Question

Jason, a college student, notices the lid on several of thehome-made jars of food his aunt gave him over the holiday appearsto have popped up. he opens one. it smells perfectly fine. still alittle leery, he asks his roommate if he thinks it's still good. hesuggests that Jason just boil everything for a few minutes tosterilize it if he is worried. that will kill all the bacteria, hesays, and then Jason can enjoy his meal. what contaminate might bepresent in the jars? if present, will the room-mate's advice workand why?