Bacterial Growth and Vitamin Content of Milk1

Abstract

Five brands of whole milk from retail stores were analyzed for quantitative vitamin changes when the samples had developed off flavor in storage at 10 C. Vitamins A, B₆, and niacin decreased by a small but significant amount. Average concentration of thiamine, riboflavin, and B₁₂ were not changed during bacterial growth. Cultures for Dagano cheese and yogurt and two strains of Streptococcus lactis decreased the contents of Vitamin A, riboflavin, and B₁₂ during growth. The averages for thiamine and B₆ content were not significantly changed. Niacin content was decreased by growth of each of the four cultures. Three strains of Bacillus subtilis and six other species of bacteria that caused off flavor in milk during growth produced no significant changes in contents of Vitamins A, B₆, B₁₂, and riboflavin. The mean contents of thiamine and niacin were decreased, but two species did not cause a decrease in niacin.