Before you have to try the food to know if it is really in poor condition, you can also look at its color or smell, as well as guide you through the steps explained below and know how to detect food in poor condition. Leaving a plate of food in the fridge for days or more than a week does not guarantee that it will maintain its state when we decide to eat it, so we have to be careful and look at what we explain to make sure that it has really been put in poor condition Steps to detect spoiled food Sour milk and expired yogurts. Pasteurized milk does not normally develop microorganisms that are dangerous to humans: if you have drunk a coffee with sour milk by mistake, it is very likely that nothing bad will happen to you (even if the taste is not the best). The process that causes milk to sour and curdle is actually the same as the one that allows cheese and yogurt to be produced: the latter, in particular, can be consumed up to seven days after the expiration date. However, remember that the more time passes from the date of consumption of a yogurt, the less vital the bacteria that make it such a special food will be.