Redefining Potentially Hazardous Foods
The term potentially hazardous food (PHF) was developed by the U.S. Public Health Service during the last half of the twentieth century to regulate perishable food. In 1962, PHF was defined as a perishable food that supports the rapid and progressive growth of infectious or toxigenic microorganisms. Exemptions for foods with an aw = 0.85 or pH = 4.6 were added in 1976. Thus, foods were considered non-PHF when their aw = 0.85, which is below the water activity for Staphylococcus aureus growth and toxin production or the pH = 4.6, which is below the pH for proteolytic Clostridium botulinum growth and toxin production.
