Pub Date : 2024-11-01DOI: 10.1016/j.fm.2024.104678
In the quest for a balanced diet and better health, the global shift towards nutrient-dense foods highlights the multiple roles of lactic acid bacteria exopolysaccharides (LAB-EPS) in improving food quality and health. This paper offers a comprehensive survey of LAB-EPS, focusing on their classification, biosynthesis pathways and application in the food industry, from dairy products to bakery products and meat. It highlights the impact of LAB-EPS on the texture and sensory qualities of food. Despite their promising prospects, these polysaccharides face various application challenges in the food industry. These include variability in EPS production among LAB strains, complexity in structure-function relationships, and limited understanding of their health benefits. In order to address these issues, the review identifies and suggests future research directions to optimize the production of LAB-EPS, elucidating their health benefit mechanisms, and expanding their application scope. In summary, this review aims to contribute to advance innovation and progress in the food industry by developing healthier food options and deepening the understanding of LAB-EPS in promoting human health.
{"title":"Current state, challenges and future orientations of the applications of lactic acid bacteria exopolysaccharide in foods","authors":"","doi":"10.1016/j.fm.2024.104678","DOIUrl":"10.1016/j.fm.2024.104678","url":null,"abstract":"<div><div>In the quest for a balanced diet and better health, the global shift towards nutrient-dense foods highlights the multiple roles of lactic acid bacteria exopolysaccharides (LAB-EPS) in improving food quality and health. This paper offers a comprehensive survey of LAB-EPS, focusing on their classification, biosynthesis pathways and application in the food industry, from dairy products to bakery products and meat. It highlights the impact of LAB-EPS on the texture and sensory qualities of food. Despite their promising prospects, these polysaccharides face various application challenges in the food industry. These include variability in EPS production among LAB strains, complexity in structure-function relationships, and limited understanding of their health benefits. In order to address these issues, the review identifies and suggests future research directions to optimize the production of LAB-EPS, elucidating their health benefit mechanisms, and expanding their application scope. In summary, this review aims to contribute to advance innovation and progress in the food industry by developing healthier food options and deepening the understanding of LAB-EPS in promoting human health.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142571453","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 : 2024-10-29DOI: 10.1016/j.fm.2024.104676
Patulin (PAT), a notorious mycotoxin widely found in fruits and their derived products, poses serious health risks to humans and animals due to its high toxicity. Biodegradation based on microbial enzymes has shown broad application prospects in controlling PAT contamination due to its environmental friendliness, high efficiency, strong specificity, and mild conditions of action. Bacillus subtilis is a cosmopolitan probiotic bacterium with an extensive enzymatic profile, which could serve as a valuable resource for the effective production of a range of enzymes utilized in various industrial processes and production applications. In this work, we demonstrated that a short-chain dehydrogenase/reductase from B. subtilis (BsSDR) that can effectively convert PAT to the non-toxic E-ascladiol. Multiple sequence alignment results revealed that BsSDR displayed less than 30% identity with the previously reported PAT-degrading enzymes, indicating that it is a novel PAT-degrading enzyme. BsSDR exhibited a powerful PAT-degrading ability and strong PAT tolerance, as it was capable of degrading over 95% of PAT at initial concentrations of 50–500 μM. In addition, BsSDR exhibited the highest activity at pH 8.0 and 40 °C, and retained more than 60% residual activity after incubation at 40 °C for 3 h, indicating a remarkable thermostability of BsSDR. Molecular docking and site-directed mutagenesis indicated that the catalytic triad formed by the residues (S, Y, and K) was the key for short-chain dehydrogenase/reductase activity and this conserved catalytic mechanism was followed in BsSDR catalysis. More importantly, BsSDR is able to eliminate 83.61% of PAT in apple juice without compromising its quality during the biodegradation process. These results suggest that BsSDR may serve as a promising detoxification agent for the degradation of PAT in food processing.
棒曲霉素（PAT）是一种臭名昭著的霉菌毒素，广泛存在于水果及其衍生产品中，因其毒性高而对人类和动物的健康构成严重威胁。基于微生物酶的生物降解技术具有环境友好、高效、特异性强、作用条件温和等特点，在控制 PAT 污染方面具有广阔的应用前景。枯草芽孢杆菌是一种世界性的益生菌，具有广泛的酶谱，可以作为有效生产各种酶的宝贵资源，用于各种工业过程和生产应用。在这项工作中，我们证明了一种来自枯草杆菌（BsSDR）的短链脱氢酶/还原酶能有效地将 PAT 转化为无毒的 E-ascladiol。多重序列比对结果显示，BsSDR与之前报道的PAT降解酶的相同度低于30%，表明它是一种新型的PAT降解酶。BsSDR 具有强大的 PAT 降解能力和较强的 PAT 耐受性，在初始浓度为 50-500 μM 时，它能够降解 95% 以上的 PAT。此外，BsSDR在pH值为8.0和40 °C时活性最高，在40 °C下培养3小时后仍能保持60%以上的残余活性，这表明BsSDR具有显著的恒温性。分子对接和定点突变表明，由残基（S、Y 和 K）形成的催化三元组是短链脱氢酶/还原酶活性的关键，BsSDR 的催化过程遵循了这一保守的催化机理。更重要的是，在生物降解过程中，BsSDR 能够消除苹果汁中 83.61% 的 PAT，而不会影响苹果汁的质量。这些结果表明，BsSDR 可以作为一种很有前途的解毒剂，用于降解食品加工过程中的 PAT。
{"title":"Enzymatic degradation of mycotoxin patulin by a short-chain dehydrogenase/reductase from Bacillus subtilis and its application in apple juice","authors":"","doi":"10.1016/j.fm.2024.104676","DOIUrl":"10.1016/j.fm.2024.104676","url":null,"abstract":"<div><div>Patulin (PAT), a notorious mycotoxin widely found in fruits and their derived products, poses serious health risks to humans and animals due to its high toxicity. Biodegradation based on microbial enzymes has shown broad application prospects in controlling PAT contamination due to its environmental friendliness, high efficiency, strong specificity, and mild conditions of action. <em>Bacillus subtilis</em> is a cosmopolitan probiotic bacterium with an extensive enzymatic profile, which could serve as a valuable resource for the effective production of a range of enzymes utilized in various industrial processes and production applications. In this work, we demonstrated that a short-chain dehydrogenase/reductase from <em>B. subtilis</em> (<em>Bs</em>SDR) that can effectively convert PAT to the non-toxic E-ascladiol. Multiple sequence alignment results revealed that <em>Bs</em>SDR displayed less than 30% identity with the previously reported PAT-degrading enzymes, indicating that it is a novel PAT-degrading enzyme. <em>Bs</em>SDR exhibited a powerful PAT-degrading ability and strong PAT tolerance, as it was capable of degrading over 95% of PAT at initial concentrations of 50–500 μM. In addition, <em>Bs</em>SDR exhibited the highest activity at pH 8.0 and 40 °C, and retained more than 60% residual activity after incubation at 40 °C for 3 h, indicating a remarkable thermostability of <em>Bs</em>SDR. Molecular docking and site-directed mutagenesis indicated that the catalytic triad formed by the residues (S, Y, and K) was the key for short-chain dehydrogenase/reductase activity and this conserved catalytic mechanism was followed in <em>Bs</em>SDR catalysis. More importantly, <em>Bs</em>SDR is able to eliminate 83.61% of PAT in apple juice without compromising its quality during the biodegradation process. These results suggest that <em>Bs</em>SDR may serve as a promising detoxification agent for the degradation of PAT in food processing.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593902","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 : 2024-10-28DOI: 10.1016/j.fm.2024.104675
Listeria monocytogenes is a major foodborne pathogen. In our previous study, we found that L. monocytogenes ST5 and ST121 strains were dominant in two food plants of Shanghai. Genetic characterization revealed that the environmental tolerance of these strains was attributable to the plasmids pLM33 and pLM5578. To further evaluate the function of L. monocytogenes plasmids, we selected ST5 and ST121 wild-type strains, and used their plasmid-cured strains as controls to conduct tolerance tests. In addition, we analyzed 108 L. monocytogenes strains isolated from four major food categories in Shanghai. Our results showed that compared with the plasmid-cured strain, the ST5 strain carrying pLM33 showed higher tolerance to environmental stress conditions, including low acid, high salt, oxidizing, and high-temperature conditions; as well as higher virulence. Furthermore, we found that the plasmid carriage rate of food isolates was 97.22%, with the highest carriage rate of 68.57% for pLM5578, followed by 24.76% for pLM33. Notably, all L. monocytogenes ST5 isolates from ready-to-eat food products (n = 11) carried plasmids, suggesting that contamination of these food products may pose a serious risk to human health. In summary, the results of this study broaden our understanding regarding the role of L. monocytogenes plasmids in stress responses.
{"title":"pLM33 provides tolerance of persistent Listeria monocytogenes ST5 to various stress conditions and also enhances its virulence","authors":"","doi":"10.1016/j.fm.2024.104675","DOIUrl":"10.1016/j.fm.2024.104675","url":null,"abstract":"<div><div><em>Listeria monocytogenes</em> is a major foodborne pathogen. In our previous study, we found that <em>L. monocytogenes</em> ST5 and ST121 strains were dominant in two food plants of Shanghai. Genetic characterization revealed that the environmental tolerance of these strains was attributable to the plasmids pLM33 and pLM5578. To further evaluate the function of <em>L. monocytogenes</em> plasmids<em>,</em> we selected ST5 and ST121 wild-type strains, and used their plasmid-cured strains as controls to conduct tolerance tests. In addition, we analyzed 108 <em>L. monocytogenes</em> strains isolated from four major food categories in Shanghai. Our results showed that compared with the plasmid-cured strain, the ST5 strain carrying pLM33 showed higher tolerance to environmental stress conditions, including low acid, high salt, oxidizing, and high-temperature conditions; as well as higher virulence. Furthermore, we found that the plasmid carriage rate of food isolates was 97.22%, with the highest carriage rate of 68.57% for pLM5578, followed by 24.76% for pLM33. Notably, all <em>L. monocytogenes</em> ST5 isolates from ready-to-eat food products (n = 11) carried plasmids, suggesting that contamination of these food products may pose a serious risk to human health. In summary, the results of this study broaden our understanding regarding the role of <em>L. monocytogenes</em> plasmids in stress responses.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142555031","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 : 2024-10-22DOI: 10.1016/j.fm.2024.104674
The safety of ready-to-eat (RTE) deli meats, especially those sliced in retail establishments, may be improved by light-based surface decontamination. Conventional 254 nm ultraviolet-C (UVC) systems have strong germicidal effects but pose human-health hazards that make them unsuitable for retail use. This study therefore explores the efficacy of microplasma-based 222 nm far-UVC lamps as a safer alternative for decontaminating liquid buffer, two common food-contact surfaces (polyethylene terephthalate and stainless steel), and RTE turkey breast. In all three non-meat cases, the system achieved approximately 5-log reductions of both Listeria monocytogenes and Salmonella Typhimurium. The system also caused a 1.3-log reduction of L. monocytogenes and a 1-log reduction of S. Typhimurium on turkey breast at the highest tested dose of 786.3 mJ/cm2. Color is a key quality indicator for RTE meat consumers, and treatment caused no significant change in L∗, a∗, or b∗ color values (p > 0.05) until doses reached 224.7 mJ/cm2. However, higher doses could lead to statistically significant color changes. Given that far-UVC light has been deemed human-safe by other studies, the proposed system has considerable potential to improve RTE food-related safety in retail establishments, even when consumers and workers are present.
{"title":"Improving ready-to-eat meat safety: Evaluating the bacterial-inactivation efficacy of microplasma-based far-UVC light treatment of food-contact surfaces and deli turkey breast","authors":"","doi":"10.1016/j.fm.2024.104674","DOIUrl":"10.1016/j.fm.2024.104674","url":null,"abstract":"<div><div>The safety of ready-to-eat (RTE) deli meats, especially those sliced in retail establishments, may be improved by light-based surface decontamination. Conventional 254 nm ultraviolet-C (UVC) systems have strong germicidal effects but pose human-health hazards that make them unsuitable for retail use. This study therefore explores the efficacy of microplasma-based 222 nm far-UVC lamps as a safer alternative for decontaminating liquid buffer, two common food-contact surfaces (polyethylene terephthalate and stainless steel), and RTE turkey breast. In all three non-meat cases, the system achieved approximately 5-log reductions of both <em>Listeria monocytogenes</em> and <em>Salmonella</em> Typhimurium. The system also caused a 1.3-log reduction of <em>L. monocytogenes</em> and a 1-log reduction of <em>S.</em> Typhimurium on turkey breast at the highest tested dose of 786.3 mJ/cm<sup>2</sup>. Color is a key quality indicator for RTE meat consumers, and treatment caused no significant change in L∗, a∗, or b∗ color values (<em>p</em> > 0.05) until doses reached 224.7 mJ/cm<sup>2</sup>. However, higher doses could lead to statistically significant color changes. Given that far-UVC light has been deemed human-safe by other studies, the proposed system has considerable potential to improve RTE food-related safety in retail establishments, even when consumers and workers are present.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142555030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1016/j.fm.2024.104673
Plasma-activated water (PAW) has been shown to have antimicrobial properties, making it a promising tool for surface decontamination. This study evaluated the ability of PAW generated from high voltage atmospheric cold plasma to remove Salmonella from common surfaces (stainless steel (SS), polyvinyl chloride (PVC), concrete, and wood) found in poultry houses. PAW was generated by exposing distilled water to atmospheric cold plasma in 80% humid air at 90 kV and 60 Hz for 30 min. The resulting PAW contained 1120 ppm of nitrate and 1370 ppm of hydrogen peroxide, with a pH of 1.83. PAW was then applied to coupons of SS, PVC, wood, and concrete surfaces inoculated with 7–8 log10 CFU of cocktail of Salmonella spp. (S. Typhimurium, S. Newport, S. Montevideo, and S. Enteritidis). PAW effectively reduced Salmonella levels on SS and PVC surfaces to below the detection limit within 30 s. On wood surfaces, a longer treatment time of 7.5 min was required to achieve a maximum reduction of 2.63 log10 CFU, likely due to the porosity of the wood limiting PAW contact with the bacteria. On concrete surfaces, the reduction in Salmonella levels was only 0.98 log10 CFU. This was likely due to the greater surface roughness and high alkalinity, which neutralized the PAW species.
{"title":"Using plasma-activated water for decontamination of Salmonella spp. on common building surfaces in poultry houses","authors":"","doi":"10.1016/j.fm.2024.104673","DOIUrl":"10.1016/j.fm.2024.104673","url":null,"abstract":"<div><div>Plasma-activated water (PAW) has been shown to have antimicrobial properties, making it a promising tool for surface decontamination. This study evaluated the ability of PAW generated from high voltage atmospheric cold plasma to remove <em>Salmonella</em> from common surfaces (stainless steel (SS), polyvinyl chloride (PVC), concrete, and wood) found in poultry houses. PAW was generated by exposing distilled water to atmospheric cold plasma in 80% humid air at 90 kV and 60 Hz for 30 min. The resulting PAW contained 1120 ppm of nitrate and 1370 ppm of hydrogen peroxide, with a pH of 1.83. PAW was then applied to coupons of SS, PVC, wood, and concrete surfaces inoculated with 7–8 log<sub>10</sub> CFU of cocktail of <em>Salmonella</em> spp. (<em>S.</em> Typhimurium, <em>S</em>. Newport, <em>S.</em> Montevideo, and <em>S.</em> Enteritidis). PAW effectively reduced <em>Salmonella</em> levels on SS and PVC surfaces to below the detection limit within 30 s. On wood surfaces, a longer treatment time of 7.5 min was required to achieve a maximum reduction of 2.63 log<sub>10</sub> CFU, likely due to the porosity of the wood limiting PAW contact with the bacteria. On concrete surfaces, the reduction in Salmonella levels was only 0.98 log<sub>10</sub> CFU. This was likely due to the greater surface roughness and high alkalinity, which neutralized the PAW species.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536294","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 : 2024-10-18DOI: 10.1016/j.fm.2024.104661
When maternal milk is unavailable, donor human milk (DHM) from human milk banks (HMBs) is the optimal alternative, as recommended by the World Health Organisation. The microbiota of DHM could contain opportunistic pathogens, which means rigorous microbiological screening for DHM, prior to pasteurisation, is recommended to safeguard recipients. Here, an analysis of 6863 DHM samples from 1419 donors at the Hearts Milk Bank between 2017 and 2023 showed approximately 70.1% of samples exhibited a total viable count (TVC) between 10³-10⁵ CFU/mL, while 18.3% yielded no growth; 11.5% of samples exceeded the 10⁵ CFU/mL threshold. Staphylococcus was the most prevalent genus, with S. epidermidis found in 61.5% of samples. A significant (p < 0.05) negative co-occurrence was observed between S. epidermidis and Gram-negative opportunistic pathogens. Overall, 16.8% of DHM samples failed to meet UK microbiological screening criteria, with 68.3% of these failures due to exceeding TVC thresholds. S. epidermidis accounted for approximately 10.2% of the total failed samples. The majority of DHM samples met the current microbiological criteria specified in the National Institute for Health and Care Excellence (NICE) clinical guidance (CG93), “Donor milk banks: service operation”. The core species in DHM reflects microorganisms typically found on the skin. These findings highlight that the current UK thresholds and criteria could potentially be modified to increase the available supply of DHM without increasing microbiological risk.
{"title":"Microbiological analysis of donor human milk over seven years from the Hearts Milk Bank (United Kingdom)","authors":"","doi":"10.1016/j.fm.2024.104661","DOIUrl":"10.1016/j.fm.2024.104661","url":null,"abstract":"<div><div>When maternal milk is unavailable, donor human milk (DHM) from human milk banks (HMBs) is the optimal alternative, as recommended by the World Health Organisation. The microbiota of DHM could contain opportunistic pathogens, which means rigorous microbiological screening for DHM, prior to pasteurisation, is recommended to safeguard recipients. Here, an analysis of 6863 DHM samples from 1419 donors at the Hearts Milk Bank between 2017 and 2023 showed approximately 70.1% of samples exhibited a total viable count (TVC) between 10³-10⁵ CFU/mL, while 18.3% yielded no growth; 11.5% of samples exceeded the 10⁵ CFU/mL threshold. <em>Staphylococcus</em> was the most prevalent genus, with <em>S. epidermidis</em> found in 61.5% of samples. A significant (<em>p</em> < 0.05) negative co-occurrence was observed between <em>S. epidermidis</em> and Gram-negative opportunistic pathogens. Overall, 16.8% of DHM samples failed to meet UK microbiological screening criteria, with 68.3% of these failures due to exceeding TVC thresholds. <em>S. epidermidis</em> accounted for approximately 10.2% of the total failed samples. The majority of DHM samples met the current microbiological criteria specified in the National Institute for Health and Care Excellence (NICE) clinical guidance (CG93), “Donor milk banks: service operation”. The core species in DHM reflects microorganisms typically found on the skin. These findings highlight that the current UK thresholds and criteria could potentially be modified to increase the available supply of DHM without increasing microbiological risk.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-16DOI: 10.1016/j.fm.2024.104659
Salmonella contamination in pig slaughterhouses is linked to infection rate on farms. Accurate diagnosis in heavy pigs relies on isolating pathogens from the gut wall or lymph nodes. A key technique is Immunocapture using Magnetic Beads (IMS), which purifies target bacteria from Salmonella enrichment broths. This is followed by an Enzyme-Linked Immunomagnetic Electrochemical (ELIME) assay for rapid detection. In our study, we developed an ELIME-IMS hybrid assay to detect Salmonella in swine mesenteric lymph nodes (MNL), involving a clean-up with N-acetylcysteine and centrifugation. Detection limits for S. Typhimurium and S. Derby were estimated at 2.80 and 3.52 Log CFU/ml, respectively. We analysed 103 MNL samples from a northern Italy slaughterhouse. Additionally, we examined 15 carcass swabs. Both the ELIME assay and the IMS-based culture method showed strong agreement with the ISO 6579–1:2017 method, especially after 20 h of enrichment (89.47% concordance). The clean-up step significantly influenced the results, as samples processed without it showed higher variability. A logistic regression model indicated high classification accuracy for negative samples using ELIME values. The ELIME-IMS assay facilitates rapid Salmonella screening and isolation in swine mesenteric lymph nodes.
{"title":"ELIME-IMS hybrid assay for Salmonella detection in swine mesenteric lymph nodes at slaughterhouse","authors":"","doi":"10.1016/j.fm.2024.104659","DOIUrl":"10.1016/j.fm.2024.104659","url":null,"abstract":"<div><div><em>Salmonella</em> contamination in pig slaughterhouses is linked to infection rate on farms. Accurate diagnosis in heavy pigs relies on isolating pathogens from the gut wall or lymph nodes. A key technique is Immunocapture using Magnetic Beads (IMS), which purifies target bacteria from <em>Salmonella</em> enrichment broths. This is followed by an Enzyme-Linked Immunomagnetic Electrochemical (ELIME) assay for rapid detection. In our study, we developed an ELIME-IMS hybrid assay to detect <em>Salmonella</em> in swine mesenteric lymph nodes (MNL), involving a clean-up with N-acetylcysteine and centrifugation. Detection limits for <em>S.</em> Typhimurium and <em>S.</em> Derby were estimated at 2.80 and 3.52 Log CFU/ml, respectively. We analysed 103 MNL samples from a northern Italy slaughterhouse. Additionally, we examined 15 carcass swabs. Both the ELIME assay and the IMS-based culture method showed strong agreement with the ISO 6579–1:2017 method, especially after 20 h of enrichment (89.47% concordance). The clean-up step significantly influenced the results, as samples processed without it showed higher variability. A logistic regression model indicated high classification accuracy for negative samples using ELIME values. The ELIME-IMS assay facilitates rapid <em>Salmonella</em> screening and isolation in swine mesenteric lymph nodes.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-13DOI: 10.1016/j.fm.2024.104660
The loss of probiotics viability in yogurts and fermented milk is a significant challenge in producing yogurt and fermented milk. Thus, pre-exposure of probiotics to stress conditions can be a viable alternative to increase the probiotic viability. Moreover, the use of fruit pulp and agro-industrial residues in these products has demonstrated promising results in promoting growth and improving the viability of probiotics. Thus, this study aimed to evaluate the effects of pre-exposure to acid, oxidative and osmotic stress on the growth and viability of Lactobacillus acidophilus in yogurts and naturally fermented milk containing buriti (Mauritia flexuosa Mart.) pulp or orange byproduct. L. acidophilus was individually pre-exposed to acid, oxidative, and osmotic stress and used in the production of yogurts and fermented milk to determine both the acidification profile and growth of the cultures. Furthermore, during cold storage, the post-acidification profiles and viability of microbial cultures added to the yogurts and fermented milk were monitored. Results showed that pre-exposure to stress conditions influenced the growth parameters as the growth rate (μ) and lag phase (λ) of L. acidophilus and the starter cultures of S. thermophilus and L. delbrueckii subsp. bulgaricus. Moreover, an increase in the viability of L. acidophilus - pre-exposed to acid stress - was observed on the 21st day of storage of natural yogurts containing orange byproduct compared with non-stressful conditions. This study reports new data on the growth of probiotic cultures pre-exposed to stress conditions in products added of pulps and agro-industrial residues, which have not yet been shown in the literature.
{"title":"Impact of pre-exposure stress on the growth and viability of Lactobacillus acidophilus in regular, buriti pulp and orange byproduct fermented milk products","authors":"","doi":"10.1016/j.fm.2024.104660","DOIUrl":"10.1016/j.fm.2024.104660","url":null,"abstract":"<div><div>The loss of probiotics viability in yogurts and fermented milk is a significant challenge in producing yogurt and fermented milk. Thus, pre-exposure of probiotics to stress conditions can be a viable alternative to increase the probiotic viability. Moreover, the use of fruit pulp and agro-industrial residues in these products has demonstrated promising results in promoting growth and improving the viability of probiotics. Thus, this study aimed to evaluate the effects of pre-exposure to acid, oxidative and osmotic stress on the growth and viability of <em>Lactobacillus acidophilus</em> in yogurts and naturally fermented milk containing buriti (<em>Mauritia flexuosa</em> Mart.) pulp or orange byproduct. <em>L. acidophilus</em> was individually pre-exposed to acid, oxidative, and osmotic stress and used in the production of yogurts and fermented milk to determine both the acidification profile and growth of the cultures. Furthermore, during cold storage, the post-acidification profiles and viability of microbial cultures added to the yogurts and fermented milk were monitored. Results showed that pre-exposure to stress conditions influenced the growth parameters as the growth rate (μ) and lag phase (λ) of <em>L. acidophilus</em> and the starter cultures of <em>S. thermophilus</em> and <em>L. delbrueckii</em> subsp. <em>bulgaricus</em>. Moreover, an increase in the viability of <em>L. acidophilus</em> - pre-exposed to acid stress - was observed on the 21st day of storage of natural yogurts containing orange byproduct compared with non-stressful conditions. This study reports new data on the growth of probiotic cultures pre-exposed to stress conditions in products added of pulps and agro-industrial residues, which have not yet been shown in the literature.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142442242","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 : 2024-10-12DOI: 10.1016/j.fm.2024.104658
The objective of this study was to provide a promising alternative to chemical fungicides for management of postharvest citrus decay, thereby promoting sustainable citrus fruit production. The postharvest decay of citrus fruit caused by Penicillium digitatum and Penicillium italicum results in substantial economic losses in citrus industry worldwide. With growing fungal resistance issues in P. digitatum and P. italicum, there is an urgent need for searching new methods to address above problems in a safe and environmentally friendly way. Streptomyces sp. N2, a new species from Streptomyces genus, exhibits significant antagonistic activity against Rhizoctonia solani. However, its biocontrol efficacy against postharvest decay caused by P. digitatum and P. italicum and its action mechanism remain unknown. In this study, Streptomyces sp. N2 was found to have significant potential in controlling green and blue mold diseases in postharvest navel oranges. Moreover, the action mechanism of Streptomyces sp. N2 against both P. italicum and P. digitatum was elucidated. On the one hand, Streptomyces sp. N2 stimulated fruit resistance to fight against invading fungal pathogens. It significantly reduced ROS content in navel orange upon the infection of mold disease, increased the production of defense-related enzymes including peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) and pathogenesis-related proteins of chitinase and β-1,3-glucanase. On the other hand, Streptomyces sp. N2 secreted bioactive substances to inhibit the growth of P. italicum and P. digitatum so as to prevent the development of postharvest decay. The bioactive substances secreted by Streptomyces sp. N2 significantly inhibited the spore germination and mycelial growth and led to microstructural damages to the cell wall and membrane, ROS burst, and mitochondrial dysfunction in both P. italicum and P. digitatum. This study provides a theoretical reference and application potential for the biological control of Streptomyces sp. N2 on green and blue mold diseases.
这项研究的目的是为柑橘采后腐烂的管理提供一种替代化学杀菌剂的可行方法，从而促进柑橘果实的可持续生产。由数字青霉（Penicillium digitatum）和意大利青霉（Penicillium italicum）引起的柑橘采后腐烂给全球柑橘产业造成了巨大的经济损失。随着数字青霉和意大利青霉的抗真菌性问题日益严重，迫切需要寻找新的方法，以安全、环保的方式解决上述问题。Streptomyces sp. N2 是链霉菌属的一个新物种，对根瘤菌具有显著的拮抗活性。然而，它对由 P. digitatum 和 P. italicum 引起的采后腐烂的生物防治效果及其作用机制仍不清楚。本研究发现，链霉菌 N2 在防治采后脐橙的绿霉病和蓝霉病方面具有显著的潜力。此外，还阐明了链霉菌 N2 对意大利脐橙霉菌和数字脐橙霉菌的作用机制。一方面，链霉菌 sp. N2 增强了果实的抵抗力，以对抗入侵的真菌病原体。一方面，链霉菌 sp. N2 能增强果实的抗病能力，在脐橙感染霉病时能明显降低 ROS 含量，增加过氧化物酶（POD）、多酚氧化酶（PPO）、苯丙氨酸氨解酶（PAL）等防御相关酶以及几丁质酶和β-1,3-葡聚糖酶等致病相关蛋白的产量。另一方面，链霉菌 N2 分泌的生物活性物质可抑制 P. italicum 和 P. digitatum 的生长，从而防止采后腐烂的发生。N2 链霉菌分泌的生物活性物质明显抑制了伊犁金丝桃和地肤金丝桃的孢子萌发和菌丝生长，并导致细胞壁和细胞膜的微结构损伤、ROS爆发和线粒体功能障碍。这项研究为链霉菌 N2 对绿霉病和蓝霉病的生物防治提供了理论参考和应用前景。
{"title":"Biocontrol potential of Streptomyces sp. N2 against green and blue mold disease in postharvest navel orange and the action mechanism","authors":"","doi":"10.1016/j.fm.2024.104658","DOIUrl":"10.1016/j.fm.2024.104658","url":null,"abstract":"<div><div>The objective of this study was to provide a promising alternative to chemical fungicides for management of postharvest citrus decay, thereby promoting sustainable citrus fruit production. The postharvest decay of citrus fruit caused by <em>Penicillium digitatum</em> and <em>Penicillium italicum</em> results in substantial economic losses in citrus industry worldwide. With growing fungal resistance issues in <em>P. digitatum</em> and <em>P. italicum</em>, there is an urgent need for searching new methods to address above problems in a safe and environmentally friendly way. <em>Streptomyces</em> sp. N2, a new species from <em>Streptomyces</em> genus, exhibits significant antagonistic activity against <em>Rhizoctonia solani</em>. However, its biocontrol efficacy against postharvest decay caused by <em>P. digitatum</em> and <em>P. italicum</em> and its action mechanism remain unknown. In this study, <em>Streptomyces</em> sp. N2 was found to have significant potential in controlling green and blue mold diseases in postharvest navel oranges. Moreover, the action mechanism of <em>Streptomyces</em> sp. N2 against both <em>P. italicum</em> and <em>P. digitatum</em> was elucidated. On the one hand, <em>Streptomyces</em> sp. N2 stimulated fruit resistance to fight against invading fungal pathogens. It significantly reduced ROS content in navel orange upon the infection of mold disease, increased the production of defense-related enzymes including peroxidase (POD), polyphenol oxidase (PPO), and phenylalanine ammonia-lyase (PAL) and pathogenesis-related proteins of chitinase and β-1,3-glucanase. On the other hand, <em>Streptomyces</em> sp. N2 secreted bioactive substances to inhibit the growth of <em>P. italicum</em> and <em>P. digitatum</em> so as to prevent the development of postharvest decay. The bioactive substances secreted by <em>Streptomyces</em> sp. N2 significantly inhibited the spore germination and mycelial growth and led to microstructural damages to the cell wall and membrane, ROS burst, and mitochondrial dysfunction in both <em>P. italicum</em> and <em>P. digitatum</em>. This study provides a theoretical reference and application potential for the biological control of <em>Streptomyces</em> sp. N2 on green and blue mold diseases.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432200","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 : 2024-10-10DOI: 10.1016/j.fm.2024.104656
Traditional cheesemaking processes often involve backslopping practice. However, over successive inoculations, acidification deficiencies may arise. In such cases, adding a starter is recommended to restore the ecosystem stability. This study examines the impact of an autochthonous starter composed of three Lactococcus lactis strains on a raw goat milk microbial community during their evolution. Bacterial composition and technological features (acidification and aroma) were analyzed during communities’ evolution over 800 generations. 16S rRNA gene metabarcoding showed that Lactococcus lactis strains predominated. The raw goat milk community acidification capacities varied early in the evolution and then remained stable. Adding the L. lactis starter to this community stabilized the ecosystem from the beginning of the evolution. The acetoin production was associated with the starter presence, consistent with the establishment of the diacetylatis biovar strain from the starter in the raw goat milk community throughout the evolution. Increased or decreased production of some volatile organic compounds when the starter was added revealed a specific aroma footprint due to interactions between the two communities. This study showed that adding a starter could help to achieve the maximum acidification rate from the early inoculation cycles and could significantly modify the aroma profile during long-term backslopping.
{"title":"Interaction between a Lactococcus lactis autochthonous starter and a raw goat milk microbial community during long-term backslopping","authors":"","doi":"10.1016/j.fm.2024.104656","DOIUrl":"10.1016/j.fm.2024.104656","url":null,"abstract":"<div><div>Traditional cheesemaking processes often involve backslopping practice. However, over successive inoculations, acidification deficiencies may arise. In such cases, adding a starter is recommended to restore the ecosystem stability. This study examines the impact of an autochthonous starter composed of three <em>Lactococcus lactis</em> strains on a raw goat milk microbial community during their evolution. Bacterial composition and technological features (acidification and aroma) were analyzed during communities’ evolution over 800 generations. 16S rRNA gene metabarcoding showed that <em>Lactococcus lactis</em> strains predominated. The raw goat milk community acidification capacities varied early in the evolution and then remained stable. Adding the <em>L. lactis</em> starter to this community stabilized the ecosystem from the beginning of the evolution. The acetoin production was associated with the starter presence, consistent with the establishment of the <em>diacetylatis</em> biovar strain from the starter in the raw goat milk community throughout the evolution. Increased or decreased production of some volatile organic compounds when the starter was added revealed a specific aroma footprint due to interactions between the two communities. This study showed that adding a starter could help to achieve the maximum acidification rate from the early inoculation cycles and could significantly modify the aroma profile during long-term backslopping.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444767","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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