I had an inquiry some time back from Dana:
"I have a bet going with a friend - my mother who worked for the Los Angeles Times years ago and she was told by the food critic there that the FDA will approve ketchup (katsup) with a maximum 20% worm content. I'm not making a joke about this. Do you know if this is true, or simply an old urban legend? Thanks for your time."
The problem is in the percentage. I think that you can safely say you lost this one. The FDA mostly protects against contamination of stored or processed foods, and limits the amount that naturally occurs in the field or grove. Hopefully not too many picky eaters will be even pickier to think they've been eating insects! It is impossible to process food that is free of insects. On some foods the limit is in insect parts, such as flour, I quote the FDA: For instance, the permissible level of certain insect fragments in 50 grams, or about two cups, of flour is 75 parts. (This is the uppermost level at which fragments pose no health hazard in the product.) In other cases, processed fruits or vegetables can have certain centimeters of insect damage. I cannot find the exact numbers for ketchup. (It also allows an average of 30 or more insect fragments and one or more rodent hairs per 100 grams of Peanut Butter. I've even found an entire beetle in a can of green beans in more than one occasion, and just tossed the beetle.
When the Caribbean fruit fly first reached Florida, it happened we had a nursery license to sell crotons, palms and a few other plants. We also had quite a few fruit trees including a peach, guava, loquats and Suriname cherries that hosted the larvae. In addition, the papaya wasp larvae got the papayas. Whenever the inspector came by we had interesting conversations about insect contamination. Being a "farm girl" I knew all along we were eating some insects, so it didn't disgust me.
The peaches were a total loss unless individually bagged while still green; the worms made them unwholesome before they were ripe enough to eat. The cherries were okay as long as they weren't too ripe. The loquats were pretty badly hit, and we ended up cutting both it and the peach tree down.
Guavas are a popular staple in many tropical countries, in the form of guava paste or gel, as well as preserved guava shells and puree for flavoring desserts. The guavas had to be picked while just ripe enough to taste good, but before the worms got big enough to deteriorate the fruit. What the inspector did at his home, and we did, was to pick a cherry or guava, crack it open, and if we didn't see any worms or deterioration we ate it. (We didn't look really hard, just for anything obvious.)
Tomatoes sometimes have worms, but by the time they are ripe enough to process, any worms would be starting to damage the quality of the fruit. This would make the ketchup unwholesome. The food critic was either trying to gross out your mother, or mistook parts per million, or pieces per gallon, or some such measurement which would be within reasonable limits and still preserve quality. The only allowable place worms could come from would be those occurring naturally in the tomato, and 20% (one-fifth) worms and the tomato would be seriously rotten already.
If you find insects in flour, pasta or other grain product, check for overall deterioration of the product and severity of infestation. If it's minor, sift or otherwise remove any larger insects and put the product in a waterproof container in the freezer for 48 hours. I always told my kids "It's just protein!" If there's a severe infestation or the product looks or smells off, toss it, and check anything else that was in the same cupboard and seal, freeze, etc.
On the other hand, if a product has been damaged by rodents or mold, I highly recommend you dispose of it entirely, as these are disease-causing agents, unlike most minor insect infestation.
By the way, genetically engineered foods are being produced that kill off insects. I personally feel that if they kill bugs, they can't be good for people. I'd far rather eat a small amount of insect protein than play roulette with genetically altered crops that kill bugs.