Factors Affecting the Vitamin B1 Content of Evaporated Milk

Abstract

The work of several investigators who have studied the vitamin B1 content of evaporated milk has been recently reviewed by Daniels. She reported two trends in results: certain workers had found about 50% destruction of vitamin B1 when evaporated milk was compared with raw milk, whereas others had observed only 0-20% destruction. Using a modification of the 10-day rat growth technic of Schlutz and Knott, Daniels assayed raw Guernsey milk and commercial evaporated milk. Her results indicated 60% less vitamin B1 in the evaporated milk than was present in the raw milk. Since certain studies in our laboratory differed from the results presented by Daniels, and because she had used repeated assays on the same animals but had not employed an improvement we had reported for our basic ration, we have thought it advisable to investigate further the effect of the process of evaporation upon vitamin B1. Fresh raw milk was immediately iced and delivered by special messenger together with evaporated milk prepared from the same lot. By careful refrigeration the raw milk was kept sweet for the duration of the test. The evaporated milk was stored at room temperature. Sixty-gram rats were fed the following ration: 15.0% vitamin-free casein, 15.0% dried autoclaved liver, 45.5% sucrose, 17.0% Crisco, 3.0% cod liver oil and 4.5% modified Wesson's salts. After 22-25 days when a rat had been depleted of its vitamin B1 reserve and was losing weight slowly but steadily, it was given a daily supplement of the material to be assayed. The dose was continued for 10 days, the amount being changed from day to day, if necessary, to maintain a gain of about 2 g per day.