Human milk composition and the effects of pasteurisation on activity of components

Abstract Background Human milk is the ideal source of nutrition for infants, especially during the first six months of life. Milk components can protect against inflammation and infection and stimulate immune maturation. In cases where mothers are unable to express breastmilk, pasteurised donor milk is a preferred option. Distributed from human milk banks, donor milk is particularly important to preterm infants. Born with an immature gut, these infants are at risk of developing diseases such as necrotising enterocolitis and sepsis. While Holder pasteurisation of breastmilk is recommended, this together with other heat treatment processes can lead to the inactivation of bioactive components and change the composition and content of the major milk components. Scope and approach This review examines previous studies on the impact of pasteurisation of human milk on the bioactivity of proteins, content and composition of oligosaccharides and lipids. More recent studies investigated the effect of pasteurisation on the enzymatic properties of bile salt-stimulated lipase, which naturally occurs in human milk and contributes to lipid digestion and absorption. These studies highlight the potential consequence of pasteurised donor milk on the growth and development of an infant. Key findings and conclusion The bioactivity of proteins is reduced due to pasteurisation thereby hindering their ability to exert their immunological properties. However, the content and composition of oligosaccharides and lipids still remain the same following heat treatments. Despite this, the decrease in bioactivity of lipases would impair the digestion and absorption of lipids. It is thus critical to ensure that conditions such as the temperature and heating time are chosen carefully when producing donor human milk.