Pub Date : 2025-12-13DOI: 10.1016/j.fm.2025.105013
Vinícius S.A. Vaz , Jéssica de A.F.F. Finger , Raul F. Pereira , Mariana S. Derami , Jean-Yves Maillard , Maristela S. Nascimento
Salmonella and Cronobacter sakazakii have been associated with outbreaks linked to low-moisture foods (LMF), and their persistence under desiccation stress can contribute to biofilm formation. This study evaluated different dry surface biofilm (DSB) formation protocols on stainless steel (SS) and polypropylene (PP), which differ with the combination of their hydrated (from 24 to 48h) and dry phase (from 48 to 120h). By the end of the protocols (C2), culturable sessile cells (CSC) reached counts up to 7.2 and 7.4 log CFU/cm2 for Salmonella and C. sakazakii, respectively. In general, T5 (8/48 h) resulted in the lowest CSC counts (p < 0.05), ranging from 3.7 to 5.5 log CFU/cm2 for Salmonella and 4.5 to 6.3 log CFU/cm2 for C. sakazakii. In addition, by the end of C2 there was no significant difference (p < 0.05) between the surface materials. After catalase resuscitation, the culturability of the DSB increased between 1.1 log CFU/cm2 and 2.8 log CFU/cm2 for Salmonella, and 0.6 and 2.2 log CFU/cm2 for C. sakazakii, indicating cells in the viable but non-culturable (VBNC) state. Confocal laser scanning microscopy showed the DSB thickness was impacted by the protocol type, being greatest in T1 and T4 (10.4–12.7 μm) and lowest in T3 (3.3–7.1 μm). Morphological changes such as elongation, spherical shape, desiccation, and cell lysis were observed in all biofilms. Overall, the duration of the hydrated phase was the main factor influencing DSB formation and the transition to VBNC state for both pathogens. It highlights the importance of strict moisture control and effective sanitation in LMF plants.
{"title":"Dry surface biofilm of Salmonella and Cronobacter sakazakii: a real concern for the low moisture food industry","authors":"Vinícius S.A. Vaz , Jéssica de A.F.F. Finger , Raul F. Pereira , Mariana S. Derami , Jean-Yves Maillard , Maristela S. Nascimento","doi":"10.1016/j.fm.2025.105013","DOIUrl":"10.1016/j.fm.2025.105013","url":null,"abstract":"<div><div><em>Salmonella</em> and <em>Cronobacter sakazakii</em> have been associated with outbreaks linked to low-moisture foods (LMF), and their persistence under desiccation stress can contribute to biofilm formation. This study evaluated different dry surface biofilm (DSB) formation protocols on stainless steel (SS) and polypropylene (PP), which differ with the combination of their hydrated (from 24 to 48h) and dry phase (from 48 to 120h). By the end of the protocols (C2), culturable sessile cells (CSC) reached counts up to 7.2 and 7.4 log CFU/cm<sup>2</sup> for <em>Salmonella</em> and <em>C. sakazakii,</em> respectively. In general, T5 (8/48 h) resulted in the lowest CSC counts (p < 0.05), ranging from 3.7 to 5.5 log CFU/cm<sup>2</sup> for <em>Salmonella</em> and 4.5 to 6.3 log CFU/cm<sup>2</sup> for <em>C. sakazakii</em>. In addition, by the end of C2 there was no significant difference (p < 0.05) between the surface materials. After catalase resuscitation, the culturability of the DSB increased between 1.1 log CFU/cm<sup>2</sup> and 2.8 log CFU/cm<sup>2</sup> for <em>Salmonella</em>, and 0.6 and 2.2 log CFU/cm<sup>2</sup> for <em>C. sakazakii</em>, indicating cells in the viable but non-culturable (VBNC) state. Confocal laser scanning microscopy showed the DSB thickness was impacted by the protocol type, being greatest in T1 and T4 (10.4–12.7 μm) and lowest in T3 (3.3–7.1 μm). Morphological changes such as elongation, spherical shape, desiccation, and cell lysis were observed in all biofilms. Overall, the duration of the hydrated phase was the main factor influencing DSB formation and the transition to VBNC state for both pathogens. It highlights the importance of strict moisture control and effective sanitation in LMF plants.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 105013"},"PeriodicalIF":4.6,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787686","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 : 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":"2025-12-12","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}
Pub Date : 2025-12-11DOI: 10.1016/j.fm.2025.105014
Fotios Lytras , Muhammad Ahmed Ihsan , Georgios Psakis , Ruben Gatt , Guillermo Cebrián , Javier Raso , Vasilis P. Valdramidis
This study aimed to identify the principal mechanisms of action by which Listeria monocytogenes EGD-e responds to pulsed electric field (PEF) treatments at pH 7.0, given its recognition as a robust target microorganism and strain. Microbiologically challenged buffer samples (pH 7.0) were subjected to pulses with an electric field strength of 20 kV/cm and their transcriptional response was assessed using RNA sequencing. Our analysis revealed 119 differentially expressed genes, 51 of which were upregulated and 68 downregulated. From the 51 upregulated genes, 4 were transcription regulators (lmo1974, glnR, lmo806 and lmo0371) with the potential to influence the resistance of L. monocytogenes EGD-e. Additionally, assessment of 11 isogenic mutants at a PEF treatment (20 kV/cm, 184 kJ/kg) relative to the wild type identified the ΔyneA and ΔclpB deletion mutants as more resistant and more sensitive (p<0.05). Finally, the isogenic mutant ΔclpB was assessed against the wild type at 25 kV/cm at different total specific energies (54, 113, 135 and 160 kJ/kg) resulting in statistical difference(p<0.05) only under the highest parameter. In conclusion, transcriptomic analysis revealed that the primary mechanistic pathways of L. monocytogenes in response to PEF involve the preservation of homeostasis, energy availability, and quorum sensing. Additionally, the increased sensitivity of the ΔclpB mutant highlights a supplementary mechanism related to protein disaggregation and refolding under high-energy. These findings suggest that L. monocytogenes mounts a complex and multifaceted response to PEF treatments. These results can provide insights and support PEF treatment decontamination alone or as pretreatment in combination with other hurdles.
{"title":"Insights on the microbial resistance mechanisms of Listeria monocytogenes to Pulsed Electric Fields (PEF) treatments","authors":"Fotios Lytras , Muhammad Ahmed Ihsan , Georgios Psakis , Ruben Gatt , Guillermo Cebrián , Javier Raso , Vasilis P. Valdramidis","doi":"10.1016/j.fm.2025.105014","DOIUrl":"10.1016/j.fm.2025.105014","url":null,"abstract":"<div><div>This study aimed to identify the principal mechanisms of action by which <em>Listeria monocytogenes</em> EGD-e responds to pulsed electric field (PEF) treatments at pH 7.0, given its recognition as a robust target microorganism and strain. Microbiologically challenged buffer samples (pH 7.0) were subjected to pulses with an electric field strength of 20 kV/cm and their transcriptional response was assessed using RNA sequencing. Our analysis revealed 119 differentially expressed genes, 51 of which were upregulated and 68 downregulated. From the 51 upregulated genes, 4 were transcription regulators (<em>lmo1974, glnR, lmo806</em> and <em>lmo0371</em>) with the potential to influence the resistance of <em>L. monocytogenes</em> EGD-e. Additionally, assessment of 11 isogenic mutants at a PEF treatment (20 kV/cm, 184 kJ/kg) relative to the wild type identified the Δ<em>yneA</em> and Δ<em>clpB</em> deletion mutants as more resistant and more sensitive (<em>p<0.05</em>). Finally, the isogenic mutant Δ<em>clpB</em> was assessed against the wild type at 25 kV/cm at different total specific energies (54, 113, 135 and 160 kJ/kg) resulting in statistical difference(<em>p<0.05</em>) only under the highest parameter. In conclusion, transcriptomic analysis revealed that the primary mechanistic pathways of <em>L. monocytogenes</em> in response to PEF involve the preservation of homeostasis, energy availability, and quorum sensing. Additionally, the increased sensitivity of the Δ<em>clpB</em> mutant highlights a supplementary mechanism related to protein disaggregation and refolding under high-energy. These findings suggest that <em>L. monocytogenes</em> mounts a complex and multifaceted response to PEF treatments. These results can provide insights and support PEF treatment decontamination alone or as pretreatment in combination with other hurdles.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 105014"},"PeriodicalIF":4.6,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787741","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 : 2025-12-11DOI: 10.1016/j.fm.2025.105010
Guangyu Wang , Yuxin Liu , Fang Ma , Weifen Qiu
Meat spoilage represents a critical challenge in food security and sustainability. Although extensive research has characterized meat microbiota composition and identified specific spoilage organisms, comprehensive understanding of the complex ecological dynamics within meat microbiomes remains limited. This review critically examines current knowledge of meat-associated microbiomes by applying an ecological perspective to address four key questions: the functional roles assigned to microorganisms during community assembly, microbial colonization and adaptation mechanisms in meat ecosystems, nutrient utilization patterns driving metabolic activities and ecological interactions, and microbial interaction effects on community ecology and functional outcomes. Through systematic exploration of these questions, we reveal that meat spoilage is determined by community dynamics and functional activities of entire microbial ecosystems rather than individual species alone. Our analysis identifies critical research gaps including inadequate understanding of core and keystone taxa contributions, limited exploration of microbial interactions, and insufficient integration of multi-omics approaches with ecological modeling. Based on these findings, future practical applications should focus on ecology-guided preservatives that target key spoilage pathways and predictive models integrating metabolic fluxes with environmental parameters. This comprehensive paradigm shift from composition-focused to function-oriented research will enhance theoretical understanding and provide practical insights for more effective spoilage control in the food industry.
{"title":"Insights into meat-microbiome interactions: from community assembly to meat spoilage","authors":"Guangyu Wang , Yuxin Liu , Fang Ma , Weifen Qiu","doi":"10.1016/j.fm.2025.105010","DOIUrl":"10.1016/j.fm.2025.105010","url":null,"abstract":"<div><div>Meat spoilage represents a critical challenge in food security and sustainability. Although extensive research has characterized meat microbiota composition and identified specific spoilage organisms, comprehensive understanding of the complex ecological dynamics within meat microbiomes remains limited. This review critically examines current knowledge of meat-associated microbiomes by applying an ecological perspective to address four key questions: the functional roles assigned to microorganisms during community assembly, microbial colonization and adaptation mechanisms in meat ecosystems, nutrient utilization patterns driving metabolic activities and ecological interactions, and microbial interaction effects on community ecology and functional outcomes. Through systematic exploration of these questions, we reveal that meat spoilage is determined by community dynamics and functional activities of entire microbial ecosystems rather than individual species alone. Our analysis identifies critical research gaps including inadequate understanding of core and keystone taxa contributions, limited exploration of microbial interactions, and insufficient integration of multi-omics approaches with ecological modeling. Based on these findings, future practical applications should focus on ecology-guided preservatives that target key spoilage pathways and predictive models integrating metabolic fluxes with environmental parameters. This comprehensive paradigm shift from composition-focused to function-oriented research will enhance theoretical understanding and provide practical insights for more effective spoilage control in the food industry.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 105010"},"PeriodicalIF":4.6,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734846","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":"2025-12-11","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 : 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":"2025-12-11","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}
Pub Date : 2025-12-11DOI: 10.1016/j.fm.2025.105009
Junyan Liu , Zhenbo Xu , Tengyi Huang , Thanapop Soteyome , Yaqin Li , Yuting Luo , Yuzhu Mao , Lei Yuan , Aijuan Xu , Zhijian Zeng , Shaohong Huang , Mahesh Premarathna , Yanrui Ye
As a frequently identified foodborne pathogen, Salmonella enterica can enter into the viable but nonculturable (VBNC) state and form biofilm, thereby posing high risk to food safety. In this study, 4 types of rice and flour foods, 4 microbial growth status including different biofilm formation stages in comparison with planktonic state, and 2 storage temperatures (4 °C and −20 °C), were applied to explore the VBNC state formation within S. enterica biofilms during low temperature food storage. The ability of S. enterica cells to express virulence gene invA during low temperature storage was also determined. Partial or all S. enterica cells could enter into the VBNC state depending on food type and storage temperature, leading to false negative detection results by culture-based methods. Mature biofilms acquiring high resistance were easier to enter into the VBNC state. Comparing food composition and storage conditions in different food samples, temperature and nutrient were assumed as major factors for the induction of VBNC state. In addition, decreased but continuous invA gene expression was recorded during storage, and the entry into the VBNC state did not influence invA gene expression. The combination of both biofilm and VBNC state which are hard to remove and detect and have high persistence could increase the risks posed by the contamination of S. enterica in food products. Persistence of virulence-associated gene expression in VBNC cells causes further safety issues. These findings provided risk warning for contamination of S. enterica VBNC cells within biofilms during low temperature food storage.
{"title":"Salmonella enterica biofilm is capable of VBNC state formation and virulence gene expression during low temperature food storage","authors":"Junyan Liu , Zhenbo Xu , Tengyi Huang , Thanapop Soteyome , Yaqin Li , Yuting Luo , Yuzhu Mao , Lei Yuan , Aijuan Xu , Zhijian Zeng , Shaohong Huang , Mahesh Premarathna , Yanrui Ye","doi":"10.1016/j.fm.2025.105009","DOIUrl":"10.1016/j.fm.2025.105009","url":null,"abstract":"<div><div>As a frequently identified foodborne pathogen, <em>Salmonella enterica</em> can enter into the viable but nonculturable (VBNC) state and form biofilm, thereby posing high risk to food safety. In this study, 4 types of rice and flour foods, 4 microbial growth status including different biofilm formation stages in comparison with planktonic state, and 2 storage temperatures (4 °C and −20 °C), were applied to explore the VBNC state formation within <em>S. enterica</em> biofilms during low temperature food storage. The ability of <em>S. enterica</em> cells to express virulence gene <em>invA</em> during low temperature storage was also determined. Partial or all <em>S. enterica</em> cells could enter into the VBNC state depending on food type and storage temperature, leading to false negative detection results by culture-based methods. Mature biofilms acquiring high resistance were easier to enter into the VBNC state. Comparing food composition and storage conditions in different food samples, temperature and nutrient were assumed as major factors for the induction of VBNC state. In addition, decreased but continuous <em>invA</em> gene expression was recorded during storage, and the entry into the VBNC state did not influence <em>invA</em> gene expression. The combination of both biofilm and VBNC state which are hard to remove and detect and have high persistence could increase the risks posed by the contamination of <em>S. enterica</em> in food products. Persistence of virulence-associated gene expression in VBNC cells causes further safety issues. These findings provided risk warning for contamination of <em>S. enterica</em> VBNC cells within biofilms during low temperature food storage.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 105009"},"PeriodicalIF":4.6,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734844","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 : 2025-12-11DOI: 10.1016/j.fm.2025.105011
Nerea García , Marta Hernández , Jorge Santamaría-Palacios , Irene Martínez , Alejandro Navarro , Milagros Muñoz-Chimeno , Franco Escobar , Gislaine Fongaro , Nadine Yeramian , Monika Trząskowska , Ana Avellón , José María Eiros , Lucas Domínguez , Antonio Valero , Joaquín Goyache , David Rodríguez-Lázaro
We investigated the presence of hepatitis E virus (HEV) in pigs at the moment of slaughter in Spain in years 2015 and 2017. A total of 1786 caecal content, liver, and serum samples from animals at slaughterhouses were tested by reverse transcription real-time quantitative PCR (RT-qPCR) and anti-HEV antibodies were evaluated in 623 serum samples by an ELISA test. The overall seroprevalence obtained was 70.9 %. A total of 398 RT-qPCR positive samples were identified in caecal content (26.8 %; 156/583), serum (21.8 %; 136/623) and liver (18.3 %; 106/580). A total of 32 RT-qPCR positive samples were genotyped; 3f (84.4 %) and the 3c (9.4 %) being the most prevalent subgenotypes. This is the first report on detection of HEV in pigs at the moment of slaughter with a Spain nation-wide representation. The data show a large high seroprevalence (70.9 %) in pigs, while the presence of the virus (HEV RNA) was significantly lower. HEV RNA detection varied markedly between matrices, with caecal samples showing higher positivity (30–50 %) than serum (5–25 %); both simple and interaction GEE models confirmed strong effects of sample type and its interaction with year on prevalence estimates. However, the percentage of positive liver samples (18.3 %) and the concurrence between the HEV 3 subtypes identified (3f, 3m and 3c) and those identified in human patients in Spain, underscores the possibility of foodborne zoonosis. It can represent a real risk for consumers if pork products are not cooked adequately. A holistic One-Health approach, including a better understanding of HEV prevalence in the swine population, would allow implementation of control measures in the meat chain to mitigate the main transmission routes for humans.
{"title":"Hepatitis E virus in pigs at the moment of slaughter in Spain, 2015 and 2017","authors":"Nerea García , Marta Hernández , Jorge Santamaría-Palacios , Irene Martínez , Alejandro Navarro , Milagros Muñoz-Chimeno , Franco Escobar , Gislaine Fongaro , Nadine Yeramian , Monika Trząskowska , Ana Avellón , José María Eiros , Lucas Domínguez , Antonio Valero , Joaquín Goyache , David Rodríguez-Lázaro","doi":"10.1016/j.fm.2025.105011","DOIUrl":"10.1016/j.fm.2025.105011","url":null,"abstract":"<div><div>We investigated the presence of hepatitis E virus (HEV) in pigs at the moment of slaughter in Spain in years 2015 and 2017. A total of 1786 caecal content, liver, and serum samples from animals at slaughterhouses were tested by reverse transcription real-time quantitative PCR (RT-qPCR) and anti-HEV antibodies were evaluated in 623 serum samples by an ELISA test. The overall seroprevalence obtained was 70.9 %. A total of 398 RT-qPCR positive samples were identified in caecal content (26.8 %; 156/583), serum (21.8 %; 136/623) and liver (18.3 %; 106/580). A total of 32 RT-qPCR positive samples were genotyped; 3f (84.4 %) and the 3c (9.4 %) being the most prevalent subgenotypes. This is the first report on detection of HEV in pigs at the moment of slaughter with a Spain nation-wide representation. The data show a large high seroprevalence (70.9 %) in pigs, while the presence of the virus (HEV RNA) was significantly lower. HEV RNA detection varied markedly between matrices, with caecal samples showing higher positivity (30–50 %) than serum (5–25 %); both simple and interaction GEE models confirmed strong effects of sample type and its interaction with year on prevalence estimates. However, the percentage of positive liver samples (18.3 %) and the concurrence between the HEV 3 subtypes identified (3f, 3m and 3c) and those identified in human patients in Spain, underscores the possibility of foodborne zoonosis. It can represent a real risk for consumers if pork products are not cooked adequately. A holistic One-Health approach, including a better understanding of HEV prevalence in the swine population, would allow implementation of control measures in the meat chain to mitigate the main transmission routes for humans.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 105011"},"PeriodicalIF":4.6,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734847","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}
Various biological agents (bacteria, molds, yeasts …) contribute by their metabolic activity to cheese's ripening. Cheese care procedures during ripening, like wiping, may disperse microorganisms from cheese rinds. Chronic inhalation of potential allergenic particles in ripening cellars may cause, for operators, development of respiratory diseases as asthma. However, microorganisms' emissions and transfers across ripening cellars during cares remained poorly documented. To evaluate microorganisms transfer consecutive to cheese wiping, we focused on microbial community from long-ripened cheeses (CH_LR) and its dispersion in air and on short-ripened cheeses (CH_SR). Twenty-four short-ripened cheeses, all wiped, were distributed into 3 experimental cellars (INRAE, Aurillac), two of which also received 6 long-ripened cheeses either wiped (cellar 2) or unwiped (cellar 3). Samples were taken over a period of 4 weeks in four environments: cheese rinds, cheese cloths, air and cellar walls. Levels of culturable microorganisms were assessed (n = 92). Microbial community compositions were analyzed by metabarcoding (16S rRNA and ITS genes, respectively) (n = 100 samples). Results showed an increase in airborne mold levels up to 7 log CFU. m−3 of air during cheese wiping, compared to 2–3 log CFU. m−3 without wiping activity. Microbial profiles analyses revealed dominant species on CH_LR such as Mucor, Penicillium and Glutamicibacter sp. In CH_LR, Glutamicibacter sp. (60 %), Mucor sp and Penicillium sp (50 % altogether), were transferred to air (respectively 60 % for Glutamicibacter sp and 90 % for both fungal species), cheese cloths and CH_SR. Wiping of CH_LR also contributed to the dispersion in air of less abundant genera of interest for cheese ripening like Chrysosporium (<10 %).
{"title":"Microbial community transfers across a pilot ripening cellar are increased by cheese wiping","authors":"Reshad Fantelli , Patricia Battais , Sébastien Theil , Elisa Michel , Mathilde Lacalmontie , Sandrine Jacquenet , Sullivan Lechêne , Christophe Chassard , Philippe Duquenne , Céline Delbès","doi":"10.1016/j.fm.2025.105006","DOIUrl":"10.1016/j.fm.2025.105006","url":null,"abstract":"<div><div>Various biological agents (bacteria, molds, yeasts …) contribute by their metabolic activity to cheese's ripening. Cheese care procedures during ripening, like wiping, may disperse microorganisms from cheese rinds. Chronic inhalation of potential allergenic particles in ripening cellars may cause, for operators, development of respiratory diseases as asthma. However, microorganisms' emissions and transfers across ripening cellars during cares remained poorly documented. To evaluate microorganisms transfer consecutive to cheese wiping, we focused on microbial community from long-ripened cheeses (CH_LR) and its dispersion in air and on short-ripened cheeses (CH_SR). Twenty-four short-ripened cheeses, all wiped, were distributed into 3 experimental cellars (INRAE, Aurillac), two of which also received 6 long-ripened cheeses either wiped (cellar 2) or unwiped (cellar 3). Samples were taken over a period of 4 weeks in four environments: cheese rinds, cheese cloths, air and cellar walls. Levels of culturable microorganisms were assessed (n = 92). Microbial community compositions were analyzed by metabarcoding (16S rRNA and ITS genes, respectively) (n = 100 samples). Results showed an increase in airborne mold levels up to 7 log CFU. m<sup>−3</sup> of air during cheese wiping, compared to 2–3 log CFU. m<sup>−3</sup> without wiping activity. Microbial profiles analyses revealed dominant species on CH_LR such as <em>Mucor</em>, <em>Penicillium</em> and <em>Glutamicibacter</em> sp. In CH_LR, <em>Glutamicibacter</em> sp. (60 %), <em>Mucor</em> sp <em>and Penicillium</em> sp (50 % altogether), were transferred to air (respectively 60 % for <em>Glutamicibacter</em> sp <em>and</em> 90 % for both fungal species), cheese cloths and CH_SR. Wiping of CH_LR also contributed to the dispersion in air of less abundant genera of interest for cheese ripening like <em>Chrysosporium</em> (<10 %).</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"136 ","pages":"Article 105006"},"PeriodicalIF":4.6,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787738","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 : 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":"2025-12-10","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}
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