Generally, if a food contains a poisonous or deleterious substance that may render it injurious to health, it is considered to be adulterated.
Thus, a food that contains a natural toxin at very low levels that would not ordinarily be harmful (for instance, small amounts of amygdalin in apricot kernels) is not adulterated.
Second, if the poisonous or deleterious substance is unavoidable and is within an established tolerance, regulatory limit, or action level, the food will not be deemed to be adulterated.
Filth and extraneous material include any objectionable substances in foods, such as foreign matter (for example, glass, metal, plastic, wood, stones, sand, cigarette butts), undesirable parts of the raw plant material (such as stems, pits in pitted olives, pieces of shell in canned oysters), and filth (namely, mold, rot, insect and rodent parts, excreta, decomposition).
Under a strict reading of the FD&C Act, any amount of filth in a portion of food would render it adulterated.
A portion of food is adulterated if it omits a valuable constituent or substitutes another substance, in whole or in part, for a valuable constituent (for instance, olive oil diluted with tea tree oil); conceals damage or inferiority in any manner (such as fresh fruit with food coloring on its surface to conceal defects); or any substance has been added to it or packed with it to increase its bulk or weight, reduce its quality or strength, or make it appear bigger or of greater value than it is (for example, scallops to which water has been added to make them heavier).
The fact that a food is contaminated with pathogens (harmful microorganisms such as bacteria, viruses, or protozoa) may, or may not, render it adulterated.
However, USDA's Food Safety and Inspection Service (FSIS) has ruled that raw meat or poultry products contaminated with E. coli O157:H7 are adulterated.
With the exception of infant formula, neither the FDA nor FSIS has the authority to require a company to recall an adulterated food product.
State regulators generally have similar enforcement tools at their disposal to prevent the manufacture and distribution of adulterated food.
Federal agencies often will coordinate with state or local authorities to remove unsafe food from the market as quickly as possible.