I was wondering if thawing something that is vacuum sealed can result in the seal being broken (or if it's the air expansion due to warming). I left salmon burgers on counter to thaw for half an hour so I could separate the two patties and when I came back to the kitchen (actually 40 minutes) the plastic was all loose around the burgers. I put them back in the freezer for now. I think it looked vacuum sealed when I took them out of the freezer. I wonder if I should throw them out. Thanks!
The question I would have is whether it was frozen when you bought it, or if you froze it yourself. If you froze it and the packaging was good when you did then there's no reason to throw it out unless it's gotten too freezer-burned to be palatable. It's the temperature of the freezer, not the packaging that preserves food when in the freezer, so it should be safe providing it was properly handled before being frozen. As for the bag being loose it may very well have a hole in it, it's more likely to have happened in the freezer than during thawing. Because you froze it yourself and the packaging was good you know whatever happened occurred after you bought it, so it should be just fine.
If you bought it frozen then I would suggest throwing it out because you don't know when the packaging was broken or what the food could have been exposed to.