The thing is, most of the vegetables will be peeled first and then cooked. The fruit will be well washed before eating. Meat will be cooked. I can see that, say, bread will need to have some sort of cover, as it may not be heated before eating. Similarly ham or tongue.

Our milk came in glass bottles which one later washed for the milkman to collect. They were refilled at the dairy.

But decades ago, we had a nice compost heap where the peelings went.
We never became ill from food poisoning. In fact, I'd say we were healthier in those days than people are nowadays.

I'm so tempted to do what has been suggested on 'green' websites, and after passing through the checkout, unwrapping/removing all the plastic junk and leaving it for the supermarket to deal with! It amounts to absolute piles and piles from a single visit.