Waiter, there is a fly...

From a FDA booklet describing levels of natural or unavoidable defects in foods that present no health hazards for humans (published by F.D.A.’s Center for Food Safety and Applied Nutrition).

From here: Tomato juice, for example, may average “10 or more fly eggs per 100 grams [the equivalent of a small juice glass] or five or more fly eggs and one or more maggots.” Tomato paste and other pizza sauces are allowed a denser infestation — 30 or more fly eggs per 100 grams or 15 or more fly eggs and one or more maggots per 100 grams.
Canned mushrooms may have “over 20 or more maggots of any size per 100 grams of drained mushrooms and proportionate liquid” or “five or more maggots two millimeters or longer per 100 grams of drained mushrooms and proportionate liquid” or an “average of 75 mites”
Curry powder is allowed 100 or more bug bits per 25 grams; ground thyme up to 925 insect fragments per 10 grams; ground pepper up to 475 insect parts per 50 grams. One small shaker of cinnamon could have more than 20 rodent hairs before being considered defective.

Here is the kicker:
You’re probably ingesting one to two pounds of flies, maggots and mites each year without knowing it...

Image: I took this picture of Andy falling into a Campbell soupcan at a recent exhibition on a visit to Chelsea.