Are questions about raw food on-topic?
As based on the domain prefix (cooking), the site looks like it's only about the cooking.
Any questions on food preparation are on-topic. Indeed, this is our core topic, with a few related ones also being in scope.
English doesn't have a word which is unique to food preparation, so it uses "cooking" instead, even though this is frequently associated with preparing food by using heat. If you keep in mind that it is this broader sense of cooking which is meant here, it becomes more clear.
The usual off topic reasons still apply, of course. "Are raw carrots healthier than pureed carrots" is obviously off topic, as it is about nutrition. "What dressing to use for a raw tomato salad" is off topic, because it's about food pairing. And so on.