First run with UMAi–

[Ron Pratt]

Paul,
There’s not a lot you can do to prevent contamination in that case that won’t in itself risk more chance for contamination! The best I can advise you is to keep an eye out for signs of mold inside the bag on the surface of the meat. Some white mold spores can later be washed off, but green mold spores mean trouble. Also your nose will give you an indication that the meat has started to go bad. Good luck!
Ron