Are these strawberries safe to eat?

[wildhorseluvr]

I put a package of store bought frozen strawberries in my fridge 2 days ago to thaw. Just opened the package to make myself a strawberry lemonade and noticed a lot of tiny bubbles rising to the top for a minute or two, almost like it was carbonated.  I haven't purchased frozen strawberries in a very long time, but can't remember ever seeing this before. Is this normal or did they get contaminated somehow during processing?

[paquebot]

Possibly they began to ferment. If so, no problem. Have had that happen before with fruit in the fridge. Sugar and liquid are all that's needed for the natural yeasts to start working. to

Martin