To be on the safe side, don’t eat your cereal once it’s expired. Cereal expired how long can not eat, can not be generalized, depending on the preservation status of the food, the shelf life of the food is affected by a variety of factors, such as water content, storage temperature, the number of flora, closed, whether to add preservatives and so on. So it’s hard to tell how long you can’t eat the food when it’s expired. Expired food may have many risk factors such as exceeding the bacterial flora count, loss of nutrients, increase of harmful substances and so on. Consuming expired cereals may cause serious damage to the body. There are countless cases of food poisoning reported in China every year, and a significant number of them are caused by consuming expired products. Food safety is a big deal, so just in case, don’t eat cereal once it expires.