Contaminants in food

Some contaminants are naturally present in the environment, for example in soil, water, and air, and may enter food as crops are grown or animals are raised. Others are formed unintentionally during food processing, particularly as a result of heat treatment, even when Good Agricultural Practices (GAPs), Good Manufacturing Practices (GMPs), and other appropriate practices are followed. In addition, some foods naturally contain substances that may pose food safety risks if present at high levels or if foods are not properly prepared.

Contaminants are therefore substances that are not intentionally added to food or feed, but that may be present as a result of production, processing, preparation, packing, transport, or storage, or due to environmental contamination or their natural presence in foods. They may originate from natural sources or human activities, and their presence in food is often unavoidable and unintended, even when measures to contain and minimize contamination are properly applied. Consequently, food safety management focuses on monitoring and mitigation measures to levels that do not pose a risk to human health, rather than complete elimination.

The Codex Alimentarius and contaminants in food

The Codex Committee on Contaminants in Foods (CCCF) is the primary body responsible for developing Codex Alimentarius standards in this area. The Committee recommends risk management measures, most notably maximum levels (MLs) for contaminants in foods, including feed commodities, for adoption by the Codex Alimentarius Commission (CAC). These measures are developed in accordance with the Risk Analysis Principles applied by CCCF, which also govern its interaction with the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the body that provides the scientific advice underpinning the establishment of risk-based MLs. Biological agents such as bacteria and viruses have not been the subject of systematic risk management by CCCF, but by the Codex Committee on Food Hygiene (CCFH).

MLs and CoPs

CCCF establishes MLs for contaminants in foods and feed moving in international trade. To support the application of these MLs, the Committee also develops codes of practice (CoPs), which are compendia of risk management measures applied across the food chain (e.g., GAPs, GMPs) that help contain food contamination, thereby facilitating compliance with MLs when they exist.

MLs and GLs

There may be circumstances in which, due to an incomplete risk assessment or the nature of the contaminant, establishing a maximum level (ML) is not yet possible or appropriate. In such cases, CCCF may establish guideline levels (GLs) rather than MLs. GLs use scientific risk assessment to guide decisions when MLs are unavailable and can offer provisional risk management until more data allows for setting MLs.

Guideline levels are not enforcement limits and are therefore not intended to trigger automatic rejection of food consignments. Instead, they serve as intervention levels, assisting competent authorities in interpreting analytical results and determining whether contamination levels warrant concern. Where such concern is identified, GLs help trigger appropriate follow-up actions, such as investigating sources of contamination or applying targeted risk-reduction measures to facilitate continued safe trade.

MLs and sampling plans

Codex maximum levels (MLs) for contaminants are not applied in isolation. They are typically supported by codes of practice (CoPs) and, where relevant, sampling plans linked to the ML. Sampling plans are particularly important for contaminants that are unevenly distributed within a lot, such as mycotoxins. For these contaminants, sampling plans help ensure that MLs are applied in a scientifically robust and fair manner by reducing the likelihood that highly contaminated lots are accepted and by minimizing the rejection of lots that genuinely comply with MLs but exhibit natural variability.

Sampling plans, together with appropriate performance criteria and corresponding analytical methods, are therefore a core component of the Codex risk‑based management framework for contaminants, supporting consumer protection, risk‑proportionate enforcement, and fair practices in international trade.