JOURNAL OF FOOD MICROBIOLOGY
Year:2021 | Volume:8 | Issue:2|Papers Count:10

Allium sativum (A. sativum) is one of the most important plants used in foods for its flavouring, prophylactic and therapeutic properties. It has been revealed that garlic has activity against bacteria and fungi. Aspergillus, Penicillium, Alternaria, and Fusarium are among the most common fungi that are mycotoxin producers, frequently isolated from foods. This study aimed to evaluate the antifungal activity of A. sativum extracts against saprophytic and toxigenic fungi isolated from contaminated mayonnaise sauce. The fungi grow on mayonnaise were transferred to sabouraud's dextrose agar supplemented with chloramphenicol and were identified based on macroscopic and microscopic features. Disc and well diffusion methods were applied to measure the inhibitory effects of the extracts against all targeted strains tested in the experiment; also, the minimum inhibitory concentration of each extract was determined. Aspergillus niger, A. flavus, A, fumigatus, Penicillium sp., Mucor sp., Rhizopus sp., Cladosporium sp., Fusarium sp., Alternaria sp., and Geotrichum sp. were identified. Aqueous extracts showed higher antifungal activity than the methanolic and ethanolic extracts. Fusarium and A. niger showed the highest and lowest sensitivity to all extracts, respectively. The MIC of the aquatic extract was determined to be 350 μ g/ml for A. niger, A. fumigatus, A. flavus, Mucor sp., Rhizopus sp., Penicillium sp., and Alternaria sp. and 300 μ g/ml for, Cladosporium sp., Fusarium sp. and Geotrichum sp. The MIC of methanolic and ethanolic extracts was higher than the corresponding figures for aqueous extracts. It seems that A. sativum can be used as an antifungal agent in some food products.

The outbreak of Escherichia coli (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 were 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 an 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 significant 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 E. 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 E. coli in raw foods such as meat, it can be concluded that the source of this outbreak was cantaloupe syrup contaminated with E. coli O157: H7 via meat grinder.

Plants contain Phenolic compounds are ranging from simple molecules such as phenolic acids to highly polymerized molecules such as tannins Phenols and polyphenols in plant tissues have gained increasing scientific interest because of their potential beneficial effects on human health. In this study, Allium ampelloprasum L. known as “ Ajar” was prepared and homogenized from Sabzevar, Iran The extraction was performed by the ultrasound extraction method using ethanol and water solvent. The amount of and antioxidant compounds of extracts was investigated by and DPPH method, respectively. The results of the optimization process have shown that the optimum conditions of alcoholic extraction were determined as 17. 81 minutes with a concentration of 800 ppm. Also, the optimum conditions for the aqueous extraction were determined as the concentration of 800 ppm and the time of 13. 52 minutes. According to the optimization results, the extraction amount of antioxidant compounds in aqueous and alcoholic extractions were reported as 33. 893-33. 499, respectively. The results of the oxidative stability of oil have shown that the peroxide and thiobarbituric acid index in water and alcoholic extractions were 1. 938-3. 158 and 0. 173-0. 337, respectively.

Enterococci are an important and diverse group of bacteria that are known to be resistant to most antibiotics used to treat diseases. In this cross-sectional study, 104 samples of red meat and 1000 urine samples suspected of urinary tract infection in the border city of Kermanshah were examined for Enterococcus faecalis. First, the samples were approved by biochemical and molecular methods, then in order to evaluate their ability to produce biofilm, Microtiter Plate method was used, and their sensitivity to antibiotics was also determined by Kirby-Bayer method. Enterococcus faecalis infection in human samples and red meat samples was reported to be 5% and 40. 38%, respectively. In the strains isolated from red meat samples, the highest resistance was observed against Streptomycin, while the lowest resistance was to Vancomycin. In the human isolate samples, the highest resistance was reported to be to Co-trimoxazole, while the lowest resistance was to Nitrofurantoin. In strains isolated from red meat, ebp A, ebp B and ebp C were reported to be 71. 43%, 59. 52% and 64. 28%, respectively. No statistically significant relationship was observed between biofilm production and ebp genes in these isolates. However, a significant relationship was detected between ebp genes and biofilm production in strains isolated from urine. Similarly, it was reported that there was no statistically significant relationship between the meat type and the virulence gene type. But, the findings of the study showed a significant relationship between the frequency of efa A, gel E, ace and esp genes.

This study aimed to determine the health status, chemical and organoleptic properties of some nomadic dairy products in Chaharmahal and Bakhtiari province. Referring to the nomadic areas of the province, three products including Curd, Gharaghorot, and Ghee were sampled for organoleptic, chemical, and microbiological tests. Sensory tests included aroma, taste, texture, color, and overall acceptance. The amount of protein, fat, salt, moisture, ash, and some minerals elements in the samples and the level of contamination of the samples with E. coli, Staphylococcus aureus, coliforms, mold, and yeast, and total microorganisms count were examined. The amount of protein and fat in Curd samples was lower than the standard level (P<0. 05 and P<0. 01, respectively) but the amount of salt in these samples had no statistically significant difference from the standard level. The percentage of protein in Gharaghorot samples was lower than the standard level (P<0. 01) and the amount of ash, moisture, and fat in these samples had no statistically significant differences with their standards levels. The amount of iron and copper in Ghee samples was higher than the standard (P<0. 01) and the lead content of those was lower than the standard level (P<0. 05). From a hygienic point of view, in only 25 percent of the Curd samples, the total number of microorganisms and mold and yeast contamination was higher than the standard level (P<0. 001) and other specimens were completely hygienic. All of the samples of each of the three products had a very high score in sensory evaluation.

Tomato ketchup is a widely used product in the world and in Iran, therefore, preparing symbiotic products from it will promote health. In this study, a completely randomized design and response surface method (rotating central composite design) and Design Expert software (version 7), and Duncan test were used to compare the means. According to the results, the best treatments among the sauce samples in terms of survival of the probiotic bacterium Lactobacillus acidophilus after 30 days of storage, the sample contained 2% lactulose and 2. 5% fiber (whether encapsulated or free bacteria). Bacterial residue at the end of the storage period was 4. 09 *107 cfu/ml in the sauce sample containing encapsulated bacterium and 1. 19 * 107 cfu/ml in the sauce sample containing the free bacterium. Electron imaging of optimal specimens showed that dimensions of the encapsulated bacterium were larger than those of the sauce containing the free bacteria. The transfer of optimal samples to the simulated environment of the stomach and intestines indicated that the sample of the sauce contained encapsulated bacteria in the formulation of which 2. 5% fiber and 2% lactulose were used, having a significant difference (p <0. 05) with other samples and due to the preservation of bacteria in both stomachs and Intestine above 106 cfu/ml and having prebiotic compounds of fiber and lactulose is a symbiotic sample.

The present study aimed to determine the prevalence of enterotoxin-producing S. aureus in creamy pastries producing in confectioneries in the Shahrekord area also, determining the antibiotic resistance of the isolates. One hundred fifty creamy pastries samples were randomly selected from confectioneries. Microbial tests were performed for isolating of S. aureus and then on the Beards Parker Agar. Suspected colonies were confirmed by microbiological and biochemical tests including gram stain, catalase, and coagulase tests. Isolates were tested for the presence of enterotoxin genes (A, B, C, and D) by Multiplex PCR and, also antibiotic resistance of the isolates was determined by the disk diffusion method. Overall, 38 (25. 3%) samples were contaminated with S. aureus. Twenty-one (28%) and 17 (22. 7%) isolates were related to summer and winter samples, respectively. Thirteen isolates (29%) of S. aureus contained enterotoxin genes. Eleven isolates (84. 61%) contained SEA, and 2 isolates (5. 3%) contained the SEC gene. Nine (70%) and 4 (30%) of the enterotoxigenic isolates were related to summer and winter samples, respectively. None of the isolates had SEB, SED genes. Four (30%) enterotoxigenic isolates were related to creamy pastry and 9 (70%) to creamy bread. The antibiogram test showed the highest sensitivity to sulfamethoxazole (97. 36%) and erythromycin (63. 15%). Also, all enterotoxigenic isolates were resistant to penicillin, and 95% of isolates containing the SEA gene were resistant to erythromycin and ciprofloxacin. In general, the results showed that creamy pastries were contaminated with S. aureus strains which have the potential to produce enterotoxins. According to the results, the antibiotic resistance of enterotoxigenic isolates was much higher than isolates without enterotoxin genes.

Cheddar cheese is a hard type of cheese. It is coated traditionally with a special wax. Commercial coating materials which are used for coating are non-edible as a result they are undesirable due to environmental pollution and allergies caused in some consumers. Today, biodegradable films are receiving more attention. In this study, the effect of edible coating of basil seed mucilage containing zinc oxide nanoparticles (ZnO-NP) in three levels of zero, 0. 25, and 0. 5% on the quality properties of cheddar cheese was investigated during ripening for 90 days. The results of experiments showed that at the end of ripening, the highest amount of salt and fat and the lowest amount of moisture were related to the sample with mucilage coating containing 0. 5% of ZnO-NP. Also, during ripening, in all samples, the number of non-starters lactic acid bacteria increased, but the number of starter bacteria increased first and then decreased (P<0. 01). Also, in all treatments, the total number of mesophilic aerobic bacteria, Pseudomonas, mold, and yeast increased significantly during storage, which was the lowest in samples with a coating containing ZnO-NP (P<0. 01). In addition, ZnO-NP coatings prevented mold growth on the surface of cheddar cheese samples. According to the results obtained from this study, basil seed mucilage containing 0. 5% ZnO-NP can be used as a coating in cheddar cheese without any adverse effect on the flavor of the cheese.