Steroid hormones level in milk of non-pregnant and pregnant river buffalos at various gestational trimesters

Background: Milk is a valuable sources of nutrition in the human diet however; there are reports on safety of milk steroid hormones contain. This study designed to determine the level of steroid hormones including estrone (E1), 17β-estradiol (E2), and estriol (E3) in raw and pasteurized milk from non-pregnant and pregnant buffalos.

Methods: Steroids was extracted using liquid extraction, enzymatical deconjugation, and C18 solid-phase extraction from collected milk samples. Estrogens were analyzed using high performance liquid chromatography equipped by fluorescence detector.

Results: Free E1 (554.1±77.0 ng/L) and deconjugated E1 (701.6±44.7 ng/L) was found highest level estrogen followed by E2, while E3 level was under the detection limit (10 ng/L). The lowest E1: 554.1±77.0 and E2: 28.1±4.4ng/L estrogens level were determined in raw milk from non-pregnant and highest E1: 1014.7±123.8 and E2: 108.2±9.1 ng/L estrogens were found in milk of animals in the third trimester of gestation. The estrogens concentration in pasteurized milk did not show significant (P>0.05) differences with those in raw milk.

Conclusion: As buffalo milk poses more fat than cow's milk, it may contain higher level of steroid hormones. Since consumption of buffalo's milk with higher amount of steroidal hormones could be considered one of the potential risk factors for carcinogenesis.