Mmm ... maggots. FlickrCC/Massimiliano Calamelli

A Wawa customer in New Jersey on Tuesday claimed that he found two live maggots — the larval stage of flies and other related insects — crawling in his hoagie.

While this could be an extreme case (Wawa said it was "highly unlikely and probably impossible"), it's not unusual for maggots to be in food.

The US Food and Drug Administration even allows it.

The FDA’s sanitation standards for food processors allow for a small number of insects to remain in food. Even when farmers apply insecticides, bugs find crops to eat and procreate on. They can stay on long after a crop is harvested.

"It is economically impractical to grow, harvest, or process raw products that are totally free of non-hazardous, naturally occurring, unavoidable defects," the agency says on its website. By "defects," the FDA means rodent hairs, insect eggs, mold, animal feces, fruit flies, and maggots.

For example, the FDA allows up to 4% of a can of cherries to have maggots (and 5% if they are brined or Maraschino). Up to one maggot (or five fly eggs) per 250 milliliters of canned fruit juice is also allowed.

For tomato juice, the FDA limits up to five fly eggs and one maggot per 100 grams, the equivalent of a small juice glass. Up to 15 fly eggs and one maggot per 100 grams is allowed for tomato paste and other pizza sauces.

Mushrooms are granted more leeway — 20 maggots "of any size" per 100 grams of drained mushrooms or 15 grams of dried mushrooms.

Americans on average most likely ingest 1 to 2 pounds of flies, maggots, and mites each year without knowing it — a level the FDA says is safe. The agency established these guidelines in 1995 and has revised them several times.

Since the guidelines were established, some Americans have warmed up to the idea of purposefully eating insects, a common practice in some countries that has increasingly taken hold in the US. Several tech startups and restaurateurs have launched bug-related food products, including cricket bars, insect cookbooks, grasshopper guacamole, toasted grasshoppers, and countertop mealworm hives. Some entrepreneurs refer to insects as the "future of protein," since they require far less water and land than livestock.

While you shouldn't deliberately eat maggots, they do have some medicinal powers. As Mental Floss notes, before the rise of antibiotics, maggots were used in World War I to help heal injuries and inhibit infection. At the time, the orthopedic surgeon William Baer found that soft-tissue wounds would heal faster when infested with maggots.