the fact it has been sealed for that long means no air not additional moisture got in. most food products are packaged in a way that it removes air/humidity and sterilized(often thru the process we call Pasteurization).

as long as the product remains sealed(before you 1st open it yourself+ the packaging is undamaged) you can generally be safe in the knowledge it will be good at least until their "best-by" date and that it hasnt been tampered with.

tho fair warning, depending on how it was stored, this doesnt mean it still "good", temperature extremes can alter the charactirstics of the product.