The FDA keeps a document called the Defect Levels Handbook that outlines exactly what types of defects mass-produced food can have and still be considered safe to eat.
The Handbook (which you can read in full here!) describes in detail the "levels of natural or unavoidable defects in foods that present no health hazards for humans." The reason it exists is because it's impossible to mass-produce food without the occasional defect, and the FDA needs to draw the line somewhere to guarantee that people who eat that food stay safe and healthy.
Listed below are some of the defect limits set by the FDA — that is, the point where the food becomes "adulterated." Defects less than what's listed below won't hurt you, and are legally allowed.
(But thinking about them may just make you sick. Sorry about that!)
Before you, uh, dig in to this information, you should read what the FDA's Handbook has to say about these limits:
It is incorrect to assume that because the FDA has an established defect action level for a food commodity, the food manufacturer need only stay just below that level. The defect levels do not represent an average of the defects that occur in any of the products—the averages are actually much lower. The levels represent limits at which FDA will regard the food product "adulterated"; and subject to enforcement action under Section 402(a)(3) of the Food, Drug, and Cosmetics Act.
Got all that? Good. Now read on, and prepare to completely lose your appetite:
1. Beetle eggs in your canned or frozen asparagus.
Too much, per the Handbook, is when "10% by count of spears or pieces are infested with 6 or more attached asparagus beetle eggs and/or sacs."
2. Bugs in your apple butter.
The limit is an "average of 5 or more whole or equivalent insects (not counting mites, aphids, thrips, or scale insects) per 100 grams of apple butter."
3. Rot in your canned beets.
Canned beets become "adulturated" when checks reveal an "average of 5% or more pieces by weight with dry rot."
4. Mites in your frozen broccoli.
Too many mites in your frozen broccoli: When the people checking find an "average of 60 or more aphids and/or thrips and/or mites per 100 grams."
5. Maggots in your brined or Maraschino cherries.
You've got adulterated maraschino cherries when an "average of 5% or more pieces are rejects due to maggots."
6. Rodent hairs in your cinnamon.
Just how many rodent hairs are too many? When checkers find an "average of 11 or more rodent hairs per 50 grams" of cinnamon.
7. Stems in your cloves.
Stems become an official problem with the FDA when the cloves contain an "average of 5% or more stems by weight."
8. Decomposition in your frozen egg products.
When dealing with frozen egg products, the cans become adulterated when there are "2 or more cans decomposed and at least 2 subsamples from decomposed cans have direct microscopic counts of 5 million or more bacteria per gram."
9. Insect heads in your fig paste.
This is too much when a batch of fig paste "contains 13 or more insect heads per 100 grams of fig paste in each of 2 or more subsamples" during the checking process.
10. "Mammalian excreta"... in your ginger.
The FDA does not allow an "average of 3 mg or more of mammalian excreta per pound" of ginger.
11. Parasitic cysts in your blue fish or fresh water herring.
The FDA draws the line here: "60 parasitic cysts per 100 fish (fish averaging 1 pound or less) or 100 pounds of fish averaging over 1 pound), provided that 20% of the fish examined are infested."
12. Copepods (parasites) with pus pockets in your red fish and ocean perch.
You're looking at a problem when "3% of the fillets examined contain 1 or more copepods accompanied by pus pockets."
13. Mildew in your canned greens.
During examination of canned greens, the FDA draws the line at an "average of 10% or more of leaves, by count or weight, showing mildew over 1/2" in diameter."
14. Insect fragments in your macaroni.
There are too many insect parts in that macaroni if checkers find an "average of 225 insect fragments or more per 225 grams in 6 or more subsamples."
15. Mold in your apricot, peach, and pear nectars.
Nectar is too moldy when the "average mold count is 12% or more."
16. Worms and mold in your canned and frozen peaches.
How do you know if a batch of canned or frozen peaches are no good? If checkers finds an "average of 3% or more fruit by count are wormy or moldy."
17. Sand in your raisins.
Too much sand is an "average of 40 mg or more of sand and grit per 100 grams of natural or golden bleached raisins."
18. Thrips in your sauerkraut.
Thrips are bugs. And too many thrips are when people checking find an "average of more than 50 thrips per 100 grams" of sauerkraut.
19. Larvae in your canned or frozen spinach.
The FDA draws the line at "2 or more 3 mm or longer larvae and/or larval fragments or spinach worms (caterpillars) whose aggregate length exceeds 12 mm are present in 24 pounds."
20. Fly eggs and maggots in your canned tomatoes.
A batch of canned tomatoes becomes officially adulterated when checkers find an "average of 10 or more fly eggs per 500 grams OR 5 or more fly eggs and 1 or more maggots per 500 grams OR 2 or more maggots per 500 grams."
21. Rodent "pellets" in your wheat.
Too much rodent poo is an "average of 9 mg or more rodent excreta pellets and/or pellet fragments per kilogram" of wheat.