Stability of ascorbic acid in milk at different stages of processing

Abstract

Mixed herd milk was pasteurized on a commercial scale by the holding method, in typical dairy plant equipment. At twenty-two intervals during the school year samples were collected at four stages of processing; namely, a sample of the thoroughly mixed raw milk, a sample of the hot milk as soon as pasteurization was completed, a sample of the first milk through the cooling and bottling equipment, and a sample from the last milk through the equipment. The stability of the ascorbic acid was determined by assaying the various samples initially and at twenty-four-hour intervals during ninety-six hours storage in darkness at 10° C. The amount of ascorbic acid varied widely for milk at different stages of processing. The stability of the ascorbic acid was low, and milk taken at all four stages of processing lost ascorbic acid very rapidly during storage in a home-type electric refrigerator. Thus, when milk constitutes the major portion of the diet as in infant feeding, it should be accurately enriched with ascorbic acid. Mixed herd milk was pasteurized on a commercial scale by the holding method, in typical dairy plant equipment. At twenty-two intervals during the school year samples were collected at four stages of processing; namely, a sample of the thoroughly mixed raw milk, a sample of the hot milk as soon as pasteurization was completed, a sample of the first milk through the cooling and bottling equipment, and a sample from the last milk through the equipment. The stability of the ascorbic acid was determined by assaying the various samples initially and at twenty-four-hour intervals during ninety-six hours storage in darkness at 10° C. The amount of ascorbic acid varied widely for milk at different stages of processing. The stability of the ascorbic acid was low, and milk taken at all four stages of processing lost ascorbic acid very rapidly during storage in a home-type electric refrigerator. Thus, when milk constitutes the major portion of the diet as in infant feeding, it should be accurately enriched with ascorbic acid.