نشریه بهداشت مواد غذایی
سال سوم شماره 2 (پیاپی 10، تابستان 1392)

The antibacterial effect of etbhanolic extract of Sumac (Rhus coriaria L.) was investigated quantitatively and qualitatively on Escherichia coli. The results of well diffusion test showed that extracts of Sumac in concentration of 0.5%, 1%, 2.5% and 5% could inhibited E. coli. In this study it was shown that MIC of the alcoholic extract of Sumac against E. coli was 6.25 mg/ml and its MBC against this bacterium was 50 mg/ml. The results from evaluation of the antibacterial effects of the Sumac revealed that at 4 and 15 °C, the growth of E. coli in test tubes containing meat extracts has increased Throughout the 48 h of incubation period. Results showed that the growth of this bacteria in different concentration of Sumac extract as decreased in the both tested temperatures in comparison to time zero (p<0.05). Furthermore, there was a significant difference in the number of microorganism at various times between control and experimental groups in both tested temperatures (p<0.05).

Mechanically deboning poultry meat (MDPM) is widely used due to its suitable technological properties as well as low lipids and saturated fatty acids contents. Besides, production processes applied during the surimi production can improve the technological properties of MDPM. That is to say, the production steps of surimi can change chemical composition and concentration of myofibrillar proteins and improve functional properties of MDPM. In this study, MDPM was prepared from the poultry meat. The production process consisted of 2 washing steps with sodium bicarbonate solution followed by another washing step with 4°C water. Afterwards, chemical properties of MDPM and surimi (moisture content, protein, lipid, and ash content) as well as electrophoresis pattern were evaluated. Result showed that surimi production steps could significantly decrease protein, lipid and ash contents; however, moisture content of MDPM increased significantly. The result of electrophoresis indicated a significant increase in heavy chain myosin with 200 KDa and actin with 45 KDa molecular weights. It was concluded that the production steps improved the chemical properties and increased the concentration of MDPM myofibrillar proteins.

A new single drop micro-extraction method based on ionic liquids was developed for the preconcentration of ultra-traces of silver and copper prior to its determination by electro-thermal atomic absorption spectrometry (ETAAS). An 8-μL drop of ionic liquid, 1-hexyl-3 methylimidazolium hexafluorophosphate, [C6MIM][PF6], was used for the extraction of silver and copper ions as dithizone complex. Important variables affecting microextraction efficiency and ETAAS signal, such as pyrolysis and atomization temperature, dithizone concentration, extraction time, drop volume and stirring rate were investigated and optimized. Under the optimum experimental conditions, the detection limits (3 s) of the method were 4 and 8 ng L-1, for Ag and Cu, respectively and corresponding relative standard deviations (0.1 μg L-1, n = 6) were 4.2% and 4.8%. The developed method was successfully applied to the determination of copper and silver in food and water samples.

Heavy metal pollution of agricultural soils is a major environmental problem that can affect plant production, food safety and human health. Soil contamination with heavy metals occurs as a result of human activities. Heavy metals can easily accumulate in edible tissues of leafy vegetables, fruits and seeds. Few studies have been conducted on heavy metals concentration in soil and greenhouse crops. Therefore, this study aimed to determine the concentrations of lead (Pb) and zinc (Zn) in greenhouse cucumbers produced in Hamadan province. The concentrations of heavy metals were measured using atomic emission method. Results showed that the mean concentrations of Pb and Zn in cucumber samples were 0.33 and 3.14 mg/kg, respectively. Also the results of the statistical analysis revealed a negative correlation between the measured concentrations. Moreover, the concentration of Zn in the samples obtained from Hamadan greenhouses and lead concentration in Tuyserkan, Famenin, as well as Malayer samples were above the recommended limits. Daily intake amounts of Pb and Zn from vegetables consumption for three age categories (children, adolescents, and adults) were calculated. In conclusion, daily intake of Pb and Zn were determined below the recommended limits.

Aflatoxins are a group of mycotoxins mainly produced by common fungi Aspergillus flavus, A. parasiticus and A. nomius. Aflatoxin M1 (AFM1) is the major metabolite of aflatoxin B1. AFM1 is also known to be hepatotoxic and carcinogenic. The purpose of this study was to investigate the contamination level of AFM1 in raw cow milk of Tabriz. A total of 90 raw cow milk samples was collected randomly from Tabriz suburb milk-collection-centers between July to September 2012. Determination of AFM1 was based on ELISA assay. Based on the results, AFM1 was found in 100% of cow milk samples. The mean contamination rate was 148.37 ± 19.27 ng/l. Moreover, 37.77% of cow milk samples had the contamination level over the maximum tolerance limit (100 ng/l) accepted by Iranian National Standard. It was concluded that high incidence and contamination level of AFM1 in cow's milk is of great concern. The periodic monitoring of cow raw milk for the contamination of AFM1 in Tabriz area is recommended.

This study was conducted to determine the concentration of Vanadium (V) and Nickel (Ni) in the edible muscle tissues in male and female Fenneropenaeusindicus. For determination of the concentration of heavy metals in muscle tissues of edible Indian prawn in Shiraz city in autumn of 2011, 120 samples have been obtained randomly from Shiraz retail. Preparation and analysis of samples were performed by standard method using Atomic Absorption (Varian V10-ES) and then the concentrations of the heavy metals were compared with the recommended international standard. In this study the mean concentration of V in muscle of male and female were estimated at 1.06 ± 0.64 and 0.7 ± 0.54 mgKg-1, respectively. However, the concentration of Ni in muscle of male and female was determined as 8.1 ± 1.173 and 9.1 ± 0.79 mgKg-1, respectively. The analysis of the data showed that the concentration of Ni in the muscle of male and female samples had significant difference (P<0.05). In this study, concentration levels of metals in the muscle tissues were above the acceptable limit established by WHO and FAO.