Abstract: The objective of this study is to establish a rapid detection method for milk with urea content exceeding physiological range. Based on the fact that pH increase could result from urea enzymolysis positively correlated with urea concentration. Bromothymol blue was chosen as the acid-base indicator to determine high-urea milk. The indicator can develop color from yellow-brown to green-blue when urea content was higher than 40 mg/100 mL. On the basis of our present study, the developed reagent kit for the determination of high-urea milk is useful for practical application.

Key words: adulterated milk, pathological high-urea milk, test paper, milk-urea reagent kit, urease, milk urea nitrogen