Probably, at some point in your life, you have accidentally had a sip of spoiled milk, and the taste disgusted you. However, despite the horrible taste, it does not necessarily mean that you are in danger.
However, be careful when it comes to these things since there are products in the kitchen that can really affect your health in ways you have never imagined. Therefore, never ignore the expiration date of these products.
A lot of people consider that potatoes have no expiration date, but this is not true. In fact, potatoes whose date has expired have a toxin that wards off pests which is highly dangerous for people. So, the next time you see a green potato in your kitchen, be sure to get rid of it immediately. Otherwise, if you consume it, serious problems with the nervous system may develop. Furthermore, if you notice a mold on bread, do not just remove it, but throw the bread away because its consumption may cause stomach problems, and even lead to more serious health problems, like cancer. Also, you need to avoid consuming bad eggs which can cause stomach problems or more serious conditions such as salmonella. A good way to determine the quality of an egg is to see whether the yolk and the white are separated. If they are separated, get rid of the egg right away, otherwise it is safe for consumption.
Reference: Super Tasty Recipes