Evaluation of the Male and Female Sex Steroid Hormones Residues in Eggs, Milk and their Productsin Alqassim Region

ABSTRACT. The residues of the sex steroid hormones were determined in the milk, eggs and their products. Sixty five samples of eggs (Baladi and Pure Breeds), milk (liquid, powder and condensed), cheese (soft, semi-soft and hard), ice cream, chocolates, butter (local and imported) and yoghurt were used in addition to 97 processed samples were used in this study. Five grams of each sample was taken out after homogenizing the sample in an electric blender, mixed with 10 ml hexane in a conical flask (100 ml) and incubated under shaking in a shaking water bath for 2 hours (30ºC). The sample was poured off into a clean centrifuge tube and centrifuged (3000 rpm/15 minutes, 5°C). The supernatant was aspirated and poured into a clean labeled glass tube. The steroid extract was then exposed to a weak stream of nitrogen gas while samples were incubated on a warm (25ºC) metal block until the whole liquid was evaporated. The precipitate was reconstituted in 5 ml phosphate buffer saline (PBS, pH 7.2). Hormone determinations of progesterone (P4), estradiol17β (E2), testosterone (T) and androstenedione (A2) were conducted by commercial ELISA kits. Results exhibited that the highest residues of the four hormones were detected in fresh eggs followed by milk due to the condensed and powder milk, then cheeses. However, the lowest levels of the four hormones existed in yoghurt. Butter, sweets, ice creams and bakeries contained intermediate levels of the four hormones. Also, baladi eggs contained less residues o