The U.S. Centers for Disease Control and Protection and the National Association of State Public Health Veterinarians have published an updated, Compendium of Measures to Prevent Disease Associated With Animals in Public Settings.
The package includes guidelines for animals in school settings, handwashing recommendations, suggested visitor handouts, and information for vendors and staff.
Sounds great. The challenge is, how to compel individual petting zoo operators to actually follow best practices, short of being sued by Bill Marler.