I volunteer in my children’s elementary school cafeteria. While peanuts aren’t banned, we do have to take extra measures to keep the allergic kids safe.
Everyone in the cafeteria has assigned seating. The children with allergies sit at two specific tables, which are a different color. They don’t take up all the spaces, of course, so there are kids eating regular meals at those tables, too. The non-allergic kids who sit next to the allergic ones are taught to switch seats when they bring peanut butter for lunch. Each allergic child’s specific allergies and treatment plan in case of exposure is posted on the wall.
After each class is done, we wipe down the tables for the next group. The regular tables get cleaned with a rag. The “allergic” tables have a separate bucket of soapy water and we use paper towels-one time only, no double dipping. We carefully wash down the entire table, the underside of the lip, and the benches.
The reason for this is that children with more severe allergies can have a reaction just from getting the oil on their skin. So a child eating a peanut butter sandwich, who might understandably get fingerprints on the table or the seat, can easily leave behind oils that would affect the next child to sit down.
One of the other volunteer parents told us about how her sister ate some pistachios, neglected to wash her hands thoroughly, and then, hours later, touched her nephew on his face. He broke out in hives immediately.
In the classrooms, the parents are given several options. Some parents, especially of younger children with severe reactions (who might not be as competent at protecting themselves) ask for no homemade treats at parties. The nurse checks the labels on the packaged treats. Others simply provide their children with their own treats to substitute for those that might be brought in.
I have never heard of airborne particles causing reactions, and I suspect that those are probably (and understandably, for the individual who has had repeated, frightening episodes) psychosomatic. However, it is all too easy to leave behind unseen traces of oils, which might explain some of the reactions that happen when there has, so far as anyone can tell, been no physical exposure.
This is an issue for, it seems, increasing numbers of children. But it doesn’t have to cause hysteria. We can protect them with some fairly simple measures.