Comparative study of the quality of processed stored milks

Abstract

Cow’s milk is part of the diet of children older than 1 year. The thermal processes used by the dairy industry may affect some of the nutrients present in milk. This study evaluated the effect of processing milk in terms of the nutritional and chemical quality of pasteurized, spray dried and UHT milks using the same batch of milk as raw material. All milks showed no change in macronutrients immediately after production and after a 90 day storage period for spray dried and UHT milk, with similar contents when expressed on a liquid basis and comparative solid levels. Regarding micronutrients, a significant decrease in the content of available lysine and vitamin A in spray dried milk and in linoleic acid in UHT milk was found after storage. The results of the sensory panel showed that although UHT milk obtained higher scores in some attributes of the quality test and in acceptability, all milks presented with good quality, good acceptability, and showed minimal differences between them, and compared to a control at both evaluation times. We conclude that inspite of the adverse changes found in some of the nutrients of both milks, the nutritional status of the infants should not be affected if they are receiving other foods as part of a balenced diet.