JOURNAL OF FOOD MICROBIOLOGY
Year:2022 | Volume:8 | Issue:4|Papers Count:8

Enterococci are microorganisms that are mainly found in the intestines. Their high presence in food can cause fecal contamination, and they are isolated from various foods such as vegetables, meat, etc. Among the food, a hamburger is one of the products used by hand and widely by people. In this study, 50 hamburger samples were examined for biochemical and molecular methods for the presence of Enterococcus faecalis. A PCR reaction temperature program was performed to detect virulence genes in the fact of specific primer pairs. In this study, out of 50 samples, 33 samples (66%) were infected with E. faecalis. Of 33 E. faecalis isolates isolated from hamburgers, efaA was reported in 8 isolates (24. 24%), cylA was reported in 15 isolates (45. 45%), gel E was reported in 9 isolates (27. 27%), esp reported in 2 isolates (6. 06%), agg reported in 2 isolates (6. 06%), and aca, asa, and cyl B were not observed in any of the isolates. Enterococci and coliforms are considered two essential health indicators. Considering that the high presence of enterococci in food can be a reason for fecal contamination, the results of this study indicate the high contamination of burgers offered in Shahrekord city.

The current study aimed to remove aflatoxin (0. 5 and 0. 75 ng/mL) from the reconstituted milk by adding three probiotics, Lactobacillus rhamnosus, L. plantarum, and Saccharomyces boulardii, at the cell concentration of 107 and 109 CFU/mL at 4° C and 37° C within 30 and 90 minutes. The highest activity of Lactobacillus rhamnosus in removing aflatoxin M1 was observed in the cell concentration of 107 CFU/mL and 0. 75 ng/mL toxin concentration at 37° C (Figure 1) after 90 minutes exposure (64. 31% ± 3. 79%) and had no significant difference with the optimum value at 30 minutes exposure (63. 86% ± 5. 00%) (P >0. 05). Regardless of aflatoxin M1 and probiotics concentrations, the highest mean marginal estimation of aflatoxin M1 removal from the milk at 4° C in the early minutes belonged to L. plantarum, which gradually became identical for all the three probiotics until 90 min. The potential of S. boulardii in removing aflatoxin M1 from the milk (96. 88% ± 3. 79%) gradually increased within the initial minutes (90 minutes) with increasing the concentration of aflatoxin M1 (0. 75 ng/mL) and the yeast by 109 CFU/mL at 37° C; binding affinity also decreased with decreasing the temperature. The current study results indicated that 107 CFU/mL of S. boulardii can efficiently remove aflatoxin M1 from milk.

Various factors such as oxygen, light, heat, metal ions, and enzymes can affect the oxidative stability of oils and lipids, and finally, oxidative rancidity can occur. The application of synthetic antioxidants has been questioned to delay oxidative rancidity due to their toxicity and carcinogenic probability. This study aims to optimize the oxidant performance of an ethanolic extract of Cirsium vulgare on oxidative stability of soybean oil and compare it with synthetic antioxidants (BHT). In this study, C. vulgare extract was extracted under the influence of concentration (100-300 ppm), duration hours, and temperatures. After performing different experiments on the extraction of the best extraction conditions, the best extraction conditions were determined using response surface methodology and extraction in optimum conditions. Data analysis was carried out. The optimization process results showed that the oxidative stability of oil showed that; time 24. 0 min and concentration 100/01temperature 44/745 were determined. Results showed that the optimum sample of C. vulgare in the stability of soybean oil during storage time was more effective than synthetic antioxidant (BHT) due to higher levels of phenolic compounds and antioxidants present in the optimized sample of C. vulgare.

Anisakiasis is a zoonotic disease caused by the nematode Anisakis caused by eating infected and uncooked fish. Because this disease is zoonotic, the necessary health advice should be given to people who eat raw and incredibly raw foods of different types of seafood. Based on the search results with the keywords Iran and Anisakis in information sources and search engines, 24 studies conducted in Iran on Anisakiasis disease were found. This parasite has been reported in Iran to a greater extent than the shores of the Caspian Sea, the Persian Gulf, and Oman since 1349, which according to the results obtained in regular reviews, this amount has been higher in the southern regions of the country (the Persian Gulf and Oman). Due to the high percentage of contamination in some of the fish studied, up to 97% of the need to pay attention to this parasite for food preparation is more evident.

Annually, numerous reports of food poisoning following the consumption of seafood contaminated with Vibrio species have been reported. The present survey was carried out to evaluate the frequency rate of Vibrio species in seafood products from the fish samples in Isfahan, Iran. In this survey, 64 fresh fish samples were purchased from market in Isfahan and transferred to the Food Quality Control Laboratory, Islamic Azad University of Shahreza. According to Iran's National Standard methods, samples were tested for Vibrio parahaemolyticus. Positive samples were evaluated for the presence of bacterial species using Nested Polymerase Chain Reaction. The presences of V. parahaemolyticus, V. cholera, V. vulnificus, and V. mimicus were studied. Results showed that 95% of samples were contaminated with Vibrio species. In studied samples, V. parahaemolyticus had the highest frequency rate (35%), while V. mimicus had the lowest frequency rate (15%). The frequency of V. cholera and V. vulnificus were 20% and 35%, respectively. The results of microbial investigations of raw fish collected from different markets of Isfahan cannot be defined satisfactorily. The high prevalence of Vibrio species in samples confirmed the lack of hygienic conditions in fish production and distribution centers. It seems that processing plants as well as transportation methods are not of appropriate sanitary conditions.

Hypericum perforatum is a medicinal plant of the genus Hypercasia with phenolic and flavonoid compounds with high antimicrobial and antioxidant properties. The present study was performed to evaluate the antimicrobial effects of the methanolic extract of Hypericum perforatum on food-borne bacteria. The aerial part of Hypericum perforatum was prepared from the research farm, and after approval by experts, it was dried and powdered and used to prepare the methanolic extract. The diameter of the growth inhibition zone of Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus was assessed using disk diffusion and compared with antibiotics. Minimum inhibitory concentration (MIC) and Minimum Bacterial Concentration (MBC) of methanolic extract of Hypericum perforatum were evaluated on the target bacteria using an ELISA plate. The diameter of the growth inhibition zone of bacteria against the methanolic extract of Hypericum perforatum ranged from 9. 33± 0. 45 to 15. 28± 0. 60 mm. Application of 100 mg/ml concentration of methanolic extract of Hypericum perforatum caused the highest diameter of the growth inhibition zone of Pseudomonas aeruginosa (12. 27± 0. 53 mm), Escherichia coli (13. 20± 0. 59 mm), and Staphylococcus aureus (15. 28± 0. 60 mm). The antimicrobial effects of methanolic extract of fenugreek were dose-dependent (P <0. 05). The lowest and highest levels of MIC and MBC of methanolic extract of Hypericum perforatum were obtained for Staphylococcus aureus (0. 0010 and 0. 0019, respectively) and Escherichia coli (0. 50 and 1. 00, respectively). The diameter of the growth inhibition zone of bacteria treated with methanolic extract of Hypericum perforatum was higher than some antibiotic discs.

This study aimed to extract dietary fiber from the Ziziphus mauritiana seeds by the alkaline-hydrogen peroxide extraction method and evaluate its prebiotic and functional properties. For this purpose, Z. mauritiana seeds were first defatted. Then, their dietary fibers were extracted using alkaline hydrogen peroxide treatment. Prebiotic effect (at concentrations of 1 and 5%) in sugar-free culture medium on Lactobacillus acidophilus was studied (anaerobic conditions) at 37 ° C for 72 hours. The technological and functional properties of the extracted dietary fibers, including DPPH test, cholesterol-binding capacity, glucose absorption capacity, oil binding capacity, and water holding capacity, were measured. Z. mauritiana seed dietary fiber had water holding capacity, oil binding capacity, glucose adsorption capacity, and cholesterol binding capacity equal to 0. 51 ml/g, 2. 50 g/g, 37. 60 mmol/L 14. 52 mg/g, respectively. The results of the prebiotic evaluation showed that the sample containing 1% Z. mauritiana seed dietary fiber had the lowest pH with pH 5. 69 at 48 h (p<0. 05). Also, the trend of pH decrease was variable during the test time (p<0. 05). The results of Lactobacillus acidophilus count indicated that the culture containing 1% Z. mauritiana seed dietary fiber at 48th hour with 4. 7 Log CFU/ml had the highest total count. Besides, the trend of bacterial multiplication was variable concerning its concentration and over time (p<0. 05). Examination of the obtained data revealed that the samples containing 1% Z. mauritiana seed dietary fiber had the highest prebiotic effect on the growth of L. acidophilus. Besides, due to its beneficial properties, Z. mauritiana seed dietary fiber can be used as an available and inexpensive source of dietary fiber in the food and pharmaceutical industries.

Aeromonas hydrophila is an important pathogenic agent in aquatics and zoonotic in humans. This pathogenic agent can extensively be found in water and also is a part of fishes' digestive system microflora. Extensive researches have been carried out on the antimicrobial effects of natural compounds against food-borne pathogens, indicating that these products can substitute antibiotics. Essential oils of Thymus carmanicus, Zataria multiflora, Cinnamomum verum, Rosmarinus officinalis have antimicrobial effects due to their phenolic compounds. In this study, the bioactive compounds were detected using Gas Chromatography equipped with the mass spectrometer. Then minimum inhibitory concentrations and minimum bactericidal concentrations of the essential oils against A. hydrophila were calculated. According to the results, the lowest and the highest MIC and the minimum MBC were observed in T. carmanicus and Z. multiflora, respectively. The result indicated that the inhibition zone diameter increased with the increase of essential oil concentration. The inhibition zone, in the concentration of 1500 ug mL-1 T. carmanicus was 24. 33± 0. 57 mm. The findings of this study showed the antimicrobial resistance of these compounds. Considering the increasing limitations against chemicals and antibiotics, such compounds could be recommended for prevention of bacterial contamination.