The aim of this study was to estimate the prevalence rate of Escherichia coli O157: H7 in raw milk and traditional cheese at Marand retails. Moreover, the isolates were assessed for the presence of virulence gene of stx1, stx2, eaeA and hly. For this reason, 100 traditi More
The aim of this study was to estimate the prevalence rate of Escherichia coli O157: H7 in raw milk and traditional cheese at Marand retails. Moreover, the isolates were assessed for the presence of virulence gene of stx1, stx2, eaeA and hly. For this reason, 100 traditional cheese and 50 raw milk samples were collected randomly. The samples were enriched in EC broth containing novobiocin and were isolated on sorbitol MacConkey agar with cefixime and tellurite. The isolates were further assayed by VRBA, tryptone broth and Escherichia coli Chromogenic agar for the lactose fermentation, indole production and beta-glucuronidase activity, respectively. The selected colonies were confirmed by E. coli O157: H7 antiserum and finally the isolates were analyzed for the presence of virulence genes. According to the results, 9% (9/100) of cheese and 10% (5/50) of raw milk samples were found contaminated with sorbitol-negative E. coli. Using the anti-E. coli antiserum, 1 isolate (2%) among the milk samples was confirmed and the presence of virulence genes of eaeA and stx1 were determined by multiplex PCR. With respect to the occurrence of E. coli O157: H7 in raw milk and its high persistence to acidic environment, it was concluded that raw milks and traditional cheeses marketed at Marand could be considered as the potential source of infection to humans.
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Vegetable essential oils and their components have anti-bacterial known effects. The aim of this study was to evaluate different concentrations of essential oils of Mentha spicata on the survival rate of Escherichia coli O157: H7 in traditional Lighvan cheese during rip More
Vegetable essential oils and their components have anti-bacterial known effects. The aim of this study was to evaluate different concentrations of essential oils of Mentha spicata on the survival rate of Escherichia coli O157: H7 in traditional Lighvan cheese during ripening. Essential oils were extracted using the Kelevenger apparatus, and they were analyzed by GC/MS. To determine the necessary oil concentration in terms of the organoleptic, sensory evaluation was conducted by a test panel. Cheese samples prepared with the help of local manufacturers based in the village of Lighvan in triplicates, including zero and 100 and 200 ppm from essential oils of Mentha spicataand doses of 103 and 105 CFU/mL from the E. coli O157: H7 bacterium. The numbers of the E. coli O157: H7 bacteria were analyzed during the days 0, 30, 60, and 90 of the ripening period.Mentha spicata essential oils had considerable antimicrobial effects against E. coli O157: H7. Using the vital oils caused a decrease in the numbers of E. coli O157: H7 bacteria in the 90th days of ripening (P<0.05). Using from Mentha spicata at a concentration of 200 ppm can reduce the survival of E. coli O157: H7 in Lighvan cheese. Therefore, it can be argued that the studied essential oil can be used as a natural preservative traditional Lighvan cheese but should be used in concentrations such that do not have any adverse effects on the flavor of food.
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The outbreak of E.coli O157: H7 has been confirmed in human specimens in the spring of 1396 in one of the universities of Yazd. This study was designed to determine the source of infection. This is a case-control study in which 80 patients and 80 healthy students were e More
The outbreak of E.coli O157: H7 has been confirmed in human specimens in the spring of 1396 in one of the universities of Yazd. This study was designed to determine the source of infection. This is a case-control study in which 80 patients and 80 healthy students were examined. The formal validity and content of the questionnaire used was confirmed by the experts and the outbreak team. For data analysis, binary logistic regression and odds ratios with 95% confidence intervals were by SPSS-19 software. In this study, cantaloupe syrup with the odds ratio of 47.37 had the highest factor in the incidence of disease. In the next stage, dinner and rice dinner with a chance ratio of 4.25 and 3.12 respectively, remained significantly in the model. Due to the high chance of cantaloupe syrup in this study and the available records such as laboratory confirmation of the presence of Escherichia coli O157: H7 in human samples and the report of the outbreak team on the preparation of cantaloupe syrup using a sitting meat grinder and also confirm similar studies in Possibility of presence Escherichia coli in raw foods such as meat, it can be concluded that the source of this outbreak was cantaloupe syrup contaminated with Escherichia coli O157: H7 via meat grinder.Keywords: Outbreak, Escherichia coli, Shiga toxin, O157: H7, Yazd.
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