The three or four major natural things that prevent bactera from growing in your small intestin are, number one, stomach acid. Bile acts as a very strong anti microbl it's also important to absorb fat soluble nutrients. Then you have the migrating mortar complex, which is this electrical sweeping of the bowels to move food particls through and substraits that the microbes could potentially metabolize.
Kiran Krishnan is the chief microbiologist at Just Thrive with 17 years of experience in the dietary supplement and nutrition market. He comes from a strict research background, having spent several years with hands-on R&D in the fields of molecular medicine and microbiology at the University of Iowa. Full show notes: https://maxlugavere.com/podcast/252