Many methods are available for verifying the viability of a sanitation program, and most facilities use a combination of different methods to ensure that the sanitation program is performing as expected. Pathogen environmental monitoring (PEM) programs are a key prerequisite program to a sanitation program and to any facility's overall food safety program. There is no one-size-fits-all PEM program for facilities; rather, a PEM program is based on a facility's risk factors and what product(s) the facility manufactures.