How do i tell infection

Had a blowoff while I was at work,not sure how long the top was blown off,how does an infection taste or smell what should I be looking for?

You won't be able to tell immediately. If something got in it, it would take time for it to propegate and produce any tell tale signs of infection. There are loads of reference material for infections. Some tastes, smells and appearance during fermentation may indicate infection, but are not.

You'll know it by taste for sure.

That being said, it could be fine, and probably is. If the fermentation was that vigorous it is possible any off gassing would create to much pressure coming out of the fermenter to let any little bacterias or dust drift into it.

Check out this thread on thinking you ruined your beer.