The food regulations define a potentially hazardous food as a food that requires temperature control (TCS) to limit pathogenic microorganism growth or toxin formation and includes an animal food that is raw or heat-treated, a plant food that is heat-treated (such as rice) or consists of raw seed sprouts, cut melons, cut leafy greens, cut tomatoes or mixtures of cut tomatoes, which are not modified in a way so that they are unable to support pathogenic microbial growth or toxin formation, or garlic-in-oil mixtures, which are not modified in a way that results in mixtures that do not support pathogenic microbial growth or toxin formation.

A PHF may be rendered non-potentially hazardous if its water activity (AW) and/or acidity (pH) is modified. See Chapter 1, Potentially Hazardous Food (B)(2), Tables A and B of the regulations for these parameters.