Estrone, 17b-estradiol and progesterone concentrations in processed milk with different fat content

Abstract

Introduction. The aim of this study was to determine estrone (E1), 17β-estradiol (E2) and progesterone (P4) concentrations in processed milk with different fat contents and to compare the concentrations of these hormones in commercial ultrahigh temperature (UHT) processed milk and commercial pasteurized milk.

Materials and Methods. Commercial milks with different fat contents (UHT 0.5 %, UHT 1.5 %, UHT 3.5 % and pasteurized 3.5 % (10 samples of each type of milk)) were purchased in local stores. E1, E2 and P4 concentrations were determined by commercial ELISA kits.

Results and Conclusions. E1 concentrations were below the limit of detection (15 pg mL^-1) in all milks except in one each of UHT 3.5 % and pasteurized 3.5 % milks. Mean E2 and P4 concentrations in UHT 3.5 % milk (25.37 ± 1.15 pg mL^-1 and 10.76 ± 0.43 ng mL^-1, respectively) were significantly higher than in UHT 0.5 % milk (19.38 ± 0.79 pg mL^-1 and 7.06 ± 0.26 ng mL^-1, respectively). Significant positive correlations were determined between hormone concentrations and milk fat contents. Relatively high E2 and P4 concentrations indicate that the bulk of milk in the commercial milks examined originated from pregnant cows.