Add an anosmia status condition, in which you have no sense of smell:

• Tins cannot be identified by their smell, unless they contain spinach or are empty.
• Messages involving smell, such as when you cast stone to flesh on rocks, are suppressed.
• Food detection scrolls and the spell of detect food don’t work.
• Food appraisal doesn’t work.

Not specified what things in the game might cause this condition, or if it should be a roleplay birth option.

Detect food sources additionally detect potions of fruit juice, and possibly potions of booze.