Bamdad Riahi-Zanjani - Medical Toxicology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
Gholamreza Karimi - Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
Mostafa Heidarzadegan - Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
Hasan Badibostan - Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran

Due to nutritional facts of milk in human life, the quality assessment of dairy products is of the utmost importance. The aim of the current study was to determine the 17β-estradiol level in commercial pasteurized and sterilized milk brands in Mashhad, Iran. In this regard, 160 samples including 80 pasteurized (40 high-fat and 40 low-fat) and 80 sterilized milk (40 high-fat and 40 low-fat) of widely used brands from different supermarkets were collected. The quantitative analysis of 17β-estradiol in the milk samples was performed by competitive enzyme immunoassay method based on antigen–antibody reaction, using the commercially ELISA kit. The mean level of 17β-estradiol was 8.2 ± 0.59 pg/ ml. The mean amount of estradiol was found to be 7.6 ± 0.47, 7.9 ± 0.45, 8.6 ± 0.63, and 8.9 ± 0.54 pg/ml for the low-fat pasteurized, low-fat sterilized, high-fat pasteurized and high-fat sterilized milk, respectively. There was no significant difference between the amount of estradiol in pasteurized and sterilized milk. As expected, the level of estradiol was statistically higher in high fat milks than that of low-fat milks. Considering the levels of 17β-estradiol measured here and the maximum permissible daily level of external estradiol entered to body through edible products recommended by EU and CAC (3.5 μg), at least in the short term, there will be no remarkable impact on the endocrine system. However, judging the long-term effects of using these products is not easy and simple at all, as cancers develop during a long period of time and has a multifactorial etiology. Hence, dairy cattle milk samples of various livestocks must be regularly/strictly checked and controlled for 17β-estradiol.

17β-estradiol; Pasteurized milk; Sterilized milk