International journal of food microbiology最新文献

{"title":"Cooperation mechanism of flavonoid transformation by Bifidobacterium animalis subsp. lactis and Lacticaseibacillus paracasei.","authors":"Chenxi Wang, Yixuan Wang, Yingdi Teng, Junkai Kong, Fujin Dong, Jie Du, Yan Zhang","doi":"10.1016/j.ijfoodmicro.2024.111019","DOIUrl":"https://doi.org/10.1016/j.ijfoodmicro.2024.111019","url":null,"abstract":"<p><p>Elaeagnus moorcroftii Wall. ex Schlecht (EWS) as a suitable food matrix contains abundant flavonoids for promoting human health, this study aimed to use flavonoid-targeted metabolomics and transcriptome sequencing to investigate the transformation of flavonoids in EWS juice (EWSJ) by mono- and mixed-cultures fermentations of Bifidobacterium animalis subsp. lactis HN-3 (B.an3) and Lacticaseibacillus paracasei YL-29 (L.cp29). A total of 33 flavonoids were identified in mono- and mixed-cultures fermented EWSJ. Among them, fermentation by B.an3 produced specific deglycosylation products (kaempferol (17.6 mmol/L) and luteolin (4.5 mmol/L)) and methoxylation products (syringaldehyde (59.05 mmol/L)), and fermentation by L.cp29 resulted in a specific deglycosylation product (quercetin (9.2 mmol/L)). The co-culture fermentation further increased the levels of isorhamnetin (52.3 mmol/L), and produced a specific product (homoplantaginin (0.03 mmol/L)), which significantly increased the bioactive-form flavonoids. Moreover, we analyzed changes in different flavonoid metabolites and differential genes before and after fermentation. After L.cp29 fermentation the expression of glycoside hydrolases and oxidoreductases were increased compared to other groups. After B.an3 fermentation the expression of isomerases and synthetases were increased compared to other groups. In particular, 6-phosphogluconolactonase (Pgl) and glucose-6-phosphate isomerase (Pgi) were increased in B.an3 fermentation. Thus, we validated the predicted transformation reactions by the biotransformation of flavonoids by the collected strains and crude enzyme extracts of B.an3 and L.cp29. These findings provided a basis for the development of functional plant-based foods with enhanced bioactive flavonoids.</p>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"429 ","pages":"111019"},"PeriodicalIF":5.0,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142828488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cold-active β-galactosidase from Weissella confusa SW1 for the preparation of low-lactose milk.","authors":"Yingxin Huo, Fanghong Zou, Zihui You, Guoyan Zhao, Meixue Dai, Susu Zhang","doi":"10.1016/j.ijfoodmicro.2024.111003","DOIUrl":"https://doi.org/10.1016/j.ijfoodmicro.2024.111003","url":null,"abstract":"<p><p>β-Galactosidases can be used to degrade lactose in milk to prepare lactose-free milk, which is sweeter than ordinary milk and suitable for people with lactose intolerance. The β-galactosidase gene (WcGal2809) was cloned from Weissella confusa SW1 and successfully expressed in Escherichia coli BL21(DE3). The active WcGal2809 was identified to be a heterodimer composed of two distinct proteins LacL (72.4 kDa) and LacM (33.2 kDa), and it belonged to glycoside hydrolase family 2. The purified WcGal2809 showed the maximum activity at 25 °C and pH 7.0 for o-nitrophenyl-β-D-galactopyranoside (oNPG). WcGal2809 was strongly activated by Mn²⁺, Mg²⁺, and Fe²⁺, and significantly inhibited by Zn²⁺, Cu²⁺, and Ni⁺. The activity of WcGal2809 decreased quickly after incubation at 40 °C or higher temperature, suggesting it was a cold-adapted enzyme. Additionally, 6 U of WcGal2809 could hydrolyze 85.23 % of the lactose in 1 mL of milk at 25 °C after incubation for 48 h, while 2 U of WcGal2809 could hydrolyze 74.40 % of the lactose in 1 mL of milk at 25 °C after incubation for 7 d. Taken together, WcGal2809 is a promising industrial biocatalyst for efficiently hydrolyzing lactose in milk at room temperature during milk storage or transportation.</p>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"429 ","pages":"111003"},"PeriodicalIF":5.0,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142812491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical and microbiological assessment of early wine fermentation phase can predict yeast cell viability during post-fermentation process.","authors":"Jacopo Sica, Giulia Crosato, Zeno Molinelli, Chiara Nadai, Alessio Giacomini, Viviana Corich","doi":"10.1016/j.ijfoodmicro.2024.111011","DOIUrl":"https://doi.org/10.1016/j.ijfoodmicro.2024.111011","url":null,"abstract":"<p><p>The management of post-fermentation phase is essential for the protection of wine oxidation. The prolonged contact of yeast lees and wine can help to limit this problem, although off-flavours can originate. It is known that some cellular components (mannoproteins, lipids, glutathione, etc.) released into the wine influence oxygen protection; however, still active cells could contribute to maintaining protection against oxidation. To date, in the literature there is a lack of data that evaluates cell viability, especially in the post-fermentation phase, particularly using methods different by plate count that identifies only a small part of the viable population. The aim of the work was to investigate the yeast viability of 12 wine Saccharomyces cerevisiae strains during 45 days after the fermentation in natural grape juice. The major fermentation parameters were measured at early phase (40 h) and at the end of the process, and were correlated with total and viable cells in the post-fermentation phase. Contrary to what has been observed in the literature, this work demonstrates that cell viability in the post-fermentation phase is very high and dependent on the yeast strain. A predictive model that can estimate viability in the post-fermentation phase, based on parameters measured at the early fermentation phase, was successfully set up. This approach can be adopted by wineries or winemakers as it uses fermentation data (sugar and nitrogen residues, ethanol and glycerol production, total cell count) obtained through simple chemical and microbiological analyses.</p>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"429 ","pages":"111011"},"PeriodicalIF":5.0,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142818198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Is Bacillus cytotoxicus from edible insects a threat?","authors":"Hooriyeh Mohammadpour, Adiba Akram, Martina Marcolin, Lisa Carraro, Sarah Currò, Barbara Cardazzo, Stefania Balzan, Luca Fasolato","doi":"10.1016/j.ijfoodmicro.2024.111015","DOIUrl":"https://doi.org/10.1016/j.ijfoodmicro.2024.111015","url":null,"abstract":"<p><p>Bacillus cytotoxicus is considered a potential emerging foodborne pathogen that has been under investigation in recent years. Most studies have focused on strains from vegetables, particularly potato products, but there is limited information on strains from other food sources. This study addresses the current research gap by investigating the genomic and phenotypic features of B. cytotoxicus isolated from edible insects. The whole genomes and key phenotypic traits of 20 strains isolated from edible insects were investigated. The comparative genome analysis also included 44 available genomes from other sources to identify possible genetic links and the mosaicism of virulence profiles (VP) and antimicrobial resistance genes (AMR). B. cytotoxicus isolated from edible insects showed marked thermotolerance, when vegetative forms could grow at 50-60 °C and survive at 65 °C and exhibited marked proteolytic activities, even at higher temperatures. The heterogeneous phenotypes observed suggest potential issues with defining suitable protocols for isolation and identification in this food matrix. Despite the limited genomic diversity observed, it was possible to identify links between isolates, demonstrating the co-isolation of different genomes/phenotypes from various insect samples and suggesting trade links between insect companies and the persistence of certain strains. A genomic comparison suggested segregating strains from edible insects with similar VP and AMR profiles. These findings indicate a degree of adaptation to different food niches, with strains from insects or insect-based products differing partially from those isolated from vegetable sources, showing possible associations with their respective food environments. The survival advantage conferred by thermotolerance underscores the need to assess the presence of these spore-forming bacteria carefully and to calibrate treatments and processes, to address the emerging risk posed by this pathogen and its implications for food safety.</p>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"429 ","pages":"111015"},"PeriodicalIF":5.0,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142824037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antimicrobial properties of Bifidobacterium animalis subsp. lactis Bb-12 paraprobiotic obtained using ohmic heating against Salmonella enterica: A metabolomic approach.","authors":"Mahmoud Yolmeh, Mauricio Luis Sforça, Anderson S Sant'Ana","doi":"10.1016/j.ijfoodmicro.2024.111016","DOIUrl":"https://doi.org/10.1016/j.ijfoodmicro.2024.111016","url":null,"abstract":"<p><p>This study aimed to obtain paraprobiotics from Bifidobacterium animalis subsp. lactis Bb-12 (BB) presenting optimized antimicrobial activity against Salmonella enterica (SE). The paraprobiotics of BB (BBP) were obtained using ohmic heating (OH) under different conditions, and their effects on critical features of Salmonella, such as bacterial growth, biofilm formation, and adherence to Caco-2 cells, were studied. In addition, a metabolomic analysis was performed using ¹H NMR spectroscopy to identify the metabolites involved in antimicrobial activity against SE. Through an optimization approach, it was found that the linear model demonstrated the highest predictive potential for the antimicrobial activity (AMA) of BBP among the fitted models. In contrast, the quadratic model was more predictive for the antibiofilm activity (ABA) and anti-adherence activity (AAA). The highest effects on the AMA, ABA, and AAA of BBP were associated with the variables electric field (EF), OH time, and OH temperature, respectively. Glycerol (37.6 μmol/g), ethanol (22.6 μmol/g), and lactate (9.8 μmol/g) were measured as the main metabolites in BB, while glycerol (47.8 μmol/g), acetate (34.0 μmol/g), and lactate (24.6 μmol/g) were the main metabolites in BBP. All the anti-SE characteristics of BBP obtained under the optimal conditions of the OH process were higher than those of BB (the untreated sample), which could be related to the higher levels of detected metabolites. The OH process, EF of 8.7 V/cm, OH temperature of 88 °C, cell concentration of 8.7 log CFU/mL, and OH time of 3.6 min, was the best OH condition for obtaining a BBP effective against SE.</p>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"429 ","pages":"111016"},"PeriodicalIF":5.0,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142823941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Delving into Roccaverano PDO cheese: A comprehensive examination of microbial diversity and flavour profiles compared to non-PDO cheeses.","authors":"Davide Buzzanca, Manuela Giordano, Elisabetta Chiarini, Ilario Ferrocino, Luca Cocolin, Giuseppe Zeppa, Valentina Alessandria","doi":"10.1016/j.ijfoodmicro.2024.111014","DOIUrl":"https://doi.org/10.1016/j.ijfoodmicro.2024.111014","url":null,"abstract":"<p><p>Roccaverano Protected Designation of Origin (PDO) is a fresh soft cheese produced in Roccaverano area (Italy). This study aimed to evaluate Roccaverano PDO microbiota, together with aromatic profile and sensory analysis to be compared with 15 non-PDO cheeses of the same type. Microbiota was evaluated through shotgun metagenomics sequencing, while GC-MS analysis was conducted to study volatile organic compounds (VOCs) presence and concentration. Sensory analyses were conducted through ONAF (Italian National Organization of Cheese Tasters) evaluation parameters followed by flash profile sensory analysis of selected cheeses. The results demonstrated Lactococcus lactis predominance in both non-PDO and PDO cheeses, while Streptococcus thermophilus was more abundant in non-PDO group. A higher abundance of Kluyveromyces lactis was observed in Roccaverano PDO, which exhibited greater fungal diversity compared to non-PDO cheeses. Metagenome-Assembled Genomes of 26 L. lactis and 19 Leuconostoc mesenteroides showed absence of significant differences in terms of average nucleotide identity and pangenomes partitions. The ONAF sensory evaluation demonstrated a higher average score of Roccaverano PDO group. Flash profile analysis demonstrated that lactic aroma/odour, acid, astringent, vegetal odour, exotic fruit and fermented aroma, hazelnut flavour and sweet were associated with high ONAF scores. The concentration of butanoic acid, 2-methyl-, ethyl ester and butanoic acid, 3-methyl- (sweat, acid, rancid related) were higher in PDO cheeses, while reads related to butanoate metabolism were less abundant compared to non-PDO samples. Several fungal species (included K. lactis) were associated with astringents, acid and chalky flavours. Roccaverano PDO demonstrates unique characteristics even maintaining a certain degree of variability between samples.</p>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"429 ","pages":"111014"},"PeriodicalIF":5.0,"publicationDate":"2024-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142822100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transfer of Salmonella enterica and Enterococcus faecium from food-contact surfaces to stone fruits.","authors":"Yucen Xie, Xiaonuo Long, Nitin Nitin, Linda J Harris","doi":"10.1016/j.ijfoodmicro.2024.111004","DOIUrl":"https://doi.org/10.1016/j.ijfoodmicro.2024.111004","url":null,"abstract":"<p><p>Contaminated food-contact surfaces are a potential route for spreading microorganisms to stone fruit during postharvest handling. The objective of this study was to investigate the factors that affect the transfer of bacteria from food-contact surfaces to stone fruits. Coupons (1 × 1 cm) of polyurethane (PU) or polyvinyl chloride (PVC) were inoculated with rifampin-resistant variants of Salmonella (five-strain cocktail) or Enterococcus faecium NRRL B-2354 at ~5 or ~7 log CFU/cm². Inoculated coupons (n = 8-11) were attached to a texture analyzer, and uniform contact conditions (5 N, 5 s) were used to explore the impact of bacterial species, inoculation level, donor surface, the presence of dried peach juice or wax, recipient produce commodity, and the dryness of inoculum. Whole fruits were transferred to 20 mL of 0.1 % peptone, rubbed for 2 min, and then the diluent was plated onto tryptic soy agar supplemented with rifampin at 50 μg/mL. Whole fruits were enriched when populations were anticipated to fall below the limit of detection (1.6 log CFU/fruit). At an inoculum of ~5 log CFU/coupon, Salmonella and E. faecium were recovered from the fruit by enrichment but not by plating. At ~7 log CFU/coupon, transfer rates, i.e., ratio of populations on recipient fruit to donor surface, were not significantly (P > 0.05) influenced by either bacterial species (Salmonella [0.26 % ± 0.77 %] versus E. faecium [0.068 % ± 0.071 %]) or donor surface (PU [0.085 % ± 0.098 %] versus PVC [0.16 % ± 0.16 %]). The rates of transfer of E. faecium from contaminated PU to peaches (0.050 % ± 0.031 %), nectarines (0.066 % ± 0.076 %), and onion skins (0.048 % ± 0.059 %) were not significantly different. The mean transfer rates of E. faecium increased significantly (P < 0.05) in the presence of dried wax (18 % ± 16 %) or peach juice (1.3 % ± 2.6 %) on the PU surface compared with the control (0.080 % ± 0.086 %). The transfer rates of E. faecium from contaminated surfaces were also significantly influenced by the drying time post-inoculation; the drier the inoculum, the lower the transfer rates. The presence of residues or moisture on food-contact surfaces facilitated the transfer of microorganisms during dry handling of fresh stone fruits. The results underscore the importance of implementing adequate cleaning, sanitation and, where appropriate, drying of equipment surfaces to effectively remove organic residues and mitigate the risks of cross-contamination.</p>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"429 ","pages":"111004"},"PeriodicalIF":5.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142807004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Beyond guaiacol and halophenols: Unravelling isobutyric and isovaleric acids as new culprits in off-flavour spoilage by Alicyclobacillus spp.","authors":"Inês Carvalho Leonardo, António Ferreira, Maria do Rosário Bronze, Ana Patrícia Quendera, Ana Filipa Fernandes, Maria Teresa Barreto Crespo, Frédéric Bustos Gaspar","doi":"10.1016/j.ijfoodmicro.2024.111002","DOIUrl":"https://doi.org/10.1016/j.ijfoodmicro.2024.111002","url":null,"abstract":"<p><p>Industries that produce or use fruit-based products have faced several spoilage events, resulting in economic losses caused by product recalls and loss of consumer confidence. Some of these events correlate to the presence of Alicyclobacillus (ACB) in food products since they can produce off-flavours and odours in the final products. Guaiacol (2-methoxyphenol) and halophenols (2,6-dichlorophenol and 2,6-dibromophenol) have been widely explored as the primary culprits of off-flavour spoilage by ACB. However, different compounds might be correlated with these spoilage events. In this work, volatile metabolites produced by distinct ACB species (Alicyclobacillus acidoterrestris, Alicyclobacillus acidocaldarius, and Alicyclobacillus cycloheptanicus) in laboratory medium and fruit juices were identified by HS-SPME-GC-MS and investigated as potential spoilage-related compounds. Isobutyric acid (2-methylpropanoic acid) and isovaleric acid (3-methylbutanoic acid) were revealed to be produced by all three ACB species at concentrations that surpass the odour threshold. These cheesy, sweaty, and sour compounds were responsible for dissonant odours in peach, orange, and tomato juice, harming fruit-based products' quality. More importantly, this work suggests that ACB species previously identified as non-spoilage bacteria, based on a lack of ability to produce guaiacol and halophenols, can also threaten the juice, beverage, and dairy industries. As such, identification methods currently used in industries for ACB control in final products should be revised.</p>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"429 ","pages":"111002"},"PeriodicalIF":5.0,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142822096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"BCP4: A novel antimicrobial peptide with potent efficacy against Bacillus cereus in rice porridge.","authors":"Weihong Tao, Wenjie Li, Ritian Jin, Duo Liang, Wuyin Weng, Rong Lin, Shen Yang","doi":"10.1016/j.ijfoodmicro.2024.111001","DOIUrl":"https://doi.org/10.1016/j.ijfoodmicro.2024.111001","url":null,"abstract":"<p><p>Bacillus cereus is a common foodborne pathogen that frequently contaminates rice products and produces cereulide toxins, presenting a significant risk to food safety and human health. In contrast, Bacillus subtilis is a promising source of antimicrobial peptides (AMPs). In this research, a novel AMP named BCP4 (KGKTLLQ) was discovered through the fermentation of shrimp waste with B. subtilis, which speculated that BCP4 might be generated through enzymatic hydrolysis catalyzed by endogenous enzymes naturally present in shrimp waste. BCP4 demonstrated potent antibacterial activity against B. cereus with a minimum bactericidal concentration (MBC) of 62.5 μg/mL and bacterial time-kill of 3 h. BCP4 surpassed the bactericidal efficiency of nisin (500 μg/mL), a commonly used AMP of microbial origin. BCP4 operates by causing damage to the bacterial cell wall and membrane, which allows the contents of the cell to flow out. BCP4 also penetrates the cell membrane and binds with DNA, effectively sterilizing the bacteria. Meanwhile, treatment of BCP4 with mammalian red blood cells revealed that it was nonhemolytic. Furthermore, the growth of B. cereus in rice porridge was significantly inhibited by BCP4 at a concentration of 62.5 μg/mL. This study provides a theoretical basis for using BCP4 to control B. cereus contamination.</p>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"429 ","pages":"111001"},"PeriodicalIF":5.0,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142780172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The culturability of acid-tolerant Salmonella in mayonnaise, a raw egg-based sauce.","authors":"Lingyun Li, Kapil K Chousalkar, Cheryl Jenkins, Amy Jennison, Andrea R McWhorter","doi":"10.1016/j.ijfoodmicro.2024.111000","DOIUrl":"https://doi.org/10.1016/j.ijfoodmicro.2024.111000","url":null,"abstract":"<p><p>Salmonella is one of the most common bacterial foodborne pathogens and is frequently found as a contaminant of raw egg-based foods. Food safety regulations recommend the use of food acids to mitigate the risk of Salmonella persistence in raw egg-based foods. Salmonella, however, can become tolerant to acidic environments and it is not known how this can affect bacterial persistence in food. This study investigated whether acid-tolerant strains of Salmonella persisted longer in mayonnaise compared with sensitive strains. Isolates of S. typhimurium, S. infantis, S. enteritidis, and S.hessarek were used in this project. Acid-tolerant Salmonella strains were generated using a three-day step-down method where pH was decreased every 24 h from pH 7 to pH 5. Growth curves were determined for both acid-sensitive and acid-tolerant strains. Time-kill experiments were conducted to compare the survivability of acid-sensitive and acid-tolerant Salmonella serotypes in mayonnaise stored at either 5 °C or 25 °C for 72 h. Salmonella exhibited an extended lag phase with increased acid concentration, and acid-tolerant strains recovered faster in media compared with acid-sensitive strains. Elevated biofilm formation was found in acid-habituated strains compared to sensitive strains, and this varied between serotypes. The culturability of Salmonella in mayonnaise stored at 5 °C declined slower than when stored at 25 °C. Acid-tolerant strains persisted longer in mayonnaise and there was a statistically significant difference in culturability (P < 0.05). In conclusion, the current safe food recommendations to control Salmonella in raw egg-based foods are not effective in eliminating it.</p>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"429 ","pages":"111000"},"PeriodicalIF":5.0,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142780120","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}