It is believed to be a common behavior in life that when food is stored improperly and spoiled, it is safe to continue eating it after boiling or steaming it through and other heating methods to kill the bacteria. In fact, spoiled food is not only bacteria so simple, there are various by-products of microbial metabolism, often these products are more harmful. Why can’t you eat food after high temperature heating? Because heating can kill the bacteria, but not the toxins that remain in the food. Just out of the pot of food is almost no bacteria, but the biochemical environment, including human skin, mouth and nose are distributed in a variety of bacteria. These contaminated food (eaten, stirred, left for too long) more or less brought in a variety of microorganisms, multiplying in the food to produce a variety of by-products and then remain in the food, including staphylococci multiplying enterotoxins. The enterotoxin produced by staphylococci, for example, is highly heat resistant and can be boiled for several hours without being destroyed, but still remains toxic and is one of the most common causes of food poisoning. It is important to note that overnight food does not necessarily have a rancid taste and may not have enterotoxins, but it is always not fresh food, more or less microbial reproduction, it is not clear what other bacterial metabolites will damage health, so try not to eat, long-term is certainly not good, all still need to eat fresh food.