Mothballs in food cabinets
Mothball is a mild poison.  msds  

Contamination via vapor to food may only be mildly toxic but not a good idea. 

You can keep food in unopened cans and air tight glass containers. Wipe them down with a mild detergent. Sealed plastic containers is questionable. Remove everything then wipe the cupboards and walls with a light detergent. Let them dry / air out thoroughly before returning food to the cupboards.