共查询到20条相似文献，搜索用时 15 毫秒
1.
《Food Control》2014
Chinese sauerkraut is a kind of traditional and typical fermented food. Four lactic acid bacteria (LAB) strains, Leuconostoc mesenteroides NCU1426, Lactococcus lactis NCU1315, Lactobacillus plantarum NCU1121 and Lactobacillus casei NCU1222 isolated from Chinese sauerkraut, were used in single starter cultures. Microbiological changes and pH values were monitored during fermentation. Metabolic substrates and products during the fermentation were examined using high performance liquid chromatography (HPLC) technology. Results have shown that Leu. mesenteroides and Lc. lactis grew faster, produced lactic acid earlier and were poorly acid-resistant, whereas Lb. plantarum and Lb. casei produced much more lactic acid throughout fermentation and showed better acid-tolerance. Two Lactococcus had outstanding performance in sucrose utilization while the other two Lactobacillus were likely to use glucose and fructose during fermentation. Unexpectedly, Leu. mesenteroides and Lc. lactis showed weak citric acid metabolism in fermentation. All the four LAB strains were able to utilize malic acid in early fermentation. In conclusion, these LAB strains have shown notable differences in growth and fermentative properties during starter culture fermentation of Chinese sauerkraut, probably resulting from LAB fermentative function and a mixture of complex substrates. 相似文献
2.
《Food Control》2017
The aim of this study was to determine the effect of a submerged culture of “flor” velum yeast and lysozyme as treatments against bacterial contamination by lactic acid and acetic acid bacteria during the biological aging of sherry wine. Different submerged culture treatments with lysozyme were performed. To assess these treatments, we performed laboratory assays with wine spoiled by lactic acid bacteria (LAB) and/or acetic acid bacteria (AAB) selected from the “solera” sherry wine cellar system. The results indicate that lysozyme should be added to submerged culture conditions after the start of the yeast growth phase. The application of lysozyme at a dose of 12.5 g/hL and submerged culture conditions was very effective for the treatment of advanced heterolactic fermentation during the biological aging of wines, thereby inhibiting the LAB population and reducing the volatile acidity of the wines (<0.1 g/L). Similarly, the submerged culture was a very effective tool for the treatment of AAB contamination of recovering wines with high volatile acidity and the removal of AAB without alcohol correction of the wine. The combined lysozyme and submerged culture treatment was very effective at removing bacteria from the wine, reducing volatile acidity and preventing acetification. 相似文献
3.
《Food Control》2017
Tenuazonic acid (TeA) is a fungal secondary metabolite that is produced by a number of Alternaria species and is therefore a natural contaminant of food and feed samples. The aim of this study was to investigate the adsorption mechanism of TeA using various modified inactivated lactic acid bacteria (LAB). The bacterial cells were characterized by Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (SEM-EDS) and Transmission Electron Microscopy (TEM). The results indicated that increasing the surface area of the cell wall improves the adsorption capacity of TeA, and an ion-exchange reaction may occur during the adsorption process. Fourier Transform Infrared (FTIR) Spectroscopy and X-ray Diffraction (XRD) analysis indicated that CO, OH and NH groups, which are related to protein and carbohydrate components, were obviously involved in the adsorption of TeA. The zeta potential indicated that TeA adsorption was related to the surface charge of the bacteria cells. Above all, polysaccharides and protein were demonstrated to be important components of the LAB cell wall and are involved in TeA removal. 相似文献
4.
《Food Control》2015
The shelf life of rabbit meat during refrigerated storage was investigated under industrial conditions. Rabbit carcasses were bulk packed (BP), packed under air (PUA) and under modified atmosphere (MAP) (30% O2:40% CO2:30% N2). The main groups studied were mesophilic aerobes, psychrotrophic aerobes, Pseudomonas spp., lactic acid bacteria, yeast and moulds and Enterobacteriaceae. The microorganisms that showed faster growth were psychrotrophic aerobes (growth rate of 0.36 ± 0.09 day−1) for BP, Pseudomonas (0.26 ± 0.03 day−1) for PUA, and lactic acid bacteria (0.22 ± 0.01 day−1) for MAP, and the lag phases were 4, 4 and 8 days, respectively. The main effect of MAP was the increase in lag phase from 4 to 8 days, for lactic acid bacteria, psychrotrophic and mesophilic aerobes. The respective growth rates were similar to those observed with PUA. In addition, MAP inhibited Pseudomonas growth during 18 days. Considering 6 log CFU g−1 as maximum tolerable microbial load, the calculated values of shelf life in BP, PUA and MAP were 6, 7 and 12 days, respectively, when considering the fastest growing microorganisms. 相似文献
5.
《Food Control》2013,32(2):467-473
The functional characteristics and safety of five different putative probiotic Lactobacillus plantarum strains and one Leuconostoc citreum strain, isolated from kimchi, were studied. In view of their potential application in food biotechnology, this information was considered necessary, and included the determination of antibiotic resistance, haemolysis, gelatinase activity and biogenic amine production. In addition to a Lactobacillus fermentum strain isolated from pig faeces, two commercial probiotic strains (Lactobacillus rhamnosus GG, ATCC 53103, and Lactobacillus plantarum 299v, both originating from the human intestinal track) were included in the studies for reference purposes. With the exception of L. fermentum, which was resistant to a low concentration (MIC: 30 μg/ml) of tetracycline, all strains were susceptible to the 8 antibiotics tested (erythromycin, gentamicin, ampicillin, tetracycline, chloramphenicol, streptomycin, ciprofloxacin, and benzylpenicillin). All strains survived physiological conditions typical of the upper GIT, comprising a pH of 3.0 for 1 h, and a subsequent 2 h under conditions simulating the duodenum, which included the exposure to 10 % of bile salts. Moreover, all strains were resistant to 0.4 % phenol, and were unable to produce any detectable biogenic amines under the test conditions. These preliminary in vitro tests indicate the safety and functionality of the five selected L. plantarum strains and thus their potential as probiotic candidates. 相似文献
6.
《Food Control》2014
This study examined the dynamics of microbial growth in fresh chilled Atlantic salmon (Salmo salar) packed in a modified atmosphere. Atlantic salmon were harvested, handled, transported, and processed under optimal conditions to produce skinless fillet portions packed in pouches containing 96% CO2 at gas: product ratios of greater than 5:1 (v/w) and stored for 38 days at less than 1 °C. Microbial analysis was conducted using psychrotrophic and mesophilic plate counts and DNA-based techniques. Results revealed initial microbial counts at day 0 of 102 CFU g−1 and sequences from the genera Luteimonas, Pseudorhodoferax, Aequorivita, Gillisia, Gramella, Micrococcus, Acidovorax and Achromobacter. An extended lag phase was observed of 10 (psychrotrophic) or 15 (total) days with total plate count numbers reaching 106 CFU g−1 after 21 (psychrotrophic) and 25 days (total) and stabilising at 108 CFU g−1 after 31 days. At 31 days the microbial community was dominated by Pseudomonas spp. as determined by identification of isolates and sequencing of a 16S rRNA gene clone library. No Photobacterium spp., including the specific spoilage organism Photobacterium phosphoreum, were identified during the study. 相似文献
7.
《Food Control》2014
Moulds are the most common cheese spoilage organisms which can lead to economic loss as well as raising public health concerns due to the production of mycotoxins. In this study, 897 lactic acid bacteria (LAB) isolated from different herbs, fruits and vegetables were screened for their antifungal activity in an agar plate overlay assay. Thirty-six isolates had weak activity, 11 had moderate activity and 12 were confirmed as having strong activity. The strong antifungal isolates were obtained from a range of different sources but were all identified by 16S rDNA sequencing as being Lactobacillus plantarum. The antifungal spectra for these 12 isolates were determined against eight other moulds commonly associated with cheese spoilage and all isolates were found to possess inhibition against Penicillium solitum, Aspergillus versicolor and Cladosporium herbarum, but not against Penicillium roqueforti, Penicillium glabrum, Mucor circinelloides, Geotrichum candidum or Byssochlamys nivea. The absence of sodium acetate from MRS agar resulted in no inhibition of Penicilium commune, suggesting the synergistic effect of acetic acid with the antifungal LAB, similarly to that previously reported. To determine their potential as biopreservatives in cheese, LAB isolates were inoculated into cottage cheese prior to the addition of P. commune. All Lb. plantarum isolates were found to prevent the visible growth of P. commune on cottage cheese by between 14 and >25 days longer than cottage cheese that contained either no added LAB or LAB that did not have antifungal activity (Lactococcus lactis, Weissella soli, Leuconostoc inhae and Leuconostoc mesenteroides isolates). The results of this study shows that LAB isolated from various herbs, fruits and vegetables possess antifungal activity and have potential for use as biopreservatives in cheese. 相似文献
8.
《Food Control》2017
A novel bacteriocin-M1-UVs300, which was produced by Lactobacillus plantarum M1-UVs300, was purified and characterized. Bacteriocin-M1-UVs300 was purified sequentially by an aqueous two-phase system (ATPS) and a Sephadex G-50 gel chromatography assay, combined with reverse phase high-performance liquid chromatography (RE-HPLC). The purification resulted in a 3221.63 IU ml−1 titer with a 20.41- fold purification of the original activity. According to a Tricine-SDS-PAGE analysis, the molecular weight of the bacteriocin-M1-UVs300 was approximately 3.4 kDa. A quantitative analysis of the secondary structure of bacteriocin-M1-UVs300 results showed that it had a major β-sheet content of 52.43%, α-helix of 16.17%, β-turn of 15.27%, and a random coil of 16.12%. A partial sequence, GAKSKYGNVG-, was obtained by N-terminal amino acid sequence analysis. The antimicrobial spectrum of bacteriocin-M1-UVs300 exhibited activity against Gram-positive bacteria and Gram-negative bacteria. In addition, it was relatively heat-resistant, active over a range of pH 2–8, and sensitive to proteolytic enzymes, but it was not sensitive to α-amylase. The additives significantly increased the activity of bacteriocin-M1-UVs300 significantly. These findings indicated that bacteriocin-M1-UVs300, is a novel bacteriocin with a broad inhibitory spectrum, and that it had the potential to act as a natural preservative in the food industry. 相似文献
9.
The ecology and the population dynamics of lactic acid bacteria during malolactic fermentation of Tempranillo wine made at five wineries in Castilla-La Mancha were analysed for two consecutive vintages (years 2006 and 2007). This microbiota was typed using Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) subsequently identified using both molecular and phenotypic methods. Oenococcus oeni was the predominant species. Genotypes varied considerably in both of the vintages from each winery, although a number of coincident genotypes were found in each one. Three genotypes were present in all the wineries in at least one of the vintages. These results confirm the existence of a coincident population of O. oeni genotypes that may be considered endemic to this wine region and that seem to play an important role in all the vinifications. 相似文献
10.
《Food Control》2015
The aim of this work was to purify and characterize the bacteriocin produced by Enterococcus faecalis KT2W2G isolated from the mangrove forest in southern Thailand, in order to evaluate its potential as a new food protective agent. The active peptide from the cell-free supernatant of Ent. faecalis KT2W2G was purified in 4 steps: (i) precipitation with 70% saturated ammonium sulfate, (ii) elution on a reversed phase cartridge (Sep-Pak C8) using different concentrations of acetonitrile, (iii) cation-exchange chromatography and (iv) final purification by reversed phase-HPLC on a C8 column. Each purification step increased the specific activity and reduced the amount of contaminating non-bacteriocin proteins. The specific activity of purified bacteriocin was 13,470.53 AU/mg of protein, which corresponded to a 48.10-fold increase. Tricine–SDS-PAGE of the purified bacteriocin gave molecular weight ranging between 3.5 and 6.5 kDa. The activity of the partially purified bacteriocin was unaffected by pH (2.0–12.0) and thermostable, but was sensitive to proteolytic enzymes. This bacteriocin maintained full stability after storage at −20, 4 and 37 °C for 2 months. It was stable when incubated for 1 month at 4 °C in 0–30% NaCl. Inhibitory spectrum of this bacteriocin showed a wide range of activities against other LAB, food-spoilage and food-borne pathogens. Ent. faecalis KT2W2G was sensitive to kanamycin, tetracycline and vancomycin but resistant to ampicillin, gentamicin and penicillin. PCR amplification demonstrated that Ent. faecalis KT2W2G does not harbor virulence genes cylA, cylB and esp but has virulence genes ace, asa1 and efaAfs. The bacteriocin and its producing strain may find application as bio-preservatives for reduction of food-spoilage and food-borne pathogens in food products. 相似文献
11.
《Food Control》2015
The individual usage of Lactobacillus sakei C2 and sakacin C2 had an inhibitory effect against Listeria monocytogenes CMCC 54002, and the combination of L. sakei C2 and sakacin C2 exhibited a bactericidal action. L. sakei C2 and sakacin C2, individually or in combination, significantly lowered the pH values, proteolysis degree and odor score, and the effects were better when they were used in combination (P < 0.05). Moreover, L. sakei C2 exhibited certain anti-oxidative activity. These results showed that the usage of L. sakei C2 and its bacteriocin effectively controlled the growth of L. monocytogenes CMCC 54002, excessive proteolysis and the production of spoilage odor, did not have any unfavorable effects on the quality of vacuum-packaged sliced ham. Therefore, L. sakei C2 and its bacteriocin would provide an effective hurdle to improve the safe and quality, and would contribute to prevent the lipid oxidation of vacuum-packed sliced cooked ham at refrigeration temperature. 相似文献
12.
Biogenic amines are undesirable in all foods and beverages because if consumed at too high concentration, they may induce food-borne intoxications. The biogenic amine production by 155 strains of lactic acid bacteria, 40 strains of acetic bacteria and 36 strains of yeast isolated from wine were analysed in wine, grape must and synthetic media by HPLC. We did not observe biogenic amine production by acetic bacteria and yeast; however, we found production of histamine, tyramine, phenylethylamine and putrescine by LAB. A correlation of 100% was observed between biogenic amine production in synthetic medium and wine and between activity and presence of gene. With the results expose in this paper, we can consider than the lactic acid bacteria are the microorganisms responsible of histamine, tyramine and phenylethylamine production in wine. However, we cannot consider the microorganisms analysed in this work to be those responsible for tryptamine, cadaverine and putrescine levels in wine. These results could lead to future applications for preventing excessive amounts of histamine, tyramine and phenylethylamine forming during vinification and storage. 相似文献
13.
《Food Control》2016
Zearalenone (ZEA) contamination in food samples plays a critical role in food safety, since it causes serious health problems. Usage of microorganisms, such as lactic acid bacteria (LAB), is a promising new approach for detoxification. Eight Lactobacillus pentosus strains were evaluated for their ability to remove ZEA from a sodium acetate buffer solution with initial ZEA concentrations of 5.51–74.70 μg/mL. The adsorption capacity increased with increasing ZEA concentrations. The strain JM0812 showed the highest adsorption capability, at 83.17%, in solution containing 74.70 μg/mL ZEA, followed by UM054 (82.78%) and UM055 (81.69%), respectively. Three adsorption isotherms were applied to predict the removal efficiency of ZEA and the Freundlich isotherm appeared to have the best-fit for ZEA sorption onto bacterial cells. Our results indicate that Lb. pentosus strains are novel promising strains to reduce mycotoxin contamination in food products. 相似文献
14.
《Food Control》2014
Molecular identification of microorganisms associated with submerged cassava fermentation was carried out and isolates of lactic acid bacteria (LAB) were examined for antimicrobial activity, including ability to produce antimicrobial peptides as a first step to define starter cultures for controlled cassava fermentations. A total of 75 isolates, including 41 LAB, 31 aerobic bacteria (AB) and three anaerobic bacteria were isolated from unfermented and fermenting cassava roots, cassava leaves and fermented cassava dough and identified by a combination of phenotypic tests and sequencing of 16S rRNA, rpoA, rpoB and pheS genes. Microbial diversity at interspecies and intraspecies level was screened by, respectively, PCR amplification of the 16S-23S rDNA intergenic transcribed spacer (ITS-PCR) and repetitive sequence based PCR (rep-PCR). Antimicrobial activity of LAB cultures and supernatants against indicator bacteria; Escherichia coli, Salmonella enterica serotype Typhimurium (S. Typhimurium), Bacillus cereus and Staphylococcus aureus was studied using agar diffusion tests. Furthermore, inactivation of indicator bacteria was investigated in both liquid medium and during controlled cassava fermentation. Results revealed a diversity of bacterial genera, species and subspecies associated with submerged cassava fermentation. DNA sequencing enabled identification of LAB isolates as Lactobacillus plantarum, Weissella confusa, Weissella paramesenteroides, Lactobacillus rhamnosus, Lactobacillus hilgardii, Lactobacillus paracasei, Leuconostoc mesenteroides, Enterococcus faecium, Enterococcus casseliflavus, and Pediococcus acidilactici. Lactobacillus spp. were the predominant LAB and were present in all cassava samples studied. Aerobic bacteria were predominantly Bacillus spp., including Bacillus subtilis, Bacillus amyloliquefaciens and B. cereus. Other species identified included Staphylococcus pasteuri and Clostridium beijerinkii. Cells, supernatants and cell free supernatants (CFS) of selected LAB isolates were able to inhibit both Gram positive and Gram negative pathogenic bacteria. LAB isolates inactivated all indicator organisms during controlled cassava fermentations, with a 4–6 log reduction after 48 h fermentation. The antimicrobial effect of the LAB was attributed to acid production. 相似文献
15.
《Food Control》2016
Kimchi, probably Korea's most famous traditional fermented food, is well known for its beneficial properties. Among several hundred different types of kimchi in Korea, white (baek) kimchi is prepared without chilli and is widely appreciated also by non-Koreans because of its unique mild flavour. In an approach to identify the bacteriological basis for proposed health benefits, we isolated 11 Lactobacillus strains from six samples of white kimchi, and investigated their safety and functional features. These strains represented the species Lactobacillus brevis, Lactobacillus plantarum and Lactobacillus sakei that dominated the populations within a range of 3 × 106 to 4 × 108 CFU/mL. Following safety assessment based on antibiotic resistance and biogenic amine production, 7 different strains were selected for further studies including evaluation of their adaptation to cabbage juice and resistance to phenol. Growth in and adaptation to the cabbage juice was favourably influenced by addition of 2% salt. Final selection was based on in vitro passage of simulated stomach duodenum conditions (SSDP model). The strains L. plantarum HAC01 and L. sakei HAC10 were administered to a diet-induced obese (DIO) mouse model receiving a high-fat (HF) diet to assess their functionality in-vivo. Animal groups receiving the viable strains showed significantly lower body weight and total weight gain during 8 weeks compared to the high-fat control group. This study provides preliminary information on the use of in-vitro and in-vivo features for safety and functionality evaluation of Lactobacillus strains from white kimchi. These “first-level” criteria for strain selection may serve as model, thereby facilitating potentially new probiotic developments. 相似文献
16.
《Food Control》2015
The aim of this study was to characterise and select Lactic Acid Bacteria (LAB) from goat milk with potential probiotic use and to evaluate the safety of these cultures in artisanal cheeses. The isolates of LAB were subjected to simulation of tolerance to the gastrointestinal tract, haemolytic test, antimicrobial susceptibility, antibacterial activity, EPS production, gas production, evaluation of proteolytic activity, diacetyl production and tolerance to NaCl. The genus and species of the selected LAB isolates were confirmed using molecular identification. Three goat cheeses (1, 2 and control) were manufactured to evaluate the inhibitory action of LAB against Escherichia coli. Subsequently, all cheese samples underwent bacterial enumeration and physical–chemical analyses. Statistical analysis was performed. UNIVASF CAP 14 and 20 were differentiated by survival up to pH 2 and pancreatin, resistance to NaCl and antibacterial activity against Klebsiella pneumoniae. UNIVASF CAP 4 and 29 were characterised by resistance to intestinal juice and antibacterial activity against Salmonella Typhi and Listeria monocytogenes. UNIVASF CAP 27, 38, 43 and 139 exhibited diacetyl production, antibacterial activity against Bacillus cereus, Staphylococcus aureus and Enterococcus faecalis. UNIVASF CAP 35 and 138 were characterised by proteolytic activity, EPS production, antibacterial activity to E. coli and Shigella flexneri. A cocktail of these 10 isolates with potential probiotic properties were inoculated in artisanal goat cheese and improved microbiological safety of product against E. coli. 相似文献
17.
《Food Control》2015
This paper reports the inhibitory potential of two new silver-based biocompatible nanoparticles (Ag NPs), specifically synthesized for this study, against Gram-negative and Gram-positive bacteria, such as Escherichia coli and Staphylococcus aureus, and different wine lactic acid bacteria (LAB) (Oenococcus oeni, Lactobacillus casei, Lactobacillus plantarum and Pediococcus pentosaceus) and acetic acid bacteria (AAB) (Acetobacter aceti and Gluconobacter oxydans). Both solid nanoparticles, dried PEG-Ag NPs 1 (20.01% silver content) and glutathione-stabilized GSH-Ag NPs 2 solution (0.197 mg/mL silver content), showed homogeneous size distribution and physicochemical properties compatible with their use as antimicrobial agents. The nanoparticles showed different antimicrobial spectra, with PEG-Ag NPs 1 being more effective (lower IC50 values) against Gram-negative strains, whereas GSH-Ag NPs 2 showed similar efficiency against Gram-negative and Gram-positive strains, with the exception of O. oeni strains, which turned out to be notably susceptible to them (IC50 ∼1 μg/mL, Ag concentration). For the LAB and AAB tested, these nanoparticles showed IC50 values (particle concentration) of the same order as those for the widely used additive potassium metabisulphite, at least as calculated for PEG-Ag NPs 1. These results confirm the potential of Ag NPs in controlling microbial processes in winemaking, and open new investigations on the design and use of antimicrobial-specific silver-based nanoparticles in oenology. 相似文献
18.
《Food Control》2014
Probiotics and lactic acid bacteria (LAB) are widely used in food fermentation and preservation. This study was carried out to assess the potential of five strains of LAB and bifidobacteria to remove aflatoxin M1 (AFM1) from yoghurt. The stability of the AFM1 complexes formed with them in both viable and non-viable (heat- or acid-treated) forms was assessed by repetitive aqueous extraction. Strains with high ability in removing AFM1 were selected to study its ability to remove AFM1 from spiked milk during yoghurt production and storage. Three treatments from yoghurt that produced from spiked milk were studied. Treatment A was the control using fermented yoghurt culture (Streptococcus thermophilus and Lactobacillus bulgaricus). Treatment B was fermented by 50% yoghurt culture (S. thermophilus and L. bulgaricus) and 50% Lactobacillus plantrium. Treatment C was fermented by yoghurt culture (S. thermophilus and L. bulgaricus) and 50% Lactobacillus acidophilus. The samples were collected during different storage (5 °C) times (1, 3, 5 and 7 days) to determine the ability of the stains to reduce AFM1. The results indicted that there were significant differences (P < 0.05) between the strains in their ability to reduce AFM1 in MRS broth media in the viable stage, heated stage and acid treatment. L. plantrium was the highest strain capable of removing AFM1. Yoghurt fermented by 50% yoghurt culture (S. thermophilus and L. bulgaricus) and 50% L. plantrium recorded the highest reduction in the level of AFM1 at the end of storage period. The results revealed the possibility of using some strains of LAB and bifidobacteria in detoxification of AFM1-contaminated foods. 相似文献
19.
《Food Control》2017
The present study was focused on isolation and identification of lactic acid bacteria from pastırma (a Turkish dry-cured meat product). In this regard, one hundred and six lactic acid bacteria were isolated from pastırma obtained from fourteen different manufacturers and 16S rDNA sequencing was performed to identify these lactic acid bacteria isolates. Besides, samples were subjected to enumerations of lactic acid bacteria, Micrococcus/Staphylococcus, Enterobacteriaceae and yeast-mould and analysis of pH and water activity (aw). As a result of 16S rDNA sequence analysis, 27.4%, 24.5% and 19.8% of isolates were identified as Lactobacillus sakei, Weisella cibaria and W. confusa, respectively. Pediococcus pentosaceus (5.7%), P. acidilactici (4.7%), Leuconostoc carnosum (3.8%), W. hellenica (2.8%), L. plantarum (1.9%), L. paraplantarum (1.9%), L. curvatus (1.9%), W. halotolerans (1.9%), L. graminis (0.9%), L. carnosus (0.9%), Leu. citreum (0.9%), Leu. mesenteroides (0.9%) were also isolated from pastırma samples. In pastırma samples, the counts of Micrococcus/Staphylococcus, lactic acid bacteria and yeast-mould ranged between 5.28 and 7.69, 3.30 and 7.90, 2.30 and 6.42 log cfu/g, respectively. The count of Enterobacteriaceae was usually determined as under the detectable level (<2 log cfu/g). pH and aw values of pastırma samples varied from 5.29 to 6.65 and 0.862 to 0.924, respectively. 相似文献
20.
《Food Control》2014
Bacteria use quorum sensing (QS) to regulate the expression of certain target genes for social behaviour. A LuxS/AI-2 signalling system serves to control the virulence of some pathogenic bacteria by mechanisms such as motility, biofilm formation and attachment, and is typical of the enterohaemorrhagic Escherichia coli O157:H7 (EHEC) associated with infections of the human intestine. The LuxS/AI-2 signalling system presents an interesting potential as antimicrobial target for appropriate AI-2 inhibitors, and thus widens the scope for treatment or prevention of infections by pathogens such as EHEC. Probiotic lactic acid bacteria (LAB) are primary candidates for this approach because of their general acceptability, safety and adaptation to the intestinal and/or food ecosystem. In this paper, we report on Lactobacillus sakei NR28 as a new candidate strain for AI-2 related quorum quenching. It is considered to be a putative probiotic strain and was originally isolated from kimchi, a traditional Korean fermented food known for its special health features. This study has shown that AI-2 activity and the associated virulence factors of the EHEC ‘wild-type’ strain E. coli ATCC 43894, were significantly reduced by L. sakei NR28, while, at the same time, the cell viability of the EHEC strain was not affected. In addition, the purified AI-2 molecule, a luxS-deficient mutant of EHEC strain ATCC 43894, and an AI-2 independent EHEC mimicking strain of Citrobacter rodentium were used to determine the relationship between the virulence reducing effect of L. sakei NR28 and its AI-2 inhibiting ability. Our results showed that L. sakei NR28 has a reducing effect on the pathogenicity of the ‘wild-type’ EHEC strain ATCC 43894 by AI-2 signalling inhibition. 相似文献