It sounds like the careless actions of the general public really bother you. Let me tell you something: grocery stores are low margin retailers who make their money by volume of sale, not enforcing conformity. The moment you open your doors to the public, you are going to get all kinds of mentally ill, aloof, high/drunk, distracted, disabled, elderly/senile, and (literally) retarded people in your store. It's futile to judge their actions using your idealist looking glasses.
The moment you start kicking people out over subjective "rule-violations", you are eating into your own profits, pissing off people, and projecting your own morality onto strangers. Aunt Minny may have set down that roast because it hurts her hip to walk across the store, and she realizes she already bought a roast yesterday. But over the last 10 years she's spent $25,000 shopping there. Some guy with Crohn's disease may literally shit on your floor if he doesn't drop his perishable item and run home/to the rest room. If both of those people are regular shoppers, sure the lost perishable item eats into your bottom line, but in the long run you are making a profit off them.
Waging an unnecessary morality war can only impede your ability to run a profitable business.
Edit: why not just give employees handheld IR thermometers, and if the temperature of the product is < $MEAT_MAX or $VEGGIE_MAX degrees then allow them to restock it.