EVOLUTIONARY CHANGES IN THE CORNELL PHOSPHATASE TEST

Abstract

Summary The Cornell phosphatase test, with its single buffer for milk and all dairy products, has been adopted successfully and widely in the past 15 years. Recent changes in national and state regulations raising temperatures to high levels for acceptable pasteurization, and direct experience gained on the behavior of chemical reagents in phosphatase testing have suggested evolutionary revisions in the Cornell test, leading to greater simplicity without upsetting its demonstrated past high sensitivity and reproducibility. Changes include estabishing one hour as the incubation time for the standard test, simplifying color standard preparation, substituting CQC for BQC, reducing time of color development to 5 min, emphasizing butyl alcohol extraction and selecting a lower level phenol value for defining underpasteurization. The revised Cornell standard 1-hr phosphatase test detects 0.1% raw milk addition to pasteurized milk and a drop of between one and two degrees in HTST milk pasteurization processes. It does the above with less reagents and in a shorter time than formerly.