I'm not really cheap! Just wondered if when a blue spot of mold appears in an opened container of apple sauce or yogurt, that means the whole contents are unusable? I needed just 2 tablespoons of yogurt & used sour cream instead, but it seems such a waste from a large carton. With food prices of all kinds climbing, I'd like to know for the future. If I spoon out the mold and use just a bit of the remaining food, then throw out the whole thing, is it a terrible thing? In this case I was baking muffins so I assume the baking will sterilize all ingredients? What about a salad dressing?