Pub Date : 2025-01-10DOI: 10.1016/j.fm.2025.104731
Soundarya T. Karamcheti , Gale Brightwell , Phil Bremer , Matthew R. Schofield
A total of 476 D-values associated with 76 strains of Listeria spp. in liquid media were obtained from 27 scientific articles. Meta-analysis was carried out using hierarchical Bayesian models to assess variability, predict the D-, and estimate the -, and -values for Listeria spp. across a range of temperatures (55–70 °C) and pH values (3–8 units). Different hypotheses regarding variability between strains or studies in each model correspond to different hierarchical assumptions about the inactivation parameters. The models produced were compared based on their predictive ability, Bayes-R2 and widely applicable information criterion (WAIC) values. A hierarchical model that considered random effects due to both strain and study effects on the thermal inactivation parameters was determined to be the “best” model and was subsequently used to estimate the posterior distributions for the D-, -, and -values. The variability introduced in the parameters due to differences between studies was higher than that of variability between strains. The parameters estimated using the model for different strains of Listeria species may be applicable for processing aqueous foods such as milk and liquid products such as sauces and gravies across a temperature range of 55–70 °C and pH values of 3–8 units.
{"title":"Hierarchical Bayesian linear mixed model to estimate variability in the thermal inactivation parameters for Listeria species","authors":"Soundarya T. Karamcheti , Gale Brightwell , Phil Bremer , Matthew R. Schofield","doi":"10.1016/j.fm.2025.104731","DOIUrl":"10.1016/j.fm.2025.104731","url":null,"abstract":"<div><div>A total of 476 D-values associated with 76 strains of <em>Listeria</em> spp. in liquid media were obtained from 27 scientific articles. Meta-analysis was carried out using hierarchical Bayesian models to assess variability, predict the D-, and estimate the <span><math><mrow><msub><mi>z</mi><mi>T</mi></msub></mrow></math></span>-, and <span><math><mrow><msub><mi>z</mi><mrow><mi>p</mi><mi>H</mi></mrow></msub></mrow></math></span>-values for <em>Listeria</em> spp. across a range of temperatures (55–70 °C) and pH values (3–8 units). Different hypotheses regarding variability between strains or studies in each model correspond to different hierarchical assumptions about the inactivation parameters. The models produced were compared based on their predictive ability, Bayes-R<sup>2</sup> and widely applicable information criterion (WAIC) values. A hierarchical model that considered random effects due to both strain and study effects on the thermal inactivation parameters was determined to be the “best” model and was subsequently used to estimate the posterior distributions for the D-, <span><math><mrow><msub><mi>z</mi><mi>T</mi></msub></mrow></math></span>-, and <span><math><mrow><msub><mi>z</mi><mrow><mi>p</mi><mi>H</mi></mrow></msub></mrow></math></span>-values. The variability introduced in the parameters due to differences between studies was higher than that of variability between strains. The parameters estimated using the model for different strains of <em>Listeria</em> species may be applicable for processing aqueous foods such as milk and liquid products such as sauces and gravies across a temperature range of 55–70 °C and pH values of 3–8 units.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104731"},"PeriodicalIF":4.5,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129022","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 : 2025-01-10DOI: 10.1016/j.fm.2025.104729
Yeona Kim , Hyeonwoo Cho , Beomsoon Jang , Miru Lee , Kun Taek Park
Clostridium perfringens is a common cause of foodborne illnesses and is involved in human and animal gastrointestinal diseases. Surveillance of C. perfringens in the pork production chain is crucial to manage the risk of pathogen transmission. This study aimed to investigate the prevalence, antimicrobial resistance profile, and genomic characteristics of C. perfringens in pork production chains in Korea. The overall prevalence of C. perfringens was 23.6% (330/1397), with 48.8 (178/365), 16.6 (138/832), and 7.0% (14/200) in pig farms, slaughterhouses, and retail markets, respectively. Toxinotyping revealed 98.9% type A and 1.1% type C isolates. Among them, 29.1% carried the beta-2 toxin gene. Antimicrobial susceptibility tests identified 20 multi-drug resistant isolates, with the highest resistance against tetracycline (65.1%). Whole-genome sequencing further revealed 17 antimicrobial resistance and 12 virulence genes. Subsequent phylogenetic analysis identified three clonal clusters, two of which revealed a clonal relationship with human clinical isolates reported in China. The ST408 isolate from the retail pork meat, IJCP45, harboured the optrA gene in a plasmid and was identical to known optrA-carrying plasmids in C. perfringens from livestock in China, suggesting the introduction and dissemination of optrA by the transmission of a specific plasmid in east Asian countries. To our knowledge, this is the first comprehensive study of C. perfringens in the pork meat production system as an “One Health” approach. The study findings provide baseline data for the distribution and genetic characteristics of pig-associated C. perfringens in Korea and indicate the zoonotic transmission potential of C. perfringens from pigs to humans.
{"title":"Molecular characterization of emerging multi-drug resistant Clostridium perfringens isolated from pork production chains in Korea","authors":"Yeona Kim , Hyeonwoo Cho , Beomsoon Jang , Miru Lee , Kun Taek Park","doi":"10.1016/j.fm.2025.104729","DOIUrl":"10.1016/j.fm.2025.104729","url":null,"abstract":"<div><div><em>Clostridium perfringens</em> is a common cause of foodborne illnesses and is involved in human and animal gastrointestinal diseases. Surveillance of <em>C. perfringens</em> in the pork production chain is crucial to manage the risk of pathogen transmission. This study aimed to investigate the prevalence, antimicrobial resistance profile, and genomic characteristics of <em>C. perfringens</em> in pork production chains in Korea. The overall prevalence of <em>C. perfringens</em> was 23.6% (330/1397), with 48.8 (178/365), 16.6 (138/832), and 7.0% (14/200) in pig farms, slaughterhouses, and retail markets, respectively. Toxinotyping revealed 98.9% type A and 1.1% type C isolates. Among them, 29.1% carried the beta-2 toxin gene. Antimicrobial susceptibility tests identified 20 multi-drug resistant isolates, with the highest resistance against tetracycline (65.1%). Whole-genome sequencing further revealed 17 antimicrobial resistance and 12 virulence genes. Subsequent phylogenetic analysis identified three clonal clusters, two of which revealed a clonal relationship with human clinical isolates reported in China. The ST408 isolate from the retail pork meat, IJCP45, harboured the <em>optrA</em> gene in a plasmid and was identical to known <em>optrA</em>-carrying plasmids in <em>C. perfringens</em> from livestock in China, suggesting the introduction and dissemination of <em>optrA</em> by the transmission of a specific plasmid in east Asian countries. To our knowledge, this is the first comprehensive study of <em>C. perfringens</em> in the pork meat production system as an “One Health” approach. The study findings provide baseline data for the distribution and genetic characteristics of pig-associated <em>C. perfringens</em> in Korea and indicate the zoonotic transmission potential of <em>C. perfringens</em> from pigs to humans.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104729"},"PeriodicalIF":4.5,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-09DOI: 10.1016/j.fm.2025.104730
Jiaxin Liu , Yin Wang , Ping Yang , Hongbo Li , Haizhen Mo , Prince Chisoro , Dong Han , Chunhui Zhang
Prepared dishes have high water content and complex nutritional composition, making them highly susceptible to microbial contamination and oxidative spoilage during storage. To elucidate the effects of microorganisms on the quality of prepared dishes and the formation of contaminants, the dishes “stewed pork with cabbage” were stored at 4 °C for 0, 1, 3, 5, and 7 days. Techniques such as high-performance liquid chromatography (HPLC), ion chromatography (IC), and 16S rRNA sequencing were used to explore changes in quality of the prepared dishes. The results showed that the total volatile basic nitrogen (TVB-N) and total viable count (TVC) consistently increased at similar rates during storage. The thiobarbituric acid reactive substances (TBARS) value reached 1 mg MDA/kg after 7 days of storage. Nitrite content and nitrate reductase activity rose as nitrate content decreased with longer storage. The contents of four free amino acids (FAAs) (Glu, His, Phe, Lys) and biogenic amines (BAs) (Putrescine, Histamine, Phenethylamine, Cadaverine) showed opposite trends. The abundance of the dominant genus, including Brochothrix, Acinetobacter and Weissella was significantly (P < 0.05) changed after the 3rd day of storage. Brochothrix, Acinetobacter, Pseudomonas, and Weissella promoted the decarboxylation of FAAs to form (BAs). Acinetobacter and Brochothrix accelerated the conversion of nitrate to nitrite. This study elucidates degradation of the quality of prepared dishes and the effect of five genera (Brochothrix, Acinetobacter, Pseudomonas, Weissella and Brochothrix) on the formation of nitrite and BAs, providing important theoretical support for enhancing nutritional quality and preserving the freshness during storage of prepared dishes.
{"title":"Quality decline of prepared dishes stored at 4 °C: Microbial regulation of nitrite and biogenic amine formation","authors":"Jiaxin Liu , Yin Wang , Ping Yang , Hongbo Li , Haizhen Mo , Prince Chisoro , Dong Han , Chunhui Zhang","doi":"10.1016/j.fm.2025.104730","DOIUrl":"10.1016/j.fm.2025.104730","url":null,"abstract":"<div><div>Prepared dishes have high water content and complex nutritional composition, making them highly susceptible to microbial contamination and oxidative spoilage during storage. To elucidate the effects of microorganisms on the quality of prepared dishes and the formation of contaminants, the dishes “stewed pork with cabbage” were stored at 4 °C for 0, 1, 3, 5, and 7 days. Techniques such as high-performance liquid chromatography (HPLC), ion chromatography (IC), and 16S rRNA sequencing were used to explore changes in quality of the prepared dishes. The results showed that the total volatile basic nitrogen (TVB-N) and total viable count (TVC) consistently increased at similar rates during storage. The thiobarbituric acid reactive substances (TBARS) value reached 1 mg MDA/kg after 7 days of storage. Nitrite content and nitrate reductase activity rose as nitrate content decreased with longer storage. The contents of four free amino acids (FAAs) (Glu, His, Phe, Lys) and biogenic amines (BAs) (Putrescine, Histamine, Phenethylamine, Cadaverine) showed opposite trends. The abundance of the dominant genus, including <em>Brochothrix</em>, <em>Acinetobacter</em> and <em>Weissella</em> was significantly (<em>P</em> < 0.05) changed after the 3rd day of storage. <em>Brochothrix</em>, <em>Acinetobacter</em>, <em>Pseudomonas</em>, and <em>Weissella</em> promoted the decarboxylation of FAAs to form (BAs). <em>Acinetobacter</em> and <em>Brochothrix</em> accelerated the conversion of nitrate to nitrite. This study elucidates degradation of the quality of prepared dishes and the effect of five genera (<em>Brochothrix</em>, <em>Acinetobacter</em>, <em>Pseudomonas</em>, <em>Weissella</em> and <em>Brochothrix</em>) on the formation of nitrite and BAs, providing important theoretical support for enhancing nutritional quality and preserving the freshness during storage of prepared dishes.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104730"},"PeriodicalIF":4.5,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-09DOI: 10.1016/j.fm.2025.104724
Yin-Xiao Peng , Bin Feng , Zi-Jie Zhang , Kai Li , Shuangfei Wang , Debao Niu
The study aimed to explore the impact of ceramic membrane filtration used to terminate the fermentation process on the aroma of low-alcohol sugarcane fruit wines as compared to traditional methods. The sugarcane fruit wine of termination fermentation by ceramic membrane filtration results in a more fruity character due to the higher content of some volatile compounds (hexanal, hexyl butanoate, butanoic acid butyl ester, hexanoic acid ethyl ester, and β-Damascenone). In comparison to traditional method (pasteurization), sugarcane fruit wine of termination fermentation by ceramic membrane filtration exhibits a greater abundance of the characteristic aroma compounds (hexanal, isobutyl isobutyrate, pentanal, and butanal) of sugarcane juice, resulting in a more pronounced sugarcane aroma. In addition, results showed that a total of 73 volatile compounds were identified in sugarcane wine, with 17 being identified as key differential compounds and 20 as key aroma-active compounds.
{"title":"Effect of fermentation alcohol termination by ceramic membrane filtration on the aroma of sugarcane fruit wine","authors":"Yin-Xiao Peng , Bin Feng , Zi-Jie Zhang , Kai Li , Shuangfei Wang , Debao Niu","doi":"10.1016/j.fm.2025.104724","DOIUrl":"10.1016/j.fm.2025.104724","url":null,"abstract":"<div><div>The study aimed to explore the impact of ceramic membrane filtration used to terminate the fermentation process on the aroma of low-alcohol sugarcane fruit wines as compared to traditional methods. The sugarcane fruit wine of termination fermentation by ceramic membrane filtration results in a more fruity character due to the higher content of some volatile compounds (hexanal, hexyl butanoate, butanoic acid butyl ester, hexanoic acid ethyl ester, and β-Damascenone). In comparison to traditional method (pasteurization), sugarcane fruit wine of termination fermentation by ceramic membrane filtration exhibits a greater abundance of the characteristic aroma compounds (hexanal, isobutyl isobutyrate, pentanal, and butanal) of sugarcane juice, resulting in a more pronounced sugarcane aroma. In addition, results showed that a total of 73 volatile compounds were identified in sugarcane wine, with 17 being identified as key differential compounds and 20 as key aroma-active compounds.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104724"},"PeriodicalIF":4.5,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-08DOI: 10.1016/j.fm.2025.104725
Emily Everhart , Audrey Worth , Dennis J. D'Amico
Outbreaks of salmonellosis linked to consumption of raw milk and cheese made from raw milk continue to occur, highlighting the need for additional controls. This study determined the susceptibility of nine selected serovars of Salmonella enterica spp. enterica to commercially available bacteriophage preparations as well as the efficacy of phage application to control Salmonella in pasteurized and raw milk during storage and in the production of raw milk queso fresco and Gouda cheese. Except for serovar Cerro, both SalmoFresh™ and PhageGuard S™ demonstrated high lytic efficiency. Broth microdilution assays identified multiplicities of infection (MOI) ranging from log 1.84–6.69, which varied between serovars and products. Addition of SalmoFresh™ phage product to pasteurized milk at log MOI 6 rapidly reduced Salmonella counts such that mean counts were 2.33–3.22 log CFU/mL lower than control after 7 d at 7 °C. Aside from serovar Cerro, SalmoFresh™ addition was also effective in raw milk with mean counts 1.12–2.27 log CFU/mL lower than control at the end of storage. Despite these observations, counts of Salmonella Montevideo did not differ from control during queso fresco production or storage at 7 °C for 28 d when SalmoFresh™ was added at log MOI 6. Salmonella counts were lower in Gouda before brining when SalmoFresh™ was added to milk at log MOI 6 and was undetectable one week earlier in aged Gouda when added at log MOI 6 or 7. These data demonstrate the potential of commercial phage products to enhance the safety of raw milk, including that used to produce cheese.
{"title":"Control of Salmonella enterica spp. enterica in milk and raw milk cheese using commercial bacteriophage preparations","authors":"Emily Everhart , Audrey Worth , Dennis J. D'Amico","doi":"10.1016/j.fm.2025.104725","DOIUrl":"10.1016/j.fm.2025.104725","url":null,"abstract":"<div><div>Outbreaks of salmonellosis linked to consumption of raw milk and cheese made from raw milk continue to occur, highlighting the need for additional controls. This study determined the susceptibility of nine selected serovars of <em>Salmonella enterica</em> spp. <em>enterica</em> to commercially available bacteriophage preparations as well as the efficacy of phage application to control <em>Salmonella</em> in pasteurized and raw milk during storage and in the production of raw milk queso fresco and Gouda cheese. Except for serovar Cerro, both SalmoFresh™ and PhageGuard S™ demonstrated high lytic efficiency. Broth microdilution assays identified multiplicities of infection (MOI) ranging from log 1.84–6.69, which varied between serovars and products. Addition of SalmoFresh™ phage product to pasteurized milk at log MOI 6 rapidly reduced <em>Salmonella</em> counts such that mean counts were 2.33–3.22 log CFU/mL lower than control after 7 d at 7 °C. Aside from serovar Cerro, SalmoFresh™ addition was also effective in raw milk with mean counts 1.12–2.27 log CFU/mL lower than control at the end of storage. Despite these observations, counts of <em>Salmonella</em> Montevideo did not differ from control during queso fresco production or storage at 7 °C for 28 d when SalmoFresh™ was added at log MOI 6. <em>Salmonella</em> counts were lower in Gouda before brining when SalmoFresh™ was added to milk at log MOI 6 and was undetectable one week earlier in aged Gouda when added at log MOI 6 or 7. These data demonstrate the potential of commercial phage products to enhance the safety of raw milk, including that used to produce cheese.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104725"},"PeriodicalIF":4.5,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-08DOI: 10.1016/j.fm.2025.104726
Maha Rockaya, József Baranyi
The focus of this paper is to analyze the reliability of the error estimation when well-known primary models of predictive microbiology are used to fit growth parameters. We also demonstrate the application of rescaling and reparametrization to improve this reliability. We highlight that the technique can be useful for achieving linearity and homoscedasticity, reducing the complexity of the model, generating initial parameter estimates when fitting experimental data by non-linear regression, and obtaining realistic standard errors for the parameter estimates, which are crucial for decision-making in food safety.
We classify the sources of the total variability and correlation of the parameter estimates as "wet" and "dry". We point out that, rescaling and reparametrization do not change the model in a mechanistic sense but they can reduce the variances of (and/or the correlation between) the parameter estimates, thus mitigate the effects of such “dry” (i.e. statistical) relationships.
We analyze the reliability of the error estimation when the model of Baranyi and Roberts (BRM) and the Gompertz function (GF) are used to fit data. The comparison is based on the distribution of the standard error of the maximum specific growth rate estimates. The results show that the error structure of the BRM-fit is closer to that of the linear regression, making BRM more reliable for constructing confidence intervals by conventional means, using the t-distribution assumption for the parameter estimates.
{"title":"Variability of growth parameter estimates - The role of rescaling and reparametrization","authors":"Maha Rockaya, József Baranyi","doi":"10.1016/j.fm.2025.104726","DOIUrl":"10.1016/j.fm.2025.104726","url":null,"abstract":"<div><div>The focus of this paper is to analyze the reliability of the error estimation when well-known primary models of predictive microbiology are used to fit growth parameters. We also demonstrate the application of rescaling and reparametrization to improve this reliability. We highlight that the technique can be useful for achieving linearity and homoscedasticity, reducing the complexity of the model, generating initial parameter estimates when fitting experimental data by non-linear regression, and obtaining realistic standard errors for the parameter estimates, which are crucial for decision-making in food safety.</div><div>We classify the sources of the total variability and correlation of the parameter estimates as \"wet\" and \"dry\". We point out that, rescaling and reparametrization do not change the model in a mechanistic sense but they can reduce the variances of (and/or the correlation between) the parameter estimates, thus mitigate the effects of such “dry” (i.e. statistical) relationships.</div><div>We analyze the reliability of the error estimation when the model of Baranyi and Roberts (BRM) and the Gompertz function (GF) are used to fit data. The comparison is based on the distribution of the standard error of the maximum specific growth rate estimates. The results show that the error structure of the BRM-fit is closer to that of the linear regression, making BRM more reliable for constructing confidence intervals by conventional means, using the t-distribution assumption for the parameter estimates.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104726"},"PeriodicalIF":4.5,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129020","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 : 2025-01-08DOI: 10.1016/j.fm.2025.104727
Sonia Almeria , John Grocholl , Jeremi Mullins , Mauricio Durigan , Laura Ewing-Peeples , Ellie Lauren Rogers , Kirsten Hirneisen , Shauna Madson , Shizhen Steven Wang
Cyclospora cayetanensis is a foodborne protozoan parasite that causes the human diarrheal disease cyclosporiasis. Recently, the US FDA developed a modified real-time PCR method based on a specific mitochondrial target gene (Mit1C) to detect C. cayetanensis in fresh produce. The method was validated by single laboratory validation (SLV) studies in Romaine lettuce, cilantro, and raspberries. The present study aimed to evaluate the performance of the new real-time Mit1C (Mit1C qPCR) method by comparing it with the current BAM Chapter 19b qPCR (18S qPCR) as the reference method for the detection of the protozoan parasite C. cayetanensis in fresh produce in a multi-laboratory validation (MLV) setting with the participation of 13 collaborating laboratories. Each laboratory analyzed twenty-four blind-coded Romaine lettuce DNA test samples that included: two unseeded samples, three samples seeded with five oocysts, and one sample seeded with 200 oocysts in the first round and five unseeded samples, eight samples seeded with five oocysts, and five samples seeded with 200 oocysts in the second round. The overall detection rates across laboratories for Romaine lettuce samples inoculated with 200 and 5 oocysts and un-inoculated samples were 100% (78/78), 69.23% (99/143), and 1.1% (1/91), respectively, for Mit1C qPCR, and 100% (78/78), 61.54% (88/143) and 0% (0/91), respectively, for 18S qPCR. The relative level of detection (RLOD = LOD50, Mit1C/LOD50, 18S) was 0.81 with a 95% confidence interval (0.600, 1.095), which included 1. Thus, Mit1C qPCR and 18S qPCR had statistically similar levels of detection. Mit1C qPCR was highly reproducible as the between-laboratory variance in the test results was nearly zero (0) and showed a high specificity at 98.9%. In conclusion, this study demonstrated that the new, more specific Mit1C qPCR method is an effective alternative analytical tool for detection of C. cayetanensis in fresh produce.
{"title":"Multi-laboratory validation of a modified real-time PCR assay (Mit1C) for the detection of Cyclospora cayetanensis in fresh produce","authors":"Sonia Almeria , John Grocholl , Jeremi Mullins , Mauricio Durigan , Laura Ewing-Peeples , Ellie Lauren Rogers , Kirsten Hirneisen , Shauna Madson , Shizhen Steven Wang","doi":"10.1016/j.fm.2025.104727","DOIUrl":"10.1016/j.fm.2025.104727","url":null,"abstract":"<div><div><em>Cyclospora cayetanensis</em> is a foodborne protozoan parasite that causes the human diarrheal disease cyclosporiasis. Recently, the US FDA developed a modified real-time PCR method based on a specific mitochondrial target gene (Mit1C) to detect <em>C. cayetanensis</em> in fresh produce. The method was validated by single laboratory validation (SLV) studies in Romaine lettuce, cilantro, and raspberries. The present study aimed to evaluate the performance of the new real-time Mit1C (Mit1C qPCR) method by comparing it with the current BAM Chapter 19b qPCR (18S qPCR) as the reference method for the detection of the protozoan parasite C. cayetanensis in fresh produce in a multi-laboratory validation (MLV) setting with the participation of 13 collaborating laboratories. Each laboratory analyzed twenty-four blind-coded Romaine lettuce DNA test samples that included: two unseeded samples, three samples seeded with five oocysts, and one sample seeded with 200 oocysts in the first round and five unseeded samples, eight samples seeded with five oocysts, and five samples seeded with 200 oocysts in the second round. The overall detection rates across laboratories for Romaine lettuce samples inoculated with 200 and 5 oocysts and un-inoculated samples were 100% (78/78), 69.23% (99/143), and 1.1% (1/91), respectively, for Mit1C qPCR, and 100% (78/78), 61.54% (88/143) and 0% (0/91), respectively, for 18S qPCR. The relative level of detection (RLOD = LOD<sub>50</sub>, <sub>Mit1C</sub>/LOD<sub>50</sub>, <sub>18S</sub>) was 0.81 with a 95% confidence interval (0.600, 1.095), which included 1. Thus, Mit1C qPCR and 18S qPCR had statistically similar levels of detection. Mit1C qPCR was highly reproducible as the between-laboratory variance in the test results was nearly zero (0) and showed a high specificity at 98.9%. In conclusion, this study demonstrated that the new, more specific Mit1C qPCR method is an effective alternative analytical tool for detection of <em>C. cayetanensis</em> in fresh produce.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104727"},"PeriodicalIF":4.5,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129088","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 : 2025-01-04DOI: 10.1016/j.fm.2025.104723
Jae-Hyun Yoon , Danbi Kim , Hyunwoo Joung , Sun-Young Lee
This study was to examine the relationship between preexposure to salt and stress-responsive resistance to acid, bile salt, and heat in Cronobacter sakazakii, Salmonella enterica serovar Enteritidis, Bacillus cereus, and Staphylococcus aureus. Stationary phase-grown cultures of C. sakazakii, S. Enteritidis, B. cereus or St. aureus were subjected to elevated concentrations of salt (maximally 14.0%), and the cells of each bacterium were allowed to grow at 37 °C for consecutive 6 d. The 6-d habituated cells were then subjected to acid (pH 2.0), 10% bile salt, and heat (60 °C) stresses. C. sakazakii, S. Enteritidis, and St. aureus were more sensitive to acid after the habituation process than their stationary phase-grown counterparts. Although the 0.5% salt-habituated cells of B. cereus better survived at a subsequent acid challenge than did the nonhabituated cells of this bacterium, there were no significant (p 0.05) differences in the Gompertz-derived growth kinetics between salt-habituated and nonhabituated cultures. Similarly, C. sakazakii and S. Enteritidis cells preexposed to salt was far more heat-sensitive, whereas the preexposure of B. cereus and St. aureus to 0.5 and 8.0% salt, respectively, resulted in their increased survival against heat as compared with their nonhabituated control. Nevertheless, the resultant growth parameters revealed that salt has no clear inducive effect on the acquisition of resistance responses to heterogeneous stresses. Overall, the habituation to different concentrations of salt may variably influence the ability of C. sakazakii, S. Enteritidis, B. cereus, and St. aureus to resist acid, bile salt, and heat stresses.
{"title":"The habituation to different concentrations of salt may variably influence the ability of Cronobacter sakazakii, Salmonella enterica serovar Enteritidis, Bacillus cereus, and Staphylococcus aureus to resist acid, bile salt, and heat stresses","authors":"Jae-Hyun Yoon , Danbi Kim , Hyunwoo Joung , Sun-Young Lee","doi":"10.1016/j.fm.2025.104723","DOIUrl":"10.1016/j.fm.2025.104723","url":null,"abstract":"<div><div>This study was to examine the relationship between preexposure to salt and stress-responsive resistance to acid, bile salt, and heat in <em>Cronobacter sakazakii</em>, <em>Salmonella enterica</em> serovar Enteritidis, <em>Bacillus cereus</em>, and <em>Staphylococcus aureus</em>. Stationary phase-grown cultures of <em>C</em>. <em>sakazakii</em>, <em>S</em>. Enteritidis, <em>B</em>. <em>cereus</em> or <em>St</em>. <em>aureus</em> were subjected to elevated concentrations of salt (maximally 14.0%), and the cells of each bacterium were allowed to grow at 37 °C for consecutive 6 d. The 6-d habituated cells were then subjected to acid (pH 2.0), 10% bile salt, and heat (60 °C) stresses. <em>C</em>. <em>sakazakii</em>, <em>S</em>. Enteritidis, and <em>St</em>. <em>aureus</em> were more sensitive to acid after the habituation process than their stationary phase-grown counterparts. Although the 0.5% salt-habituated cells of <em>B</em>. <em>cereus</em> better survived at a subsequent acid challenge than did the nonhabituated cells of this bacterium, there were no significant (<em>p</em> <span><math><mrow><mo><</mo></mrow></math></span> 0.05) differences in the Gompertz-derived growth kinetics between salt-habituated and nonhabituated cultures. Similarly, <em>C</em>. <em>sakazakii</em> and <em>S</em>. Enteritidis cells preexposed to salt was far more heat-sensitive, whereas the preexposure of <em>B</em>. <em>cereus</em> and <em>St</em>. <em>aureus</em> to 0.5 and 8.0% salt, respectively, resulted in their increased survival against heat as compared with their nonhabituated control. Nevertheless, the resultant growth parameters revealed that salt has no clear inducive effect on the acquisition of resistance responses to heterogeneous stresses. Overall, the habituation to different concentrations of salt may variably influence the ability of <em>C</em>. <em>sakazakii</em>, <em>S</em>. Enteritidis, <em>B</em>. <em>cereus</em>, and <em>St</em>. <em>aureus</em> to resist acid, bile salt, and heat stresses.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104723"},"PeriodicalIF":4.5,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-03DOI: 10.1016/j.fm.2025.104721
Maoyun Li , Sicheng Du , Yue Xiao , Yanping Wu , Kai Zhong , Yina Huang , Renyou Gan , Hong Gao
Amidst the increasing demand for premium dark tea, the utilization of Aspergillus niger-inoculated fermentation has emerged as a potential solution to address the challenges associated with extended processing cycles and inconsistent quality. This study comprehensively investigated the efficacy and mechanisms of A. niger PW-2 inoculation in enhancing dark tea quality compared to spontaneous fermentation, using metabolomics, electronic tongue, molecular docking, and high-throughput sequencing. A. niger PW-2 shaped the fungal community within 7 days, degrading terpene glycosides and lactones while generating terpenoids and unsaturated fatty acids, which enriched the floral aroma of PW-2-inoculated fermentation dark tea (AF). Flavonoid degradation and reduced theaflavins/thearubigins levels in AF decreased astringency, while increased bitter dipeptides and isoflavonoids enhanced bitterness, and the accumulation of umami dipeptides and theabrownins improved umami taste perception of AF. Molecular docking identified key compounds responsible for astringency (kaempferol glycosides), bitterness (6″-caffeoylisoorientin, kaempferol 4′-glucoside 7-rhamnoside, dihydrodaidzein 7-O-glucuronide), and umami (3-O-p-trans-coumaroylalphitolic acid, dihydrodaidzein 7-O-glucuronide, 1-methoxyphaseollidin). Overall, A. niger PW-2 inoculation accelerates fermentation process and enhances flavor characteristics of dark tea, offering a promising approach for high-quality dark tea production.
{"title":"Enhancing the quality of dark tea through fermentation with Aspergillus niger: Unveiling aroma and taste characteristics","authors":"Maoyun Li , Sicheng Du , Yue Xiao , Yanping Wu , Kai Zhong , Yina Huang , Renyou Gan , Hong Gao","doi":"10.1016/j.fm.2025.104721","DOIUrl":"10.1016/j.fm.2025.104721","url":null,"abstract":"<div><div>Amidst the increasing demand for premium dark tea, the utilization of <em>Aspergillus niger</em>-inoculated fermentation has emerged as a potential solution to address the challenges associated with extended processing cycles and inconsistent quality. This study comprehensively investigated the efficacy and mechanisms of <em>A</em>. <em>niger</em> PW-2 inoculation in enhancing dark tea quality compared to spontaneous fermentation, using metabolomics, electronic tongue, molecular docking, and high-throughput sequencing. <em>A. niger</em> PW-2 shaped the fungal community within 7 days, degrading terpene glycosides and lactones while generating terpenoids and unsaturated fatty acids, which enriched the floral aroma of PW-2-inoculated fermentation dark tea (AF). Flavonoid degradation and reduced theaflavins/thearubigins levels in AF decreased astringency, while increased bitter dipeptides and isoflavonoids enhanced bitterness, and the accumulation of umami dipeptides and theabrownins improved umami taste perception of AF. Molecular docking identified key compounds responsible for astringency (kaempferol glycosides), bitterness (6″-caffeoylisoorientin, kaempferol 4′-glucoside 7-rhamnoside, dihydrodaidzein 7-<em>O</em>-glucuronide), and umami (3-<em>O</em>-<em>p</em>-<em>trans</em>-coumaroylalphitolic acid, dihydrodaidzein 7-<em>O</em>-glucuronide, 1-methoxyphaseollidin). Overall, <em>A. niger</em> PW-2 inoculation accelerates fermentation process and enhances flavor characteristics of dark tea, offering a promising approach for high-quality dark tea production.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104721"},"PeriodicalIF":4.5,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129084","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 : 2024-12-31DOI: 10.1016/j.fm.2024.104720
Lingyun Liu , Pan Mao , Jinni Chen , Lingling Li , Yan Wang , Jingdong Song , Zhenghong Chen , Changyun Ye
Listeria monocytogenes (LM) is an opportunistic foodborne pathogen responsible for listeriosis in both humans and animals. The disease manifests in a variety of ways, including febrile gastroenteritis, septicemia, meningitis, and in some cases, preterm birth and spontaneous abortion. It is therefore crucial to develop effective strategies to control this bacterium. In this study, we isolated and characterized a novel Listeria phage, named LMLPA3. Morphological and genomic analyses revealed that phage LMLPA3 belongs to the class Caudovirales, family Herelleviridae, Myovirus-like. Phage LMLPA3 demonstrated remarkable stability across a range of pH values (4-10), temperatures (4–50 °C), and high NaCl concentrations (12% w/v). A total of 68 strains, comprising nine serotypes of L. monocytogenes and five other Listeria species, were found to be susceptible to lysis by phage LMLPA3. It is noteworthy that treatment with phage LMLPA3 resulted in a significant disruption of the biofilms formed by seven different serotype strains of L. monocytogenes, in comparison to the control. Furthermore, phage LMLPA3 effectively reduced the number of L. monocytogenes cells by 4 log10 CFU/mL and 2.9 log10 CFU/sample, respectively, in milk and on the surface of raw beef at an MOI of 10000. In light of these findings, it can be concluded that phage LMLPA3 has the potential to serve as an effective antimicrobial in the elimination of L. monocytogenes contamination in foodstuffs.
{"title":"Isolation, characterization and genomic analysis of the novel Listeria bacteriophage LMLPA3 as a potential antimicrobial in foods","authors":"Lingyun Liu , Pan Mao , Jinni Chen , Lingling Li , Yan Wang , Jingdong Song , Zhenghong Chen , Changyun Ye","doi":"10.1016/j.fm.2024.104720","DOIUrl":"10.1016/j.fm.2024.104720","url":null,"abstract":"<div><div><em>Listeria monocytogenes</em> (LM) is an opportunistic foodborne pathogen responsible for listeriosis in both humans and animals. The disease manifests in a variety of ways, including febrile gastroenteritis, septicemia, meningitis, and in some cases, preterm birth and spontaneous abortion. It is therefore crucial to develop effective strategies to control this bacterium. In this study, we isolated and characterized a novel <em>Listeria</em> phage, named LMLPA3. Morphological and genomic analyses revealed that phage LMLPA3 belongs to the class <em>Caudovirales</em>, family <em>Herelleviridae</em>, <em>Myovirus-like.</em> Phage LMLPA3 demonstrated remarkable stability across a range of pH values (4-10), temperatures (4–50 °C), and high NaCl concentrations (12% w/v). A total of 68 strains, comprising nine serotypes of <em>L. monocytogenes</em> and five other <em>Listeria</em> species, were found to be susceptible to lysis by phage LMLPA3. It is noteworthy that treatment with phage LMLPA3 resulted in a significant disruption of the biofilms formed by seven different serotype strains of <em>L. monocytogenes</em>, in comparison to the control. Furthermore, phage LMLPA3 effectively reduced the number of <em>L. monocytogenes</em> cells by 4 log<sub>10</sub> CFU/mL and 2.9 log<sub>10</sub> CFU/sample, respectively, in milk and on the surface of raw beef at an MOI of 10000. In light of these findings, it can be concluded that phage LMLPA3 has the potential to serve as an effective antimicrobial in the elimination of <em>L. monocytogenes</em> contamination in foodstuffs.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104720"},"PeriodicalIF":4.5,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143129082","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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