While preschool was difficult for my son, who just doesn't like playing according to a schedule, I can gratefully point to one rule I needed help reinforcing: washing his hands. Like all the rest of the kids, he was required to wash hands after going to the potty and before eating snacks.

Clearly, the food workers of America did not learn this lesson.

Salmonella can infect a food in two ways: (1) if the raw meat or uncooked eggs from an infected chicken or other animal is ingested (either by eating raw food or by contaminating other foods with chicken juices, etc.) or (2) a human's feces come into contact with food. Because someone didn't wash his hands after using the potty. The CDC says the source of contamination is "still under investigation," but as this is the first-ever peanut butter contamination I'm just going to go out on a limb and say "human feces."

Peter Pan and Great Value peanut butter products (starting with code 2111) have been recalled by ConAgra Foods, Inc. (NYSE:CAG), thanks to a salmonella outbreak. I'm sure the parents who just sent their children to school with peanut butter and jelly sandwiches told them to wash their hands before lunch.

It's not like this is the first time this has happened, even in the past few months.