Issi b. Guria says: "Holiness" is mentioned here (in respect to meat and milk [Devarim 14:21]), and "holiness" is mentioned elsewhere (Exodus 22:30) "And men of holiness shall you be unto Me, and flesh in the field, treifah (torn) you shall not eat." Just as there, eating is forbidden, so, here.
Where the Meat-and-milk Prohibition Is Stated
Mekhilta Tractate Kaspa 5:26