Year:2014 | Volume:4 | Issue:2 (14)|Papers Count:8

Staphylococcus aureus is a major cause of bovine mastitis. Several virulence factors are involved in mastitis. One of the important virulence factors is the ability of the bacterium to produce biofilms. These bacteria are capable of producing polysaccharides and proteinaceous substances attached to the surfaces, leads to biofilm formation. In this study, a total of 120 raw milk samples was obtained from Kurdistan province and analyzed for the presence of S. aureus. The presence of S. aureus was assessed by conventional culture method and confirmed by PCR assay. For this, nuc gene was exploited as the specific target sequence to detect S. aureus. Moreover, Multiplex PCR was used to identify the presence of clfaB, fnbA, icaD and icaA genes which encode biofilm formation. Based on results, S. aureus was found in 49 (40.83%) of the samples. The frequency of each of the genes was determined as 69.38%, 32.6%, 38.77%, and 59.18 for fnbA, clfaB, icaD and icaA, respectively. Results revealed a high contamination rate of raw milks with S. aureus, and the ability of the isolates to form biofilms.

Nano silver, as nano-particles of silver, is one of the most widely used in the field of nano- technology. The particles cause widespread use of poultry houses due to their antimicrobial properties. Application of excess material in poultry houses lead to the residual of silver in muscle, liver and kidney in broiler chickens after a period of administration that it should be evaluated. In this study, 270 one-day old broiler chickens (Ross strain) were selected. The nano silver that used in this study (nonacid) was manufactured by Chemical Bahaman Iran Co. The Concentration of nanocid was between 1 to 7 ppm. A week after end of nano silver administration, chickens were slaughtered and liver, kidney and breast muscles (total of 36 samples for each limb) were obtained. The data was analyzed by SAS statistical program and Duncan test. Total mean residual of silver in different organs were 1.5 (ppm). The residual silver of the experimental group were significantly higher than those of the control group (P<0.01). There were no significant differences between residual amount of silver in the liver and muscles, but there was significant difference between kidney and other tissues. Results indicated that the amount of silver residue in the different organ was depended to the level of nano silver consumption. These results seem to support the hypothesis that application of nano silver must be with precaution.

Vibrio species are important seafood-borne pathogens that are responsible for 50-70% of gasteroenteritis. The present study was carried out in order to determine the prevalence of Vibrio species and the distribution of tdh, tlh and trh virulence genes in Vibrio parahaemolyticus isolated from fresh and salted shrimp samples. Totally, 60 fresh and salted shrimp samples were collected from the Genaveh seaport. Microbial culture was used to isolate Vibrio species. In addition, the presences of Vibrio parahaemolyticus, Vibrio cholera, Vibrio vulnificus and Vibrio harveyi and the virulence genes of V. parahaemolyticus were studied using the PCR method. Results showed that 20% of fresh and 23.33% of salted shrimp samples were positive for Vibrio species. In studied samples, V. vulnificus had the highest prevalence rate (8.33%), while V. cholera had the lowest prevalence rate (1.66%). From a total of 4 detected V. parahaemolyticus, all of them had tlh gene (100%). The distribution of tdh and trh genes in isolated V. parahaemolyticus strains were 50% and 25%, respectively. High prevalence of Vibrio species and especially virulent V. parahaemolyticus in samples confirmed the lack of hygienic condition in the production and distribution centers of shrimp.

Awareness of the information provided on food labels is important and will help the consumers to select standard food packaging. This knowledge can lead to improving the diet and health in the community. This study was carried out to determine the knowledge and practice of food producer retailers and consumers of food labels in Bostanabad, East-Azarbaijan province. In a descriptive and cross-sectional study, 1013 individuals were selected through random selection. Data on demographics and knowledge and practice of food retailers and consumers were collected by filling in a questionnaire and the results were compared. The age of participants ranged 16-65 years old and majority of them were between 40 and 60 years of age. According to the results, 75.7% of the participants read food labels during shopping. Amongst mostly considered food labels to observe the production and expiry dates on labels. A minority of the participants read food labels for nutritional information, product weight, types of additives and artificial colors, etc. The results showed that knowledge of people about the nutritional information on food labels is very slight. Due to the high impact of nutritional knowledge on the performance of people, having an idea about the individual’s attention to the information on food labels is essential. It is important to achieve the proper nutritional behavior and reduce the risk of adverse effects associated with packaged foods.

Nowadays, due to the antioxidant and antimicrobial properties of essential oil and the trend towards the substitution of chemical materials by natural ones, the use of this natural product is prevalent. The essential oil of Pistacia atlantica subsp. kurdica is among essential oils which demonstrate antimicrobial activity against some microorganisms. In Iran, the growth of mould on UF-cheese has been a constant problem resulted in the increased number of returns. The most common type of cheese contamination among fungi is Penicillium, especially P. citrinum. This study investigates the effect of P. atlantica subsp. kurdicaʼs essential oil on the growth of P. citrinum in culture media and UF-cheese. According to the results, the essential oil with concentration of 2500 mL/L reduced the growth of P. citrinum in culture medium and its minimum inhibitory concentration was estimated at 3000 mL/L. The effective inhibitory concentration of the essential oil on the growth of fungus on cheese was 24000 mL/L. From the organoleptic point of view, the use of this essential oil in cheese is partly acceptable.

Staphylococcus aureus is one of the main causes of food-born illnesses. The aim of this study was to determine the prevalence of S. aureus in meat products and to detect the presence of S. aureus enterotoxin A (SEA) gene. Totally 150 meat products were collected and analyzed using standard culture techniques to detect S. aureus. PCR assay by specific primers was performed on the isolates to identify SEA gene. According to the results, 19 (12.6%) of the samples were found positive for S. aureus. Highest prevalence rate was determined in smoked fish (30%), followed by fried morsels (16.6%), Salami and Ham (13.3%), and Shensel chicken (3.3%). S. aureus was not observed in any of Sausage samples. Statistical analysis showed that there is statistically significance association between the prevalence of S. aureus and meat products. Moreover, results did not show SEA gene in any of the isolates. This study concluded a remarkable occurrence of S. aureus in meat products.

This study was conducted to determine the effects of peppermint essential oils on Bacillus cereus, Salmonella typhimurium, Listeria monocytogenes and Yersinia enterocolitica. In the first step, Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of peppermint essential were determined by the tube dilution method in tryptic soy broth (TSB). Then, the growth behavior of each of the aforementioned bacteria was assessed in presence of peppermint essential oil in concentration of less than MIC. The result of first step showed that Y. enterocolitica is more sensitive to peppermint essential oil than other tested bacteria (MIC = 0.1% & MBC = 0.22%), followed by L. monocytogenes (MIC = 0.12% & MBC = 0.15%), S. typhimurium (MIC = 0.22% & MBC = 0.25%) and B. cereus (MIC = 0.3% & MBC = 5%), respectively. The results revealed that, the peppermint essential oils in low concentration inhibited the growth rate of bacteria thus may use as a natural preservative and flavoring in foods.

Nowadays, the tendency towards the extraction of phytochemicals by ultrasound method has been increased. In this research, the effect of ultrasound waves pretreatment on extraction of beta-carotene from carrot residue was studied. Carrot residues were treated with ultrasound waves with 205 W power, constant 35 KHz frequency during six stages of 0 (without ultrasound), 16, 20, 30, 40 and 44 min and at temperatures of 66, 70, 80, 90 and 94 ºC and using ethyl acetate as solvents. Then, the extract from each sample was evaluated considering the amount of total phenolic components as well as beta-carotene and antioxidant capacity of beta-carotene. According to the results, it was observed that, there was a significant difference (P<0.01) between samples in the case of beta-carotene amount with increasing of temperature and time. In order to achieve the highest extraction of carotene from carrot residues, the temperature of 90 ˚C and 40 minutes was determined as the best temperature and time. The results also revealed that at low temperatures the antioxidant capacity was higher. With increasing time of ultrasonic at low temperatures, the antioxidant capacity was enhanced. Moreover, the temperature of 70 ˚C and 40 min was determined as the optimum condition to achieve the highest antioxidant capacity of carrot residues. The result showed that the total phenolic compounds are greater at low temperature compared with high temperature. Besides, at all selected temperatures, with the increasing of ultrasonic duration the amount of total phenolics increased. Most phenols obtained at 66˚C for 40 min of ultrasonic treatment.