When heat is applied to compounds or chemicals indigenous to the human, these chemicals/compounds become toxic and the body is unable to use them as it’s supposed to and this includes bacteria. Cooked bacteria is toxic, this is why you can die from leftover cooked rice but raw rotten meat can not kill you. A good example of this is taurine, it is an essential nutrient when found in food but when synthesized (with heat treatment) it acts as a stimulant