JOURNAL OF FOOD HYGIENE
Year:2013 | Volume:3 | Issue:3 (11)|Papers Count:8

This study was conducted to detect the classical enterotoxins of Staphylococcus aureus isolated from chicken nugget and ready-to-eat foods in Esfahan province by ELISA technique. During summer 2012, a total number of 420 chicken nuggets was collected randomly from retails of Esfahan province. The samples were subjected to bacteriological examinations. The isolates were analyzed for the production of enterotoxins using ELISA techniques. The ability to synthesize Staphylococcal enterotoxins (SEs) was determined in 20 of 24 (83.3%) isolates, which SEA was the most common (40%) enterotoxin found in the isolates. Afterwards, SEC (15%) and SED (10%) were the most detected enterotoxins. Amongst, three strains were able to synthesize both of the SEA and SED and three isolates were able to synthesize both of SEA and SEE. However, no isolate was able to produced SEE. Results showed that chicken nugget and ready-to-eat foods can potentially be a source of staphylococcal food poisoning. Therefore, it is important to study the prevalence of enterotoxigenic S. aureus in the other food types.

Herbs due to having natural antioxidant compounds are widely used by food, pharmaceutical and cosmetics industries. The purpose of this study was to study the effects of antioxidant activities of black cumin as well as black caraway extracts individually and in the combination form on chemical and sensory properties of silver carp during refrigerator storage. To do this, fish was cut into four parts. Three parts were dipped in I % solution of black cumin and black caraway extracts, and their combination. The forth part was dipped in distilled water as a control sample. All fish cuts were packed up in polyethylene bags and were stored at refrigerator (4±1oC). Chemical indices (i.e., PV, TBA and FF A) and sensory properties were measured over a period of 15 days (0, 3, 6, 9, 12, and 15 days). According to the results, in all three treatments lipid oxidation was delayed significantly (p<0.05) in comparison with the control sample. Moreover, sensory analysis revealed that the sample treated with black cumin extract had the best quality over the period of 15 days. Besides, the rising trend of the chemical indices was hindered significantly in comparison with the other treatments. Based on the results, it was concluded that extracts of black cumin and black caraway and their combination had an antioxidant effect on silver carp fish and could lengthen the shelf-life of the treated samples.

Probiotics are dietary supplements of live microorganisms which when consumed in adequate amounts, can have a beneficial effect on the bost. Among all bacteria, lactic acid bacteria are the most common type that has been introduced as probiotics. These bacteria are present in dairy products and produce lactic acid during the fermentation process. The aim of this study was to isolate and identify the probiotics from microbial flora of milk and traditional yogurt in Kaleibar, Heris and Varzaghan areas. In this study, lactic acid bacteria were isolated by culture and identified based on biochemical properties and resistant to stomach acid and bile salts were evaluated. Then, for more accurate identification of the isolates, the 16S rRNA genes of Lactobacilli were amplified with specific primers and the purified PCR product was sent for sequencing. According to our results, 17 strains of Lactobacilli and 6 strains of Enterococci were reported in Kaleibar, Heris and Varzaghan areas which could be a good candidate for further investigation as probiotic.

Regarding the significance of harmful effects of heavy metals in human diet, this study aimed to investigate the concentrations of lead and cadmium in raw milk samples. To achieve this goal, a total number of 48 samples was collected from various regions of Hamadan province during April 2011. The samples were analyzed by atomic absorption spectroscopy. According to the results, the mean concentrations of lead and cadmium estimated at 4.48 and 3.21 mg/kg, respectively which were below the approved level determined by WHO as well as FAa. Although, concentrations of Pb and Cd among the various sampling regions revealed a significant (p<0.01) difference, a correlation was not observed between heavy metal concentrations and influencing factors such as density of cars, industrial plants as well as human populations in each region. Results showed that Pb and Cd concentrations were higher in the area where metal mines were located. It seems that the elements could enter the animal's body via the contaminated feed and water. Due to the importance of this issue, complementary investigations are necessary.

Milk is a complicated liquid that contains necessary components for the growth of mammalian neonate. Milk can get polluted by heavy metals such as lead and cadmium. In this study, the concentrations of lead and cadmium were measured in 12 yoghurt and 12 OF cheese samples produced in each of the Isfahan and Golpayegan-Pegah Dairy Processing Establishments. The samples were analyzed using atomic absorption spectrometry by furnace according to AOAC instruction. According to the results, lead concentrations (Mean ± SO) in yoghurt and UF cheese samples produced in Isfahan and Golpayegan-Pegah were estimated at 54.96 ± 35.21, 61.65 ± 19.62, 105.38 ± 59.09, 141.94 ± 63.44 mg/Kg, respectively. In the case of cadmium, the concentrations were determined as 19.03 ± 1.23, 16.84 ± 8.08, 53.79 ± 19.29, 37.67 ± 22.58 mg/Kg, respectively. Results revealed a significant difference (P ³0.05) in lead and cadmium concentrations among the cheese samples of the two Dairy Processing Establishments. However, lead and cadmium concentrations in all samples were within the international approved limit (200 ppb).

In this study, survival of Lactobacillus acidophilus and Bacillus coagulans after freezing and during 90 days of storage at -is-c in probiotic and low-fat synbiotic ice-cream was evaluated. Addition to a control group (which was ordinary ice-cream), two probiotic ice-creams were formulated using L. acidophilus and B. coagulans and two synbiotic ice-creams were prepared using the aforementioned microorganisms but replacing 5% of milk-fat with inulin. The total solids of the ice-cream mixes did not differ significantly, however there was a significant difference (p<0.0 I) between their fat contents. The viable counts of L. acidophilus and B. coagulans were higher than the recommended minimum limit of 6 log cfu/g in all probiotic and synbiotic ice-creams during the 90-days of frozen storage. The survival rate either after freezing or at the end of frozen storage was higher in the samples with B. coagulans. Inulin had not preservative effect on probiotic microorganisms during frozen storage. Moreover, survival of high populations of probiotic microorganisms for a long time revealed that ice-cream has a great potential to be a functional food.

Food security along with the protection of environment has become a global issue. Accumulation of Arsenic and Zinc in rice is considered as a major problem for South-East Asia, where rice is a staple food. Given that, rice is considered as the highly consumed food in the diet of Iranian people, this study was conducted to estimate the concentrations of Zinc and Arsenic in rice cultivated in Firoozabad fields. For this purpose, 38 rice samples were collected from 22 nearby villages. Samples were digested by Digesdahl device and the concentrations of Arsenic and Zinc were determined by ICP. The results showed that the concentration (mean ± SD) of Zinc was 20.87 ± 1.9 mg/kg of dry matter (ranged from 25.26 to 32.97); meanwhile mean value of Arsenic concentration was estimated at 22.89 ± 2.2 mg/kg of dry matter (ranged from 17.61 to 26.77).Comparing the concentrations of Arsenic and Zinc in rice samples with the standard limit set by WHO/FAO it was revealed that Arsenic concentrations in 100% of the samples were higher than standard level, whereas Zinc concentrations in 97.36% of the samples were below the limit.

Unpasteurized traditional ice-cream has long being manufactured in Iran and is consumed during hot seasons especially by kids. Contamination of ice-cream with microbial pathogens could results in humans' infections or intoxication. The aim of this survey was to evaluate the microbial quality of traditional ice-creams produced in Maragheh. First, the markets were classified as 1, 2 and 3 considering their facilities as well as the hygienic measures absorbed by the personnel. A total number of 99 samples was obtained and subjected to microbial analysis. Enumeration of total bacteria and enterobacteriaceae as well as detection of Escherichia coli, salmonella and coagulase positive staphylococci were performed according to the Iranian National Standard. Results showed that 78.8% and 17.2% of the samples had the total bacteria and enterobacteriaceae counts above the approved limit, respectively. In the case of staphylococci and E. coli it was estimated at 41.8% and 21.4%, respectively. Conversely, any salmonella was isolated from the samples. Microbial contamination rate in terms of staphylococci and E. coli among third-class markets were significantly (p<0.05) higher than first-class ones. However, no significant difference was observed among other microbial groups. It was concluded that high percentage of the ice- creams produced in Maragheh had microbial quality beyond the acceptable limit. Furthermore, it was revealed that outward features of the ice-cream markets could not be an appropriate indicator to make a judgment about the microbial quality of their products.