The trick to sealing anything with moisture is to put it in the freezer until the moisture solidifies then take it out and seal the bag. Works every time.
This^^
Pre-freeze any kind of meat or fish for a couple of hours and it'll seal just fine. Don't pre-freeze and it'll suck moisture into the seal and the seal will eventually fail.
I like the bags instead of the rolls. For some reason the roll stuff never seems to seal well, decent bags rarely fail if you follow the pre-freeze ritual.
