A friend of mine once gave me a guided tour of the Green Giant plant where he worked. They were processing corn at that time. He explained that it's standard practice, after the corn is put in cans, but before labels are put on, to put the cans in the warehouse and wait several days. If a batch wasn't properly sterilized, the corn would ferment and the cans would explode. If nothing happened, they figured the batch was OK so they would label it and ship it out.

There were no exploding cans while I was there, but he had seen it happen, and he said it was a stinky mess.