John A. Marcello Retail Food Specialist U.S. Food and Drug Administration John Marcello is one of nine Retail Food Specialists assigned to the Office of Human and Animal Food Operations, Office of State Cooperative Programs - Retail Food Branch 3. Retail Food Specialists provide technical assistance to regulatory and industry food safety professionals; train and standardize regulatory personnel, and provide consultation on nationally recognized standards for state/local/tribal/territorial retail food protection programs. He currently serves as one of the two NEHA Technical Advisors for the Food Protection and Food Defense area