Infant formula physical stability.

The physical nature of liquid infant formula products is characterized in terms of emulsion, suspension, and solution processes. Such mixtures inevitably undergo phase separation. A variety of physical and chemical phenomena govern the gradual changes in the appearance of these products. The consequent loss of physical elegance is primarily a question of consumer acceptance. Only in the most extreme cases do the physical characteristics deteriorate to the point that swallowing and digestion are affected. Recently, both public and regulatory attention has been focused on the physical characteristics of liquid infant formula products. Formula appearance is the product aspect most readily evaluated by the consumer. The design and manufacture of products that will have consistent appearance over extended periods is a difficult technical problem. This presentation summarizes the phenomena responsible for changes in the physical characteristics of liquid infant formula products. Product defects are discussed and methods for product evaluation are described. Representative data on the effect of storage on product physical elegance also are presented.