Question:

Why does my milk smell soured or soapy?

Answer:

Rarely, some mothers notice their defrosted breastmilk has a soapy taste or odor. This is due to lipase, an enzyme, which helps to digest the fat content of the breastmilk. If this occurs, scald the breastmilk (do not bring to a boil) on a stove until tiny bubbles appear along the sides of the pan; do this before freezing. The scalding process will neutralize the enzyme, preventing the soapy taste or smell.