I can't say I'm familiar with them, although I've occasionally eaten very little cooked food. Bulk of the calories could come from fish, milk, eggs, nuts, fruit and vegetables. Fish and eggs carry a risk of food poisoning if you don't know your source. So does red meat.

It's possible that this wouldn't be a significant problem if your GI-tract and immune system were used to these kinds of threats however. It's also possible that bacteria causing food poisoning are more potent and more common than they used to be or than they are in nature.