Repeat A: What's the white stuff on your food? B: It's sour cream. Want to try some? A: I don't think so! It sounds gross. B: It's not really sour. A: Why is it called sour cream, then? B: I think it's because they let the milk go sour to make it. A: You're eating sour milk? Yuk! B: Cheese is made in a similar way. A: I thought cheese was made with bacteria. B: Of course! Bacteria cause milk to go sour. A: Dairy products are so strange. B: Even so, I think they're delicious!