A lot of food poisoning occurs because the food is not heated for a period out of the danger zone which kills bacteria. I run the risk everytime I eat a rare steak or burger, and have had some issues, but not to the point I had to be hospitalized. If when reheated, you don't bring it out of the danger zone, it is like eating rare meat, so you can get sick. The chance of mold can occur, even in a fridge after 4-5 days, and you will not see that at first, so just be careful.

Sometimes, if I know I cannot eat a leftover before 3-4 days, I will vacuum pack and freeze it, then it becomes like a frozen dinner. 💡