The vitamin B12 potency of pharmaceutical (including dietetic) products estimated by the Ochromonas method.

Abstract

Abstract The vitamin B12 potencies of a number of pharmaceutical products were estimated microbiologically using Ochromonas malhamensis. The low B12 contents found in 9 samples of dried milk, compared with the contents of fresh milk samples, indicated losses during normal drying processes. Rather smaller losses occurred during vacuum drying. In 12 samples of infants' and children's foods the vitamin B12 contents ranged from nil to 21 mμg./g., excluding one sample fortified with the vitamin. Storage experiments indicated no significant loss of vitamin B12 in dried milk, in foods based on dried milk or in non-allergenic foods based on modified cows' milk or on malt and soya fortified with the vitamin. There was, however, a marked and rapid loss of the vitamin in products which also contained ascorbic acid. This could be prevented by stabilisation of the vitamin with gelatin. Storage experiments on capsules and tablets containing vitamin B12 and ascorbic acid did not detect losses of vitamin B12 during normal storage in this country. There were marked losses of the vitamin in two brands of capsules, but not in one brand of tablets, during a year's storage in the tropics. These all contained ascorbic acid.