Is it permissible to use breast milk as an ingredient in food products such as probiotic sources?

Summary

Using components or content from breast milk as a food ingredient, including as a probiotic source, is prohibited for all age groups. The reasons include that breast milk must not be treated as merchandise and that surplus milk is better given to nursing infants. The ruling also cites precaution against confusion of lineage, the fact that such products are only a complementary need (tahsiniyyat), and the choice of the view that forbids selling any part of the human body, including breast milk. Surplus milk is best given to other infants in need.

Written in our own words from the original fatwa — check the source before acting on it.