Pub Date : 2026-06-01Epub Date: 2025-12-19DOI: 10.1016/j.fm.2025.105018
Kuan Zhang , Xiaoyan Yu , Xinru Yang , Zhiqi Yang , Yan Zhang , Jiayi Liu , Xiangjing Wang , Junwei Zhao , Wensheng Xiang
Gray mold caused by Botrytis cinerea has a severe impact on postharvest green beans, leading to quality degradation and substantial economic losses. The application of plant endophytic microorganisms has proven to be a reliable and safe strategy for controlling fungal diseases. In the present study, an endophytic bacterium, Bacillus velezensis NEAU-HLD-9, was isolated from healthy bean seeds and exhibited strong inhibitory activity against Botrytis cinerea. This strain could form biofilms, enhance the activity of defense enzymes, and boost the content of active secondary metabolites in green beans. The crude lipopeptide extracts from NEAU-HLD-9 remarkably suppressed the mycelial growth and spore germination of B. cinerea. It is worth noting that the crude lipopeptide extracts also effectively controlled gray mold in green beans by reducing both disease incidence and lesion diameter. PCR and LC-MS analyses suggested that the crude lipopeptide extracts comprised two antifungal compounds. Whole genome sequencing revealed that the strain contained 15 gene clusters responsible for secondary metabolite synthesis, including those for antifungal compounds. In summary, both Bacillus velezensis NEAU-HLD-9 and its crude lipopeptide extracts strongly inhibited Botrytis cinerea in vitro and in vivo, suggesting a promising approach for the management of gray mold in green beans.
{"title":"Biocontrol potential and mechanism of a seed-endophytic Bacillus velezensis NEAU-HLD-9 against gray mold in green beans","authors":"Kuan Zhang , Xiaoyan Yu , Xinru Yang , Zhiqi Yang , Yan Zhang , Jiayi Liu , Xiangjing Wang , Junwei Zhao , Wensheng Xiang","doi":"10.1016/j.fm.2025.105018","DOIUrl":"10.1016/j.fm.2025.105018","url":null,"abstract":"<div><div>Gray mold caused by <em>Botrytis cinerea</em> has a severe impact on postharvest green beans, leading to quality degradation and substantial economic losses. The application of plant endophytic microorganisms has proven to be a reliable and safe strategy for controlling fungal diseases. In the present study, an endophytic bacterium, <em>Bacillus velezensis</em> NEAU-HLD-9, was isolated from healthy bean seeds and exhibited strong inhibitory activity against <em>Botrytis cinerea</em>. This strain could form biofilms, enhance the activity of defense enzymes, and boost the content of active secondary metabolites in green beans. The crude lipopeptide extracts from NEAU-HLD-9 remarkably suppressed the mycelial growth and spore germination of <em>B</em>. <em>cinerea</em>. It is worth noting that the crude lipopeptide extracts also effectively controlled gray mold in green beans by reducing both disease incidence and lesion diameter. PCR and LC-MS analyses suggested that the crude lipopeptide extracts comprised two antifungal compounds. Whole genome sequencing revealed that the strain contained 15 gene clusters responsible for secondary metabolite synthesis, including those for antifungal compounds. In summary, both <em>Bacillus velezensis</em> NEAU-HLD-9 and its crude lipopeptide extracts strongly inhibited <em>Botrytis cinerea in vitro</em> and <em>in vivo</em>, suggesting a promising approach for the management of gray mold in green beans.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 105018"},"PeriodicalIF":4.6,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2025-12-19DOI: 10.1016/j.fm.2025.105017
Kangning Zhao , Runhua Ji , Can Li , Xiaoya Wang , Menghua Duan , Shuhao Zeng , Shaochuang Zhang , Tianzhen Ma , Haoran Cui , Yajing Kong , Hui Yang , Ziyi Zhang , Chao Shi
Hydrogen peroxide and silver ions (HPS) is an emerging disinfectant widely used for sanitizing food contact surfaces and equipment. Escherichia coli O157:H7 is a major foodborne pathogen that represents a significant threat to public health. This study systematically evaluated the impact of growth medium (LB broth and beef broth, a food model) and temperature (25 °C and 37 °C) on the HPS-induced formation of the viable but non-culturable (VBNC) state in E. coli O157:H7 biofilms. The results indicated that, upon complete entry into the VBNC state following treatment with the same concentrations of HPS (1:40 and 1:80 dilutions), the biofilms cultured in beef broth formed the fewest VBNC state cells, at 9.26 ± 3.27 % and 13.36 ± 1.73 %, respectively, while those cultured at 37 °C formed the most VBNC state cells, at 22.60 ± 2.39 % and 23.81 ± 1.87 %, respectively. Compared to untreated cells, VBNC state cells exhibited elevated reactive oxygen species (ROS) levels, increased activities of superoxide dismutase (SOD) and catalase (CAT), reduced intracellular ATP concentrations, and depolarized membrane potentials, indicating oxidative stress and diminished metabolic activity. Morphologically, VBNC cells showed shrinkage, rough and unevenly wrinkled surfaces, and reduced cell volumes relative to untreated cells. Resuscitation of VBNC state cells was achieved within 24 h upon incubation in LB broth, LB broth supplemented with 2.0 mg/mL pyruvate, or beef broth. These findings underscore food safety risks from HPS-induced VBNC E. coli O157:H7 in biofilms, offering insights for safe HPS application in the food industry.
{"title":"The effects and physiological phenotypic changes in Escherichia coli O157:H7 induced into VBNC state by hydrogen peroxide silver ion treatment in biofilms","authors":"Kangning Zhao , Runhua Ji , Can Li , Xiaoya Wang , Menghua Duan , Shuhao Zeng , Shaochuang Zhang , Tianzhen Ma , Haoran Cui , Yajing Kong , Hui Yang , Ziyi Zhang , Chao Shi","doi":"10.1016/j.fm.2025.105017","DOIUrl":"10.1016/j.fm.2025.105017","url":null,"abstract":"<div><div>Hydrogen peroxide and silver ions (HPS) is an emerging disinfectant widely used for sanitizing food contact surfaces and equipment. <em>Escherichia coli</em> O157:H7 is a major foodborne pathogen that represents a significant threat to public health. This study systematically evaluated the impact of growth medium (LB broth and beef broth, a food model) and temperature (25 °C and 37 °C) on the HPS-induced formation of the viable but non-culturable (VBNC) state in <em>E. coli</em> O157:H7 biofilms. The results indicated that, upon complete entry into the VBNC state following treatment with the same concentrations of HPS (1:40 and 1:80 dilutions), the biofilms cultured in beef broth formed the fewest VBNC state cells, at 9.26 ± 3.27 % and 13.36 ± 1.73 %, respectively, while those cultured at 37 °C formed the most VBNC state cells, at 22.60 ± 2.39 % and 23.81 ± 1.87 %, respectively. Compared to untreated cells, VBNC state cells exhibited elevated reactive oxygen species (ROS) levels, increased activities of superoxide dismutase (SOD) and catalase (CAT), reduced intracellular ATP concentrations, and depolarized membrane potentials, indicating oxidative stress and diminished metabolic activity. Morphologically, VBNC cells showed shrinkage, rough and unevenly wrinkled surfaces, and reduced cell volumes relative to untreated cells. Resuscitation of VBNC state cells was achieved within 24 h upon incubation in LB broth, LB broth supplemented with 2.0 mg/mL pyruvate, or beef broth. These findings underscore food safety risks from HPS-induced VBNC <em>E. coli</em> O157:H7 in biofilms, offering insights for safe HPS application in the food industry.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 105017"},"PeriodicalIF":4.6,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2025-12-10DOI: 10.1016/j.fm.2025.105007
Lingxuan Huang , Chao Yang , Qian Ge , Bangzhu Peng
Aroma formation during alcoholic fermentation is largely driven by yeast metabolism. Non-Saccharomyces strains have attracted increasing attention for their ability to enhance flavor diversity and sensory complexity. In this study, three non-Saccharomyces strains—Hanseniaspora uvarum QTX22, Metschnikowia pulcherrima YC-15, and Pichia kluyveri QTX15—were isolated from Marselan wine. Whole-genome sequencing and comparative genomic analyses revealed that P. kluyveri QTX15 exhibited moderate gene family expansion, with significant enrichment in redox-related pathways, suggesting enhanced metabolic potential. Notably, gene families associated with redox processes and ester biosynthesis were prominently represented, indicating potential for elevated aroma compound production. To experimentally validate these genomic insights, fermentation trials were performed using Marselan grape must that was sterilized at 121 °C to ensure microbiological control. While this standardized condition guarantees reproducibility, it should be noted that such intense heat may alter must composition compared to typical winemaking practice. Fermentations with P. kluyveri QTX15 and S. cerevisiae RC212 were conducted under static conditions at 28 °C. Gas chromatography–mass spectrometry (GC-MS), combined with multivariate statistical analysis including variable importance in projection (VIP) scores and sensory thresholds, highlighted 15 aroma compounds that may contribute to the wine's aroma profile. Compared with S. cerevisiae RC212, P. kluyveri QTX15 produced higher levels of acetate esters such as phenylethyl acetate (9190 μg/L vs. 1580 μg/L), isobutyl acetate, and isoamyl acetate —showing 2- to 6-fold increases—contributing to intensified fruity and floral aromas. These findings identify P. kluyveri QTX15 as a valuable non-Saccharomyces resource for enhancing aroma quality in fermented beverages, supporting its application in food and beverage fermentation.
{"title":"Integrative genomics reveals Pichia kluyveri's potential for enhanced flavor compounds production during alcoholic fermentation","authors":"Lingxuan Huang , Chao Yang , Qian Ge , Bangzhu Peng","doi":"10.1016/j.fm.2025.105007","DOIUrl":"10.1016/j.fm.2025.105007","url":null,"abstract":"<div><div>Aroma formation during alcoholic fermentation is largely driven by yeast metabolism. Non-<em>Saccharomyces</em> strains have attracted increasing attention for their ability to enhance flavor diversity and sensory complexity. In this study, three non-<em>Saccharomyces</em> strains—<em>Hanseniaspora uvarum</em> QTX22, <em>Metschnikowia pulcherrima</em> YC-15, and <em>Pichia kluyveri</em> QTX15—were isolated from Marselan wine. Whole-genome sequencing and comparative genomic analyses revealed that <em>P. kluyveri</em> QTX15 exhibited moderate gene family expansion, with significant enrichment in redox-related pathways, suggesting enhanced metabolic potential. Notably, gene families associated with redox processes and ester biosynthesis were prominently represented, indicating potential for elevated aroma compound production. To experimentally validate these genomic insights, fermentation trials were performed using Marselan grape must that was sterilized at 121 °C to ensure microbiological control. While this standardized condition guarantees reproducibility, it should be noted that such intense heat may alter must composition compared to typical winemaking practice. Fermentations with <em>P. kluyveri</em> QTX15 and <em>S. cerevisiae</em> RC212 were conducted under static conditions at 28 °C. Gas chromatography–mass spectrometry (GC-MS), combined with multivariate statistical analysis including variable importance in projection (VIP) scores and sensory thresholds, highlighted 15 aroma compounds that may contribute to the wine's aroma profile. Compared with <em>S. cerevisiae</em> RC212, <em>P. kluyveri</em> QTX15 produced higher levels of acetate esters such as phenylethyl acetate (9190 μg/L vs. 1580 μg/L), isobutyl acetate, and isoamyl acetate —showing 2- to 6-fold increases—contributing to intensified fruity and floral aromas. These findings identify <em>P. kluyveri</em> QTX15 as a valuable non-<em>Saccharomyces</em> resource for enhancing aroma quality in fermented beverages, supporting its application in food and beverage fermentation.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 105007"},"PeriodicalIF":4.6,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Campylobacter jejuni is a foodborne pathogen with limited ability to thrive at low temperatures. This study investigated the survival and proteomic responses of C. jejuni NCTC 11168 during prolonged storage at 4 °C, with specific focus on its behavior in chicken juice. An initial rapid decrease of 80–90 % in viable cell counts across various broth media was observed within the first 10 days; however, chicken juice provided the most conducive environment for slowing the decline in cell viability compared to Brain Heart Infusion Broth (BHI) and Mueller Hinton (MH) broths. Electron microscopy revealed morphological transitions from spiral to coccoid forms over time, indicative of a stress adaptation strategy. Proteomic analysis identified 50 upregulated and six downregulated proteins, with key enriched functional categories including translation, ribosomal biogenesis, energy metabolism, cell envelope biogenesis, and motility. KEGG pathway analysis highlighted significant changes in metabolic pathways, flagellar assembly, and bacterial secretion systems. A protein-protein interaction network revealed clusters associated with ribosomal function, cell envelope maintenance, and motility. The acidic periplasmic protein Cj0424 (8.92-fold), previously linked to biofilm formation and oxidative stress response, was the most upregulated protein. Notably, no virulence-associated proteins were detected under cold storage conditions. These findings suggest that C. jejuni employs a multifaceted stress response to low temperatures, enhancing its persistence in food matrices and posing a potential transmission risk.
{"title":"Protein expression and morphological adaptations of Campylobacter jejuni under prolonged cold stress in chicken juice","authors":"Kidon Sung , Miseon Park , Ohgew Kweon , Alena Savenka , Angel Paredes , Saeed Khan","doi":"10.1016/j.fm.2025.105020","DOIUrl":"10.1016/j.fm.2025.105020","url":null,"abstract":"<div><div><em>Campylobacter jejuni</em> is a foodborne pathogen with limited ability to thrive at low temperatures. This study investigated the survival and proteomic responses of <em>C. jejuni</em> NCTC 11168 during prolonged storage at 4 °C, with specific focus on its behavior in chicken juice. An initial rapid decrease of 80–90 % in viable cell counts across various broth media was observed within the first 10 days; however, chicken juice provided the most conducive environment for slowing the decline in cell viability compared to Brain Heart Infusion Broth (BHI) and Mueller Hinton (MH) broths. Electron microscopy revealed morphological transitions from spiral to coccoid forms over time, indicative of a stress adaptation strategy. Proteomic analysis identified 50 upregulated and six downregulated proteins, with key enriched functional categories including translation, ribosomal biogenesis, energy metabolism, cell envelope biogenesis, and motility. KEGG pathway analysis highlighted significant changes in metabolic pathways, flagellar assembly, and bacterial secretion systems. A protein-protein interaction network revealed clusters associated with ribosomal function, cell envelope maintenance, and motility. The acidic periplasmic protein <em>Cj0424</em> (8.92-fold), previously linked to biofilm formation and oxidative stress response, was the most upregulated protein. Notably, no virulence-associated proteins were detected under cold storage conditions. These findings suggest that <em>C. jejuni</em> employs a multifaceted stress response to low temperatures, enhancing its persistence in food matrices and posing a potential transmission risk.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 105020"},"PeriodicalIF":4.6,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Quorum quenching through natural and nontoxic N-acyl homoserine lactonase (AHL-lactonase) has been regarded as a promising approach for inactivating QS-mediated bacterial spoilage. However, their poor catalytic performance remains a major challenge for practical application. To address these limitations, we developed an efficient rational design strategy for AHL lactonase AiiA to obtain a variant with high catalytic efficiency and a broad substrate spectrum, based on computer-aided structural analysis, molecular dynamics simulation, and energy calculation. Results showed that three highly flexible regions in AiiA were identified as vital sites to recognize and position different substrates, possessing high engineering potential. Among the obtained 10 mutants, AiiAA130T exhibited the strongest degradation against short-chain AHL (C4-HSL and C6-HSL), along with improved thermostability, compared to wild-type enzyme (AiiAWT). In Pseudomonas fluorescens PF07, a majority of AHLs were quenched to undetectable levels by AiiAA130T, and the lactone ring of C4-HSL was verified to hydrolyze and produce form butyryl-L-homoserine. Its biofilm biomass, exopolysaccharides, exoprotein contents, and exoprotease activity were effectively repressed by 64.63 %, 48.86 %, 51.85 %, 61.50 % by AiiAA130T, respectively, in contrast with 46.51 %, 29.08 %, 23.55 %, 19.5 % by AiiAWT, without affecting bacterial growth. Moreover, the transcription levels of 16 crucial QS and biofilm-related genes in PF07 were dramatically downregulated (P < 0.05), as evidenced by qRT-PCR. In contrast with the slight preservation for AiiAWT, AiiAA130T effectively retarded the fillet deterioration of large yellow croaker and extended their shelf life by 2 days. Overall, this study presents an efficient strategy for modifying AHL lactonase and yields a high-performance mutant, offering the application potential of AHL lactonase for controlling QS-mediated microbial spoilage of seafood.
{"title":"Efficient quenching activity and thermostability of N-acyl homoserine lactonase AiiA against fish spoilage mediated by Pseudomonas fluorescens via rational design","authors":"Jiashi Li, Zhong Lu, Xiaoli Zeng, Hanxiao Zhang, Haixia Lu, Lifang Feng , Junli Zhu","doi":"10.1016/j.fm.2025.105002","DOIUrl":"10.1016/j.fm.2025.105002","url":null,"abstract":"<div><div>Quorum quenching through natural and nontoxic <em>N</em>-acyl homoserine lactonase (AHL-lactonase) has been regarded as a promising approach for inactivating QS-mediated bacterial spoilage. However, their poor catalytic performance remains a major challenge for practical application. To address these limitations, we developed an efficient rational design strategy for AHL lactonase AiiA to obtain a variant with high catalytic efficiency and a broad substrate spectrum, based on computer-aided structural analysis, molecular dynamics simulation, and energy calculation. Results showed that three highly flexible regions in AiiA were identified as vital sites to recognize and position different substrates, possessing high engineering potential. Among the obtained 10 mutants, AiiA<sup>A130T</sup> exhibited the strongest degradation against short-chain AHL (C<sub>4</sub>-HSL and C<sub>6</sub>-HSL), along with improved thermostability, compared to wild-type enzyme (AiiA<sup>WT</sup>). In <em>Pseudomonas fluorescens</em> PF07, a majority of AHLs were quenched to undetectable levels by AiiA<sup>A130T</sup>, and the lactone ring of C<sub>4</sub>-HSL was verified to hydrolyze and produce form butyryl-L-homoserine. Its biofilm biomass, exopolysaccharides, exoprotein contents, and exoprotease activity were effectively repressed by 64.63 %, 48.86 %, 51.85 %, 61.50 % by AiiA<sup>A130T</sup>, respectively, in contrast with 46.51 %, 29.08 %, 23.55 %, 19.5 % by AiiA<sup>WT</sup>, without affecting bacterial growth. Moreover, the transcription levels of 16 crucial QS and biofilm-related genes in PF07 were dramatically downregulated (<em>P</em> < 0.05), as evidenced by qRT-PCR. In contrast with the slight preservation for AiiA<sup>WT</sup>, AiiA<sup>A130T</sup> effectively retarded the fillet deterioration of large yellow croaker and extended their shelf life by 2 days. Overall, this study presents an efficient strategy for modifying AHL lactonase and yields a high-performance mutant, offering the application potential of AHL lactonase for controlling QS-mediated microbial spoilage of seafood.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 105002"},"PeriodicalIF":4.6,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2025-12-12DOI: 10.1016/j.fm.2025.105004
Maureen Kuboka , Ianetta Mutie , Karin Artursson , Johanna Lindahl , Gunnar Carlsson , Florence Mutua , Delia Grace
Pathogenic Escherichia coli, Salmonella spp. and Campylobacter spp. are bacteria associated with foodborne diseases. This systematic review and meta-analysis investigates the prevalence of these pathogens in foods sold across seven East African Community (EAC) countries and identifies key risk factors for contamination. A comprehensive search for peer-reviewed papers and grey literature was conducted in six databases (PubMed, CAB Direct, African Journals Online, Google Scholar, ScienceDirect, and Web of Science), as well as 12 online repositories. The review encompassed studies published in English and French between January 2000 and June 2022, adhering to the 2020 guidelines for the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Eligible studies employed probabilistic sampling and reported the proportion of contaminated samples. Out of 4134 initial records, 53 studies met the inclusion criteria. Most were conducted in Kenya (n = 22) and Tanzania (n = 21), with no eligible studies found for Burundi and South Sudan. E. coli and Salmonella spp. were the most frequently studied pathogens, while Campylobacter spp. was less represented. Using a random-effects model in Stata®, pooled prevalence estimates were 41 % for E. coli (95 % CI: 34–52 %), 12 % for Salmonella spp. (95 % CI: 12–27 %), and 9 % for Campylobacter spp. (95 % CI: 7–32 %). Significant heterogeneity was observed and further explored through meta-regression and subgroup analyses. Contamination levels varied by food type, processing status, sample size, and country. Meat, especially poultry, showed the highest prevalence of bacterial contamination across all pathogens. Alarmingly, beverages were also highly contaminated, with E. coli detected in 66.3 % (95 % CI: 31–89 %) and Salmonella spp. in 11.8 % (95 % CI: 1–55 %) of samples. Key risk factors included poor hygiene practices, inadequate sanitation, high storage temperatures, and a lack of food safety training. These findings underscore the urgent need for improved food safety measures in the EAC region for improved public health and support trade advancement. The study also highlights critical gaps in surveillance, particularly for Campylobacter spp., pathogenic E. coli, and data from some EAC countries.
{"title":"Prevalence of Escherichia coli, Campylobacter spp. and Salmonella spp. in the East African Community: a systematic literature review and meta-analysis","authors":"Maureen Kuboka , Ianetta Mutie , Karin Artursson , Johanna Lindahl , Gunnar Carlsson , Florence Mutua , Delia Grace","doi":"10.1016/j.fm.2025.105004","DOIUrl":"10.1016/j.fm.2025.105004","url":null,"abstract":"<div><div>Pathogenic <em>Escherichia coli</em>, <em>Salmonella</em> spp. and <em>Campylobacter</em> spp. are bacteria associated with foodborne diseases. This systematic review and meta-analysis investigates the prevalence of these pathogens in foods sold across seven East African Community (EAC) countries and identifies key risk factors for contamination. A comprehensive search for peer-reviewed papers and grey literature was conducted in six databases (PubMed, CAB Direct, African Journals Online, Google Scholar, ScienceDirect, and Web of Science), as well as 12 online repositories. The review encompassed studies published in English and French between January 2000 and June 2022, adhering to the 2020 guidelines for the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Eligible studies employed probabilistic sampling and reported the proportion of contaminated samples. Out of 4134 initial records, 53 studies met the inclusion criteria. Most were conducted in Kenya (n = 22) and Tanzania (n = 21), with no eligible studies found for Burundi and South Sudan. <em>E. coli</em> and <em>Salmonella</em> spp. were the most frequently studied pathogens, while <em>Campylobacter</em> spp. was less represented. Using a random-effects model in Stata®, pooled prevalence estimates were 41 % for <em>E. coli</em> (95 % CI: 34–52 %), 12 % for <em>Salmonella</em> spp. (95 % CI: 12–27 %), and 9 % for <em>Campylobacter</em> spp. (95 % CI: 7–32 %). Significant heterogeneity was observed and further explored through meta-regression and subgroup analyses. Contamination levels varied by food type, processing status, sample size, and country. Meat, especially poultry, showed the highest prevalence of bacterial contamination across all pathogens. Alarmingly, beverages were also highly contaminated, with <em>E. coli</em> detected in 66.3 % (95 % CI: 31–89 %) and <em>Salmonella</em> spp. in 11.8 % (95 % CI: 1–55 %) of samples. Key risk factors included poor hygiene practices, inadequate sanitation, high storage temperatures, and a lack of food safety training. These findings underscore the urgent need for improved food safety measures in the EAC region for improved public health and support trade advancement. The study also highlights critical gaps in surveillance, particularly for <em>Campylobacter</em> spp., pathogenic <em>E. coli</em>, and data from some EAC countries.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 105004"},"PeriodicalIF":4.6,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With rising interest in legume-based fermented products, traditional legume fermentation practices are gaining renewed attention. One such example is Kaak, a traditional Lebanese baked product made using naturally fermented chickpea-soaked water. This study presents the first comprehensive analysis of Kaak production and microbial species diversity. Despite practices variations among bakers, five key steps were consistently identified: chickpea-soaked water fermentation, preparation of two starters, dough preparation and baking. Fungal species diversity, analyzed using Illumina Miseq ITS1 sequencing, revealed high variation in fungal species composition of chickpea-soaked water (W) between bakeries, with dominance of Saccharomyces cerevisiae in some samples. In contrast, the fermented starters (F1 and F2) and the dough (D) consistently included Alternaria species and S. cerevisiae. Bacterial species analysis, using 16S rDNA V3-V4 sequencing, revealed a dominance of Weissella species in some dough samples while Clostridium perfringens was consistently the most abundant bacterial species in chickpea-soaked water and throughout the process. This species seems to have a major contribution to the organoleptic properties of traditional Kaak made with chickpea-soaked water as evidenced by descriptive quantitative sensory analysis that revealed unique distinctive features of traditional Kaak, pertaining to aroma, taste and texture in comparison to Kaak made with commercial S. cerevisiae strains without chickpea-soaked water. Altogether, these findings reveal, for the first time, the unique sensorial profile of traditional Kaak associated with its specific microbial diversity and traditional production. These findings contribute to a deeper understanding of traditional legume-based fermentation and highlight the value of preserving artisanal practices.
{"title":"From process to flavor: Microbial and sensory characterization of traditional Kaak and its artisanal production methods","authors":"Rachelle Alhosry , Lucie Arnould , Olivier Rué , Rosette Daoud , Pierre Abi Nakhoul , Delphine Sicard , Marie-José Ayoub","doi":"10.1016/j.fm.2025.104999","DOIUrl":"10.1016/j.fm.2025.104999","url":null,"abstract":"<div><div>With rising interest in legume-based fermented products, traditional legume fermentation practices are gaining renewed attention. One such example is Kaak, a traditional Lebanese baked product made using naturally fermented chickpea-soaked water. This study presents the first comprehensive analysis of Kaak production and microbial species diversity. Despite practices variations among bakers, five key steps were consistently identified: chickpea-soaked water fermentation, preparation of two starters, dough preparation and baking. Fungal species diversity, analyzed using Illumina Miseq ITS1 sequencing, revealed high variation in fungal species composition of chickpea-soaked water (W) between bakeries, with dominance of <em>Saccharomyces cerevisiae</em> in some samples. In contrast, the fermented starters (F1 and F2) and the dough (D) consistently included <em>Alternaria</em> species and <em>S. cerevisiae.</em> Bacterial species analysis, using 16S rDNA V3-V4 sequencing, revealed a dominance of <em>Weissella</em> species in some dough samples while <em>Clostridium perfringens</em> was consistently the most abundant bacterial species in chickpea-soaked water and throughout the process. This species seems to have a major contribution to the organoleptic properties of traditional Kaak made with chickpea-soaked water as evidenced by descriptive quantitative sensory analysis that revealed unique distinctive features of traditional Kaak, pertaining to aroma, taste and texture in comparison to Kaak made with commercial <em>S. cerevisiae</em> strains without chickpea-soaked water. Altogether, these findings reveal, for the first time, the unique sensorial profile of traditional Kaak associated with its specific microbial diversity and traditional production. These findings contribute to a deeper understanding of traditional legume-based fermentation and highlight the value of preserving artisanal practices.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 104999"},"PeriodicalIF":4.6,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2025-12-03DOI: 10.1016/j.fm.2025.104989
Hui Zhang , Meiyue Han , Zemin Pang , Weiwei Li , Xiuting Li , Baoguo Sun
Lactic acid stress is common in traditional fermented foods. Pichia kudriavzevii owes its industrial prevalence to its superior acid tolerance, making deciphering its response mechanism imperative for sustainable fermentation processes. This work explored the remarkable acid tolerance of P. kudriavzevii, which can tolerate 80 g/L lactic acid. The key lactic acid tolerance gene lldD of P. kudriavzevii was determined through transcriptomic analysis. Importantly, this work knocked out the key gene lldD related to lactic acid tolerance for the first time by using the CRISPR-Cas9 technology. Meanwhile, the lldD knockout strain (pk-ΔlldD) was successfully constructed. There were significant differences between pk-ΔlldD and P. kudriavzevii in terms of tolerance to lactic acid, metabolism of lactic acid, utilization of glucose and ethanol production. In addition, the deletion of the gene lldD has a significant impact on the ABC transporter and metabolites of the amino acid metabolic pathway in P. kudriavzevii. In conclusion, this work provides a theoretical basis for engineering high acid-tolerant industrial yeast strains through targeted genetic modification. It helps enhance the stability of fermentation processes under lactic acid stress and ultimately lays a foundation for promoting efficient and low-loss production in the fermentation industry.
{"title":"The lldD lactate dehydrogenase is a determinant of lactic acid tolerance in Pichia kudriavzevii by pyruvate metabolism pathway","authors":"Hui Zhang , Meiyue Han , Zemin Pang , Weiwei Li , Xiuting Li , Baoguo Sun","doi":"10.1016/j.fm.2025.104989","DOIUrl":"10.1016/j.fm.2025.104989","url":null,"abstract":"<div><div>Lactic acid stress is common in traditional fermented foods. <em>Pichia kudriavzevii</em> owes its industrial prevalence to its superior acid tolerance, making deciphering its response mechanism imperative for sustainable fermentation processes. This work explored the remarkable acid tolerance of <em>P. kudriavzevii</em>, which can tolerate 80 g/L lactic acid. The key lactic acid tolerance gene <em>lldD</em> of <em>P. kudriavzevii</em> was determined through transcriptomic analysis. Importantly, this work knocked out the key gene <em>lldD</em> related to lactic acid tolerance for the first time by using the CRISPR-Cas9 technology. Meanwhile, the <em>lldD</em> knockout strain (pk-Δ<em>lldD</em>) was successfully constructed. There were significant differences between pk-Δ<em>lldD</em> and <em>P. kudriavzevii</em> in terms of tolerance to lactic acid, metabolism of lactic acid, utilization of glucose and ethanol production. In addition, the deletion of the gene <em>lldD</em> has a significant impact on the ABC transporter and metabolites of the amino acid metabolic pathway in <em>P. kudriavzevii</em>. In conclusion, this work provides a theoretical basis for engineering high acid-tolerant industrial yeast strains through targeted genetic modification. It helps enhance the stability of fermentation processes under lactic acid stress and ultimately lays a foundation for promoting efficient and low-loss production in the fermentation industry.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 104989"},"PeriodicalIF":4.6,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2025-12-11DOI: 10.1016/j.fm.2025.105008
Ran Li , Geertrui Rasschaert , Ulric Van Rossum , Sjarlotte Willems , Hans Steenackers , Koen De Reu
Listeria monocytogenes can persist for longer periods in the food production environment. Studies show that certain L. monocytogenes strains are more persistent and others more transient. One of the persistent strategies mentioned in literature is biofilm protection. We studied the difference in biofilm formation of persistent and transient L. monocytogenes isolates at lower temperatures, which better reflect realistic conditions in food production environments. First, the dynamic changes in biofilm biomass and planktonic cell numbers over nine days at 10 °C and 18 °C were studied for nine isolates randomly selected from 40 persistent isolates. Results showed that biofilm production was highest on day three, with an optical density ranging from 0.18 to 0.62 at 10 °C and from 0.29 to 0.94 at 18 °C for the nine L. monocytogenes isolates. Next, the biofilm formation capacity of 40 persistent and 36 transient isolates was studied using the crystal violet staining method after 3 days of incubation at both temperatures. Temperature proved to be an influential factor, with the higher temperature supporting increased biofilm production. Additionally, persistent L. monocytogenes isolates produced significantly more biofilm than transient isolates at 10°C and 18°C, with a more pronounced difference at 18 °C. Finally, the effect of intra-pulsotype variation in biofilm-forming potential was analyzed. Seventeen pairs of isolates exhibited significant differences at least at one temperature (p < 0.05). These findings improve further insights into the factors contributing to L. monocytogenes persistence and offer valuable information for controlling contamination in the food industry.
{"title":"Biofilm formation and intra-pulsotype variability of Listeria monocytogenes at temperatures relevant to food processing environments","authors":"Ran Li , Geertrui Rasschaert , Ulric Van Rossum , Sjarlotte Willems , Hans Steenackers , Koen De Reu","doi":"10.1016/j.fm.2025.105008","DOIUrl":"10.1016/j.fm.2025.105008","url":null,"abstract":"<div><div><em>Listeria monocytogenes</em> can persist for longer periods in the food production environment. Studies show that certain <em>L. monocytogenes</em> strains are more persistent and others more transient. One of the persistent strategies mentioned in literature is biofilm protection. We studied the difference in biofilm formation of persistent and transient <em>L. monocytogenes</em> isolates at lower temperatures, which better reflect realistic conditions in food production environments. First, the dynamic changes in biofilm biomass and planktonic cell numbers over nine days at 10 °C and 18 °C were studied for nine isolates randomly selected from 40 persistent isolates. Results showed that biofilm production was highest on day three, with an optical density ranging from 0.18 to 0.62 at 10 °C and from 0.29 to 0.94 at 18 °C for the nine <em>L. monocytogenes</em> isolates. Next, the biofilm formation capacity of 40 persistent and 36 transient isolates was studied using the crystal violet staining method after 3 days of incubation at both temperatures. Temperature proved to be an influential factor, with the higher temperature supporting increased biofilm production. Additionally, persistent <em>L. monocytogenes</em> isolates produced significantly more biofilm than transient isolates at 10°C and 18°C, with a more pronounced difference at 18 °C. Finally, the effect of intra-pulsotype variation in biofilm-forming potential was analyzed. Seventeen pairs of isolates exhibited significant differences at least at one temperature (<em>p</em> < 0.05). These findings improve further insights into the factors contributing to <em>L. monocytogenes</em> persistence and offer valuable information for controlling contamination in the food industry.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 105008"},"PeriodicalIF":4.6,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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