مجله میکروب شناسی مواد غذایی
سال هشتم شماره 4 (زمستان 1400)

The current study aimed at removing aflatoxin (0.5 and 0.75 ng/mL) from the reconstituted milk by adding three probiotics Lactobacillus rhamnosus, L. plantarum and Saccharomyces boulardii in 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 the removal of 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 the minute 90. 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 results of the current study 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, Cirsium 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 results of the optimization process 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 Cirsium 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 antioxidant present in the optimized sample of Cirsium vulgare.

Anisakiasis is a zoonotic disease caused by the nematode Anisakis caused by eating infected and uncooked fish. Due to the fact that this disease is zoonotic, the necessary health advice should be given to people who tend to eat raw and especially 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, 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 (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, many reports of occurrence of food poisoning due to the consumption of sea-foods contaminated with Vibrio species have been reported. The present survey was carried out to evalution the frequency rate of Vibrio species in sea-food products from the fish samples in Isfahan, Iran.In this survey, 64 fresh fish samples were purchased from markets in Isfahan and transferred to the food quality control laboratory of the Islamic Azad University of Shahreza . Samples were tested for count Vibrio parahaemolyticus and detection according to Iranian national standard methods . positive specimens were evaluated for presence of bacterial species using Nested Polymerase Chain Reaction . the presences of Vibrio parahaemolyticus, Vibrio cholera, Vibrio vulnificus and Vibrio mimicus were studied using the Nested PCR method. 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%). 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 can not be defined satisfactorily . High prevalence of Vibrio species in samples confirmed the lack of hygienic condition in the production and distribution centers of fish . It seems that, places of fishing and processing and the moods of transportation and distribution of fish don’t have suitable hygiene in Isfahan .

Hypericum perforatum is a medicinal plant of the genus Hypercasia that has 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. 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 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 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 compared to some antibiotic discs.

This study aimed to extract dietary fiber from the Ziziphus mauritiana seeds by alkaline-hydrogen peroxide extraction method and evaluate its prebiotic and functional properties. For this purpose, seeds were first defatted. Then, its dietary fiber was extracted using alkaline hydrogen peroxide treatment. Prebiotic effect (at concentrations of 1 and 5%) in sugar-free culture medium on Lactobacillus acidophilus was studied for 72 hours. The technological and functional properties of the extracted dietary fibers including DPPH test, cholesterol-binding capacity, glucose adsorption capacity, oil binding capacity and water adsorption capacity were measured. Z. mauritiana seed dietary fiber had water adsorption, oil binding capacity, glucose adsorption capacity, and cholesterol binding capacity equal to 0.51 ml/g, 2.50 g/g, 37.60 mmol/L, and 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 time of the test (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 count. Besides, the trend of bacterial multiplication was variable concerning its concentration and over time (p<0.05). 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.