5.8%, and 88.4%, respectively, and we detected resistant isolates both in retail wild-caught and farm-raised fish products. The erythromycin- and oxytetracycline-resistant L. petauri isolate harbored the plasmid harboring the multidrug-resistance genes (erm(B), tet(L), and tet(S)). Phylogenetic analysis revealed that genetically similar isolates were present across the same and different supermarkets over several months. These results suggest that L. petauri, L. formosensis, and L. garvieae could be useful indicators for monitoring antimicrobial-resistant bacteria in seafood, and highlight the potential for bacterial cross-contamination throughout the food supply chain.
In the context of sustainable waste valorization, we investigated microbiological safety hazards associated with spore-forming bacteria, focusing in particular on Bacillus cereus contamination and diversity during Hermetia illucens (Black Soldier Fly, BSF) bioconversion at different developmental stages. Larvae were reared on authorized (carrots, apricots, wheat bran) and unauthorized substrates (expired unpackaged retail food products and cafeteria waste). After 7 days of spontaneous fermentation of these substrates, total aerobic mesophilic bacterial counts were comparable across substrates; however, aerobic spore counts were significantly higher in unauthorized than authorized substrates. Notably, B. cereus was undetectable in authorized substrates but reached 5.2-6.0 log CFU/g in unauthorized waste. Despite substrate differences, BSF larvae and frass showed similar levels of total mesophilic and spore counts, with B. cereus consistently detected, indicating that vertical transmission may take place. Phylogenetic analysis revealed the persistence of potentially enterotoxigenic B. cereus group III strains harboring nheI and cytK genes throughout the bioconversion process. Additionally, group IV strains initially present in the substrate became dominant in larvae and frass by day 14. These findings demonstrate that BSF larvae are unable to significantly reduce B. cereus during entomoconversion. Frass and larvae from both authorized and unauthorized substrates showed similar contamination levels. Both types of substrates were suitable for larval rearing and did not lead to significant differences in B. cereus levels, however, the persistence of high loads in larvae and frass, regardless of the substrate, may represent a potential health hazard in the absence of further treatment.
Food microbiologyWen Si Hu, So Hyeon An, Dong Woo Kim, Hyeong Uk Im, Seung Hun Lee, Yu Bao Li, Zi Xuan Liu, Zhi Wei Wang, A Ram Lee, Ui In Kim, Hyeon Ji Je, Yeon Ju Seo, Jin Sa…
Listeria monocytogenes is a gram-positive and facultatively anaerobic foodborne pathogen causing listeriosis. The detection of L. monocytogenes in enoki mushrooms sourced from South Korea and China is particularly critical, given their confirmed implication in recent serious listeriosis outbreaks across the global food supply chain. This study investigates the prevalence, genetic diversity, and phenotypical characteristics of L. monocytogenes in enoki mushrooms from South Korea and China. Out of 129 samples, 24 (18.6%) tested positive, with contamination rates of 17.5% in Korean mushrooms and 19.7% in Chinese mushrooms. Whole-genome sequencing, cgMLST, and pan-genome analyses resolved lineage and sequence-type distributions, revealing predominant serogroup 1/2a (83.3%) and lineage II (90.9%). The pan-genomic assessment of L. monocytogenes strains originating from diverse geographical locations indicated the presence of open genomes, which establishes a strong genetic underpinning for adaptation to varied environments. These strains carrying a multitude of virulence genes that significantly contribute to their heightened pathogenic potential. The phylogenetic tree further demonstrated that these highly related Korean and Chinese isolates were intricately intermingled with outbreak-related strains from the USA, Canada, and Europe, confirming a minimal core-genome genetic distance across the global supply chain. This highly homogenous clone, which was ultimately traced back to enoki mushrooms in South Korea and China, suggests that the globalization of the food trade is the primary driver of its rapid, international dissemination.
With growing public health awareness, medicine and food homology (MFH) has gained increasing attention in functional food development for integrating edibility and physiological functions. However, many MFH suffer from low bioavailability and dissolution efficiency. As a cost-effective bioconversion technology, fermentation can enhance these properties through microbial action. This review systematically summarizes recent advancements from the following perspectives: (1) optimization of fermentation strategies for comparative analysis of single-strain, mixed-strain, solid-state, and liquid-state fermentation approaches; (2) the regulatory mechanisms of fermentation on active ingredients in MFH; (3) health benefits of fermented MFH (FMFH); (4) potential risks and safety evaluation system of FMFH. Furthermore, critical gaps are also discussed, including simplification in mechanism analysis, discrepancies between in vitro activity and in vivo effects, and the scarcity of clinical data. This review aims to provide a theoretical framework for the precise optimization of MFH fermentation technology and the development of high-value products, promoting the broader utilization of MFH resources in the health industry.