not recommended, especially by the health dept. ;) but ya gotta do what ya gotta do.
4 days on the fish is pushing the envelope, so to speak(unless it was your whole flash frozen tuna). Beef, depending on how it was wrapped, stored may be okay-unless it sat out for a week before going in first......
Too many variables. First, follow all health dept. regs in your area(especially if serving to the public). Second, use your nose-if its on the edge now, it ain't gonna help it. You will experience much degradation with repeated freezing and thawing. Can you cook now and then freeze final product?
did i mention following your local health dept regs? especially if serving to the public.