Hi,
This is no isolated incident, nor is it confined to Pennsylvania nor to health inspectors.
A local St. Joseph's Dinner once was a community potluck with dishes of Italian, Mexican and other ethnicities. You brought a dish and a $5 contribution that went to feed the poor. The last year of the potluck, a health inspector arrived to make sure cold food was cold and hot food was hot. The very next year, it was rather bland catered meal with the fee raised. I made some inquiries to find they couldn't do the potluck largely due to the cost of liability insurance. An event conducted by a caterer rides on the caterer's insurance, if someone falls ill. It was cheaper to have a caterer than a potluck due to insurance.
Just bring a homemade item to school event, your donation may be turned away if it wasn't individually wrapped, no ingredient list and not a commercial product.
(I wrote this before leaving at 8:30 AM today ... sorry for any theme repetition)
Regards,