A carton of egg whites is pretty easy. It's pastuerized so no salmonella risk, not sure if pasturezation temp is sufficient to destroy avadin tho. If you're going high protein a liquid form is a welcome option after a week or two. How much protein can you really chew down day after day? Guess some guys can but I find chewing 200+g a day, day after day, to be a drag.
I know, there's whey but this is just another option.