A Quantitative Procedure for the Determination of an Inhibitory Substance in Milk—Penicillin

Abstract

A method for the quantitative estimation of penicillin based upon the ability of this antibiotic to inhibit the production of nitrite from nitrate by an actively growing culture of Micrococcus pyogenes var. aureus is described. The test is applicable for the critical range of penicillin in milk, (0-0.5) units/ml.