If there are any doubts about the safety of a food product, you should:
a. discard the food
b. heat it to 165f
c. donate to charity
d. use it right away

A. Discard the food

There are two kinds of foodborne bacteria: one that spoils your food and one that makes you sick. It's good to be familiar with bothbut it's critical that you follow safe food handling practices to keep the second one at bay.

Foodborne Illness_ Often called "food poisoning," foodborne illness comes from a food you eat. It's caused by ingesting pathogenic bacteria.
Spoilage BacteriaSpoilage bacteria are bacteria that cause food to go bad - in other words, to "spoil." With spoilage bacteria, the food looks or smells funny or bad, so you know to throw it out. These bacteria can grow at lower temperatures — even in the refrigerator. But while they can make food unappealing and inediblethey do not usually cause illness.

Pathogenic Bacteria_These are the ones you need to watch out for 

"air pollution" is the correct answer i believe

Answerspermicides;