نشریه بهداشت مواد غذایی
سال چهارم شماره 4 (پیاپی 16، زمستان 1393)

Staphylococcus aureus is proposed as the third important foodborne organism worldwide. The purpose of this study was to estimate the prevalence of in traditional Kouzeh cheese at Saqqez retails and to determine the antibiotic susceptibility of the isolates. For this purpose, 100 Kouzeh cheese were collected from different parts of Saqqez. The samples were analyzed for the presence of S. aureus using conventional culture techniques. Afterwards, the pattern of antibiotic resistance of the isolates was investigated against 12 antibiotics using the disk diffusion’s method. According to the results, S. aureus was detected in 41 samples (41%). Amongst, only one of the isolates was found sensitive to all of the 12 antibiotics. In contrast, one of the isolates showed resistance to 9 antibiotics. Other isolates demonstrated various degrees of resistance (2 to 8 antibiotics). Regarding the high prevalence rate of contamination in Kouzeh cheese, application of efficient heat treatments of cheese-milk together with the and maintaining the hygiene conditions during cheese preparation is essential.

Demineralized whey powder is one of the materials which isused in medical and infant milk powder industries recently. The aim of this study was to evaluate theratio of aflatoxin M1 (AFM1) detoxification in 90% demineralized whey powder (DWP-90), produced from sweet whey. For this purpose, 36 samples gathered from different steps of production line including Sweet whey (12 sample), demineralized whey (12 sample) and DWP-90 (12 sample). The samples gathered from Nutricia-MMP factory during one year (from 2012 to 2013). AFM1 detected by High performance liquid chromatography (HPLC) method. Based on results, AFM1 was found in 100% of the samples but the concentration of AFM1 in all samples was less than maximum limit defined by Iranian national standards, No 5925 (100ppt for wheyand 1000ppt for whey powder). The Average amount of AFM1 in sweet whey (32. 5ppt) and DWP-90 (45. 8ppt) was less than maximum limit in CODEX and EC 1881/2006, defined for raw milk (50ppt). Considering total solid in sweet whey (6%±0. 1) and DWP-90 (٪97) and concentration of AFM1 in these samples, about 91% reduction was found in concentration of AFM1during DWP-90 production.

This study aimed to evaluate protein, fat and ash contents as well as the concentrations of As, Hg and Cd in muscle tissues of Liza auratus cached from Anzali Wetland. Eighteen samples of Liza auratus were collected using gill net. Heavy metals were extracted using wet digestion method and the concentrations were measured by Atomic Absorption Spectrophotometer. Concentration of Hg, As and Cd in the muscle of mullet was 57.20±7.56, 97.29±13.27 and 200.80±31.39 µg/Kg. Moreover, the percentage (mean±SD) of protein, fat and ash in the muscle of the samples were determined as 17.69±0.42, 0.74±0.08 and 1.37±0.12%, respectively. The positive and significant relationship was observed between the concentration of Hg, As and Cd in the muscle of mullet (P<0.05). Besides, the highest correlation was found between Hg and As (R=0.982, R2=0.952, P < 0.05). Results also showed a relationship between concentrations of Hg, As and Cd with the chemical compositions of the muscle (P < 0.05).

Sodium hydrosulfite/blanket is used as a decolorizing agent for the bleaching of produced sugar in the sugar industry. Due to sensitivity of using this chemical substance with defined allowed range in sugar product, the sensitive and exact method of voltammetry/polarography was used to measure the residual blanket in this product and moreover, its results were compared with titration method as a common method for measurement of this substance in reference laboratories. Among the active sugar plants in Zanjan province, three different samples of loaf sugar batch were selected from each production unit based on sampling method of Standard and Industrial Research of Iran and all samples were evaluated using polarography 797 VA Computrace. Then, some of the samples evaluated by the polarography method were also checked with titration method and the results of the two methods were compared with each other. Statistical analysis of obtained data from polarography method shows that various sugar factories have different average sugar content values in blanket residual. Comparative system shows that titration method gives a more than usual response to the amount of blanket residual. Polarography method shows that the dithionite content in the samples ranged from <1.40 to 13.24 ppm. However, in 6 percent of obtained samples from different plants, amount of blanket is more than allowable maximum (10 ppm). Comparing the results obtained from assessment of blanket residual amount in polarography method with titration method, shows significant differences between methods.

Today, due to the accumulation of heavy metals in vegetables irrigated with wastewater and treated with sewage sludge has become increasing concern in the field of food safety and health of consumers. Therefore this study was conducted for analysis of Pb, Cd, Cr and Ni concentrations of 3 types of cabbage marketed in Hamedan City during 2013. For this purpose after buying 30 samples of each species of cabbage and then acid digestion of the samples according to standard methods, elements (Pb, Cd, Cr and Ni) were determined using ICP-OES (Varian, 710-ES, Australia). All statistical analyses were performed using the SPSS statistical package. The results showed that mean concentrations of Pb, Cd, Cr and Ni in Cabbage samples were 15.53±3.43, 59.33±5.35, 2.22±1.61 and 14.97±2.83 mg/kg, respectively; mean concentrations of these elements in red cabbage samples were 23.03±5.89, 37.53±4.21, 13.33±3.24 and 15.03±3.04 mg/kg, respectively; and mean concentrations of elements in broccoli samples were 8.00±3.63, 45.90±5.86, 8.20±3.39 and 16.93±3.08 mg/kg, respectively. Also comparison of the mean concentrations of evaluated metals in specimens with FAO/WHO permissible limits showed that significant difference (p<0.05), so that the mean concentrations of Pb and Cd in all evaluated samples and the mean concentrations of Cr in red cabbage and broccoli samples are significantly higher than permissible limits. Therefore these species is not suitable for consume by human and manage the culture conditions is recommended.

Antioxidants due to the extensive biological properties and their role in preventing of various diseases¡ are considered as components of health. Grape pomacevitisviniferacv.rish baba contains high amounts of antioxidant compounds. Fermentation of grape pomace by Aspergillusoryzae increases the extraction of these compounds. Ultrasound – assisted extraction is the most important methods for the extraction of valuable compounds from plant sources and accelerates the rate of extraction. The aim of this study was to evaluate of various factors effect on the extraction of phenolic compounds¡ flavonoids and antioxidant properties of grape pomace fermented by Aspergillusoryzae and using response surface methodology. The variables were temperature (55-67°c)¡ time (24-32 min)¡ solvent concentration (37-49%) and whey powder content (10-50gr). The highest rate of phenolic compounds and flavonoids were obtained at 64°c for 30 min and the solvent concentration of 46%. The highest level of DPPH and FRAP were obtained at 58°c for 30 min and the solvent concentration of 46%. With increasing extraction time phenolic compounds¡ flavonoids¡ DPPH and FRAP were ascending. Obtained results proved that fermentation by Aspergillusoryzae and using ultrasound – assisted extraction was a suitable method for the extraction of biological material from grape pomace with benefites such as high extraction rate¡ reducing the amount of solvent¡ temperature and time required.

Contamination of dairy products with heavy metals, lead (Pb) and Cadmium (Cd) in particular, induces their toxic effects on humans. Therefore, this study aimed to determine the contamination levels of Pb and Cd levels in milk powders produced in Tehran area. In this study, a total of 25 samples of milk powder was obtained from four different dairy establishments. The samples were digested and extracted prior to analysis. Pb and Cd concentrations was determined using atomic absorption method with graphite furnace. The results were showed a mean value 57.36 ppb (18.99 to112.90 ppb) for Pb and 14.11 ppb (5.73 to 39.43 ppb) for Cd. According to Codex Alimentarius, approved levels for Pb and Cd in milk are 1000 and 100 ppb, respectively. Based on results, Pb level was less than standard limit in all samples, whereas Cd concentration in 68% of the samples was estimated higher than the standard limit. Since the percentage of Cd-contaminated samples was high, there is a necessity for frequent monitoring of the contamination levels in dairy products as well as to discover the potential contamination sources.

Nowadays, the entrance of heavy metals in the aquatic environment is an important and also a global environmental concern due to the indiscriminate discharging of various industrial wastewaters, which cause accumulation of heavy metals in body of aquatic animals including fishes. The present study aimed to evaluate the amount of Chromium and Vanadium in muscle tissue of Chondrostoma regium and Cyprinion macrostomum fish in Kermanshah Gharasou River in 2013. For sampling eight different places were chosen along the river and according to places of discharging municipal and industrial wastewaters. A total of 10 samples were collected from each place and all samples were analyzed for determination of Chromium and Vanadium metals using atomic absorption spectrophotometer. Based on results, mean concentrations of Chromium and Vanadium in muscle tissue of investigating different species among all places were significantly different (P <0.05). The minimum amount of Chromium and Vanadium content was observed at the 3 and 8 sampling stations; while the maximum quantity was determined at the 6 and 8 stations. Results revealed that mean content of Vanadium at the 3, 4, 5 and 6 station was significantly lower (P <0.05) than the standard limit approved by WHO, however, at the other stations the Vanadium content was significantly higher (P <0.05) than the WHO limit. The estimated Chromium quantity of all stations was higher than the FDA and WHO standards (P <0.05). Comparing the results of the present study with findings of other researches and also existing standards (FDA and WHO) indicate high levels of Chromium and Vanadium residues in muscle tissue of fishes. High loads of Pollutants with different types of industrial and municipal wastewater in Kermanshah Gharasou River are the major cause of heavy metals residues. Therefore, it is crucial to apply practical approaches to reduce these pollutants in Gharasou River.