Pastry packet bulging within best before date

[FourPlasticRings]

I have a package of puff pastry dated use by 6th August, but it was bulging with gas when I took it out of the fridge to use. I opened it and it looks OK, I think, but smells a tad vinegar-y. Is it safe?

I'm sure it's safe. I find any pastry I buy always does this. I still use it