نشریه بهداشت مواد غذایی
سال پنجم شماره 4 (پیاپی 20، زمستان 1394)

For centuries, antimicrobial compounds derived from plants, have been used for medicinal treatment. The aim of this study was to evaluate the antibacterial activity of castor seed oil extracted from Mashhad and Isfahan varieties on Staphylococcus aureus, Escherichia coli and Listeria inocula. The sensitivity of the indicator bacteria was evaluated using disc diffusion technique and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were tested by broth micro-dilution assays. Oil from castor seeds was extract by Soxhlet method and the extracted oils were analyzed by a gas chromatograph connected to a mass spectrometer (GC/MS). According to the results of various dilutions of the extracts, MIC for castor oils ranged 12.5-25%, except for the Isfahan variety that was estimated at 6.25-12.5% for E. coli. The two varieties of castor oils showed the MBC activity on the indicator organisms at the original (100%) concentration. Based on GC/MS data, ricinoleic acid (1.307%), genetistic acid (0.597%) and palmitic acid (1.947%) were detected in oil extracted from Isfahan variety; meanwhile these compounds did not found in Mashhad variety. According to the results, the two castor varieties had antibacterial impact on E. coli. In addition, the overall antimicrobial activity of Isfahan variety was higher than Mashhad type. It seems that the presence of phenolic compounds as well as camphoric and unsaturated fatty acids is the major reason for the higher antibacterial effect of Isfahan variety on E. coli. Considering the inhibitory impact of castor oil, it can be used as a natural preservative in food industry.

Oxidation of bread lipids during baking and storage reduces the nutritional value of the product and leads to the formation of off-flavors and off-odors. In this research, oxidative stability of rice bran, corn, canola, sunflower and soybean oils during Brotchen bread baking process and storage was evaluated. Baking process caused a significant increase in oxidative indices such as peroxide, anisidine, Totox and thiobarbitoric acid values and free fatty acid content. However, storage of breads for 6 days in room temperature did not affect the value of the indices. Generaly, the value of the indices in bread containing rice bran oil was lower than those of the other breads, which indicated the higher oxidative stability of rice bran oil in baking process and storage. Pure oils treated in simulated baking process and storage had an oxidative quality similar to that of breads. This means that bread ingridients may not have an effect on oil oxidative stability. Bread containing rice bran oil gained also higher scores in sensory evaluation, which of course were in agree with its better oxidative status.

Foodborne bacterial pathogens play an important role in food infections/intoxications in human population. With ever increasing the number of antibiotic-resistant bacterial strains, there is an attempt to use the antimicrobial properties of herbs. Peganum harmala is a medicinal plant of Iraniantraditional medicine which was used as an antiseptic in the past. Amongthe foodborne bacterial pathogens, Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes are considered as the most important and hazardous pathogens. The aim of this study was to evaluate the antibacterial effect of methanolic extract of Peganum harmala against these bacteria in vitro. The minimum inhibitory concentration (MIC) and minimum bactericidal concentrations (MBC) of methanolic extract of Peganum harmala was determined against three foodborne bacterial pathogens by micro-dilution method in Muller-Hinton broth. According to the results, MIC for E. coli O157:H7 and S. Typhimurium was 1.56 mg/ml. In the case of L. monocytogenes, it was estimated at 0.78 mg/ml. Moreover, results revealed that MBC for these organisms was similar to MIC concentrations. Regarding the results, Peganum harmala can be used as an ingredient in the formula of the disinfectants applied in the food systems.

The aim of this study was to determine the accumulation of nickel and cobalt in the edible tissues of Crucian (Rtilus frisii kutum) and to compare their concentrations with the FDA/FAO standards. For this purpose, the fish samples were caught from western, central and eastern stations of Anzali wetland. Using a flame atomic absorption spectrophotometer, Ni and Co contamination were determined. According to the results, the mean value of Ni concentration in the samples caught from the eastern and central stations were 0.93 and 0.80 µg/g, respectively which were not statistically different. Moreover, Ni concentration in the central region was estimated at 1.13 μg/g, which was not significantly different from the FDA standard. In the case of Co, the average concentration in the western parts was below the detection limit; however in the central and eastern parts Co level was 0.13 and 0.07 μg/g dry weight, respectively that was in the approved limit adopted by FDA and FAO. Besides, the difference of Co concentration in the eastern, western as well as central stations was not significantly different. Based on the results, Ni and Co contents in edible tissues of Crucian of the eastern, western and central stations of Anzali wetland were found suitable for human consumption.

Due to its high concentration of polyunsaturated fatty acids, poultry meat is prone to oxidative deterioration. The aim of this study was to investigate the effect of essential oils of thyme, oregano and their combination in comparison with virginiamycin on quality of quail’s meat. The dietary treatments consisted of the basal control (without any added compounds or with 100 mg/kg of virginiamycin), 100 and 200 mg/kg of thyme and oregano essential oils, as well as an equal mixture of thyme and oregano essential oil (levels of 50 and 100 mg /kg). At the end of 35 days of the experiment, two birds from each group were slaughtered for testing the meat quality (including malondialdehyde, pH, water holding capacity, dripping loss and cooking loss). Results showed that essential oils of thyme, oregano and their mixture reduced the thiobarbituric acid value, dripping loss and cooking loss; on the other hand pH value and water holding capacity was increased. Oregano and thyme essential oils contain compounds with high antioxidant properties. Therefore, the presence of these compounds in the bloodstream and their accumulation in the muscle tissue could results in an increase in the antioxidant capacity and consequently enhance the keeping quality of meat. It seems that the application of natural antioxidants such as thymol or carvacrol could be helpful to improve the quality of poultry meat.

This research aimed to investigate the attitude of broiler breeders toward the production of antibiotics-free chickens in Tehran province. The statistical population in this study included all broiler breeders (N=450) in Tehran province. Using stratified-random-sampling method 136 breeders were selected. The main tool for data gathering was a questionnaire contained 44 questions and items. Results showed that 52.9% of the respondents had “positive” or “relatively positive” viewpoints about the production of antibiotic-free chicken. The results also indicated that there were a significant (p

In the last years, the presence of nitrates and nitrites in vegetables has been a public health concern. This study was conducted to examine the accumulation of nitrate and nitrite in vegetables of Shahre-Kord retails. For this purpose, a total of 222 fresh vegetables samples were collected in winter 2011 and summer 2012 and were analyzed for the accumulation of nitrate and nitrite. Results showed a vast deviation between the mean concentrations of nitrate. In other words, the nitrate accumulation for mint was 310.9 mg/kg fresh weight (FW) and for savory was estimated at 3309.1 mg/kg FW. Nitrate accumulation in more than 85% of the vegetable samples was below the approved limit of 2500 mg/kg FW; meanwhile in savory it was higher than 3000 mg/kg FW. Moreover it was revealed that in comparison with nitrate, the mean value of nitrite accumulation was remarkably low (below 1.65 mg/kg FW). According to the results, the nitrate accumulation was significantly (P

The objective of this research was to determine the effect of ultrasound treatment on bioactive compounds (including total phenolic, total flavonoids, total carotenoids, ascorbic acid) of carrot juice in comparison with conventional thermal process. Carrot juice samples were sonicated according to D-optimal response surface design with processing variables of temperature (25, 37.5 and 50°C), time (10, 20 and 30 min) and power (350 and 400 w) at a constant frequency of 24 kHz. Results showed that ultrasound temperature (P