[folli]

Breast milk is inherently sterile (unless the mother has a severe bacterial infection). It usually gets contaminated with the skin microbiota during feeding.

So no, I wouldn't count on L. reuteri being found in a random sample of breast milk.

[joe-collins]

Breast milk is not sterile.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2643565/

[folli]

That's hotly debated. Even the study you cite cannot rule out skin contamination.

But unequivocally showing the existence of entero-mammary pathway (translocation of maternal gut bacteria from the gut to the mammary glands) would be very exciting news indeed.

[bawolff]

In the context of this conversation, does it matter whether the cause is skin contamination or not?

[TedDoesntTalk]

Yes, because if you are buying breast milk from a woman who used a breast pump, then the skin contamination is very very little compared to actual breast suckling.

A seller:

https://cosprings.craigslist.org/hab/d/colorado-springs-brea...

[__alexs]

So you're telling me I should actually be drinking all of this e-girl bath water I bought?

[TedDoesntTalk]

The article says that L. reuteri is present in other places in the body besides the gut.

[candiddevmike]

You can get HIV from breast milk, it's not sterile.

[folli]

HIV is an infectious virus. Also, bacteria in milk is usually a sign of mastitis. I'm explicitly talking about healthy mothers.

[stefantalpalaru]

> Breast milk is inherently sterile

There is nothing sterile in the human body. Not even the brain.

[folli]

You've put more confidence in your statement than the scientific consensus allows.

A brain microbiome is hotly debated, no concrete proof (yet?). I personally also have a hard time believing in a healthy bacterial blood microbiota, but it's also proposed.