Would it be safe to eat leftover food after microwaving it?

This may sound like a strange question but this is the situation I m in. I m a vegan, which means I don t consume any animal products. I do miss eating meat though. I have a friend who works at a restaurant and I was thinking of eating leftover food from people s plates that would normally be thrown out. This way I could eat the foods I love without supporting the cruelty to animals that happens on factory farms. Would it be safe to do this if I microwaved or reheated the food in an oven to sanitize it? Would this kill the herpes virus? And I know you can’t get HIV from saliva but what if someone had bleeding gums or a canker sore and it got on the food? Also how likely is it to get hepatitis this way? Does either microwaving or cooking in the oven work better than the other for killing germs? Thank you for your help!!