So far, we were told that Mother’s milk is sterile. Absolutely pure.
And with this image, we also strive for Dairy milk. Pasteurized! Sterile. No bacteria at all!
That is the level of modern scientific temper we are proud of. 
🙂 And investing heavily so that our kids are groomed under it. 🙂 (This does not mean I do not respect science and her achievements. Just a direction and outlook to look at nature is wrong).
In Ayurvedic understanding, no organism is harmful. Everyone is doing their job (or following their Dharma). Bacteria in milk are necessary. They are their to help the consumer of the milk.
“Culture-dependent and -independent techniques have revealed the dominance of staphylococci, streptococci, lactic acid bacteria and bifidobacteria in this biological fluid, and their role on the colonization of the infant gut. These bacteria could protect the infant against infections and contribute to the maturation of the immune system, among other functions.”
It is high time we get rid of this germ-phobia. ASAP. Sooner the better.
The way mother’s milk helps infant, Gau milk helps adults.
On immediate basis, dairy milk should be replaced with raw milk from Gau shala where ethical practices are followed (Calf’s milk is not snatched. No hormone injections are used. Machines are not used for milking etc)
Research
The human milk microbiota: origin and potential roles in health and disease.
https://www.ncbi.nlm.nih.gov/pubmed/22974824
Human milk has been traditionally considered sterile; however, recent studies have shown that it represents a continuous supply of commensal, mutualistic and/or potentially probiotic bacteria to the infant gut. Culture-dependent and -independent techniques have revealed the dominance of staphylococci, streptococci, lactic acid bacteria and bifidobacteria in this biological fluid, and their role on the colonization of the infant gut. These bacteria could protect the infant against infections and contribute to the maturation of the immune system, among other functions. Different studies suggest that some bacteria present in the maternal gut could reach the mammary gland during late pregnancy and lactation through a mechanism involving gut monocytes. Thus, modulation of maternal gut microbiota during pregnancy and lactation could have a direct effect on infant health. On the other hand, mammary dysbiosis may lead to mastitis, a condition that represents the first medical cause for undesired weaning. Selected strains isolated from breast milk can be good candidates for use as probiotics. In this review, their potential uses for the treatment of mastitis and to inhibit mother-to-infant transfer of HIV are discussed.
