a). When they're leaving for a long trip their instructions are always to do with some food related topic e.g. "Make sure when you open the fridge don't leave the door open too long or else the chicken will taste bitter when i cook it Sammy."
b). Everytime you use one of their food items without telling them you make sure you wash the dishes way very fast so that they don't realize it and you can replace it before she goes to use it next. Usually this happens with eggs or milk
c). All the fondest stories they will tell you will always involve them quoting what food they ate that day e.g. "My sister's wedding was so good. We ate so much cake and ice cream after, and her dress was also good"