Pasteurization of human milk causes loss of the bifidogenic effect in vitro and in vivo

Purpose This study aims to investigate in vivo and in vitro the bifidogenic effect of holder pasteurization of human milk. In addition, the effect formula milk feeding and the type of delivery on the early intestinal microbiota of newborns was also investigated. Design/methodology/approach The modulation of good bacteria, particularly bifidobacteria, by human milk feeding either breast (BM) or pasteurized from milk banking (PHM) and formula (FM) was investigated by examining faecal samples of neonates aged between seven and 21 days. The growth of bifidobacteria in raw and pasteurized human milk was investigated using two strains of animal origin and 25 of human origin. Findings Bifidobacteria counts in infants breast-fed were higher (p < 0.05) than in those fed PHM when born naturally. Lactobacilli count in infants fed with FM and BM and born naturally were higher (p < 0.001) than those born through caesarean, suggesting the possibility of microbiota transfer from mother to child. Candida albicans was the predominant yeasts in the infant microbiota. The in vitro growth of all bifidobacteria of human origin was lower (p < 0.001) in pasteurized human milk compared to raw milk. The fat fraction of milk did not influence the growth of bifidobacteria. Originality/value The finding that pasteurization of human milk negatively affects the growth of bifidobacteria, highlighting the need to replace prebiotic thermolabile compounds in human milk banks after holder pasteurization step or to use an alternative technology that better preserves its properties.