Musannaf Ibn Abi Shaybah

Hazrat Aamir (may Allah have mercy on him) says that there is no khums on food; khums is only on gold and silver.

Hazrat Ibn Aun (may Allah have mercy on him) says that I asked Hasan (may Allah have mercy on him), "We find honey, ghee, and cheese, etc. in the enemy's land, so should we also pay khums on these?" Hasan (may Allah have mercy on him) replied, "We also used to find all this, and we would just eat it."