首页期刊导航|Food microbiology
期刊信息/Journal information
Food microbiology
Elsevier Science: Harcourt Publishers Ltd.
Food microbiology

Elsevier Science: Harcourt Publishers Ltd.

0740-0020

Food microbiology/Journal Food microbiologySCI
正式出版
收录年代

    Food products confiscated from air passengers travelling from third countries into the European Union: Microbiological analyses and genomic characterization of zoonotic and multiresistant bacteria

    Nicola RinnAnja MiillerAnn-Sophie BraunGabriel Greif...
    104783.1-104783.12页
    查看更多>>摘要：Illegal imports of food of animal origin from third countries into the EU are a potential transmission route for zoonotic and multiresistant bacterial pathogens. Here, we collected illegally imported food products that were confiscated from passengers arriving from non-EU countries at Frankfurt International Airport (FRA), Germany. A total of 100 food samples were microbiologically tested for the presence of foodborne and multiresistant pathogens and hygiene parameters were determined. For this, samples were qualitatively examined for Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, Shiga toxin-producing Escherichia coli (STEC), methicillin-resistant S. aureus (MRSA), and extended-spectrum p-lactamase (ESBL)-/AmpC-producing Enter-obacterales. Quantitative microbiological analyses included aerobic mesophilic colony counts, L monocytogenes, coagulase-positive staphylococci, Enterobacterales and E. coli counts. Overall, Enterobacterales and E. coli were detected in 36 % and 23 % of the samples, respectively, indicating hygiene deficiencies, while foodborne pathogens were observed in 17 % of the samples. Selected isolates were subjected to a comprehensive genotypic analysis, for which they were whole genome sequenced. It was demonstrated that the S. aureus isolates (n = 11) revealed a wide variety of genotypic profiles, with one isolate belonging to a newly assigned sequence type ST8323. Three S. aureus isolates were classified as multiresistant, including one MRSA. The Salmonella enterica isolates (n = 3) belonged to three serovars (Uganda, Altona, Rauform) and were susceptible to all antimicrobial agents tested. Further, no resistance was detected in the obtained L. monocytogenes isolates (n = 3; ST8, ST121, ST425). In three of the 23 presumed commensal E. coli isolates multiresistance was observed, whereas the single STEC isolate (O43:H2) was susceptible. In addition, we obtained five ESBL-producing Enterobacterales isolates, of which one isolate carried a rarely described bla_(SHV-168) subtype. Overall, the data show that illegal imports in the baggage of airline passengers can facilitate the spread of zoonotic and multiresistant bacterial isolates, including those resistant to third-generation cephalosporins and quinolones. This contributes to the transmission of newly described or uncommon lineages.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Mechanisms of Priestia megaterium PH3 in alleviating postharvest disease caused by Penicillium expansum in Nanguo pear fruit

    Zilong LiJiamin JiangKeyu SunShuhong Ye...
    104784.1-104784.11页
    查看更多>>摘要：Penicilium expansum is one of the primary pathogens causing rot in fruit and vegetables. The progression of blue mold damages the appearance and nutritional value of produce, leading to significant economic losses. Recent studies have shown that endophytes, as a vital component of potential microbial agents, can control various fungal diseases. This study focuses on the inhibitory mechanism of the peanut endophyte Priestia megaterium PH3 against blue mold in Nanguo pear. The results demonstrated that the endophytic P. megaterium PH3 and its metabolites not only inhibit the spore germination of P. expansum. Most notably, after rapidly colonizing the surface of Nanguo pear fruit, P. megaterium PH3 enhances the activity of antioxidant enzymes (SOD, CAT, APX, MDHAR, DHAR and GR) and non-enzymatic antioxidants (AsA and GSH), suppressing the ROS surge caused by P. expansum infection. Additionally, the P. megaterium PH3 upregulates the activity of enzymes (PAL, C4H, 4CL, PPO and POD) and gene expression (PuPAL, PuC4H and Pu4CL) related to phenolics metabolism, promoting the synthesis and metabolism of phenolics and flavonoids compounds, effectively inhibiting the onset of blue mold in Nanguo pear. These findings indicate that P. megaterium PH3 is a promising and effective microbial agent for mitigating postharvest blue mold in Nanguo pear.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    D-tagatose biotransformation from lactose by lactase and recombinant Bacillus subtilis expressing L-arabinose isomerase, and the product separation, purification and crystallization

    Xin WenHuibin LinGuangwen LiuYuhang Ning...
    104785.1-104785.9页
    查看更多>>摘要：D-Tagatose is a low-calorie rare sugar with notable physiological benefits. The recombinant Bacillus subtilis expressing L-arabinose isomerase (LAI) was constructed and used together with lactase for biotransformation of D-tagatose from cheap substrate of lactose. Under optimum conditions, 45.6 g/L D-tagatose was produced from 200 g/L lactose, achieving a conversion yield of 0.228 g D-tagatose/g lactose. D-Glucose produced by lactose hydrolysis was removed by anaerobic fermentation with Saccharomyces cerevisiae. Subsequently, the sugar solution containing D-galactose and D-tagatose was decolorized by using powdered activated carbon, desalinated by anion and cation exchange resin beds, and separated by chromatographic column, resulting in decolorization rate of 95.5 %, desalinization rate of 93.8 % and D-tagatose solution purity of 97.9 %. Finally, the separated d-tagatose solution was concentrated and crystallized, resulting in D-tagatose crystals with 99.9 % purity. In summary, this paper establishes a complete bioprocess for D-tagatose from lactose catalyzed by using recombinant B. subtilis and lactase. The methods developed in this study show promise for mass production of food-grade D-tagatose from the inexpensive substrate lactose.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Impact of radio frequency inactivation on bacterial DNA and membrane integrity in meat-based food model systems with various microstructures

    Julian EspitiaDavy VerheyenShubhangi MehrotraDmytro S. Kozak...
    104786.1-104786.12页
    查看更多>>摘要：Radio Frequency (RF) bacterial inactivation has been successfully used in several food products. However, RF dielectric heating can be affected by several factors, including food composition. Changes in the food matrix can not only influence microbial inactivation but also potentially alter RF inactivation mechanisms. Despite this, limited studies have been conducted to understand RF heating in different food matrices and its inactivation mechanisms. In the present study, three meat-based model systems were used (Liquid, Emulsion and Aqueous gel) for RF inactivation of Listeria monocytogenes and Salmonella Typhimurium at 27.12 MHz. The presence of fat and gel in the matrix increased I. monocytogenes heat resistance only at mild temperatures (<60 ℃) compared to liquid. On the contrary, S. Typhimurium inactivation rate was always slower in the presence of fat and gel in the matrix than in liquid during the whole RF treatment. dsDNA integrity did not show significant differences between treated and untreated samples, while cell membrane was damaged during RF heating for both microorganisms. Thus, RF microbial inactivation can be directly affected depending on the organisms and the medium complexity (e.g. fat, gel). Regarding RF inactivation mechanisms at 27.12 MHz, this study found no evidence of nonthermal effects. However, further research at the microscopic level is needed in order to better understand RF inactivation mechanisms.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Impact of organic acid treatment on the microbial community composition of raw beef during extended refrigerated storage

    Samuel C. WatsonNirosh D. AluthgeRebecca A. FurbeckSamodha C. Fernando...
    104787.1-104787.10页
    查看更多>>摘要：Limiting bacterial spoilage and thereby protecting the economic value of raw beef destined for export is a top priority of the United States beef industry. Organic acid processing aids are commonly used to decrease pathogenic loads on raw beef, but knowledge of their efficacy against common spoilage bacteria is limited. Beef chuck rolls (IMPS 116A, N = 24) were obtained from two different processing facilities in Nebraska and treated with either 4.5 % lactic acid, 2.5 % Beefxide®, or 380 ppm peroxyacetic acid alongside a no-treatment control. Samples were stored at 2.7 ℃ for 112 days. Every 28 days, samples were evaluated using aerobic, anaerobic, psychrotrophic, lactic acid bacteria, and Pseudomonas plate counts and using amplicon sequencing of the V4 region of the 16S rRNA gene. Significant differences (P < 0.05) between groups were determined using DeSeq2. Lactococcus became the most abundant genus on day 28 and every subsequent sampling point regardless of treatment group. Pseudomonas and Yersinia were also present at perceptible levels and were identified to be higher in control samples compared to lactic acid treated samples through differential abundance analysis. Concentrations of culturable bacteria increased during storage across all plating methods (P < 0.05), but treatment differences were minimal. Overall, these treatments had impact on the bacterial diversity during storage. When considering the use of processing aids to limit spoilage, the treatment should be chosen based on a targeted specific spoilage organism.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Physical fields reverse FeS04-induced VBNC state in Listeria monocytogenes and facilitate ferroptosis

    Xiaolin ZhuYunhong WangShurui PengJiayi Zhang...
    104796.1-104796.15页
    查看更多>>摘要：Non-thermal sterilization methods are effectively in eliminating foodborne pathogens while preserving the appearance and quality of food. In this study, three physical fields, magnetic field (MF), ultrasound (US), and blue light (BL), were introduced for their efficacy in sterilizing FeSO_4-induced viable but non-culturable (VBNC) Listeria monocytogenes (L. monocytogenes) cells over a 4 h treatment. The Fe-MF treatment induced L. monocytogenes cells to form VBNC state, resulting in an 80.13 % reduction in culturable cells, with a 90.58 % survival rate. The ultrasound-assisted FeSO_4 (Fe-US) treatment reduced the VBNC cell population by 52.63 %. In contrast, the blue light-assisted FeSO_4 (Fe-BL) treatment reversed the VBNC state toward culturable state at the node of 3 h, and induced irreversible 100 % cell death at 4 h, with a 94.73 % decrease in viability and 68.2 % membrane damage. Additionally, Fe-BL treatment led to cell wrinkling and secretion aggregation. BL treatment alone compromised membrane permeability and triggered intracellular protein aggregation. Mechanistic investigations revealed that BL-assisted treatment disrupted the protective mechanism of L monocytogenes when induced by FeSCU to form VBNC state, compromised VBNC cell membranes, promoted intracellular Fe~(2+) accumulation, and induced a reactive oxygen species (ROS) burst and lipid peroxidation, ultimately leading to ferroptosis. Prote-omic analysis identified 240 upregulated and 376 downregulated differentially expressed proteins, highlighting significant changes in pathways related to ribosome biosynthesis (related genes rplJ and hpf significant upregulated), intracellular iron homeostasis (ctaB, hemN, and bno2590 downregulated), cellular morphology (mreB and tagH downregulated), oxidative stress response (lmo0720 and lmo0799 downregulated), and DNA synthesis (recA, dnaD, yidC2 and fruB downregulated). In conclusion, Fe-BL treatment effectively disrupted VBNC cell membranes, induced iron homeostasis imbalance, and triggered Fenton reaction-mediated ferroptosis. These findings provide a promising non-thermal sterilization strategy for inactivating VBNC L. monocytogenes, offering potential applications in food safety.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Optimizing Monascus pigment production: Insights from mycelial morphology, gene expression, and transcriptomic analysis in simulated seawater fermentation

    Wenqian ZhaoTao LiMei PangXihong Zhao...
    104797.1-104797.14页
    查看更多>>摘要：Monascus pigments (MPs) are secondary metabolites produced by Monascus spp., which can be significantly influenced by the extreme environment. In this work, the regulatory mechanism of MPs in simulated seawater fermentation (SSF) were investigated following mycelial morphology, gene expression, and transcriptomic analysis. Yield of the extracellular yellow pigments (EYPs) was significantly increased by 34.2 % in SSF, compared with the conventional fermentation (CF). The relative proportion of four EYPs (Y1/Y2-Y4) and the relative content of intracellular orange pigments to yellow pigments (O/Y) were also significantly (p < 0.05) changed. Fluorescence inverted microscope (FIM) and field emission scanning electron microscope (FE-SEM) showed the mycelium morphology was regulated in better status to facilitate the metabolism and secretion of MPs in SSF. The pigment biosynthesis gene MpFasA2, MpFasB2, MpPKS5, mppB, mppC, mppD, and mppE were significantly (p < 0.05) up-regulated, whereas the regulatory genes mppRl, mppR2 were significantly (p < 0.05) down-regulated in SSF. Transcriptome further revealed 83 differentially expressed genes (DEGs) between the two groups (CF vs SSF), with 40 up-regulated and 43 down-regulated. Among them, polyketide synthase genes and fatty acid oxidative degradation pathways related to pigment synthesis were significantly up-regulated in SSF, which promoted the metabolism of MPs. The down-regulation of DNA replication pathway indicated a slowdown in cell growth and differentiation, which keeping a favorable state for MPs synthesis. Biometabolism-related pathways of cell wall component and secretion-related pathways were also significantly regulated to accelerate the transmembrane transport of EYPs. This study may provide clues to clarify the response mechanism of high osmotic tolerance of Monascus spp.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Characterization of riboflavin-overproducing Bifidobacterium longum subsp. infantis strains selected by roseoflavin treatment

    Hector TamesIsabel CuestaXenia VazquezPaloma Lopez...
    104799.1-104799.11页
    查看更多>>摘要：Diet is the primary source of riboflavin (B_2) for humans. It can also be produced by lactic acid bacteria ingested with foods and by gut microbial commensals, including some bifidobacteria. Herein an in silico analysis of potential regulatory mechanisms affecting ribD transcription and translation in Bifidobacterium longum subsp. infantis is presented. Riboflavin-overproducing strains were selected by treatment with roseoflavin of B. longum susbp. infantis CECT4551 and its spontaneous derivative IPLA60011. Whole genomes of both parental strains and the sequencing of the rib clusters of the riboflavin-overproducing ones were conducted. Punctual mutations affecting different stem-loops in the aptamer region of the FMN-riboswitch involved in the regulation of the rib expression were detected. Riboflavin overproduction of the derivative strains was confirmed through HPLC quantification in RAMc and MRSc cultures, ranging from 64.9 to 441.2μg/L. These levels correlated to predicted secondary folding and stability of the aptamer region and/or expression platform of the rib FMN riboswitch. Safety and technological properties of the riboflavin-overproducing derivatives, in terms of antibiotic resistance profile and carbohydrate utilization capabilities, were not altered following roseoflavin exposure, thus confirming the potential aptitude of the riboflavin-overproducing derivatives to produce biofortified foods such as those formulated on dairy matrixes.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Exploring endogenous lactic acid bacteria potential: Isolation to genetic insights on aromatic compounds

    Daniel KuhnCaroline SchmitzGabriela Rabaioli RamaManuela Araujo Costa...
    104800.1-104800.14页
    查看更多>>摘要：This study aimed to explore the technological potential of endogenous lactic acid bacteria (LAB) isolated from milk and cheese produced in Sao Paulo, Brazil, for use in the preparation of fermented dairy products. A total of 562 microorganisms were isolated, with Lacticaseibacilluis rhamnosus and Enterococcus faecalis being the predominant species. Among these, 169 isolates were characterized for their technological properties, and Principal Component Analysis (PCA) was applied to rank the most promising strains. Based on this analysis, 43 isolates were selected and evaluated for acidification potential, autolysis, antimicrobial activity, antibiotic susceptibility, and aromatic compound production. Lactobacilhis delbrueckii CTR1 exhibited the highest acidification potential (ApH 1.00). Lactlcaseibacillus rhamnosus JLR3 displayed strong antimicrobial activity, particularly against Salmonella Enteritidis and Staphylococcus aweus, while Enterococcus faecium ITR5 was effective against Escherichia coti. The aromatic compound profile of fermented milks led to the selection of Lacticaseibacilhis rhamnosus AQTR10 and Enterococcus xinjiangensis AQLM2 for sequencing and functional characterization. These strains were shown to produce diacetyl (butane-2,3-dione), acetoin (3-hydroxy-butan-2-one), acetic acid (ethanoic acid), and acetaldehyde (ethanal). Functional annotation revealed that L. rhamnosus possesses the genetic machinery for diacetyl and acetoin biosynthesis via the citrate pathway, as well as for acetaldehyde and acetic acid production through an aldehyde dehydrogenase-encoding gene. In E. xinjiangensis, genetic evidence for acetaldehyde biosynthesis was identified. These findings suggest that the two LAB strains isolated from dairy samples in southeastern Brazil hold promise as adjunct cultures for fermented dairy product development.
      原文链接:
    • NETL
    • NSTL
    • Elsevier

    Factors affecting ethanol tolerance in Kazachstania unispora Mkaz: membrane characteristics and antioxidative stress

    Jin LiuWenyu CuiYu ZhangJing Dong...
    104801.1-104801.10页
    查看更多>>摘要：Kazachstania unispora is extensively utilized as a food-grade fermentation agent due to its strong stress-resistance and superior fermentation properties. However, ethanol stress during fermentation negatively impacts its performance. Therefore, selecting ethanol-tolerant K. unispora and understanding its tolerance mechanisms are critical for enhancing fermentation efficiency and product quality. In this study, a mutant strain K. unispora Mkaz, capable of tolerating up to 20 % (vol/vol) ethanol and exhibiting favorable fermentation characteristics, was developed through mutagenesis. Comprehensive phenotypic and multi-omics analyses were conducted to elucidate the mechanisms underlying its ethanol tolerance. The results indicated that increased levels of total fatty acid (TFA), particularly long-chain fatty acid (LCFA) and very long-chain fatty acid (VLCFA), as well as trehalose and ergosterol under ethanol stress, improved membrane characteristics, thereby enhancing ethanol tolerance. Furthermore, elevated activities of adenosine triphosphatase (ATPase), superoxide dismutase (SOD), and catalase (CAT) contributed to ethanol tolerance by reducing oxidative stress. Genomic and transcriptomic analyses revealed key mutations and differentially expressed genes (DEGs) associated with the biosynthesis of fatty acid (FA), trehalose, and ergosterol, as well as the regulation of oxidative stress. This study provides novel insights into the ethanol tolerance mechanisms in K. unispora, laying a foundation for its potential application in food fermentation.
      原文链接:
    • NETL
    • NSTL
    • Elsevier