During riots, people often loot markets for food and water. Which makes perfect sense: they aren't carrying a lot of resources and a night of high adrenaline rioting will exhaust and dehydrate people.

The only real solution is to provide access to cheap or free food and water throughout and after, but who is going to do that?

The stores themselves could lock up the pricey stuff and offer water access and cheapo food stuff, ask for payment, but not lock their doors or make a huff if people don't pay. But they'd have to plan for it, and not every business is going to be riot savey.

Besides, most biz are covered by insurance, so not really a big deal.