Background: Breastmilk is the recommended aliment for preterm infants. Milk banks provide donated breastmilk for the neonatal care of preterm infants when mother's own milk is not is available. To avoid pathogen transmission, donated breastmilk is heat-treated according to different procedures before administration. There is varying information on the effect of heat treatment on folate in breastmilk. Sufficient folate intake, however, is essential for normal growth and brain development. This study determined and compared the effects of different heat treatments on breastmilk folate content and pattern of individual folate forms.
Materials and methods: Donated Swedish breastmilk samples were heat-treated according to three procedures: two low temperature treatments (57°C, 23 minutes; 62.5°C, 12 minutes) and a rapid high temperature treatment (heating to 73°C in boiling water). The folate content and pattern were determined before and after treatment by high-performance liquid chromatography.
Results: The folate content in 38 untreated Swedish breastmilk samples was 150±46 nmol/L. Two different folate vitamers were detected: 5-methyltetrahydrofolate (78±7%) and tetrahydrofolate (22±7%). Heat treatment affected only tetrahydrofolate stability and decreased folate content by 15-24%; however, the effects on folate content did not differ among the investigated heat treatment procedures.
Conclusions: Folate losses during heat treatment of human milk were considered acceptable. Yet, native folate content of heat-treated, non-fortified breastmilk supplied only 25% of the recommended daily intake for preterm infants.