Pub Date : 2026-08-01Epub Date: 2026-01-05DOI: 10.1016/j.fm.2026.105037
Qingqing Mu , Sitong Jia , Dongyao Li , Whenhao Zhao , Na Zhang , Miaoshu Wang , Hongtao Tian , Chen Li
Post-acidification during refrigeration is a critical determinant of yogurt quality. Although it is known that niacin (NA) can influence this process via aldehyde-ketone reductase (AKR) in Lactobacillus bulgaricus, its precise regulatory mechanism remains unclear. By non-targeted metabolomics analysis revealed that nicotinic acid reshapes the metabolic profile during storage, significantly reducing the accumulation of organic acids such as L-lactic acid, fumaric acid, and succinic acid. This indicates that post-acidification processes are inhibited through relevant metabolic pathways. Concurrently, the yeast two-hybrid screening identified 21 proteins interacting with AKR, confirming L-lactate dehydrogenase (L-LDH) as a key interaction partner of AKR. This enzyme directly regulates L-LDH activity. Subsequent enzyme activity assays and AKR mutation confirmed that niacin acts as a potent inhibitor of L-LDH activity by promoting the formation of an AKR-L-LDH-NA ternary complex. Regulation of L-LDH activity by AKR without altering the structure and intrinsic catalytic properties of L-LDH is expected to realize the AKR-L-LDH-NA ternary complex as a key target for the future regulation of the post-acidification process. Our study establishes a technological method to accurately regulate the post-acidification of yogurt, which provides a theoretical basis for controlling acidity in lactic acid fermented foods.
{"title":"Aldo/keto reductase regulates L-lactate dehydrogenase activity as a key target for yogurt post-acidification","authors":"Qingqing Mu , Sitong Jia , Dongyao Li , Whenhao Zhao , Na Zhang , Miaoshu Wang , Hongtao Tian , Chen Li","doi":"10.1016/j.fm.2026.105037","DOIUrl":"10.1016/j.fm.2026.105037","url":null,"abstract":"<div><div>Post-acidification during refrigeration is a critical determinant of yogurt quality. Although it is known that niacin (NA) can influence this process via aldehyde-ketone reductase (AKR) in <em>Lactobacillus bulgaricus,</em> its precise regulatory mechanism remains unclear. By non-targeted metabolomics analysis revealed that nicotinic acid reshapes the metabolic profile during storage, significantly reducing the accumulation of organic acids such as L-lactic acid, fumaric acid, and succinic acid. This indicates that post-acidification processes are inhibited through relevant metabolic pathways. Concurrently, the yeast two-hybrid screening identified 21 proteins interacting with AKR, confirming L-lactate dehydrogenase (L-LDH) as a key interaction partner of AKR. This enzyme directly regulates L-LDH activity. Subsequent enzyme activity assays and AKR mutation confirmed that niacin acts as a potent inhibitor of L-LDH activity by promoting the formation of an AKR-L-LDH-NA ternary complex. Regulation of L-LDH activity by AKR without altering the structure and intrinsic catalytic properties of L-LDH is expected to realize the AKR-L-LDH-NA ternary complex as a key target for the future regulation of the post-acidification process. Our study establishes a technological method to accurately regulate the post-acidification of yogurt, which provides a theoretical basis for controlling acidity in lactic acid fermented foods.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"137 ","pages":"Article 105037"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922895","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 : 2026-08-01Epub Date: 2026-01-30DOI: 10.1016/j.fm.2026.105047
Christel Couderc , Valérie Laroute , Nathalie Aubry , Charlotte Paës , Muriel Cocaign-Bousquet , Marie-Line Daveran-Mingot , Michael Mourez
Backslopping, which involves using the whey from a previous batch as a starter for a new production run, is one of the oldest traditional cheese-making methods and is still widely used today. However, this technique can sometimes lead to acidification failures, necessitating the use of industrial starters to quickly restart production and minimise economic loss.
This study investigated the effect of using a well-defined indigenous starter culture on raw milk during backslopping. The microbial composition and technological characteristics of successive subcultures were analyzed during one month of backslopping with and without the starter added.
The results showed that the indigenous starter remained highly stable in skim milk, predominantly drove homolactic fermentation. The raw milk alone displayed greater initial microbial diversity and metabolic variability but then stabilised and Lactococcus lactis became dominant from day four onwards of backslopping. The combination of the indigenous starter with the raw milk, rapidly established L. lactis dominance, directing the ecosystem towards homolactic fermentation from the start of backslopping.
The addition of the indigenous starter impacted particularly subdominant populations and technological properties, resulting in an acidification that met the requirements of the Rocamadour PDO from the start of the backslopping. From day fifteen onwards, comparison of bacterial communities with and without the starter added became differentiated, demonstrating that adding the indigenous starter reduced variability in bacterial composition.
Notably, coexistence between the indigenous starter and the raw milk flora was observed, suggesting that this could be a promising option for farmer producers to strengthen the link between the product and its microbial terroir.
{"title":"Impact of a well-defined indigenous starter on microbial communities and technological properties of raw milk during backslopping practice","authors":"Christel Couderc , Valérie Laroute , Nathalie Aubry , Charlotte Paës , Muriel Cocaign-Bousquet , Marie-Line Daveran-Mingot , Michael Mourez","doi":"10.1016/j.fm.2026.105047","DOIUrl":"10.1016/j.fm.2026.105047","url":null,"abstract":"<div><div>Backslopping, which involves using the whey from a previous batch as a starter for a new production run, is one of the oldest traditional cheese-making methods and is still widely used today. However, this technique can sometimes lead to acidification failures, necessitating the use of industrial starters to quickly restart production and minimise economic loss.</div><div>This study investigated the effect of using a well-defined indigenous starter culture on raw milk during backslopping. The microbial composition and technological characteristics of successive subcultures were analyzed during one month of backslopping with and without the starter added.</div><div>The results showed that the indigenous starter remained highly stable in skim milk, predominantly drove homolactic fermentation. The raw milk alone displayed greater initial microbial diversity and metabolic variability but then stabilised and <em>Lactococcus lactis</em> became dominant from day four onwards of backslopping. The combination of the indigenous starter with the raw milk, rapidly established <em>L. lactis</em> dominance, directing the ecosystem towards homolactic fermentation from the start of backslopping.</div><div>The addition of the indigenous starter impacted particularly subdominant populations and technological properties, resulting in an acidification that met the requirements of the Rocamadour PDO from the start of the backslopping. From day fifteen onwards, comparison of bacterial communities with and without the starter added became differentiated, demonstrating that adding the indigenous starter reduced variability in bacterial composition.</div><div>Notably, coexistence between the indigenous starter and the raw milk flora was observed, suggesting that this could be a promising option for farmer producers to strengthen the link between the product and its microbial terroir.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"137 ","pages":"Article 105047"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188842","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 : 2026-08-01Epub Date: 2026-01-21DOI: 10.1016/j.fm.2026.105041
Yishan Yang , Irene Falco , Xiangwu Nou
Escherichia coli O157:H7, historically associated with undercooked beef, has increasingly been linked to leafy green associated outbreaks in the United States. A subset of strains, termed reoccurring, emerging, and persistent (REP), represented by REPEXH01 and REPEXH02, has repeatedly caused multistate outbreaks since 2017, raising concerns about their enhanced environmental fitness and persistence in leafy green production regions. In this study, we evaluated the stress tolerance profiles of representative REPEXH01 (PNUSAE013458) and REPEXH02 (2705C and PNUSAE019890) strains, using the meat-associated strain EDL933 and the spinach outbreak strain EC4115 as references. REPEXH01 strains exhibited elevated tolerance to starvation, arsenic, gastric acid, and antibiotics, traits consistent with genomic islands encoding multiple resistance determinants. REPEXH02 strains showed increased tolerance to UV-C irradiation, potentially linked to mutations in DNA repair genes. Both REP groups showed significantly higher survival than EDL933 under desiccation and blue light exposure (major antimicrobial spectrum in sunlight), underscoring their enhanced persistence in agricultural and processing environments. These findings highlight distinct adaptation strategies between REPEXH01 and REPEXH02 that may facilitate their continued recurrence in leafy green outbreaks. Understanding these stress response mechanisms provides critical insights into REP strain ecology and informs the development of improved intervention strategies to reduce produce-associated E. coli O157:H7 contamination.
{"title":"Enhanced environmental stress tolerance in reoccurring, emerging, and persistent (REP) Escherichia coli O157:H7 strains from leafy green associated outbreaks","authors":"Yishan Yang , Irene Falco , Xiangwu Nou","doi":"10.1016/j.fm.2026.105041","DOIUrl":"10.1016/j.fm.2026.105041","url":null,"abstract":"<div><div><em>Escherichia coli</em> O157:H7, historically associated with undercooked beef, has increasingly been linked to leafy green associated outbreaks in the United States. A subset of strains, termed reoccurring, emerging, and persistent (REP), represented by REPEXH01 and REPEXH02, has repeatedly caused multistate outbreaks since 2017, raising concerns about their enhanced environmental fitness and persistence in leafy green production regions. In this study, we evaluated the stress tolerance profiles of representative REPEXH01 (PNUSAE013458) and REPEXH02 (2705C and PNUSAE019890) strains, using the meat-associated strain EDL933 and the spinach outbreak strain EC4115 as references. REPEXH01 strains exhibited elevated tolerance to starvation, arsenic, gastric acid, and antibiotics, traits consistent with genomic islands encoding multiple resistance determinants. REPEXH02 strains showed increased tolerance to UV-C irradiation, potentially linked to mutations in DNA repair genes. Both REP groups showed significantly higher survival than EDL933 under desiccation and blue light exposure (major antimicrobial spectrum in sunlight), underscoring their enhanced persistence in agricultural and processing environments. These findings highlight distinct adaptation strategies between REPEXH01 and REPEXH02 that may facilitate their continued recurrence in leafy green outbreaks. Understanding these stress response mechanisms provides critical insights into REP strain ecology and informs the development of improved intervention strategies to reduce produce-associated <em>E. coli</em> O157:H7 contamination.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"137 ","pages":"Article 105041"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073586","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 : 2026-08-01Epub Date: 2025-12-27DOI: 10.1016/j.fm.2025.105032
Hang-Bo Xu , Meng-Ru Du , Zhen Jiao , Pan-Feng Guan , Ruo-Nan Ma
Zinc oxide nanoparticles (ZnO NPs) have emerged as novel eco-friendly method for food sterilization. However, the usage of high-concentration ZnO NPs exhibit biological toxicity. To overcome the challenge, this study proposed the dual sterilization strategy coupling cold atmospheric plasma (CAP) with hydrophilic ZnO (H-ZnO) NPs for food decontamination to reduce ZnO NPs potential risk and investigated the synergistic sterilization effects and mechanism of CAP coupled with H-ZnO NPs at different concentration (0.001, 0.01, and 0.1 g/L). Results show that the combined treatment can efficiently inactivate Gram-negative (E. coli and S. enterica) and Gram-positive bacteria (L.monocytogenes and S. aureus) on the surface of blueberries. CAP +0.01 g/L H-ZnO NPs had the most obvious synergistic sterilization, and the bacterial reduction was increased by 0.5 log at least among the four strains. The combined treatment of CAP and 0.01 g/L H-ZnO NPs led to the enhanced generation of reactive oxygen and nitrogen species (RONS) and Zn2+ release from H-ZnO NPs in the solution. Meanwhile, the released Zn2+ flowed into the cell and accordingly increased the intracellular ROS level (670 %), consequently resulting in the improved bacterial inactivation. The low concentration of H-ZnO NPs (0.001 g/L) could not effectively cause membrane potential depolarization, and thus leading to a poor result of coupled sterilization. The high concentration of H-ZnO NPs (0.1 g/L) attaching on S. aureus cell surface may obstruct the interaction between CAP and S. aureus, which showed the worst synergistic bactericidal efficiency. This study proposed CAP/ZnO synergy offers a scalable, low-chemical alternative to conventional decontamination methods, which will address the emerging challenges in food management.
{"title":"A novel sterilization mechanism of cold plasma coupled with low-dose ZnO nanoparticles for food Decontamination: Synergistic reactive species generation and zinc ion release","authors":"Hang-Bo Xu , Meng-Ru Du , Zhen Jiao , Pan-Feng Guan , Ruo-Nan Ma","doi":"10.1016/j.fm.2025.105032","DOIUrl":"10.1016/j.fm.2025.105032","url":null,"abstract":"<div><div>Zinc oxide nanoparticles (ZnO NPs) have emerged as novel eco-friendly method for food sterilization. However, the usage of high-concentration ZnO NPs exhibit biological toxicity. To overcome the challenge, this study proposed the dual sterilization strategy coupling cold atmospheric plasma (CAP) with hydrophilic ZnO (H-ZnO) NPs for food decontamination to reduce ZnO NPs potential risk and investigated the synergistic sterilization effects and mechanism of CAP coupled with H-ZnO NPs at different concentration (0.001, 0.01, and 0.1 g/L). Results show that the combined treatment can efficiently inactivate Gram-negative (<em>E. coli</em> and <em>S. enterica</em>) and Gram-positive bacteria (<em>L.monocytogenes</em> and <em>S. aureus</em>) on the surface of blueberries. CAP +0.01 g/L H-ZnO NPs had the most obvious synergistic sterilization, and the bacterial reduction was increased by 0.5 log at least among the four strains. The combined treatment of CAP and 0.01 g/L H-ZnO NPs led to the enhanced generation of reactive oxygen and nitrogen species (RONS) and Zn<sup>2+</sup> release from H-ZnO NPs in the solution. Meanwhile, the released Zn<sup>2+</sup> flowed into the cell and accordingly increased the intracellular ROS level (670 %), consequently resulting in the improved bacterial inactivation. The low concentration of H-ZnO NPs (0.001 g/L) could not effectively cause membrane potential depolarization, and thus leading to a poor result of coupled sterilization. The high concentration of H-ZnO NPs (0.1 g/L) attaching on <em>S. aureus</em> cell surface may obstruct the interaction between CAP and <em>S. aureus,</em> which showed the worst synergistic bactericidal efficiency. This study proposed CAP/ZnO synergy offers a scalable, low-chemical alternative to conventional decontamination methods, which will address the emerging challenges in food management.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"137 ","pages":"Article 105032"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145882346","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 : 2026-08-01Epub Date: 2026-01-05DOI: 10.1016/j.fm.2025.105036
Mohini Basu , Nataliia Voloshchuk , Jacob Simmons , Josephine Wee , Ryan J. Elias , Darrell W. Cockburn
Non-alcoholic and low-alcohol beer (NABLAB) production by maltose-negative non-Saccharomyces yeast (NSY) runs the risk of excessive sweetness due to the high residual maltose in the finished beer which may overshadow the unique flavors produced by the NSY. The goal of this study was to modify the fermentable sugar profile in wort to better suit maltose-negative NSY, resulting in low residual maltose worts while maintaining low ethanol levels. This was achieved by adding amyloglucosidase (AMG) to increase the proportion of glucose by partially hydrolyzing maltose and maltotriose. Two treatments were selected from AMG-treated time-course mash experiment to produce either moderately elevated or highly elevated glucose levels with either barley malt or barley malt extract. Fermentation was then performed using nine different NSY and compared to Saccharomyces cerevisiae. Most NSY produced significantly less ethanol than S. cerevisiae under these conditions, while leaving behind relatively low levels of maltose (<10 g/L). Lower ethanol production was found to be partially driven by diversion of sugar-derived carbon to non-ethanol pathways, including organic acids and glycerol. Overall, the use of high-glucose worts appears to be a promising approach to produce NABLAB by NSY with the potential for improved sensory properties.
{"title":"Control of residual maltose in low-alcohol beer produced by non-Saccharomyces yeast with enzymatic treatment","authors":"Mohini Basu , Nataliia Voloshchuk , Jacob Simmons , Josephine Wee , Ryan J. Elias , Darrell W. Cockburn","doi":"10.1016/j.fm.2025.105036","DOIUrl":"10.1016/j.fm.2025.105036","url":null,"abstract":"<div><div>Non-alcoholic and low-alcohol beer (NABLAB) production by maltose-negative non-<em>Saccharomyces</em> yeast (NSY) runs the risk of excessive sweetness due to the high residual maltose in the finished beer which may overshadow the unique flavors produced by the NSY. The goal of this study was to modify the fermentable sugar profile in wort to better suit maltose-negative NSY, resulting in low residual maltose worts while maintaining low ethanol levels. This was achieved by adding amyloglucosidase (AMG) to increase the proportion of glucose by partially hydrolyzing maltose and maltotriose. Two treatments were selected from AMG-treated time-course mash experiment to produce either moderately elevated or highly elevated glucose levels with either barley malt or barley malt extract. Fermentation was then performed using nine different NSY and compared to <em>Saccharomyces cerevisiae</em>. Most NSY produced significantly less ethanol than <em>S. cerevisiae</em> under these conditions, while leaving behind relatively low levels of maltose (<10 g/L). Lower ethanol production was found to be partially driven by diversion of sugar-derived carbon to non-ethanol pathways, including organic acids and glycerol. Overall, the use of high-glucose worts appears to be a promising approach to produce NABLAB by NSY with the potential for improved sensory properties.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"137 ","pages":"Article 105036"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145922795","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 : 2026-08-01Epub Date: 2026-01-27DOI: 10.1016/j.fm.2026.105046
Jinglin Xu , Xinze Li , Changyu Zhou , Anderson S. Sant'Ana , Daodong Pan , Jinxuan Cao , Hao Zhang , Qiang Xia
Bio-fermentation process is widely used to improve the quality and flavor of meat products, but the mechanisms by which co-applied physical fields synergistically regulate microbial metabolism during fermentation remain insufficiently elucidated. In this study, yeast and lactic acid bacteria were co-inoculated for lamb liver fermentation, to which ultrasound (US), pulsed electric field (PEF), and their combination (US-PEF) were applied to evaluate their effects on the physicochemical properties, sensory characteristics, and metabolome shifts. The results showed that US-PEF significantly reduced pH, total volatile basic nitrogen, and thiobarbituric acid reactive substances by 23.86 %, 73.30 %, and 53.40 %, respectively, relative to the unfermented group, while maintaining color and texture. Additionally, the perceived off-flavor intensity decreased by 52.12 %, and overall flavor improved significantly. Microstructural characterization showed that US-PEF treatment caused localized damage to the microbial cell surface structure, including cytoplasmic loosening and increased vacuolation, corresponding to enhanced membrane permeability and substrate utilization. Untargeted metabolomics revealed clear separation of metabolic profiles among treatments, with differential regulation observed in amino acid and lipid pathways. By increasing membrane permeability and potentially activating microbial enzymes, US-PEF accelerated protein degradation and increased dipeptides and taste-active amino acids, while lowering levels of unsaturated fatty acid precursors and thereby suppressing the formation of off-flavor compounds. These findings elucidate the synergistic regulation by physical fields-assisted fermentation contributed to improving the quality and flavor of livestock by-products.
{"title":"Synergistic regulation of microbial metabolism and quality features in liver products using combined ultrasound-pulsed electric field assisted co-fermentation","authors":"Jinglin Xu , Xinze Li , Changyu Zhou , Anderson S. Sant'Ana , Daodong Pan , Jinxuan Cao , Hao Zhang , Qiang Xia","doi":"10.1016/j.fm.2026.105046","DOIUrl":"10.1016/j.fm.2026.105046","url":null,"abstract":"<div><div>Bio-fermentation process is widely used to improve the quality and flavor of meat products, but the mechanisms by which co-applied physical fields synergistically regulate microbial metabolism during fermentation remain insufficiently elucidated. In this study, yeast and lactic acid bacteria were co-inoculated for lamb liver fermentation, to which ultrasound (US), pulsed electric field (PEF), and their combination (US-PEF) were applied to evaluate their effects on the physicochemical properties, sensory characteristics, and metabolome shifts. The results showed that US-PEF significantly reduced pH, total volatile basic nitrogen, and thiobarbituric acid reactive substances by 23.86 %, 73.30 %, and 53.40 %, respectively, relative to the unfermented group, while maintaining color and texture. Additionally, the perceived off-flavor intensity decreased by 52.12 %, and overall flavor improved significantly. Microstructural characterization showed that US-PEF treatment caused localized damage to the microbial cell surface structure, including cytoplasmic loosening and increased vacuolation, corresponding to enhanced membrane permeability and substrate utilization. Untargeted metabolomics revealed clear separation of metabolic profiles among treatments, with differential regulation observed in amino acid and lipid pathways. By increasing membrane permeability and potentially activating microbial enzymes, US-PEF accelerated protein degradation and increased dipeptides and taste-active amino acids, while lowering levels of unsaturated fatty acid precursors and thereby suppressing the formation of off-flavor compounds. These findings elucidate the synergistic regulation by physical fields-assisted fermentation contributed to improving the quality and flavor of livestock by-products.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"137 ","pages":"Article 105046"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146073591","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 : 2026-08-01Epub Date: 2026-01-21DOI: 10.1016/j.fm.2026.105040
Chenxi Guo, Yucen Xie, Jaqueline Oliveira de Moraes, Luxin Wang
The consumption of collard greens (CG) and kale (KA) and different formats of their products, e.g. juices, has increased significantly. However, there have been limited studies focusing on the enhancement of the microbial quality and safety of dark leafy green vegetables (DLGVs), especially large DLGVs, despite the occurrence of several outbreaks. The larger and more rough leaf surface is one major characteristically difference between CG/KA and other DLGVs (e.g. spinach). This study evaluated the antimicrobial effectiveness of acid-based washing (vinegar, lemon juice, and peracetic acid [PAA]) in controlling the populations of native microorganisms and artificially inoculated bacteria (Enterococcus faecium) on CG and KA during washing and storage. The washing procedure included a 5 min soaking (w/v ration 1:50) and a 15 s rinsing. Results showed that PAA (80 ppm, pH ∼ 4.00) ed to the greatest reductions in native fungi (∼1.2 and 1.4 log reductions) and bacteria (∼1.0 and 1.2 log reductions on CG and KA respectively) compared to 35 % vinegar (pH ∼2.75) and 13 % lemon juice wash (pH ∼2.83). PAA-washed CG and lemon juice-washed KA also exhibited the greatest additional reductions in fungal and bacterial populations during storage. E. faecium, used as a pathogen surrogate, had the largest reductions on CG and KA washed by PAA, ∼1.5 and 2.3 log reductions respectively. Lemon juice-washed CG and PAA-washed KA showed the greatest additional reductions in E. faecium during storage. Acid washing showed promising potential in protecting the microbial safety and quality of large DLGVs; the tested washing steps can be used at retail and home settings.
{"title":"Assessing the use of acid-based sanitizers for enhancing the microbial safety and quality of collard greens and kale","authors":"Chenxi Guo, Yucen Xie, Jaqueline Oliveira de Moraes, Luxin Wang","doi":"10.1016/j.fm.2026.105040","DOIUrl":"10.1016/j.fm.2026.105040","url":null,"abstract":"<div><div>The consumption of collard greens (CG) and kale (KA) and different formats of their products, e.g. juices, has increased significantly. However, there have been limited studies focusing on the enhancement of the microbial quality and safety of dark leafy green vegetables (DLGVs), especially large DLGVs, despite the occurrence of several outbreaks. The larger and more rough leaf surface is one major characteristically difference between CG/KA and other DLGVs (e.g. spinach). This study evaluated the antimicrobial effectiveness of acid-based washing (vinegar, lemon juice, and peracetic acid [PAA]) in controlling the populations of native microorganisms and artificially inoculated bacteria (<em>Enterococcus faecium)</em> on CG and KA during washing and storage. The washing procedure included a 5 min soaking (w/v ration 1:50) and a 15 s rinsing. Results showed that PAA (80 ppm, pH ∼ 4.00) ed to the greatest reductions in native fungi (∼1.2 and 1.4 log reductions) and bacteria (∼1.0 and 1.2 log reductions on CG and KA respectively) compared to 35 % vinegar (pH ∼2.75) and 13 % lemon juice wash (pH ∼2.83). PAA-washed CG and lemon juice-washed KA also exhibited the greatest additional reductions in fungal and bacterial populations during storage. <em>E. faecium</em>, used as a pathogen surrogate, had the largest reductions on CG and KA washed by PAA, ∼1.5 and 2.3 log reductions respectively. Lemon juice-washed CG and PAA-washed KA showed the greatest additional reductions in <em>E. faecium</em> during storage. Acid washing showed promising potential in protecting the microbial safety and quality of large DLGVs; the tested washing steps can be used at retail and home settings.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"137 ","pages":"Article 105040"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146034631","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}
The current study investigated the antimicrobial mechanisms of Pulsed Electric Fields (PEF) by evaluating the resistance of 22 Escherichia coli K12 mutants. Initial screening at PEF treatment (23 kV/cm, 53.3 μs, 95.4 kJ/kg), pH 7.0, revealed increased sensitivity (p < 0.05) of ΔclpB, ΔrpoS, and ΔdnaK expressed in Log10 reductions. Further inactivation kinetic analysis of 8 selected strains at pH 7.0 and 4.0 revealed a non-linear, polyphasic behaviour. This was described by a global modelling approach combining a log-linear primary model with a second-order polynomial model incorporating treatment time, total specific energy, and survival data as variables. The calculated model parameters (C1, C2, and C3) significantly differed (p < 0.05) among strains at pH 7.0, but not at pH 4.0. Furthermore, the calculated inactivation rates, kmax, varied in relation to the total specific energy. At pH 7.0, kmax was higher at low (0–40 kJ/kg) and high (140–180 kJ/kg) total specific energies, while at pH 4.0, it raised at high total specific energies (120–160 kJ/kg). In conclusion, E. coli response to PEF was dependant on the stress regulator rpoS. This response also involved genes which encode molecular chaperones such as dnaK, clpB and recA, related proteins for DNA repair. In conclusion, resistance to PEF was found to be influenced by pH and total specific energy, indicating that E. coli mounts a multifaceted response to PEF treatments, informing advanced microbial inactivation strategies for food safety.
{"title":"Modelling gene-dependent PEF resistance of E. coli K-12","authors":"Fotios Lytras , Georgios Psakis , Ruben Gatt , Javier Raso , Vasilis Valdramidis","doi":"10.1016/j.fm.2026.105042","DOIUrl":"10.1016/j.fm.2026.105042","url":null,"abstract":"<div><div>The current study investigated the antimicrobial mechanisms of Pulsed Electric Fields (PEF) by evaluating the resistance of 22 <em>Escherichia coli</em> K12 mutants. Initial screening at PEF treatment (23 kV/cm, 53.3 μs, 95.4 kJ/kg), pH 7.0, revealed increased sensitivity (<em>p < 0.05</em>) of Δ<em>clpB</em>, Δ<em>rpoS</em>, and Δ<em>dnaK</em> expressed in Log<sub>10</sub> reductions. Further inactivation kinetic analysis of 8 selected strains at pH 7.0 and 4.0 revealed a non-linear, polyphasic behaviour. This was described by a global modelling approach combining a log-linear primary model with a second-order polynomial model incorporating treatment time, total specific energy, and survival data as variables. The calculated model parameters <em>(C</em><sub><em>1</em></sub>, <em>C</em><sub><em>2</em></sub>, and <em>C</em><sub><em>3</em></sub><em>)</em> significantly differed (<em>p < 0.05</em>) among strains at pH 7.0, but not at pH 4.0. Furthermore, the calculated inactivation rates, <em>k</em><sub><em>max</em></sub>, varied in relation to the total specific energy. At pH 7.0, <em>k</em><sub><em>max</em></sub> was higher at low (0–40 kJ/kg) and high (140–180 kJ/kg) total specific energies, while at pH 4.0, it raised at high total specific energies (120–160 kJ/kg). In conclusion, <em>E. coli</em> response to PEF was dependant on the stress regulator <em>rpoS</em>. This response also involved genes which encode molecular chaperones such as <em>dnaK</em>, <em>clpB</em> and <em>recA,</em> related proteins for DNA repair. In conclusion, resistance to PEF was found to be influenced by pH and total specific energy, indicating that <em>E. coli</em> mounts a multifaceted response to PEF treatments, informing advanced microbial inactivation strategies for food safety.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"137 ","pages":"Article 105042"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146074243","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}
Seafood safety is increasingly threatened by bacterial contamination, biofilm formation, and increasing antimicrobial resistance. Conventional methods such as refrigeration, chemical preservatives, and antibiotics often fail to effectively eliminate resilient pathogens, including Listeria monocytogenes, Vibrio spp., and Salmonella spp., necessitating alternative strategies. Bacteriophages have emerged as a promising biocontrol approach due to their high specificity and biofilm penetration, as well as their minimal impact on beneficial microbiota. This review explores the diverse applications of bacteriophages in seafood safety, including direct surface treatments, bacteriophage-embedded packaging, and pre-harvest interventions in aquaculture. Additionally, phage biocontrol in combination with natural antimicrobials, quorum sensing inhibitors, and advanced processing technologies, such as high-pressure processing, cold plasma, and plasma-activated water, is examined for enhanced reduction or elimination of pathogenic bacteria. Advances in genetic engineering have further expanded phage efficacy, enabling host range modification, improved stability, and increased bactericidal activity. The commercialization of phage biocontrol, however, faces challenges related to bacterial resistance, regulatory barriers, and variations in environmental conditions affecting phage stability. Despite these limitations, bacteriophages present a sustainable and environmentally friendly alternative to chemical preservatives and antibiotics, aligning with consumer demand for natural food safety solutions. Future research should focus on optimizing phage formulations, improving delivery systems, and establishing globally harmonized regulations to facilitate the widespread adoption of bacteriophages in seafood processing. Phage biocontrol hold significant potential to revolutionize seafood safety by mitigating contamination risks and enhancing product shelf life.
{"title":"Revolutionizing seafood safety with bacteriophages: emerging technologies and applications","authors":"Nigar Sultana Meghla , Soo-Jin Jung , Md Furkanur Rahaman Mizan , Syeda Roufun Nesa , IkSoon Kang , Sang-Do Ha","doi":"10.1016/j.fm.2025.105021","DOIUrl":"10.1016/j.fm.2025.105021","url":null,"abstract":"<div><div>Seafood safety is increasingly threatened by bacterial contamination, biofilm formation, and increasing antimicrobial resistance. Conventional methods such as refrigeration, chemical preservatives, and antibiotics often fail to effectively eliminate resilient pathogens, including <em>Listeria monocytogenes</em>, <em>Vibrio</em> spp., and <em>Salmonella</em> spp., necessitating alternative strategies. Bacteriophages have emerged as a promising biocontrol approach due to their high specificity and biofilm penetration, as well as their minimal impact on beneficial microbiota. This review explores the diverse applications of bacteriophages in seafood safety, including direct surface treatments, bacteriophage-embedded packaging, and pre-harvest interventions in aquaculture. Additionally, phage biocontrol in combination with natural antimicrobials, quorum sensing inhibitors, and advanced processing technologies, such as high-pressure processing, cold plasma, and plasma-activated water, is examined for enhanced reduction or elimination of pathogenic bacteria. Advances in genetic engineering have further expanded phage efficacy, enabling host range modification, improved stability, and increased bactericidal activity. The commercialization of phage biocontrol, however, faces challenges related to bacterial resistance, regulatory barriers, and variations in environmental conditions affecting phage stability. Despite these limitations, bacteriophages present a sustainable and environmentally friendly alternative to chemical preservatives and antibiotics, aligning with consumer demand for natural food safety solutions. Future research should focus on optimizing phage formulations, improving delivery systems, and establishing globally harmonized regulations to facilitate the widespread adoption of bacteriophages in seafood processing. Phage biocontrol hold significant potential to revolutionize seafood safety by mitigating contamination risks and enhancing product shelf life.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"137 ","pages":"Article 105021"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839563","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 : 2026-08-01Epub Date: 2025-12-26DOI: 10.1016/j.fm.2025.105015
T.L. Harrell, A. Shwani, D.L. Suarez
In March 2024, highly pathogenic avian influenza virus (HPAIV) clade 2.3.4.4. b H5N1 was detected in dairy cattle. Since detection, the virus has spread across 17 states, infecting more than 1000 dairy herds, causing concern for the dairy industry regarding the effects on dairy cattle, the risk associated with milk quality and production, and ultimately its risk to humans. It has been shown that pasteurization is sufficient to inactivate HPAIV, if present in milk, making it safe for human consumption. However, unpasteurized raw milk that is routinely consumed and used to make cheese, yogurt, and kefir is a public health concern. We acidified raw milk, a process that is analogous to the preliminary phase of generating fermented milk products, with acetic, propionic, lactic, or citric acid to pH 5; or acidified it with acetic acid to pH 6, 5, or 4. Each sample was subsequently spiked with low pathogenic avian influenza virus (LPAIV) and incubated at room temperature for up to 24 h before being inoculated into 10-day old specific-pathogen-free embryonating chicken eggs. Embryos were assessed daily for viability and hemagglutination assays on the allantoic fluid was used to confirm the presence of viable LPAIV. The reduction of viable virus was significantly correlated with both time and pH but not specific type of acid tested. An acid treatment at pH 4 and 5 progressively reduced viable LPAIV levels over time, with the most pronounced inactivation observed at 24 h. Samples at pH 6 had little reduction in virus viability.
{"title":"The impact of acids, pH, and incubation time on avian influenza virus persistence in raw milk","authors":"T.L. Harrell, A. Shwani, D.L. Suarez","doi":"10.1016/j.fm.2025.105015","DOIUrl":"10.1016/j.fm.2025.105015","url":null,"abstract":"<div><div>In March 2024, highly pathogenic avian influenza virus (HPAIV) clade 2.3.4.4. b H5N1 was detected in dairy cattle. Since detection, the virus has spread across 17 states, infecting more than 1000 dairy herds, causing concern for the dairy industry regarding the effects on dairy cattle, the risk associated with milk quality and production, and ultimately its risk to humans. It has been shown that pasteurization is sufficient to inactivate HPAIV, if present in milk, making it safe for human consumption. However, unpasteurized raw milk that is routinely consumed and used to make cheese, yogurt, and kefir is a public health concern. We acidified raw milk, a process that is analogous to the preliminary phase of generating fermented milk products, with acetic, propionic, lactic, or citric acid to pH 5; or acidified it with acetic acid to pH 6, 5, or 4. Each sample was subsequently spiked with low pathogenic avian influenza virus (LPAIV) and incubated at room temperature for up to 24 h before being inoculated into 10-day old specific-pathogen-free embryonating chicken eggs. Embryos were assessed daily for viability and hemagglutination assays on the allantoic fluid was used to confirm the presence of viable LPAIV. The reduction of viable virus was significantly correlated with both time and pH but not specific type of acid tested. An acid treatment at pH 4 and 5 progressively reduced viable LPAIV levels over time, with the most pronounced inactivation observed at 24 h. Samples at pH 6 had little reduction in virus viability.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"137 ","pages":"Article 105015"},"PeriodicalIF":4.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145973597","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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