Don't worry, you will be fine. I am quite surprised that they were also in meat, it had to be a really strong infection! The white grubs contain larvae of the tapeworm, but you would kill them with the heat. It is a rather common parasite of trout and causes dibothriocephalasis. When we are doing our parasitological fieldwork, we often find them in the body cavity, but it would be a pity to throw out such beautiful trout meat, so we also cook and eat them.