It is a tape worm cyst, but it'll take more than a few days to kill it. A couple of weeks to be sure, tape worm are resilient to hard frosts.
Maybe so when it's host is alive but when in the freezer I wouldn't have thought so.
Dogs and ferts get these after freezer and cysts removed as I get alot of these on rabbits so
don't see the point in wasting the remaining meat.
Leegreen you were right mate I was looking through skycats book for something else last night and saw what she wrote on it"freeze for 3 weeks to be sure" I'm off to the naughty step