Food microbiology最新文献

{"title":"RNA chaperone Hfq promotes the growth of Yersinia enterocolitica in refrigerated foods","authors":"Ming Liu ,&nbsp;Xinyu Zhao ,&nbsp;Zhi Wang ,&nbsp;Ling Chen ,&nbsp;Zimeng Wang ,&nbsp;Huichan Zhai ,&nbsp;Congyu Zhou ,&nbsp;Huixian Wang ,&nbsp;Yu Ding ,&nbsp;Jumei Zhang ,&nbsp;Xiuhua Lin ,&nbsp;Jiahui Zeng ,&nbsp;Feiting Peng ,&nbsp;Juan Wang ,&nbsp;Qingping Wu","doi":"10.1016/j.fm.2024.104707","DOIUrl":"10.1016/j.fm.2024.104707","url":null,"abstract":"<div><div><em>Yersinia enterocolitica</em> is a major foodborne pathogen causing yersiniosis, a significant zoonotic infection. Its unique cold tolerance makes it a potential threat to the safety of cold chain food. The RNA-binding protein Hfq is known to be involved in bacterial stress regulation, but its role in the cold tolerance of <em>Y. enterocolitica</em> remains unclear. Based on gene knockout and complementation, this study revealed that deleting the <em>hfq</em> gene disrupted the exponential growth phase of <em>Y. enterocolitica</em> under low-temperature conditions, leading to a biphasic growth phenomenon. Additionally, through the construction of point mutants, it was found that the critical amino acid sites for cold-tolerance regulation of Hfq in <em>Y. enterocolitica</em> are located on the distal and proximal surfaces. Further studies found that the biphasic growth process of the <em>hfq</em> deletion mutant was affected by the initial bacterial concentration and exogenous fatty acids. RT-qPCR results showed that Hfq regulation may affect the synthesis of branched-chain amino acids, and TCA cycle-related genes were significantly up-regulated during the second exponential growth. Studies based on milk and meat have shown that Hfq can promote the low-temperature growth of <em>Y. enterocolitica</em> in the food matrix. Our study provides evidence that Hfq-dependent regulation of energy metabolism is critical for cold tolerance in <em>Y. enterocolitica</em>. This study highlights the importance of Hfq in regulating cold tolerance in <em>Y. enterocolitica</em> and discusses its potential regulatory mechanism.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104707"},"PeriodicalIF":4.5,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143128908","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 aprD-mutated strain modulates the development of Pseudomonas fragi population but has limited effects on the spoilage profiles of native residents","authors":"Yajie Wu ,&nbsp;Fang Ma ,&nbsp;Song Tan ,&nbsp;Ajuan Niu ,&nbsp;Yuping Chen ,&nbsp;Yuxin Liu ,&nbsp;Weifen Qiu ,&nbsp;Guangyu Wang","doi":"10.1016/j.fm.2024.104708","DOIUrl":"10.1016/j.fm.2024.104708","url":null,"abstract":"<div><div>Extracellular enzymes produced by predominant bacteria exert important roles in inducing and accelerating spoilage, with their secretion regulated by specific genes. In <em>Pseudomonas fragi</em>, the <em>aprD</em> gene is a recognized regulator for secreting an alkaline extracellular protease. However, limited studies have focused on this gene in <em>P. fragi</em> population and its impact on meat microbial community structure and function. This study addressed this gap by monitoring the changes in biological properties of <em>P. fragi</em> populations and analyzing the discrepancies in spoilage phenotypes and microbial community structures of chilled chicken among groups differentiated by the initial prevalence of <em>aprD</em>-positive strains. The results showed that <em>aprD</em>-positive strains were disseminated in <em>P. fragi</em> populations, and its prevalence was associated with significant increases in swimming motility and biofilm formation capacities in specific groups. <em>In situ</em> contamination experiments revealed varying spoilage characteristics and community compositions among groups by day 3 of storage. Correlation analysis demonstrated a strong association between spoilage phenotypes and certain bacterial genera, such as <em>Pseudomonadaceae</em>_<em>Pseudomonas</em> and <em>Carnobacterium</em>. However, the microbial community structure and spoilage characteristics of samples from each group were not significantly different on the 5th day of storage. These findings suggest that even a small number of <em>aprD</em> mutants can significantly affect the assembly of the chilled meat microbial community. Nonetheless, the regulatory effect of <em>aprD</em> on spoilage at the strain and population levels of <em>P. fragi</em> is negligible in the context of complex natural microbiota. This work underscores the complex interactions between specific bacterial genes and the broader microbial ecology in refrigerated meat environments, providing deeper insights into the meat spoilage mechanisms.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104708"},"PeriodicalIF":4.5,"publicationDate":"2024-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143128846","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 food application of a novel Staphylococcus aureus bacteriophage vB_SA_STAP152 and its endolysin LysP152 with high enzymatic activity under cold temperature","authors":"Yuanyu Li ,&nbsp;Jingsha Dai ,&nbsp;Shi Wu ,&nbsp;Dongli Rong ,&nbsp;Jiahui Huang ,&nbsp;Miao Zhao ,&nbsp;Jumei Zhang ,&nbsp;Qinghua Ye ,&nbsp;Qihui Gu ,&nbsp;Youxiong Zhang ,&nbsp;Xianhu Wei ,&nbsp;Qingping Wu","doi":"10.1016/j.fm.2024.104710","DOIUrl":"10.1016/j.fm.2024.104710","url":null,"abstract":"<div><div><em>Staphylococcus aureus,</em> a foodborne bacterial pathogen, poses a serious challenge due to antibiotic resistance, highlighting the urgent need for effective and alternative antimicrobial agents. Undoubtedly, bacteriophages and bacteriophage-encoded antibacterial proteins have been considered effective biopreservatives. Herein, we report the isolation and characterization of a novel lytic bacteriophage, vB_SA_STAP152, along with its endolysin LysP152. Morphological and genomic analysis revealed that vB_SA_STAP152 could be considered as a new species in the <em>Rosenblumvirus</em> genus. Stability tests demonstrated that vB_SA_STAP152 can withstand a range of temperatures (∼65 °C) and pH values (4–11). Moreover, we successfully cloned and expressed the bacteriophage-encoded protein, endolysin LysP152, which exhibited optimal activity at temperatures between 4 and 35 °C and within a broad pH range (4–11). The antibacterial spectrum experiments revealed that phage vB_SA_STAP152 effectively targeted 76.15% of <em>S. aureus</em> strains across 14 different sequence types (STs), particularly including community-associated methicillin-resistant <em>S. aureus</em> (CA-MRSA) ST59. Furthermore, endolysin LysP152 demonstrated complete lysis all tested <em>S. aureus</em> strains spanning 17 STs. Subsequently, the efficacy of vB_SA_STAP152 and LysP152 against MRSA in pork was evaluated, revealing a significant reduction of bacterial counts by 4.27–4.42 log₁₀ CFU/mL with phage vB_SA_STAP152 at room temperature and by 3.31 log₁₀ CFU/mL with endolysin LysP152 at refrigerator temperature. Overall, the in-vitro studies and favorable physical and chemical properties suggested that phage vB_SA_STAP152 and endolysin LysP152 have the potential to be developed as antimicrobial agents against <em>S. aureus</em> in the food industry.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104710"},"PeriodicalIF":4.5,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143128907","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":"Prevalence, seasonal variation, and proteomic relationship of β-lactamase-producing Escherichia coli, Klebsiella pneumoniae, and Acinetobacter spp. in poultry meat at the abattoir level in Greece","authors":"Anestis Tsitsos ,&nbsp;Alexandros Damianos ,&nbsp;Vasilios Tsiouris ,&nbsp;Elias Papapanagiotou ,&nbsp;Nikolaos Soultos ,&nbsp;Anna Papa ,&nbsp;Ilias Tyrodimos ,&nbsp;Vangelis Economou","doi":"10.1016/j.fm.2024.104709","DOIUrl":"10.1016/j.fm.2024.104709","url":null,"abstract":"<div><div>Extended-spectrum-β-lactamase (ESBL) and carbapenemase-producing Enterobacterales and <em>Acinetobacter</em> spp. are important nosocomial pathogens that are frequently isolated from patients and food matrices. Nevertheless, comprehensive data on the prevalence, spatiotemporal variations, and characterization of β-lactam-resistant bacteria in poultry meat products are limited. This study provides the first comprehensive assessment in Greece of the prevalence, characteristics, and proteomic relationships of β-lactam-resistant strains in poultry meat at the abattoir level. Strains were selectively isolated using β-lactams and identified via MALDI-TOF MS. Antimicrobial susceptibility and the presence of common β-lactamase genes were assessed, and protein profiles were analyzed to determine strain relationships, whereas <em>E. coli</em> isolates were further classified into phylogenetic groups. The overall prevalence was 40.8% for <em>E. coli</em>, 3.3% for <em>K. pneumoniae</em>, and 46.7% for <em>Acinetobacter</em> spp., with notable seasonal and regional fluctuations especially in <em>Acinetobacter</em> spp. Most strains (97.9% of <em>E. coli</em>, 100.0% of <em>K. pneumoniae</em> and 88.1% of <em>Acinetobacter</em> spp.) were classified as multidrug or extensively drug-resistant. All <em>E. coli</em> and <em>K. pneumoniae</em> strains were phenotypically confirmed as ESBL/AmpC producers, whereas one <em>K. pneumoniae</em> strain showed additional resistance to ertapenem. The majority of <em>E. coli</em> strains (91.49%) and all <em>K. pneumoniae</em> strains carried β-lactamase genes, predominantly <em>bla</em>_CTX-M group 1 in <em>E. coli</em> and <em>bla</em>_SHV in <em>K. pneumoniae</em>. Conversely, only 10.2% of <em>Acinetobacter</em> strains harbored β-lactamase genes. Most <em>E. coli</em> isolates belonged to phylogroups A (46.9%) and B1 (34.7%). Protein profile analysis indicated relatedness among isolates across different regions and seasons. These findings underscore poultry meat's role as a reservoir of resistant strains of <em>E. coli, K. pneumoniae</em>, and <em>Acinetobacter</em> spp. and highlight the need for enhanced surveillance and mitigation strategies to reduce public health risks.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104709"},"PeriodicalIF":4.5,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143128845","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":"Cross-over fermentation dynamics and proteomic properties of acid gels with indigenous Lactobacillus spp. isolated from cheeses","authors":"Gokce Keser,&nbsp;Tulay Ozcan","doi":"10.1016/j.fm.2024.104700","DOIUrl":"10.1016/j.fm.2024.104700","url":null,"abstract":"<div><div>The present study examined the proteomic characteristics and fermentation dynamics of indigenous bacteria isolated from traditional Mihalic cheese in an acid gel matrix. Accordingly, autochthonous strains of <em>Levilactobacillus brevis</em>, <em>Lacticaseibacillus paracasei</em>, and <em>Lacticaseibacillus rhamnosus</em> were adapted to the gel matrix alongside commercial yogurt culture (<em>Streptococcus thermophilus</em> and <em>Lactobacillus delbrueckii</em> subsp. <em>bulgaricus</em>). The study evaluated bacterial activity, proteolytic behavior, physicochemical characteristics, and textural and sensory properties in acid gel samples. The microorganisms demonstrated high survival rates (&gt;7.35 log₁₀ cfu/g) in the fermented gel system and induced limited acidification throughout the product's shelf life. Regarding proteomic properties, the highest amino acid variation during the shelf life was observed in the FMB sample (28.20%). Furthermore, arginine, leucine, phenylalanine, aspartic acid, lysine, and cysteine reductions were noted in samples containing the isolated microorganisms. Including indigenous microorganisms in the fermented milk increased the levels of essential amino acids. Principal Component Analysis of sensory properties revealed that samples containing indigenous microorganisms differed significantly from the control sample (C), which contained only commercial yogurt culture. The results revealed the proteolytic changes associated with fermentation, including producing free amino acids as nutritional components, forming specific aroma compounds, and modifying textural and sensory properties. These results demonstrate the potential of utilizing local cultures to develop products enriched with novel bioactive components, offering consumers enhanced nutritional and sensory benefits.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104700"},"PeriodicalIF":4.5,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143128847","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":"Antibiofilm efficacies and mechanism of perillaldehyde against Shewanella putrefaciens","authors":"Wenxiu Zhu ,&nbsp;Yuanhang Cheng ,&nbsp;Yankun Zhang ,&nbsp;Mingxin Li ,&nbsp;Yue Teng ,&nbsp;Yunqi Gu ,&nbsp;Haisong Wang ,&nbsp;Xiaodong Xia","doi":"10.1016/j.fm.2024.104699","DOIUrl":"10.1016/j.fm.2024.104699","url":null,"abstract":"<div><div><em>Shewanella putrefaciens</em> is Gram-negative bacterium and important spoilage organism in aquatic products, negatively impacting the organoleptic properties of aquatic products. <em>S. putrefaciens</em> could form biofilm, which increases persistence and contamination in food system. Efficient antibiofilm strategies are urgently needed to reduce its presence in food environment. This study aimed to explore the impact of perillaldehyde on <em>S. putrefaciens</em> biofilm and the underlying mechanisms using transcriptomic analysis. Perillaldehyde remarkably reduced extracellular polymeric substance contents, inhibited metabolic activity of biofilm cells, disrupted bacterial motility, loose biofilm structure and decreased biofilm formation in food juice and on various surfaces (stainless steel, silicone, glass, razon clam and shrimp). Transcriptome analysis revealed that 553 differentially expressed genes were identified, among which 254 were down-regulated and 299 were up-regulated. The differentially expressed genes included ATP-binding cassette transporters, ribosome, two-component systems, resistance/nodulation/division efflux systems, quorum sensing, amino acid metabolism, biosynthesis and degradation pathways. The findings demonstrate antibiofilm properties of perillaldehyde against <em>S. putrefaciens</em> and indicate that perillaldehyde could be developed as an antibiofilm agent to mitigate existence and contamination of <em>S. putrefaciens</em> and to reduce associated food loss caused by this spoilage bacteria.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104699"},"PeriodicalIF":4.5,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143128843","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":"Regulation of citrinin biosynthesis in Monascus purpureus: Impacts on growth, morphology, and pigments production","authors":"Xizi Zhang,&nbsp;Wei Chen,&nbsp;Chengtao Wang","doi":"10.1016/j.fm.2024.104698","DOIUrl":"10.1016/j.fm.2024.104698","url":null,"abstract":"<div><div>Fungal hyphae self-assemble a variety of cellular macrostates, ranging from suspended mycelium to dense pellets, all inextricably linked to their productivity. In this study, using CRISPR/Cas technology, we constructed a <em>ctnA</em> knockout strain (Δ<em>ctnA</em>) and an overexpression strain (A2) so as to investigate the effects of interfering with citrinin biosynthesis on the growth, morphology and pigmentation of <em>M.purpureus</em>. Results indicated that deletion of <em>ctnA</em> in <em>M. purpureus</em> RP2 led to increased mycelium length, delayed conidium formation, and a citrinin content of 22% of the wild-type strain. Conversely, <em>ctnA</em> overexpression in strain A2 resulted in delayed mycelial growth, normal conidium formation, and a citrinin content of 120% compared to the wild-type strain, with minimal effects on pigments content. Notably, the Δ<em>ctnA</em> strain formed small, tightly structured pellets (mean diameter 1.2 <span><math><mrow><mo>±</mo></mrow></math></span> 0.06 mm) and exhibited low citrinin content, promoting pigments production. Our findings suggest a complex interplay between citrinin biosynthesis and morphological development, providing insights for optimizing metabolite production in industrial applications.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"127 ","pages":"Article 104698"},"PeriodicalIF":4.5,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142817616","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 investigation of the mechanism underlying variations in oxidative stress tolerance of Lacticaseibacillus paracasei resulting from fermentation methods through endogenous CRISPR-Cas9 editing methodology","authors":"Pengyu Wu ,&nbsp;Yutian Zhang ,&nbsp;Qiantong Shan ,&nbsp;Ziyang Wang ,&nbsp;Shuang Cheng ,&nbsp;Laiyou Wang ,&nbsp;Bingbing Liu ,&nbsp;Wenhuan Li ,&nbsp;Zhenmin Chen ,&nbsp;Jiancheng Luo ,&nbsp;Yunxiang Liang","doi":"10.1016/j.fm.2024.104697","DOIUrl":"10.1016/j.fm.2024.104697","url":null,"abstract":"<div><div>The probiotic effects of lactic acid bacteria make them widely used in human and animal breeding industry. However, the presence of oxidative stress during the production and application process can cause bacterial damage or even death, significantly compromising the functionality of probiotics. Despite its potential for broader application scenarios that could provide a more comprehensive understanding of bacteria's internal adaptation strategies, there is a lack of research investigating oxidative stress from the perspective of culture methods. In this study, the tolerance to oxidative stress was compared between bacteria cultivated through solid-state fermentation (SSF) and liquid-state fermentation (LSF), and the physiological and transcriptional disparities between these two bacterial strains were investigated. Additionally, a novel and efficient gene editing method was developed to elucidate the genetic basis underlying these differences in tolerance. The results demonstrated a significantly higher tolerance to oxidative stress in SSF bacteria compared to LSF bacteria, along with a stronger capacity for maintaining intracellular microenvironment stability and the activity of key metabolic enzymes. It is noteworthy that the bacteria from SSF significantly enhance the transport of carbohydrate substances and facilitate intracellular metabolic flow. Gene editing experiments have confirmed the crucial role of genes <em>glpF</em> and <em>glpO</em> in regulating the glycerol metabolism pathway, which is essential for enhancing the tolerance of bacteria from SSF to oxidative stress. Based on these findings, the mechanism underlying the disparity in oxidative stress tolerance resulting from different culture methods has been summarized. Furthermore, investigation into different culture modes has revealed that moderate oxygen levels during cultivation significantly influence variation in bacterial tolerance to oxidative stress. Importantly, these variations are species-specific and depend on the ecological niche distribution of <em>Lactobacilli</em>. These findings elucidate a novel mechanism by which <em>Lacticaseibacillus paracasei</em> Zhang tolerates oxidative stress, and also suggest that distinct cultivation and processing methods should be tailored based on the specific <em>Lactobacilli</em> groups to achieve optimal application effects in production.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"127 ","pages":"Article 104697"},"PeriodicalIF":4.5,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142817619","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":"Pseudomonadaceae increased the tolerance of Listeria monocytogenes to sanitizers in multi-species biofilms","authors":"Olena Voloshchuk ,&nbsp;M. Laura Rolon ,&nbsp;Katelyn V. Bartlett ,&nbsp;Marysabel Mendez Acevedo ,&nbsp;Luke F. LaBorde ,&nbsp;Jasna Kovac","doi":"10.1016/j.fm.2024.104687","DOIUrl":"10.1016/j.fm.2024.104687","url":null,"abstract":"<div><div>The persistence of the foodborne pathogen <em>Listeria monocytogenes</em> in food processing facilities may be facilitated by the formation of multi-species biofilms by environmental microbiota. This study aimed to determine whether multi-species biofilm formation results in an increased tolerance of <em>L. monocytogenes</em> in biofilms to the sanitizers benzalkonium chloride (BAC) and peroxyacetic acid (PAA) at concentrations commonly used in food processing facilities. Biofilms composed of microbiota previously shown to co-occur with <em>L. monocytogenes</em> in tree fruit packing facilities (i.e., <em>Pseudomonadaceae, Xanthomonadaceae, Flavobacteriaceae</em>, and <em>Microbacteriaceae</em>) were formed with <em>L. monocytogenes</em> in single- and multi-family assemblages. Multi-family biofilms were exposed to 250 or 500 ppm of PAA, or 200 ppm of BAC to determine the die-off kinetics of <em>L. monocytogenes</em>. Furthermore, the ability of a commercial biofilm remover to disrupt biofilms and inhibit bacteria in the formed single- and multi-family assemblage biofilms was assessed. The die-off kinetics of total bacteria and <em>L. monocytogenes</em> in biofilm assemblages throughout the exposure to a sanitizer was determined using the aerobic plate count and the most probable number methods, respectively. Biofilm assemblages that included <em>Pseudomonadaceae</em> resulted in an increased tolerance of <em>L. monocytogenes</em> to BAC and PAA compared to biofilm assemblages without <em>Pseudomonadaceae</em>. Further, the use of the biofilm remover significantly disrupted biofilms and reduced the concentration of <em>L. monocytogenes</em> in single- and multi-family biofilms by 5 or more logarithmic units. These findings highlight the need to improve the control of biofilm-forming microbiota in food processing facilities to mitigate the persistence of <em>L. monocytogenes.</em></div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"128 ","pages":"Article 104687"},"PeriodicalIF":4.5,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143128842","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":"Interaction and cross-contamination potential of prepared beef steak isolates Pseudomonas weihenstephanensis and Macrococcus caseolyticus in biofilms of dual-species","authors":"Wendi Zhang ,&nbsp;Yunhao Ma ,&nbsp;Yong Xie ,&nbsp;Xiaoyan Liu ,&nbsp;Lijun Tan ,&nbsp;Jinsong Zhao ,&nbsp;Yongsheng Ni ,&nbsp;Zhaoming Wang ,&nbsp;Cong Li ,&nbsp;Baocai Xu","doi":"10.1016/j.fm.2024.104685","DOIUrl":"10.1016/j.fm.2024.104685","url":null,"abstract":"<div><div>This study evaluated the interactions between single or dual-species biofilms formed by dominant spoilage bacteria <em>P. weihenstephanensis</em> and <em>M. caseolyticus</em> isolated from refrigerated, spoilage prepared beef steaks at 4 °C and elucidated the interactive behavior of biofilm development in dual species. In addition, the relationship between biofilm formation capacity and cross-contamination was analyzed by simulating surface to food contact transfer. The results showed that the two species exhibited synergism as biofilms developed, which was the main mode of interaction observed. Under aerobic conditions, <em>Pseudomonas weihenstephanensis</em> and <em>Macrococcus caseolyticus</em> co-cultured for 96 h showed obvious biofilm formation ability, resulting in greater cross-contamination. Scanning electron microscopy and Confocal laser scanning microscopy showed the formation of flattened dense biofilms in the co-culture. The significant increase in Fe content and decrease in siderophore content of the dual-species biofilm as determined by ICP-MS was attributed to respiratory inhibition resulting in a decrease in the transcription of genes regulating the two-component regulatory system of <em>Macrococcus tyrolyticus</em> SrrAB and an increase in the expression of cytoplasmic hydrolase leading to the rupture of the release of hemoglobin to provide a source of iron for <em>P. weihenstephanensis</em>. The increase of heme content in the supernatant of dual-species and the results of RT-qPCR showed that the gene expression of the heme transport system of <em>P. weihenstephanensis</em> was significantly up-regulated and the siderophore gene expression was decreased, which further revealed that <em>P. weihenstephanensis</em> preferentially uses the heme uptake system to take up the iron source provided by <em>M. caseolyticus</em> for <em>P. weihenstephanensis</em>. Overall, our results provide insight into the complex dynamics of biofilms formed by <em>P. weihenstephanensis</em> and <em>M. caseolyticus</em>, emphasizing that the iron reaction pathway may be a key factor influencing the growth of <em>P. weihenstephanensis</em> biofilms, and that these results will provide a theoretical basis for the control of spoilage of refrigerated foods.</div></div>","PeriodicalId":12399,"journal":{"name":"Food microbiology","volume":"127 ","pages":"Article 104685"},"PeriodicalIF":4.5,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142817613","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}