The definition of chemical contaminants in food: Ambiguity and consequences

Consumers may be exposed via foods to a diverse range of substances that could be considered as contaminants. However, it is not always straightforward to understand the definition of a ‘contaminant’. The present review evaluates how various categories of food-relevant substances are considered in terms of being ‘contaminants’. To this end these categories of food borne constituents are evaluated against the various criteria encountered in the available definitions of a food contaminant, including unintentional presence, harmful, existence of regulatory limits, and stakeholder perception. The categories of chemicals considered include: phytotoxins, mycotoxins, (heavy) metals, persistent organic pollutants (POPs), processing aids, process related contaminants, food contact materials (FCMs), pesticides and veterinary drugs. The evaluation revealed that usage of the term appears complex, and may differ between stakeholders. A common proposed definition of the term ‘contaminant’ could be ‘a substance considered to require control measures due to the unacceptability of its context within a food’. Use of a dimension of harm results in equivocal outcomes because risk depends on the level of exposure. As the term ‘contaminant’ has influence on risk management including public policy, the motivations for applying the term should be subject to more detailed analysis and understanding. • Understanding stakeholders' motivations for using "contaminant" is crucial for effective risk management and policy. • The study reviews how various classes of food-borne chemicals are classified as "contaminants." • A "sliding scale" is suggested using terms like "food component," "residue," or "contaminant" by intent and acceptability. • A proposed definition of "contaminant" is "a substance considered to require control measures due to the unacceptability of its context within a food."