"The first major discovery was the amount of different species present in breast milk from the very beginning – human colostrum contains more than 700 different bacteria!
By analysing the different factors that influence microbiota composition in breast milk, the researchers discovered major differences related to the type of birth. Breast milk from women who had an elective cesarean section is less diverse in its bacterial composition than breast milk from those who had a vaginal delivery or an intrapartum cesarean (non-elective) section. These findings suggest that the mother’s hormonal status during labour also plays a role."
More than 700 bacteria live in breast milk - Gut Microbiota Worldwatch