here is another good article:
Here is a very brief sampling of the FDA's Food Defect Action Level list. They begin investigation when foods reach the action level they've set. According to the FDA, typical foods contain about 10 percent of the action level, but others say they contain more like 40 percent.
CHOCOLATE AND CHOCOLATE LIQUOR
*Insect filth: Average is 60 or more insect fragments per 100 grams when 6 100-gram subsamples are examined OR any 1 subsample contains 90 or more insect fragments
*Rodent filth: Average is 1 or more rodent hairs per 100 grams in 6 100-gram subsamples examined OR any 1 subsample contains 3 or more rodent hairs
CITRUS FRUIT JUICES, CANNED
* Insects and insect eggs: 5 or more Drosophila and other fly eggs per 250 ml or 1 or more maggots per 250 ml
RED FISH AND OCEAN PERCH
* Parasites: 3% of the fillets examined contain 1 or more parasites accompanied by pus pockets
MACARONI AND NOODLE PRODUCTS
*Insect filth: Average of 225 insect fragments or more per 225 grams in 6 or more subsamples
*Rodent filth: Average of 4.5 rodent hairs or more per 225 grams in 6 or more subsamples
PEANUT BUTTER
*Insect filth: Average of 30 or more insect fragments per 100 grams
*Rodent filth: Average of 1 or more rodent hairs per 100 grams
POPCORN
*Rodent filth: 1 or more rodent excreta pellets are found in 1 or more subsamples, and 1 or more rodent hairs are found in 2 or more other subsamples OR 2 or more rodent hairs per pound and rodent hair is found in 50% or more of the subsamples OR 20 or more gnawed grains per pound and rodent hair is found in 50% or more of the subsamples
WHEAT FLOUR
*Insect filth: Average of 75 or more insect fragments per 50 grams
*Rodent filth: Average of 1 or more rodent hairs per 50 grams
http://www. sixwise.com/newsletters/05/06/29/how_many_insect_parts_and_rodent_hairs_are_allowed _in_your_food.htm