Determination of the Most Toxic Polychlorodibenzofurans in Fresh Milk from Southwest Iran

Abstract

Background: Today’s presence of polychlorinated dibenzofurans (PCDFs) in foodstuff, such as milk and milk products, is considered to be the major concern for human health. This study was aimed to determine the concentrations of the most toxic congeners of furans in pasteurized milk samples produced in southwest Iran. Material and method: 15 composite samples of pasteurized milk were collected from 3 major dairy factories in Khuzestan Province (southwest of Iran) in summer, autumn and winter from July 2011 to March 2012. After precipitation of the proteins, fat phase was reduced and extracted with hexane and ether. After dehydration, furans existed in fat percolated with hexane through a column chromatography that contained respectively silica gel/silver nitrate, silica gel, silica gel/sulphuric acid and with percolating output through another column that contained activated charcoal and silica gel and washed the lower column with a mixture of dichloromethane-hexane and toluene, concentrated and dissolved in mobile phase and analyzed using HPLC: 150 mm × 4.6 mm ID, 5 μm cosmosil 5 NPE column equipped with a UV detector at 254 and 235 nm, mobile phase: methanol/water (80:20, v/v) at flow rate of 1 ml/min. Results: All samples were found to be contaminated with furans. The average concentration of 2,3,7,8 TCDF and 2,3,4,7,8 PCDF were 1.91 pg/g and 1.77 pg/g in lipid content ranging from 2% to 3% respectively. The mean total content of furans in milk fat was 0.36 TEQ (Toxic Equivalency) pg/g which was below the recommended EU (European Union) threshold value 3 pg (WHO-PCDFs-TEQ/g fat). Also, result showed that there were statistically significant differences between each factory during 3 seasons.