Albert Barnes Commentary Leviticus 22:2

"Speak unto Aaron and to his sons, that they separate themselves from the holy things of the children of Israel, which they hallow unto me, and that they profane not my holy name: I am Jehovah." — Leviticus 22:2 (ASV)

Speak ... that they so abstain from touching the holy things (i.e., the sacrificial food of all kinds) of the children of Israel which they consecrate unto me, that they profane not my holy name. This law related to the daily life and the ordinary food of the priests.