Instrumental Milk Fat Determination. I. Effects of Potassium Dichromate Concentration and Sample Storage Time on Milko-Tester Results

Abstract

At 0.08 to 0.80% levels of K2Cr~O~ the milk fat content determined with a Milko-Tester Automatic was not measurably affected up to 3 days storage at 21 to 27 C. Official methods recommend 0.21%. A depression of less than 0.05% in the fat percentage is detectable by the Milko-Tester Automatic after three days of sample storage. Deviations of more than 0.05% between duplicates and fat percentage depressions of more than 0.1% occurred with and after the fifth day. Storage results at Days 7 and 12 were still more unsatisfactory. A reinvestigation of milk sample preservatives is recommended to establish criteria of use and quality for users and manufacturers.