Dairy starter cultures are often optimized for rapid acidification, but the relationship between growth rate and secondary metabolite (e.g. flavour) formation is unclear. We here investigated this relationship by modulating the growth rate of L. cremoris NCDO712 using partial translation inhibition (allowing growth at slower rates) or by varying temperatures in defined media and milk. Subsequently the proteome was conserved by full translational inhibition and cells were incubated in defined medium or in a cheese model system for up to 14 days to assess volatile compound formation. Proteome analysis of the cells revealed three protein clusters: ribosome-related (A), metabolism-related (B), and core (constant). Partial translation inhibition of the pre-cultures in defined media increased ribosome-related proteins and decreased amino acid metabolism proteins, including those involved in 3-methylbutanal formation. However, temperature-driven growth rate changes and partial translation inhibition in milk showed minimal changes in ribosome-related and metabolic protein fractions. Crucially, slower pre-culture growth significantly reduced key flavour compound production (up to 30-fold). These findings demonstrate that rapid growth does not necessarily sacrifice metabolic protein levels in L. cremoris NCDO712, and that pre-culture growth rates can influence secondary metabolite production, independent of enzyme levels.
{"title":"Growth rate influences flavour formation in Lactococcus cremoris independently of metabolic protein levels","authors":"Avis Dwi Wahyu Nugroho , Berdien van Olst , Douwe Molenaar , Siming Li , Adriano Guiso , Sjef Boeren , Michiel Kleerebezem , Herwig Bachmann","doi":"10.1016/j.ijfoodmicro.2026.111662","DOIUrl":"10.1016/j.ijfoodmicro.2026.111662","url":null,"abstract":"<div><div>Dairy starter cultures are often optimized for rapid acidification, but the relationship between growth rate and secondary metabolite (e.g. flavour) formation is unclear. We here investigated this relationship by modulating the growth rate of <em>L. cremoris</em> NCDO712 using partial translation inhibition (allowing growth at slower rates) or by varying temperatures in defined media and milk. Subsequently the proteome was conserved by full translational inhibition and cells were incubated in defined medium or in a cheese model system for up to 14 days to assess volatile compound formation. Proteome analysis of the cells revealed three protein clusters: ribosome-related (A), metabolism-related (B), and core (constant). Partial translation inhibition of the pre-cultures in defined media increased ribosome-related proteins and decreased amino acid metabolism proteins, including those involved in 3-methylbutanal formation. However, temperature-driven growth rate changes and partial translation inhibition in milk showed minimal changes in ribosome-related and metabolic protein fractions. Crucially, slower pre-culture growth significantly reduced key flavour compound production (up to 30-fold). These findings demonstrate that rapid growth does not necessarily sacrifice metabolic protein levels in <em>L. cremoris</em> NCDO712, and that pre-culture growth rates can influence secondary metabolite production, independent of enzyme levels.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"451 ","pages":"Article 111662"},"PeriodicalIF":5.2,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146098681","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 : 2026-04-16Epub Date: 2026-01-31DOI: 10.1016/j.ijfoodmicro.2026.111666
Daun Kim , In Min Hwang , Ho Myeong Kim , Seul-Gi Jeong , Hae Woong Park
Despite its acidic environment, kimchi has occasionally been linked with foodborne pathogen contamination, emphasizing the need to increase its microbial safety. While kimchi fermentation generally occurs at low temperatures, most previous studies on starter cultures have focused on mesophilic lactic acid bacteria (LAB). The present study investigated the potential of psychrotrophic LAB as starter cultures for kimchi fermentation, with particular focus on their antimicrobial activity and metabolic characteristics. Two psychrotrophic strains, Dellaglioa algida and Leuconostoc gelidum subsp. aenigmaticum, were individually co-inoculated with pathogens including Escherichia coli O157:H7, Staphylococcus aureus, and Listeria monocytogenes in kimchi and fermented at 4 °C for 42 days. Their performance was compared with that of a mesophilic LAB strain, Leu. mesenteroides, through microbial, physicochemical, and metabolomics analyses. The psychrotrophic starters accelerated acidification, maintained high dominance, and effectively suppressed pathogens. Moreover, E. coli O157:H7 counts were 1.8–2.4 log CFU/mL lower, and S. aureus reached the limit of detection (1.0 log CFU/mL) 7 days earlier than the mesophilic starter. Untargeted metabolomics using ultra-performance liquid chromatography-quadrupole-Orbitrap mass spectrometry revealed strain-specific inhibition of metabolic pathways in foodborne pathogens. D. algida primarily suppressed nucleotide metabolism, whereas Leu. gelidum subsp. aenigmaticum strongly inhibited energy-related and stress defense pathways, ultimately impairing pathogen growth. In contrast, Leu. mesenteroides exhibited relatively limited metabolic inhibition. In conclusion, psychrotrophic LAB exhibited broad-spectrum antimicrobial activity and strain-specific inhibition mechanisms, underscoring their potential as functional starters to enhance microbial safety and consistency in low-temperature fermented foods.
{"title":"Psychrotrophic lactic acid bacteria enhance microbial safety in kimchi: Evidence from untargeted metabolomics","authors":"Daun Kim , In Min Hwang , Ho Myeong Kim , Seul-Gi Jeong , Hae Woong Park","doi":"10.1016/j.ijfoodmicro.2026.111666","DOIUrl":"10.1016/j.ijfoodmicro.2026.111666","url":null,"abstract":"<div><div>Despite its acidic environment, kimchi has occasionally been linked with foodborne pathogen contamination, emphasizing the need to increase its microbial safety. While kimchi fermentation generally occurs at low temperatures, most previous studies on starter cultures have focused on mesophilic lactic acid bacteria (LAB). The present study investigated the potential of psychrotrophic LAB as starter cultures for kimchi fermentation, with particular focus on their antimicrobial activity and metabolic characteristics. Two psychrotrophic strains, <em>Dellaglioa algida</em> and <em>Leuconostoc gelidum</em> subsp. <em>aenigmaticum</em>, were individually co-inoculated with pathogens including <em>Escherichia coli</em> O157:H7, <em>Staphylococcus aureus</em>, and <em>Listeria monocytogenes</em> in kimchi and fermented at 4 °C for 42 days. Their performance was compared with that of a mesophilic LAB strain, <em>Leu. mesenteroides</em>, through microbial, physicochemical, and metabolomics analyses. The psychrotrophic starters accelerated acidification, maintained high dominance, and effectively suppressed pathogens. Moreover, <em>E. coli</em> O157:H7 counts were 1.8–2.4 log CFU/mL lower, and <em>S. aureus</em> reached the limit of detection (1.0 log CFU/mL) 7 days earlier than the mesophilic starter. Untargeted metabolomics using ultra-performance liquid chromatography-quadrupole-Orbitrap mass spectrometry revealed strain-specific inhibition of metabolic pathways in foodborne pathogens. <em>D. algida</em> primarily suppressed nucleotide metabolism, whereas <em>Leu. gelidum</em> subsp. <em>aenigmaticum</em> strongly inhibited energy-related and stress defense pathways, ultimately impairing pathogen growth. In contrast, <em>Leu. mesenteroides</em> exhibited relatively limited metabolic inhibition. In conclusion, psychrotrophic LAB exhibited broad-spectrum antimicrobial activity and strain-specific inhibition mechanisms, underscoring their potential as functional starters to enhance microbial safety and consistency in low-temperature fermented foods.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"451 ","pages":"Article 111666"},"PeriodicalIF":5.2,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146124877","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 : 2026-04-16Epub Date: 2026-02-05DOI: 10.1016/j.ijfoodmicro.2026.111669
Jikun He , Youqin Duan , Shuting Yang , Fidel Toldrá , Jiong Zheng , Muying Du , Linlin Wang , Nodali Ndraha , Shuyao Wang , Juan Chen
To achieve a starter culture with the ability of improving nutty aroma in the formulation of fermented sausage, this study evaluated sixteen staphylococci strains first, then demonstrated the function of the strain in sausage fermentation using volatolomics and metagenomics. Within sixteen tested strains, S. saprophyticus 108 presented superior safety and technological properties and produced the highest amounts of 3-methylbutanal. With spontaneously fermented sausage as control, S108 group distinctly enhanced the production of 3-methylbutanal, 3-methylbutanoic acid and its ethyl ester, and nutty note of S108 group was obviously perceivable. The relative abundance of S. saprophyticus in both control and S108 groups increased throughout the fermentation process and such increase was more dramatic in S108 group. Although the differences in the number of functional genes predicted by control and S108 group in CAZy, eggNOG, and KEGG databases were comparatively small, the contribution of S. saprophyticus to major nutrient metabolisms was the main difference. Both S. saprophyticus and L. mesenteroides were annotated with predominant abundances in main metabolic pathways, while S. saprophyticus abundance involved in the metabolic pathways was higher in S108 group than in control. Specifically, branched-chain amino acid degradation, phenylalanine metabolism, glycolysis, pyruvate metabolism, butanoate and propanoate metabolism, glycerolipid and glycerophospholipid metabolism were mainly driven by S. saprophyticus, linked to the higher generation of volatile compounds in S108 group compared to control. The results provided scientific support for developing a functional starter culture through clarifying the mechanism of nutty aroma formation by S. saprophyticus in the production of fermented sausages.
{"title":"Insights into the mechanism of nutty aroma formation by Staphylococcus saprophyticus in fermented sausages","authors":"Jikun He , Youqin Duan , Shuting Yang , Fidel Toldrá , Jiong Zheng , Muying Du , Linlin Wang , Nodali Ndraha , Shuyao Wang , Juan Chen","doi":"10.1016/j.ijfoodmicro.2026.111669","DOIUrl":"10.1016/j.ijfoodmicro.2026.111669","url":null,"abstract":"<div><div>To achieve a starter culture with the ability of improving nutty aroma in the formulation of fermented sausage, this study evaluated sixteen staphylococci strains first, then demonstrated the function of the strain in sausage fermentation using volatolomics and metagenomics. Within sixteen tested strains, <em>S. saprophyticus</em> 108 presented superior safety and technological properties and produced the highest amounts of 3-methylbutanal. With spontaneously fermented sausage as control, S108 group distinctly enhanced the production of 3-methylbutanal, 3-methylbutanoic acid and its ethyl ester, and nutty note of S108 group was obviously perceivable. The relative abundance of <em>S. saprophyticus</em> in both control and S108 groups increased throughout the fermentation process and such increase was more dramatic in S108 group. Although the differences in the number of functional genes predicted by control and S108 group in CAZy, eggNOG, and KEGG databases were comparatively small, the contribution of <em>S. saprophyticus</em> to major nutrient metabolisms was the main difference. Both <em>S. saprophyticus</em> and <em>L. mesenteroides</em> were annotated with predominant abundances in main metabolic pathways, while <em>S. saprophyticus</em> abundance involved in the metabolic pathways was higher in S108 group than in control. Specifically, branched-chain amino acid degradation, phenylalanine metabolism, glycolysis, pyruvate metabolism, butanoate and propanoate metabolism, glycerolipid and glycerophospholipid metabolism were mainly driven by <em>S. saprophyticus</em>, linked to the higher generation of volatile compounds in S108 group compared to control. The results provided scientific support for developing a functional starter culture through clarifying the mechanism of nutty aroma formation by <em>S. saprophyticus</em> in the production of fermented sausages.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"451 ","pages":"Article 111669"},"PeriodicalIF":5.2,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146191709","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 : 2026-04-02Epub Date: 2026-01-16DOI: 10.1016/j.ijfoodmicro.2025.111621
Yuqi Xue , Xingbiao Gao , Qineng Liu , Nana Fang , Dong Peng , Xuewei Jiang , Chunxiang Song
Staphylococcus spp. a salt-tolerant bacterium, exhibits a favorable flavor-enhancing effect during the soy sauce fermentation, especially at higher salt concentrations. To investigate the salt tolerance mechanism of staphylococci in the high-salt environment of soy sauce fermentation, a combined physiological and genomic research method was used to study three Staphylococcus strains (Staphylococcus carnosus CS1.21, S. piscifermentans CS1.22, and S. debuckii CS1.23) that were isolated from moromi. As the NaCl concentration increased from 40 to 180 g/L compared to the control, the contents of intracellular osmotic regulatory substances, such as soluble proteins and proline, increased significantly in all three Staphylococcus strains. Corresponding gene annotations revealed an abundance of protein synthesis genes and a complete proline synthesis pathway. Additionally, Na+/K+-ATPase activity increased significantly by 2.51–9.82 U/L (P < 0.05), and the Na+/K+ regulation genes have also been annotated. Catalase (CAT) activity and the rate of reactive oxygen species (ROS) scavenging were significantly enhanced by 0.75–2.51 U/mL and 28.13–62.98%, respectively, corresponding catalase synthesis genes have been annotated in all three strains. These genes form a synergistic regulatory network that, along with physiological adaptations, enhances the strains' salt tolerance under stress. The explanation of the salt tolerance mechanisms of the three staphylococci, which are based on maintaining osmotic balance and increasing ROS scavenging rates, laid the foundation for the complete utilization of the three strains in high-salt liquid fermentation.
{"title":"Physiological and genomic insights into the salt tolerance mechanisms of three Staphylococcus strains isolated from moromi","authors":"Yuqi Xue , Xingbiao Gao , Qineng Liu , Nana Fang , Dong Peng , Xuewei Jiang , Chunxiang Song","doi":"10.1016/j.ijfoodmicro.2025.111621","DOIUrl":"10.1016/j.ijfoodmicro.2025.111621","url":null,"abstract":"<div><div><em>Staphylococcus</em> spp. a salt-tolerant bacterium, exhibits a favorable flavor-enhancing effect during the soy sauce fermentation, especially at higher salt concentrations. To investigate the salt tolerance mechanism of staphylococci in the high-salt environment of soy sauce fermentation, a combined physiological and genomic research method was used to study three <em>Staphylococcus</em> strains (<em>Staphylococcus carnosus</em> CS1.21, <em>S. piscifermentans</em> CS1.22, and <em>S. debuckii</em> CS1.23) that were isolated from moromi. As the NaCl concentration increased from 40 to 180 g/L compared to the control, the contents of intracellular osmotic regulatory substances, such as soluble proteins and proline, increased significantly in all three <em>Staphylococcus</em> strains. Corresponding gene annotations revealed an abundance of protein synthesis genes and a complete proline synthesis pathway. Additionally, Na<sup>+</sup>/K<sup>+</sup>-ATPase activity increased significantly by 2.51–9.82 U/L (<em>P</em> < 0.05), and the Na<sup>+</sup>/K<sup>+</sup> regulation genes have also been annotated. Catalase (CAT) activity and the rate of reactive oxygen species (ROS) scavenging were significantly enhanced by 0.75–2.51 U/mL and 28.13–62.98%, respectively, corresponding catalase synthesis genes have been annotated in all three strains. These genes form a synergistic regulatory network that, along with physiological adaptations, enhances the strains' salt tolerance under stress. The explanation of the salt tolerance mechanisms of the three staphylococci, which are based on maintaining osmotic balance and increasing ROS scavenging rates, laid the foundation for the complete utilization of the three strains in high-salt liquid fermentation.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"450 ","pages":"Article 111621"},"PeriodicalIF":5.2,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146018431","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 : 2026-04-02Epub Date: 2026-01-23DOI: 10.1016/j.ijfoodmicro.2026.111659
Sávio Sandes , Naiara Figueiredo , Sumaia Pires , Debora Assis , Silvia Pedroso , Maria José Paiva , Elisabeth Neumann , Veronica O. Alvarenga , Carmen J. Contreras-Castillo , Anderson S. Sant'Ana
Beef is a highly perishable product due to its high moisture content, neutral pH, and rich nutrient profile, which favor microbial growth and spoilage. While vacuum packaging extends shelf life by limiting aerobic bacteria, it may promote the proliferation of anaerobic and facultative anaerobic spoilage organisms, leading to blown pack spoilage. This study investigated the effects of lactic acid spraying on split carcasses categorized by two pH levels (high or ideal) on microbial succession and volatile organic compound (VOC) production in vacuum-packaged sirloins, stored at 0 °C, 4 °C, and 7 °C for up to 120 days. Using culture-based methods, 16S rRNA gene sequencing, and VOC profiling, it has been found that lactic acid treatment significantly reduced initial bacterial loads, especially in high-pH split carcasses (P < 0,05), and modulated microbial communities over time. Treated samples exhibited a lower incidence of blown pack spoilage (BPS) under specific storage time–temperature conditions. Nevertheless, bacterial changes under specific time–temperature storage conditions were characterized by a microbiota dominated by Lactococcus, Lactobacillus, Leuconostoc, Enterococcus, Carnobacterium, Hafnia–Obesumbacterium, and Serratia, regardless type of treatment. Overall microbial diversity was not significantly affected; however, the composition of dominant bacterial genera and VOC profiles differed between treated and non-treated groups, suggesting that specific bacterial taxa and compounds may serve as indicators of spoilage progression in vacuum-packed meat under defined storage conditions.
{"title":"Lactic acid spraying on split carcasses reshapes microbial succession and reduces the occurrence of blown pack spoilage in vacuum-packaged beef stored at different temperatures over extended shelf life","authors":"Sávio Sandes , Naiara Figueiredo , Sumaia Pires , Debora Assis , Silvia Pedroso , Maria José Paiva , Elisabeth Neumann , Veronica O. Alvarenga , Carmen J. Contreras-Castillo , Anderson S. Sant'Ana","doi":"10.1016/j.ijfoodmicro.2026.111659","DOIUrl":"10.1016/j.ijfoodmicro.2026.111659","url":null,"abstract":"<div><div>Beef is a highly perishable product due to its high moisture content, neutral pH, and rich nutrient profile, which favor microbial growth and spoilage. While vacuum packaging extends shelf life by limiting aerobic bacteria, it may promote the proliferation of anaerobic and facultative anaerobic spoilage organisms, leading to blown pack spoilage. This study investigated the effects of lactic acid spraying on split carcasses categorized by two pH levels (high or ideal) on microbial succession and volatile organic compound (VOC) production in vacuum-packaged sirloins, stored at 0 °C, 4 °C, and 7 °C for up to 120 days. Using culture-based methods, 16S rRNA gene sequencing, and VOC profiling, it has been found that lactic acid treatment significantly reduced initial bacterial loads, especially in high-pH split carcasses (<em>P</em> < 0,05), and modulated microbial communities over time. Treated samples exhibited a lower incidence of blown pack spoilage (BPS) under specific storage time–temperature conditions. Nevertheless, bacterial changes under specific time–temperature storage conditions were characterized by a microbiota dominated by <em>Lactococcus</em>, <em>Lactobacillus</em>, <em>Leuconostoc</em>, <em>Enterococcus</em>, <em>Carnobacterium</em>, <em>Hafnia–Obesumbacterium</em>, and <em>Serratia</em>, regardless type of treatment. Overall microbial diversity was not significantly affected; however, the composition of dominant bacterial genera and VOC profiles differed between treated and non-treated groups, suggesting that specific bacterial taxa and compounds may serve as indicators of spoilage progression in vacuum-packed meat under defined storage conditions.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"450 ","pages":"Article 111659"},"PeriodicalIF":5.2,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146062908","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 : 2026-04-02Epub Date: 2025-12-30DOI: 10.1016/j.ijfoodmicro.2025.111620
Ama Lethicia Manizan , Amaranta Carvajal-Campos , Isabelle Piro-Metayer , David Koffi Akaki , Rose Koffi-Nevry , Didier Montet , Isabelle P. Oswald , Sophie Lorber , Olivier Puel , Catherine Brabet
The contamination of staple foods by mycotoxins is a significant issue in sub-Saharan Africa, particularly the presence of aflatoxins in raw peanuts and peanut-based products. This contamination has severe health and economic consequences. The main aflatoxin-producing fungi belong to Aspergillus section Flavi and are grouped in three main clades: A. flavus, A. tamarii and A. nomius, newly qualified as Flavi, Kitamyces and Nomiarum series respectively. The present study assessed the biodiversity of Aspergillus section Flavi species along the peanut paste production chain in the Korhogo region in northern Côte d'Ivoire. A polyphasic approach was used to identify 256 potentially aflatoxigenic strains isolated on AFPA medium. Experiments included (i) morphological characterization, (ii) aflatoxin production on PDA medium, (iii) molecular identification using a PCR-DGGE method and DNA sequencing, and (iv) phylogenetic analyses. Three species of A. flavus clade were isolated. The most prevalent was A. flavus, which comprised mainly aflatoxin-producing strains but also atoxigenic strains, followed by A. aflatoxiformans and A. korhogoensis. The latter two produced B and G aflatoxins at higher levels than A. flavus, which only produced B aflatoxins. A. aflatoxiformans, A. korhogoensis and aflatoxigenic A. flavus strains were mainly isolated after the stages of peanut pod drying and storage in villages, as well as after seed storage by wholesalers and retailers. However, AF production requires confirmation on most appropriate inducing media. The study also indicates that the PCR-DGGE method when combined with a multi-locus phylogenetic analysis is an effective strategy for discriminating and identifying Aspergillus section Flavi species, particularly those in the A. flavus clade.
{"title":"Biodiversity of Aspergillus section Flavi species isolated along the peanut paste production chain in Côte d'Ivoire","authors":"Ama Lethicia Manizan , Amaranta Carvajal-Campos , Isabelle Piro-Metayer , David Koffi Akaki , Rose Koffi-Nevry , Didier Montet , Isabelle P. Oswald , Sophie Lorber , Olivier Puel , Catherine Brabet","doi":"10.1016/j.ijfoodmicro.2025.111620","DOIUrl":"10.1016/j.ijfoodmicro.2025.111620","url":null,"abstract":"<div><div>The contamination of staple foods by mycotoxins is a significant issue in sub-Saharan Africa, particularly the presence of aflatoxins in raw peanuts and peanut-based products. This contamination has severe health and economic consequences. The main aflatoxin-producing fungi belong to <em>Aspergillus</em> section <em>Flavi</em> and are grouped in three main clades: <em>A. flavus</em>, <em>A. tamarii</em> and <em>A. nomius</em>, newly qualified as Flavi, <em>Kitamyces</em> and <em>Nomiarum</em> series respectively. The present study assessed the biodiversity of <em>Aspergillus</em> section <em>Flavi</em> species along the peanut paste production chain in the Korhogo region in northern Côte d'Ivoire. A polyphasic approach was used to identify 256 potentially aflatoxigenic strains isolated on AFPA medium. Experiments included (i) morphological characterization, (ii) aflatoxin production on PDA medium, (iii) molecular identification using a PCR-DGGE method and DNA sequencing, and (iv) phylogenetic analyses. Three species of <em>A. flavus</em> clade were isolated. The most prevalent was <em>A. flavus</em>, which comprised mainly aflatoxin-producing strains but also atoxigenic strains, followed by <em>A. aflatoxiformans</em> and <em>A. korhogoensis.</em> The latter two produced B and G aflatoxins at higher levels than <em>A. flavus</em>, which only produced B aflatoxins<em>. A. aflatoxiformans</em>, <em>A. korhogoensis</em> and aflatoxigenic <em>A. flavus</em> strains were mainly isolated after the stages of peanut pod drying and storage in villages, as well as after seed storage by wholesalers and retailers. However, AF production requires confirmation on most appropriate inducing media. The study also indicates that the PCR-DGGE method when combined with a multi-locus phylogenetic analysis is an effective strategy for discriminating and identifying <em>Aspergillus</em> section <em>Flavi</em> species, particularly those in the <em>A. flavus</em> clade.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"450 ","pages":"Article 111620"},"PeriodicalIF":5.2,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146062864","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}
Penicillium expansum, a destructive postharvest pathogen responsible for blue mold decay and produces the mycotoxin patulin, leading to considerable economic and food safety concerns. The APSES transcription factors are essential regulators in fungi, but their functions are not well understood in P. expansum. Here, we screened five members of the APSES family in P. expansum. Combining these findings with previous studies, only PEX2_045870 exhibited relatively stable and high expression during early infection stages. We constructed knockout and complementation strains of this gene and analyzed their phenotypes to investigate the role of PeStuA in P. expansum. PeStuA deletion severely inhibited growth (28.91% reduction in colony diameter), spore formation ability and hydrophobicity. And ΔPeStuA mutant exhibited markedly heightened sensitivity to osmotic stress (NaCl/KCl) and cell wall integrity stress (SDS/CR), with a 50% inhibition rate under cell wall stress. Pathogenicity test on apple showed reduction in diameter by 49.18% and fruit softening. Crucially, ΔPeStuA showed complete loss of patulin production (HPLC-UV quantification), accompanied by downregulation of patulin biosynthetic genes. RNA-seq analysis revealed 1826 significantly differently expressed genes in ΔPeStuA, including carbon metabolism, spore formation, MAPK signaling pathways, cell wall degradation enzymes and secondary metabolism in P. expansum. Collectively, this work aims to elucidate PeStuA acts as a central regulatory factor that coordinates growth, stress responses, hydrophobicity, pathogenicity and secondary metabolism in P. expansum. These findings provide novel insights and potential targets for post-harvest disease control strategies.
{"title":"The global APSES transcription factor PeStuA modulates growth, development, stress response, hydrophobicity, patulin biosynthesis and pathogenicity in Penicillium expansum","authors":"Yanling Wang, Yurui Wu, Qianrun Liang, Xin Chen, Jinfen Zhu, Wei Li","doi":"10.1016/j.ijfoodmicro.2026.111652","DOIUrl":"10.1016/j.ijfoodmicro.2026.111652","url":null,"abstract":"<div><div><em>Penicillium expansum</em>, a destructive postharvest pathogen responsible for blue mold decay and produces the mycotoxin patulin, leading to considerable economic and food safety concerns. The APSES transcription factors are essential regulators in fungi, but their functions are not well understood in <em>P. expansum</em>. Here, we screened five members of the APSES family in <em>P. expansum</em>. Combining these findings with previous studies, only <em>PEX2_045870</em> exhibited relatively stable and high expression during early infection stages. We constructed knockout and complementation strains of this gene and analyzed their phenotypes to investigate the role of <em>PeStuA</em> in <em>P. expansum</em>. <em>PeStuA</em> deletion severely inhibited growth (28.91% reduction in colony diameter), spore formation ability and hydrophobicity. And Δ<em>PeStuA</em> mutant exhibited markedly heightened sensitivity to osmotic stress (NaCl/KCl) and cell wall integrity stress (SDS/CR), with a 50% inhibition rate under cell wall stress. Pathogenicity test on apple showed reduction in diameter by 49.18% and fruit softening. Crucially, Δ<em>PeStuA</em> showed complete loss of patulin production (HPLC-UV quantification), accompanied by downregulation of patulin biosynthetic genes. RNA-seq analysis revealed 1826 significantly differently expressed genes in Δ<em>PeStuA</em>, including carbon metabolism, spore formation, MAPK signaling pathways, cell wall degradation enzymes and secondary metabolism in <em>P. expansum</em>. Collectively, this work aims to elucidate <em>PeStuA</em> acts as a central regulatory factor that coordinates growth, stress responses, hydrophobicity, pathogenicity and secondary metabolism in <em>P. expansum</em>. These findings provide novel insights and potential targets for post-harvest disease control strategies.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"450 ","pages":"Article 111652"},"PeriodicalIF":5.2,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036086","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}
This study assessed Escherichia coli as an indicator of antimicrobial resistance (AMR) in retail seafood, integrating microbiological and genomic analyses within a One Health perspective. Overall, E. coli was cultured from 55 (13%) of 422 raw samples from seven seafood categories commonly consumed in Italy. E. coli was detected across multiple seafood types, but particularly in bivalves (23%) and crustaceans (20%). Because these species can accumulate or acquire faecal contaminants from the aquatic environment or along the post-harvest chain, they represent relevant matrices for AMR monitoring. In parallel, we investigated the presence of Extended-β-Lactamase ESBL-, AmpC- and carbapenemase-producing Enterobacteriaceae. Cefotaxime-resistant E. coli isolates were identified at low but relevant frequencies, especially in bivalves, and were characterised phenotypically and by whole-genome sequencing. Most isolates carried clinically important ESBL or AmpC genes, more frequently blaCTX-M-15, often on contigs predicted as plasmid-associated, indicating their potential for horizontal spread. An ESBL-producing Atlantibacter hermannii harbouring blaCTX-M-55 was also recovered from frozen shrimps. Additional AmpC-producing Enterobacteriaceae, including Citrobacter and Enterobacter species, were detected in a subset of samples.
Overall, our findings support the suitability of E. coli as an AMR indicator organism for retail bivalves and crustaceans. The detection of ESBL-producing strains, carrying important plasmid-borne resistance determinants, highlights the need to strengthen AMR surveillance in these seafood commodities.
{"title":"Assessment of Escherichia coli as an indicator of antimicrobial resistance and monitoring of ESBL/AmpC-Producing Enterobacteriaceae in retail seafood commonly consumed in Italy","authors":"Francesca Leoni , Silvia Pieralisi , Elisa Albini , Francesca Romana Massacci , Gabriele Angelico , Serenella Orsini , Carmen Maresca , Eleonora Scoccia , Valeria Michelacci , Paola Chiani , Manuela Marra , Maria Carollo , Francesca Barchiesi , Chiara Francesca Magistrali","doi":"10.1016/j.ijfoodmicro.2026.111650","DOIUrl":"10.1016/j.ijfoodmicro.2026.111650","url":null,"abstract":"<div><div>This study assessed <em>Escherichia coli</em> as an indicator of antimicrobial resistance (AMR) in retail seafood, integrating microbiological and genomic analyses within a One Health perspective. Overall, <em>E. coli</em> was cultured from 55 (13%) of 422 raw samples from seven seafood categories commonly consumed in Italy. <em>E. coli</em> was detected across multiple seafood types, but particularly in bivalves (23%) and crustaceans (20%). Because these species can accumulate or acquire faecal contaminants from the aquatic environment or along the post-harvest chain, they represent relevant matrices for AMR monitoring. In parallel, we investigated the presence of Extended-β-Lactamase ESBL-, AmpC- and carbapenemase-producing <em>Enterobacteriaceae</em>. Cefotaxime-resistant <em>E. coli</em> isolates were identified at low but relevant frequencies, especially in bivalves, and were characterised phenotypically and by whole-genome sequencing. Most isolates carried clinically important ESBL or AmpC genes, more frequently <em>bla</em><sub>CTX-M-15</sub>, often on contigs predicted as plasmid-associated, indicating their potential for horizontal spread. An ESBL-producing <em>Atlantibacter hermannii</em> harbouring <em>bla</em><sub>CTX-M-55</sub> was also recovered from frozen shrimps. Additional AmpC-producing <em>Enterobacteriaceae</em>, including <em>Citrobacter</em> and <em>Enterobacte</em>r species, were detected in a subset of samples.</div><div>Overall, our findings support the suitability of <em>E. coli</em> as an AMR indicator organism for retail bivalves and crustaceans. The detection of ESBL-producing strains, carrying important plasmid-borne resistance determinants, highlights the need to strengthen AMR surveillance in these seafood commodities.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"450 ","pages":"Article 111650"},"PeriodicalIF":5.2,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074453","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 : 2026-04-02Epub Date: 2026-01-12DOI: 10.1016/j.ijfoodmicro.2026.111634
Denes do Rosario , Juliana X. Bissoli , Pedro H.A. Martins , Brenno A.S. Jacinto , Eniale M. Oliveira , Carlos A. Conte-Junior , Patrícia C. Bernardes
This study aimed to isolate, promote molecular identification (ITS1, ITS4, α-tubulin, and β-tubulin), and model the growth of Aspergillus westerdijkiae, Penicillium verrucosum, Penicillium citrinum, and Penicillium nalgiovense from the microbiota of the traditional Brazilian dry-cured loin “Socol”. Growth (μmax and lag phase) occurred under environmental conditions of temperatures between 15 and 35 °C and water activities between 0.83 and 0.97. A. westerdijkiae grew three times faster (0.50 mm/h) than the other fungi and was favored by higher temperatures. P. nalgiovense was slightly affected by temperature. P. verrucosum was favored at lower temperatures. This entire scenario was observed during the simulated start of production, a critical point for fungal colonization of dry-cured meat products. While producing dry-cured meat products in tropical countries is challenging, refrigeration poses the same risks as in temperate countries. Hence, understanding the microbial dynamics of these products is the key to improving the production chain in terms of consumer safety. Extending the refrigeration time at the beginning of production may be an alternative to increase safety.
{"title":"Growth modeling of autochthonous molds from the traditional Brazilian dry-cured loin “Socol”: Impact of the abiotic conditions","authors":"Denes do Rosario , Juliana X. Bissoli , Pedro H.A. Martins , Brenno A.S. Jacinto , Eniale M. Oliveira , Carlos A. Conte-Junior , Patrícia C. Bernardes","doi":"10.1016/j.ijfoodmicro.2026.111634","DOIUrl":"10.1016/j.ijfoodmicro.2026.111634","url":null,"abstract":"<div><div>This study aimed to isolate, promote molecular identification (ITS1, ITS4, α-tubulin, and β-tubulin), and model the growth of <em>Aspergillus westerdijkiae</em>, <em>Penicillium verrucosum</em>, <em>Penicillium citrinum</em>, and <em>Penicillium nalgiovense</em> from the microbiota of the traditional Brazilian dry-cured loin “Socol”. Growth (μmax and lag phase) occurred under environmental conditions of temperatures between 15 and 35 °C and water activities between 0.83 and 0.97. <em>A. westerdijkiae</em> grew three times faster (0.50 mm/h) than the other fungi and was favored by higher temperatures. <em>P. nalgiovense</em> was slightly affected by temperature. <em>P. verrucosum</em> was favored at lower temperatures. This entire scenario was observed during the simulated start of production, a critical point for fungal colonization of dry-cured meat products. While producing dry-cured meat products in tropical countries is challenging, refrigeration poses the same risks as in temperate countries. Hence, understanding the microbial dynamics of these products is the key to improving the production chain in terms of consumer safety. Extending the refrigeration time at the beginning of production may be an alternative to increase safety.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"450 ","pages":"Article 111634"},"PeriodicalIF":5.2,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146029455","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 : 2026-04-02Epub Date: 2026-01-17DOI: 10.1016/j.ijfoodmicro.2026.111647
Xiujuan Zhou , Phil Bremer , Chunlei Shi
Non-typhoidal Salmonella (NTS) is a leading cause of foodborne illness, with multidrug-resistant (MDR) strains challenging treatment and food safety. Serotype-specific plasmid associations underlie distinct antimicrobial resistance (AMR) risks: IncHI2 plasmids in S. Typhimurium, virulence-plasmid exclusion in S. Enteritidis, pESI megaplasmids in S. Infantis, and multi-plasmid carriage in S. Indiana. These profiles shape persistence in livestock, processing, and retail settings, raising the likelihood of resistance spread along the farm-to-fork continuum. Plasmid interactions, including helper-mediated mobilization, IS26-driven recombination, and fusion events, accelerate the emergence of mosaic or hybrid plasmids that combine resistance and virulence, enhancing adaptability in food-associated environments. Ecological factors such as gut microbiota, biofilms, and exposure to disinfectants or microplastics further promote plasmid transfer and maintenance. Within a One Health framework, integrating food chain surveillance, predictive modeling, and microbiota-targeted or CRISPR-based tools provides opportunities to monitor, predict, and disrupt plasmid dissemination. By combining serotype-specific, evolutionary, and ecological perspectives, this review highlights key mechanisms driving AMR in NTS and identifies actionable intervention points to reduce MDR Salmonella risks in the food chain.
{"title":"Plasmid-mediated antimicrobial resistance in non-typhoidal Salmonella: serotype-specific mechanisms and ecological implications","authors":"Xiujuan Zhou , Phil Bremer , Chunlei Shi","doi":"10.1016/j.ijfoodmicro.2026.111647","DOIUrl":"10.1016/j.ijfoodmicro.2026.111647","url":null,"abstract":"<div><div>Non-typhoidal <em>Salmonella</em> (NTS) is a leading cause of foodborne illness, with multidrug-resistant (MDR) strains challenging treatment and food safety. Serotype-specific plasmid associations underlie distinct antimicrobial resistance (AMR) risks: IncHI2 plasmids in <em>S.</em> Typhimurium, virulence-plasmid exclusion in <em>S.</em> Enteritidis, pESI megaplasmids in <em>S.</em> Infantis, and multi-plasmid carriage in <em>S.</em> Indiana. These profiles shape persistence in livestock, processing, and retail settings, raising the likelihood of resistance spread along the farm-to-fork continuum. Plasmid interactions, including helper-mediated mobilization, IS<em>26</em>-driven recombination, and fusion events, accelerate the emergence of mosaic or hybrid plasmids that combine resistance and virulence, enhancing adaptability in food-associated environments. Ecological factors such as gut microbiota, biofilms, and exposure to disinfectants or microplastics further promote plasmid transfer and maintenance. Within a One Health framework, integrating food chain surveillance, predictive modeling, and microbiota-targeted or CRISPR-based tools provides opportunities to monitor, predict, and disrupt plasmid dissemination. By combining serotype-specific, evolutionary, and ecological perspectives, this review highlights key mechanisms driving AMR in NTS and identifies actionable intervention points to reduce MDR <em>Salmonella</em> risks in the food chain.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"450 ","pages":"Article 111647"},"PeriodicalIF":5.2,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146010231","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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