International journal of food microbiology最新文献

{"title":"Determining the core bacterial and fungal genera in table olive fermentations","authors":"Annamaria Ricciardi ,&nbsp;Francisco Noé Arroyo López ,&nbsp;Marilisa Giavalisco ,&nbsp;Rocchina Pietrafesa ,&nbsp;Eugenio Parente","doi":"10.1016/j.ijfoodmicro.2025.111344","DOIUrl":"10.1016/j.ijfoodmicro.2025.111344","url":null,"abstract":"<div><div>Table olives are among the most ancient and important fermented foods of the Mediterranean basin. Their production is still strongly related to traditional practices, and the lack of thermal treatments, the reliance on natural contamination and selective factors (NaCl, pH, occurrence of phenolics, etc.) determine the dynamics of the microbial community. Lactic acid bacteria (LAB) and yeasts have a pivotal role in table olive microbial communities, but several halophilic and alkalophilic microorganisms may also contribute, positively or negatively, to the quality and safety of this fermented vegetable food.</div><div>We have used metataxonomic data extracted from the FoodMicrobionet database to provide quantitative insights on the structure of bacterial and fungal microbial communities of table olives and to identify core genera in different trade preparations.</div><div><em>Celerinatantimonas</em> and <em>Lactiplantibacillus</em> were the most prevalent genera among bacteria, followed by several LAB, halophilic and alkalophilic lactic acid bacteria (HALAB) and Gram negatives, including non-halophilic species. Similarly, 3 fungal genera (<em>Pichia</em>, <em>Candida</em>, and <em>Wickerhamomyces</em>) were the most abundant and prevalent among fungi.</div><div>The distribution of both bacteria and fungi varied significantly in different olive varieties, among olives, brines and contact surfaces or materials, and at different production stages, and no clear grouping related to the combination of ripeness and trade preparation was found, although HALAB were characteristically abundant in Spanish style green olives. Addition of starter cultures affected the composition and dynamics of microbial communities to a variable extent.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"442 ","pages":"Article 111344"},"PeriodicalIF":5.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144662120","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}

{"title":"A novel antimicrobial peptide NDYT-8 with broad-spectrum activity from Bacillus subtilis natto: Antibacterial mechanism and sequence simplification","authors":"Yunxin Yi ,&nbsp;Dongning Liu ,&nbsp;Chao Cheng ,&nbsp;Moutong Chen ,&nbsp;Teodora Emilia Coldea ,&nbsp;Haifeng Zhao","doi":"10.1016/j.ijfoodmicro.2025.111349","DOIUrl":"10.1016/j.ijfoodmicro.2025.111349","url":null,"abstract":"<div><div>The discovery of antimicrobial peptides (AMPs) holds critical significance in combating antibiotic resistance. In this study, a novel efficient antimicrobial peptide NDYT-8 with broad-spectrum activity was isolated and identified from <em>Bacillus subtilis</em> natto. Whole-genome sequencing revealed that NDYT-8 potentially derived from the minimal domain of 6-phosphogluconate dehydrogenase, exhibited broad-spectrum antibacterial activity against common foodborne pathogens, particularly <em>Escherichia coli</em> and <em>Salmonella enterica</em>, with a minimum inhibitory concentration (MIC) value of 16 μg/mL. Mechanistic investigations demonstrated that NDYT-8 exerted its antibacterial effects through increasing membrane permeability, as evidenced by the leakage of lactic dehydrogenase, intracellular proteins, and nucleic acids from the indicator strain cells. Furthermore, application of NDYT-8 in a tofu preservation model demonstrated significant short-term antibacterial efficacy, which achieved an 87.0 % reduction in bacterial count within 2 h and sustained this antibacterial effect for up to 10 h at a concentration of 20 mg/mL. Finally, the structure-activity relationship of NDYT-8 revealed that the number of positive charges or alkaline amino acids was the decisive factor in determining its antibacterial efficacy. RKILLMVK, a shorter peptide designed by deleting two amino acids, maintained its antibacterial activity against <em>Escherichia coli</em> similar to NDYT-8. These findings highlight the potential of NDYT-8 and its variants as a promising natural preservative in the food industry.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"442 ","pages":"Article 111349"},"PeriodicalIF":5.0,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144656090","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}

{"title":"Antibacterial mechanism of ultrasound combined with oregano essential oil nano-emulsion on Escherichia coli O157:H7 and application in cherry tomatoes storage","authors":"Kai Fan ,&nbsp;Lijing Li ,&nbsp;Jiaxin Wu","doi":"10.1016/j.ijfoodmicro.2025.111348","DOIUrl":"10.1016/j.ijfoodmicro.2025.111348","url":null,"abstract":"<div><div><em>Escherichia coli</em> (<em>E. coli</em>) O157:H7 on the surfaces of fruits and vegetables poses significant risks to human health. This study assessed the bactericidal mechanisms of ultrasound (US) and oregano essential oil nanoemulsion (OEON) against <em>E. coli</em>, as well as their application in storage preservation of cherry tomatoes. The results showed that US + OEON treatment exhibited markedly superior inactivation effect on <em>E. coli</em> compared to their individual treatments. OEON (2 %) combined with ultrasonic treatment (375 W) for 4 min reduced the viable <em>E. coli</em> count by 5.06 ± 0.22 log CFU/mL. This performance markedly exceeded that of single treatments, with US achieving 1.15 ± 0.10 log CFU/mL reduction and OEON 1.04 ± 0.18 log CFU/mL reduction. The synergistic treatment intensified lipid peroxidation of bacterial cell membranes and enhanced membrane permeability. Furthermore, in preservation applications on cherry tomatoes, US + OEON effectively suppressed total viable counts, achieving a 1.44 ± 0.19 log CFU/mL reduction after 4-min treatment with 2 % OEON combined with 375 W US. This approach induced no adverse effects on cherry tomato color, texture, nutritional composition, or antioxidant properties. In summary, compared to US or OEON treatment alone, US + OEON treatment exhibits superior antibacterial effect and improves the storage quality of cherry tomatoes.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"442 ","pages":"Article 111348"},"PeriodicalIF":5.0,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144634245","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}

{"title":"Survival of Listeria monocytogenes biofilms and planktonic cells on cooked ham in a contamination-storage-digestion process","authors":"Salud María Serrano-Heredia ,&nbsp;Javier Sánchez-Martín ,&nbsp;José Luis López-Carmona ,&nbsp;Mónica Sánchez-Gutiérrez ,&nbsp;Antonio Valero Díaz ,&nbsp;Elena Carrasco Jiménez","doi":"10.1016/j.ijfoodmicro.2025.111346","DOIUrl":"10.1016/j.ijfoodmicro.2025.111346","url":null,"abstract":"<div><div>In 2023, listeriosis experienced a significant increase in Europe, with 2952 invasive cases and 19.70 % mortality rate, being the ready-to-eat foods category identified as the mostly involved. This study focused on the survival of <em>L. monocytogenes</em> through a process of food contamination-storage-digestion. For this, cooked ham was artificially contaminated with biofilm or planktonic cells, followed or not by vacuum-packed storage at 7 °C for 7 days, and submitted to <em>in vitro</em> digestion. Enumeration analysis was performed at different stages during the contamination-storage-digestion process. Contamination of cooked ham by 90-s transfer from biofilm revealed inter-strain variability, with a global transfer rate of 14.07 %. On the food, <em>L. monocytogenes</em> grew ≈0.5 log during storage from an initial concentration of 3.53 log CFU/cm². <em>In vitro</em> digestion of contaminated food with or without storage, resulted in a reduction of ≈−0.5 log. In the case of planktonic cells, great differences were found after <em>in vitro</em> digestion as a function of storage (≈−2.1 log or ≈−0.6 log reduction from the initial concentration without or with storage, respectively). Interestingly, an unexpectedly high concentration of the pathogen was found after food storage and digestion. It is plausible that a biofilm was formed during storage of the contaminated food with planktonic cells. In any case, high variability in numbers was observed after storage and digestion, being L196 the most resistant strain. More research in omics sciences is needed to clarify <em>L. monocytogenes</em> behaviour.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"442 ","pages":"Article 111346"},"PeriodicalIF":5.0,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655910","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}

{"title":"Listeria monocytogenes growth under well-controlled CO2, pH, and temperature conditions through a novel gas-controlling system","authors":"Seren Oguz ,&nbsp;Vincenzo Turrisi ,&nbsp;Lotta Kuuliala ,&nbsp;Mariem Somrani ,&nbsp;Frank Devlieghere","doi":"10.1016/j.ijfoodmicro.2025.111343","DOIUrl":"10.1016/j.ijfoodmicro.2025.111343","url":null,"abstract":"<div><div>While effectively extending the shelf life of perishable foods at low temperatures by delaying the growth of spoilage microorganisms, modified atmosphere packaging (MAP) may favor the growth of certain pathogens under refrigerated and anaerobic environments. In particular, <em>Listeria monocytogenes</em> poses a major safety concern and has caused a significant increase in foodborne outbreaks over the last five years in EU. Although this pathogen has received great attention in the field of predictive microbiology, the exact relations between its growth and interconnected stress factors (CO₂, pH, and temperature) still need to be better understood, calling for extensive data collection. Thus, this study aims to understand the impact(s) of these factors by analyzing the behavior of <em>L. monocytogenes</em> in a liquid medium under well-controlled anaerobic conditions with varying CO₂ levels (0–20–40-60 %), pH values (7.7, 6.2), and temperatures (4, 7 °C). Three primary growth models – Logistic, modified Gompertz, and Baranyi – were evaluated to fit the growth data from controlled experiments, performed under anaerobic atmospheres employing an innovative gas-washing bottle incubation system (GBIS). The Baranyi model presented the best growth model to fit the growth data. This study showed that higher CO₂ (60 %) individually reduced the maximum growth rate (<em>μ</em>_<em>max</em>, 1/day) from 0.32 to 0.21 at 4 °C and from 0.46 to 0.39 at 7 °C. Similarly, lower pH decreased the <em>μ</em>_<em>max</em> from 0.40 to 0.32 at 4 °C and from 0.68 to 0.46 at 7 °C. Moreover, decreasing temperature from 7 °C to 4 °C led to a reduction in <em>μ</em>_<em>max</em> from 0.68 to 0.40 at pH 7.7 and from 0.46 to 0.32 at pH 6.2, while <em>μ</em>_<em>max</em> decreased from 0.39 to 0.21 in the presence of 60 % CO₂. In terms of interactions, lower temperature enhanced the growth-reducing effect of higher CO₂. The same stressing factor, conversely, reduced the low pH-induced effect on the growth in CO₂-free conditions. Similarly, lower pH decreased the growth-reducing effect of lower temperature. These insights highlighted the importance of studying well-controlled experimental conditions when aiming at designing MAP packaging to achieve safe, sustainable packaging solutions.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"441 ","pages":"Article 111343"},"PeriodicalIF":5.0,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144605725","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}

{"title":"Clonal distribution of livestock-associated methicillin-resistant Staphylococcus aureus in pig farms of Korea: Emergence of a novel variant staphylococcal chromosome cassette mec","authors":"Hyeonwoo Cho ,&nbsp;Yeona Kim ,&nbsp;Beomsoon Jang ,&nbsp;Kun Taek Park","doi":"10.1016/j.ijfoodmicro.2025.111341","DOIUrl":"10.1016/j.ijfoodmicro.2025.111341","url":null,"abstract":"<div><div>Livestock-associated methicillin-resistant <em>Staphylococcus aureus</em> (LA-MRSA) is a considerable concern in pig farming due to its antimicrobial resistance and zoonotic potential. However, data on the genetic characteristics of LA-MRSA in Korean pig farms remain limited. This study investigated the prevalence, antimicrobial resistance profiles, and genetic diversity of LA-MRSA in Korean pig farms using whole-genome sequencing (WGS). Overall, 1515 samples were collected from 74 pig farms nationwide, yielding 96 MRSA isolates from 17 farms. All isolates exhibited multidrug resistance, with CC398 (ST398, <em>spa</em> type t571, SCC<em>mec</em> type V) as the dominant lineage. Notably, 35 isolates carried an SCC<em>mec</em> type III + V combination, which has not been reported in Korea. WGS analysis of 28 representative isolates identified six clonal clusters and seven singletons, with potential inter-farm transmission observed in four clusters spanning different provinces. Complete genome analysis revealed a novel SCC<em>mec</em> variant, found in a distinct cluster of six isolates from two separate farms purchasing pigs from the same breeding company. These findings highlight the ongoing clonal expansion of CC398, emergence of novel SCC<em>mec</em> elements, and potential role of breeding networks in LA-MRSA dissemination. Enhanced surveillance, biosecurity measures, and antimicrobial stewardship are necessary to mitigate the spread of LA-MRSA within pig farms and its potential impact on public health.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"441 ","pages":"Article 111341"},"PeriodicalIF":5.0,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144597022","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}

{"title":"Unraveling Hepatitis E Virus susceptibility to heat treatment, pH reduction and drying in pork meat","authors":"Tatjana Locus ,&nbsp;Michael Peeters ,&nbsp;Sophie Lamoral ,&nbsp;Sjarlotte Willems ,&nbsp;Louise De Lange ,&nbsp;Ali Harmoush ,&nbsp;Steven Van Gucht ,&nbsp;Thomas Vanwolleghem ,&nbsp;Ellen Lambrecht","doi":"10.1016/j.ijfoodmicro.2025.111342","DOIUrl":"10.1016/j.ijfoodmicro.2025.111342","url":null,"abstract":"<div><div>Foodborne Hepatitis E virus infection, linked mainly to pork consumption, is a significant public health issue in Europe. Despite the known risk of HEV contamination in pork, the effectiveness of meat processing methods in inactivating the virus is unclear, emphasizing the need for comprehensive investigations. This study examined the impact of common meat processing practices—heating, drying, and pH reduction—on inactivation of HEV in both suspension and pork pâté and sausages.</div><div>HEV suspensions were exposed to various temperatures (94 °C, 71 °C, 61 °C for 10 min; 73 °C, 100 °C for 20 min) and pH levels (pH 6.5, 6.1, 5.5 for 7 days at 7 °C and 20 °C). Pork pâtés were heated to temperatures of 68 °C, 72 °C, 80 °C, and 99 °C, while sausages were dried for up to 14 days and acidified to pH 4.1. HEV infectivity was assessed via immunostaining and methods evaluating HEV integrity.</div><div>Thermal treatment reduced HEV viral load variably, with complete inactivation only at 99 °C (&gt;3.5 log reduction). Drying reduced viral RNA in sausages, but intact viral particles remained for up to 14 days. pH reduction showed minimal impact on viral particle integrity. Results in suspension were consistent with those in meat matrices.</div><div>This study is among the first to demonstrate in actual meat matrices that current meat processing methods might be insufficient for eliminating intact HEV particles in high-risk products like ready-to-eat pâté and dried sausages. The findings highlight the need for more effective HEV inactivation techniques and improved food safety measures to reduce the risk of foodborne HEV infections.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"441 ","pages":"Article 111342"},"PeriodicalIF":5.0,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144597021","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}

{"title":"Adaptive responses and molecular mechanisms of Lactiplantibacillus plantarum to citric acid stress","authors":"Han Xie ,&nbsp;Wei Zhang ,&nbsp;Cong-Rong Shi ,&nbsp;Rui-Shan Liu ,&nbsp;Zhen-Ming Lu ,&nbsp;Li-Juan Chai ,&nbsp;Hong-Yu Xu ,&nbsp;Jin-Song Shi ,&nbsp;Xiao-Juan Zhang ,&nbsp;Zheng-Hong Xu","doi":"10.1016/j.ijfoodmicro.2025.111340","DOIUrl":"10.1016/j.ijfoodmicro.2025.111340","url":null,"abstract":"<div><div><em>Lactiplantibacillus plantarum</em>, known for its environmental adaptability due to genetic flexibility, was subjected to 180 days of citric acid exposure (a prevalent stressor derived from plants) to understand its adaptive response to environmental stress. The evolved strain demonstrated a 2.4-fold increase in cell density under 10 g/L citric acid stress, indicating significantly improved citric acid tolerance compared to the ancestral strain. It also demonstrated cross-protection, particularly under HCl and cold temperature challenges. During early-stage adaptation, reversal mutations were observed, and most plastic changes indicated by gene expression alterations in the ancestral strain were reversed via genetic adaptation, indicating a compensatory effect of these mutations. Whole-genome sequencing identified a key mutation in the citrate transporter gene <em>nacT</em> (F178V). This mutation, validated through point mutation and homologous modeling, enhanced citrate transport and utilization. When applied to ferment citric acid-rich materials (green plums, lemons, passion fruits, pineapples, oranges, and white grapefruits), the evolved and point-mutated strains exhibited 3.7- and 3.4-fold higher citric acid consumption than the ancestral strain, respectively. Notably, the fruits fermented by evolved strain demonstrated significantly elevated viable cell counts, as well as a richer taste and more pleasant aroma profile based on sensory analysis. These findings advance our understanding of environmental stress adaptation and underscore the potential application of evolved strain in food fermentation.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"441 ","pages":"Article 111340"},"PeriodicalIF":5.0,"publicationDate":"2025-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588595","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}

{"title":"Control of postharvest soft rot of tomato fruit by kojic acid and the potential mechanisms involved in the inhibition on Pectobacterterium carotovorum subsp. carotovorum","authors":"Yu Xin ,&nbsp;Xiaoyun Zhang ,&nbsp;Esa Abiso Godana ,&nbsp;Solairaj Dhanasekarana ,&nbsp;Yuanyuan Xie ,&nbsp;Jun Li ,&nbsp;Lina Zhao ,&nbsp;Hongyin Zhang","doi":"10.1016/j.ijfoodmicro.2025.111339","DOIUrl":"10.1016/j.ijfoodmicro.2025.111339","url":null,"abstract":"<div><div>Soft rot is the major bacterial disease affecting postharvest tomatoes. After the tomato fruit is infected by the pathogen, <em>Pectobacterterium carotovorum</em> subsp. <em>carotovorum</em> (<em>Pcc</em>), the disease rapidly develops and leads to fruit deterioration. Kojic acid is a natural metabolite of several fungi during the fermentation process of traditional oriental food. In this study, we investigated the efficacy of kojic acid (fermentation product of <em>Aspergillus oryzae</em>) against tomato soft rot and explored the underlying mechanisms. Kojic acid at the concentration of 4 mg/mL exhibited significant efficacy in controlling tomato fruit soft rot by directly suppressing the pathogen's growth, both in vitro and in vivo, and the application of kojic acid has no adverse effects on the quality of tomatoes. The 1/2 minimal inhibitory concentration (MIC), MIC, and 4 mg/mL of kojic acid increased the permeability of the <em>Pcc</em> cell membrane, resulting in the leakage of intracellular substances. In other words, the integrity of the <em>Pcc</em> cell membrane was compromised upon kojic acid treatment. Kojic acid at different concentrations stimulated ROS accumulation and membrane lipid peroxidation of <em>Pcc</em>. In addition, kojic acid was predicted to bind with DNA through three hydrogen bonds based on molecular docking, and the binding of kojic acid to DNA was similar to that of ethidium bromide (EB). This disturbs the normal role of DNA. The control effect of kojic acid against postharvest soft rot of tomato fruit was explored for the first time, and the mechanisms involved in the inhibition of kojic acid on <em>Pcc</em> was revealed.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"442 ","pages":"Article 111339"},"PeriodicalIF":5.0,"publicationDate":"2025-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144631460","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}

{"title":"Genomic and transcriptomic analyses of ropy slime producing Latilactobacillus sakei reveal a specific exopolysaccharide cluster with temperature-dependent transcription activity","authors":"Julia A. Manninen,&nbsp;Per Johansson ,&nbsp;Johanna Björkroth","doi":"10.1016/j.ijfoodmicro.2025.111336","DOIUrl":"10.1016/j.ijfoodmicro.2025.111336","url":null,"abstract":"<div><div><em>Latilactobacillus sakei</em> is a psychrotrophic lactic acid bacterium (LAB) with a wide genomic diversity. It is mainly associated with food fermentation, but some strains can spoil meat products by generation of ropy exopolysaccharide (EPS). Despite the important role of L. <em>sakei</em> in foods, virtually nothing was known about the gene cluster related to the formation of ropy EPS or how temperature affected its expression. Furthermore, no experimental <em>in vitro</em> model system for experimenting with EPS production was available. The ability to form ropy EPS has been evaluated either with an inoculation study or testing the ropiness of a colony.</div><div>To address these limitations, we (I) sequenced the genomes of 59 <em>L. sakei</em> strains, (II) characterized their EPS gene clusters and performed comparative genomic and phylogenetic analyses, (III) developed an <em>in vitro</em> model system for EPS production and (IV) tested the effect of temperature on EPS production using transcriptomic analysis of RNA-seq data from a longitudinal growth experiment at 10 °C and 30 °C.</div><div>Genomic analyses showed showed the existence of one phylogenetically highly similar group of strains. Characterisation of the EPS gene cluster revealed that it differs from known bacterial EPS clusters in that it lacks separate <em>epsB</em> and <em>epsC</em> genes. Temperature had a noticeable effect on EPS production, with strong ropy EPS production at 10 °C whereas no visible EPS was detected at 30 °C. Transcriptomic analyses revealed differences in the EPS cluster activity, with the first half of the cluster being more active at 10 °C and the second half at 30 °C.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"441 ","pages":"Article 111336"},"PeriodicalIF":5.0,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144580385","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}