A SIMPLE QUANTITATIVE CATALASE PROCEDURE FOR ABNORMAL MILK1

Abstract

Summary A simple, quantitative catalase test for detecting abnormal milk has been described. This procedure utilizes a 10 ml. B-D Yale glass syringe with a 23 ga 1/2 inch Luer-Lok needle. The needle tip is plugged by inserting into a No. 00 rubber stopper. Five ml. of milk and 0.5 ml. of 3% H2O2 solution are measured into the syringe barrel. The plunger is inserted, syringe inverted, and stopper loosened to allow the discharge of all entrapped air from the syringe. The syringe is then re-closed, set upright, and incubated at 72 F for 3 hours. The volume of O2 released is measured as ml. O2 (directly on the scale) and converted to % O2 by multiplying the reading by 20. This test provides a simple, efficient, and reproducible procedure for reporting catalase activity on the basis of percent oxygen evolved during a standardized test period. A comparison of the Clemson and Wisconsin Catalase test procedures indicated consistently lower values for the latter. Possible reasons for this variation are mentioned.