Standards of identity for food are like rules that say what has to be in a certain type of food. Imagine if you were going to make a cake, you would need sugar, flour, eggs, and other things to make it taste like a cake. Well, the government makes rules that say if a food is called a certain name, like "chocolate milk," then it has to have certain things in it, like chocolate and milk. This helps you know what you are buying and eating. It's kind of like a recipe for making food that companies have to follow.