مجله میکروب شناسی مواد غذایی
سال ششم شماره 2 (تابستان 1398)

Helicobacter pylori is a Gram-negative, microaerophilic spiral rod. About half of the world population is infected with the bacteria that cause gastric and duodenal ulcers, and if untreated and eradication lead to the gastric cancer. Treatment is not easy and requires the administration of high doses of combination antibiotic with extensive and repeated use, in addition to side effects, the incidence of bacterial resistance as a double challenge is posed. So finding an alternative treatment, such as new natural antimicrobial resources including bee products such as honey and royal jelly is necessary. Honey due to high osmolality, low acidity, and content of hydrogen peroxide and non-peroxide components and royal jelly because of Royalisin protein, fatty acid Trans-10-Hydroxy-2- Decenoic acid (10-HAD) and Jelleins peptides; they have a wide spectrum of antibacterial activity. In this study, anti-Helicobacter pylori property of thyme honey and Royal Jelly, harvested from hive located in Damavand region near Tehran-Iran, and mixture of them, against the standard strain of H.pylori ATCC 43504, was evaluated by Minimum Inhibitory Concentration (MIC) method. This method as the golden standard technique for determining the sensitivity of microorganisms to antimicrobial agents has been known and in accordance with standard procedures in the British Society For Antimicrobial Chemotherapy (BSAC) guidelines, was performed. Thyme honey and Royal Jelly and their mixture with positive control sample as cephalexin, had respectively 31.25, 62.5, 31.25, 0.0652 mg/ml MIC against standard strain of H. pylori. There was no synergy effect between honey and Royal Jelly in this study.

It is desirable to use a preservative with both antioxidant and antimicrobial properties such as edible acids for preserving of meat. The present study was conducted to evaluate the effect of acetic acids on the shelf life and keeping quality of turkey meat fillets at refrigerated storage temperature. Samples were separated into three groups; untreated (control), treated with acetic acid 1% and 0.5%. Samples were stored at 4±1°C up to 15 days and evaluated periodically (on days 0, 3, 6, 9, 12 and 15) for microbiological (mesophilic and psychrophilic bacterial counts), chemical (pH, peroxide value; PV and total volatile nitrogen; TVN) and sensory (external aspect, muscular elasticity, odor and color) characteristics. Microbial analysis indicated that coating had significant effects (P<0.05) in reducing the mesophilic and psychrophilic bacterial counts with at least a15 days extension of shelf life. In addition, the samples which treated with acetic acid 1% showed a lower amount of TVN, PV and pH compared to other groups as well as a better sensorial acceptability. The results of this study showed that the acetic acid can increase the shelf life of turkey meat fillet without adverse effects on the organoleptic properties.

AbstractThe aim of this work was to study the influence of pomegranate peel methanol extract on the Lactobacillus plantarum PTCC 1058, Saccharomyces cerevisiae PTCC 5269 and Alicyclobacillus acidoterrestris ATCC 49025 in apple juice. Three different concentration of pomegranate peel extract (250, 500 and 1000 μg /ml) and control sample were prepared. The samples were stored at 4 °C for 60 days and acidity, pH value, microbial analysis, brix value were conducted at zero, 30 and 60 days. Physicochemical properties showed that acidity soured and pH decreased with increasing extract concentration. Turbidity was increased and brix value was decreased in storage time. Turbidity amount in 60th day were increased but treatment with 500 μg /ml had minimum turbidity. These results suggest the potential of pomegranate peel methanol extract as bio preservatives and have effect on decrease of turbidity in apple juice under refrigerated storage.

This study was conducted to study the antifungal effects of graphene nanoparticles on Aspergillus niger and Penicillium citrinum. Different concentrations of graphene nanoparticles were investigated to determine the minimum inhibitory concentration (MIC), the minimum fungicidal concentration (MFC) and inhibition zone diameter. The results showed that the concentration of graphene nanoparticle which inhibited the growth of Penicillium mold was statistically more than that of Aspergillus niger. On the other hand, there was no difference between the concentrations of MFC for these two fungi. The MIC results for Aspergillus niger and Penicillium citrinum were 10388.9 and 10527.8 μg/ml respectively. Evaluation of the growth inhibition zone showed that up to 10500 ppm, there was no difference between the inhibition zones diameter of two microorganisms. However, with an increase in the concentration of graphene nanoparticle, the difference between the zone diameters in the two molds increased, so that the diameter of the inhibition zone of Aspergillus niger in higher nanoparticle concentrations was more than that of Penicillin citrinum. According to the results of this study it can be concluded that the effect of graphene nanoparticles on Aspergillus niger was higher than that of Penicillin citrinum.

The purpose of this study was to investigate the effect of monetary shocks and food prices on food health. And it's important and necessary in many ways. The most important is food and nutrition security in Iran, food and nutrition security is achieved when all people At all times, the quantity and quality of the various foods with safe food content will be used to meet the needs and have a healthy and active life with health, a healthy environment and adequate care. Required data are extracted from the Bank of the Islamic Republic of Iran Economic Time Database and the Food and Drug Administration of the Ministry of Health and Medical Education during the period of 1975-96. The model used in the Cargo (2005) model was taken. This model is an error correction model with food contamination variables, real food prices, real per capita income, real exchange rate, and negative and positive money supply shocks. The results indicate that in the long run, positive and negative monetary shocks have a positive and negative effect on food micro-nutrients, as well as actual per capita income has a significant and positive effect on food microbial contamination in Iran.The purpose of this paper is to investigate the effect of monetary shocks and food prices on food microbial contamination, and it is important and necessary in many ways, most important of which is food and nutrition security in Iran, food and nutrition security is achieved when all people At all times, the quantity and quality of the various foods with safe food content will be used to meet the needs and have a healthy and active life with health, a healthy environment and adequate care. Required data are extracted from the Bank of the Islamic Republic of Iran Economic Time Database and the Food and Drug Administration of the Ministry of Health and Medical Education during the period of 1975-96. The model used in the Cargo (2005) model was taken. This model is an error correction model with food contamination variables, real food prices, real per capita income, real exchange rate, and negative and positive money supply shocks. The results indicate that in the long run, positive and negative monetary shocks have a positive and negative effect on food micro-nutrients, as well as actual per capita income has a significant and positive effect on food microbial contamination in Iran.

Various foods, including dairy products, may be contaminated with aflatoxin, which even in small amounts has harmful effects on human and animal health. A limited number of probiotics attach and or break down aflatoxins in foods and edible substances. The aim of this study was to investigate the effects of Lactobacillus acidophilus and Lactobacillus plantarum probiotics and their combinations on the removal of or coupling with aflatoxin M1 in yoghurt drink (Doogh). In this study, 72 treatment and control groups were prepared in three replicates. The groups were included four groups of bacterial L. acidophilus, L. plantarum, and a combination of them, and finally with a non-bacterial group as control (in general four groups). Doogh was prepared at different temperatures (4, 21 and 37 °C) was being before stored for 2, 11 and 30 days. The maximum level of aflatoxin degraded was done in industrial Doogh affected by L. acidophilus plus L. plantarum at all assigned temperatures and days. This maximum level was measured on the second day (100.00 ± 0.86), eleventh day (100.00 ± 1.27) and thirtieth day (100.00 ± 0.60). The results suggest a better food security in using industrial Doogh compared to traditional one.

Evaluation of the microbial quality of raw milk is very important due to the increasing consumption of milk and the possibility of its converting into dairy products. The study of microbial load of raw milk and the evaluation of acute phase proteins can provide accurate information on the hygienic conditions and quality of raw milk. The present study was done to evaluate the microbial load and amyloid A measurement in bulk milk samples of animal farms of Tehran province. At first, 90 raw milk samples were collected and transferred to the laboratory. Somatic cell count of milk samples was done by electronic fluorescence. Then, total microbial, coliform, Escherichia coli, Staphylococcus aureus and mold and yeast counts were done. Amyloid A concentration in raw milk samples was determined using ELISA method. Mean count of total microbes, coliform, Escherichia coli, Staphylococcus aureus and mold and yeast were 15×105, 12×104, 29×103, 14×103 and 18×105 CFU/ml, respectively. Total microbial count in 72.23% of tested samples were higher than limit standard. Mean of somatic cell count was 3×105 cells in milliliter milk which were higher than limit standard in 61.11% of milk samples. Mean and standard deviation of amyloid A in milk samples was 551.83 ±47.96 ng/ml milk. The results of the present study show the relative quality of milk samples of animal farms of Tehran province. High number of somatic cells and also the concentration of amyloid A in raw milk samples indicate the possibility of occurrence of subclinical mastitis in the target cows.

There are a variety of studies on the prevalence of TSST-1 in Staphylococcus aureus isolated from various food sources, which largely examined the frequency of this toxin. In order to obtain a better outlook for TSST-1 prevalence, this study aimed to determine the prevalence of S. aureus carrying TSST-1 toxin in contaminated milk in livestock infected with mastitis in Iran using a systematic and meta-analysis study. All articles published in Iranian journals were reviewed using standard and sensitive keywords between January 2000 and January 2018. All published articles in this field which had criteria for entering in this study were undergoing the meta-analysis process using a randomized model after qualitative control. Based on the 6 reviewed articles, the cumulative frequency of TSST-1 in S. aureus strains obtained from lactating mice with an infection of 8.2% mastitisr was estimated (95% CI: 2.6 to 23.2). There was a significant variation among the six studies (χ2 = 43.302; P