نشریه بهداشت مواد غذایی
سال هشتم شماره 4 (پیاپی 32، زمستان 1397)

The antimicrobial properties of medicinal plants essential oil are caused an increase of its application as a natural preservative in foods. The aim of this study was to investigate the effect of Foeniculum vulgare seed essential oil on the quality of minced Cyprinus carpio inoculated (103 CFU/g) with Staphylococcus aureus during refrigerated storage (4˚C). The essential oil was extracted by using a Clevenger apparatus with water distillation method and in concentrations of 4, 6 and 8 µL/g were added to the mince inoculated with Staphylococcus aureus. Microbial (S. aureus count, Total viable count (TVC) and Psychrophilic bacteria count (PTC) and chemical parameters (pH, Thiobarbituric acid (TBA) and Total volatile basic nitrogen (TVB-N) were measured at 24, 72, 144, 216 and 218 hours. According to the results of this study, S. aureus count increased in control during storage but decreased in treatments containing essential oil. The lowest count of TVC and PTC were observed in the mince containing 8 µL/g of essential oil. Significant differences (p>0.05) were observed between the pH of control and treatments containing essential oil. The TBA and TVB-N values of treatments increased during storage but this increase was lower in treatments containing essential oil.The Fillets containing 6 µL/g of essential oil had better sensory evaluation.The results of this research showed that F. vulgare seed essential oil have antioxidant and antibacterial properties and increased the shelf life of minced C. carpio during refrigerated storage.

The aim of this study was to determine selenium concentration of 16 different species of fish. Ninety six samples were obtained randomly from fish market in Ahvaz. In the marine fishes the highest and lowest concentration of selenium were measured in two species Liza klunzingeri and Platycephalus indicus 0.618±0.01 and 0.409±0.02 mg/Kg. In freshwater fishes the highest and lowest concentration of selenium were in two species Carasobarbus luteus and Barbus shrpeyi 0.291±0.01 and 0.251±0.02 mg/Kg. In farmed fish highest and lowest concentration of selenium were in two species Oncorhynchus mykiss and Aristichthys nobilis 0.202±0.009 and 0.147±0.001 mg/Kg. In marine, freshwater and farmed fishes concentration of selenium were significantly different (P<0.05). Concentration of this element in marine fishes was higher than the freshwater and farmed fishes. Also, in farmed fishes was lower than the marine and freshwater fishes. The pattern of accumulation of selenium element in the form of fishes was raised: marine fishes > freshwater fishes > farmed fishes. In this study concentration of selenium in the muscle of 16 species of fish was lower than Global Standards (2 mg/Kg).

Yersinia enterocolitica is one of the most important food-borne bacteria and it can cause yersiniosis. This study was conducted to investigate the occurrence of Y. enterocolitica in poultry meat and offal marketed in Ardabil, as well as to assess the antibiotic resistance pattern of the isolates. In this descriptive cross-sectional study, a total of 344 samples including 264 poultry meat and 80 offal samples were randomly obtained during the spring and summer of 2016. The samples were investigated for the presence of Y. enterocolitica using Iranian National Standard. Moreover, antibiotic susceptibility was examined by Kerby-Bauer method. Based on results, 22.34% of the poultry meat samples and 37.5% of the offals were contaminated with Y. enterocolitica. Antibiogram results revealed that 84.74% of the isolates were resistant to Ampicillin; in the cases of Cephalothin and Cephalexin, it was estimated at 69.49% and 64.4% of the isolates, respectively. However, resistance was observed for Chloramphenicol and Syprufluxasine. Regarding the high occurrence Y. enterocolitica in chicken meat and offal and the presence of antibiotic-resistant strains of this bacterium, the implementation of hygienic measures to reduce the occurrence of Y. enterocolitica in chicken meat and the prudent use of antibiotics in the poultry industry to prevent the spread of strains resistant to antibiotics and transferring them to the human food chain is essential.

Histamine poisoning is one of the main concerns in traditional cheese health and its most important producers are decarboxylating bacterial strains which act during cheese ripening period. The aim of this study was to determine the effect of Rosmarinus officinalis essential oil (EO) on Lactobacilli count and Histamine amount in Lighvan cheese using HPLC method. The Chemical composition of EO was detected using GC/MS. Cheese samples containing 0, 125 and 250 ppm of Rosemary EO were prepared. Lactobacillus count and Histamine amount of samples were measured on days 0, 30, 90 and 150 of the ripening period. Alfa pinene (11.1%), Camphore (10.2%) and Limonene (5.9%) were detected as three main components of rosemary EO. Lactobacillus count on the understudied days in all EO-treated groups (125 and 250 ppm) was significantly (p<0.05) lower compared to the control group during ripening period and Histamine amount in control, 125 and 200 ppm groups were 190, 170 and 51.04 mg/kg respectively. Overall it could be concluded that addition of 125 and 250 ppm of rosemary EO could act as a natural preservative in traditional Lighvan cheese.

Heavy metals contamination is one of the most serious problems around the world and regarding increasing trend of the tendency than seafood consuming in Iran, assurance to the health of this food would be important for consumers. Accordingly, the present study has been done in order to an assessment of some toxic metals concentration in the captured shrimps from the northern coasts of Oman Sea and investigating of their health risk for the eaters. So, 40 samples were prepared at two times from each station (Hormoz, Jask, and Chabahar) and were transported to the laboratory. Preparing of their edible parts and measuring of heavy metals (Cr, Pb, Zn, Cd, and Ni) have been accomplished via wet digestion method and atomic emission spectroscopy (AES), respectively. Results showed that a significant difference between cadmium concentrations of shrimps captured from Jask port (0.08 µg.g-1) with Strait of Hormuz (0.022 µg.g-1) and Chabahar Bay (0.021 µg.g-1) samples has been observed (P<0.05). Also, white Indian shrimp (Fenneropenaeus indicus) had significantly more residuals of cadmium (0.448 µg.g-1) than other species including Jinga (Metapenaeus affinis), kiddi (Parapenaeopsis stylifera), and banana shrimp (F. merguiensis) (P<0.05). According to all of the measured metals were placed in allowable range of WHO and FAO standards, and total THQ for Children (0.258) and adults (0.147) were less than 1, consumers couldn’t be prone through continuous and even daily consumption of the captured shrimps from this area.

Nisin is an antimicrobial peptide used in food industry as preservative. However, this peptide has no considerable effect on gram negative bacteria. In this study the effect of glycation on antimicrobial activity of gram negative bacteria was elucidated against gram negative bacteria. Solution of nisin and fivefold concentration of glucose, lactose and dextran and solution of nisin without any sugar were prepared in phosphate buffer and were lyophilized. The lyophilized powder was exposed to 60°C temperature and 70% humidity for 7 days. Every 24 hours, one sample was collected and dissolved in distilled. Equal molar concentration of native and conjugated nisin were made. Percent of glycation was measured by OPA (ortho-phthalaldehyde) method. MIC50 of nisin was assayed by microdilution method against Escherichia coli and Salmonella typhimurium. The result of this study has revealed that percentage of glycation is conversely related to the size of carbohydrates in which nisin-glucose had the highest and nisin-dextran had the least percentage of glycation. Glycation of nisin increased the MIC50 of nisin against E. coli after seven days. MIC50 of native nisin and glycated nisin had no difference against S. typhimurium. From this study it was concluded that conjugation of nisin with carbohydrates is not able to extend the antimicrobial activity of nisin to gram negative bacteria.

Oxidative stability of oils and fats was affected by various factors such as oxygen, light, heat, metal ions and enzyme. The use of synthetic antioxidant for preventing oxidative deterioration, despite of having high performance, due to the possibility of toxicity and carcinogenicity, has been under questioned. The aim of this study was to optimize the thermal stability of soybean oil by the addition of thymus daenensis Celakessential oil. In this study soybean oil was treated under various conditions of frying temperature (150, 170 and 190 °C), frying time (0, 6 and 12 h) and thymus daenensis Celak essential oil concentrations (0, 400 and 800 ppm) and different quality attributes of samples such as the acid value, peroxide value, thiobarbituric acid, polar compounds and conjugated dien value were studied. Results showed that Thymus essential oil due to ontaining diffrent phenolic compounds increased the thermal stability of soybean oil significantly (p<0.05). The results of the acidic value, peroxide value, thiobarbituric acid and polar compounds in fried oil samples for 12 hours at 190 ° C showed that the addition of essential oil of thyme oil keeps the quality of fried oil after 12 hours frying at 190 °C. This study shows that essential oils can be a good alternative for synthetic antioxidants.

This study was carried out to compare the enrofloxacin residue in chicken and turkey meat in Isfahan province by HPLC. For this, totally 60 meat samples were collected from chicken and turkey carcasses during of summer and autumn of 2016. The results showed that 48 out of 60 chicken and turkey samples (80%) were positive for enrofloxacin residue. The minimum and maximum concentrations of enrofloxacinin residue in chicken meat samples were 3.64 & 254.68 μg/Kg, respectively. The minimum and maximum concentrations of enrofloxacinin residue in turkey meat samples were 11.34 & 50.84 μg/Kg, respectively. Furthermore, the average of enrofloxacin concentration in all chicken and turkey samples was 38.00±62.72 & 21.36±15.31 μg /Kg. The concentration of enrofloxacin in 46.66% of chicken samples and 20% of turkey samples was higher than European MRL standard. In conclusion, for improvement of hygienic quality in poultry meat, it is necessary to apply the national strategies for monitoring of antibiotic residue in meat before slaughter.