Ive actually heard that too about deli meats and have avoided eating them. Perhaps because if you think about it, the meats at the deli have been sitting out, and you dont know how long or if theyre at the right temperature or contaminated etc?
Ive heard BBQ chicken is bad aswell basically cos you dont know if its cooked enough.
I think alot of foods to be avoided is ones that can cause food poisoning. :-k