Chlorate in food: risks for public health

These are the main conclusions of EFSA’s scientific opinion Opinions include risk assessments on general scientific issues, evaluations of an application for the authorisation of a product, substance or claim, or an evaluation of a risk assessment. on the chronic and acute public health risks from dietary exposure For the purposes of risk assessment, measurement of the amount of a substance consumed by a person or animal in their diet that is intentionally added or unintentionally present (e.g. a nutrient, additive or pesticide). to chlorate (including drinking water).

Chlorate can be present in food from the use of chlorinated water for food processing and the disinfection of food processing equipment. The most affected food groups are fruit and vegetables. Frozen varieties often account for the highest levels of chlorate within each food group. This probably depends on the amount of chlorate in chlorinated water used for food processing. Drinking water, however, is the main source of chlorate in the diet, possibly contributing up to 60% of chronic chlorate exposure for infants.

Chronic exposure A long-term constant or intermittent exposure to a substance which may have an impact on health over time. – over time, exposure to chlorate can inhibit iodine uptake. EFSA has set a tolerable daily intake An estimate of the amount of a substance in food or drinking water which is not added deliberately (e.g contaminants) and which can be consumed over a lifetime without presenting an appreciable risk to health.  ( TDI The tolerable daily intake (TDI) is an estimate of the amount of a substance in food or drinking water which is not added deliberately (e.g contaminants) and which can be consumed over a lifetime without presenting an appreciable risk to health. ) of 3 micrograms per kg (µg/kg) of body weight per day for long-term exposure to chlorate in food. EFSA’s highest estimates of chronic exposure for infants, toddlers and other children (up to 10 years of age) are over the TDI, indicating a concern for all children with mild or moderate iodine deficiency.

Acute exposure A one-off or very short term exposure to a substance, usually less than 24 hours. – a high intake of chlorate on a single day could be toxic for humans as it can limit the blood’s ability to absorb oxygen, leading to kidney failure. EFSA has, therefore, also set a recommended safe intake level for a daily intake (called the ‘acute reference dose The total amount of a substance (e.g. a chemical or nutrient) given to, consumed or absorbed by an individual organism, population or ecosystem.’) of chlorate of 36 µg/kg of body weight per day. The highest estimates of acute dietary exposure for all age groups were below this safe intake.

In addition, EFSA was asked by the European Commission to consider the impact on dietary exposure of applying the WHO guidance level for chlorate in drinking water of 0.7 milligrams per kilogram (mg/kg) to all foods covered by EU legislation. If 0.7 mg/kg were used as the maximum level in food for assessing dietary exposure to chlorate (i.e. excluding foodstuffs and drinking water containing chlorate above this level), exposures would drop only slightly and, consequently, this would not affect the potential risk. Under the unlikely scenario that chlorate levels in all food and drinking water were equal to 0.7 mg/kg, however, dietary exposure would be substantially above current levels.

There were several limitations in the available data for this work, at least partly due to the limited timeframe allowed for the assessment. Consequently, EFSA’s experts concluded that the impact of these scientific uncertainties on the risk assessment  A specialised field of applied science that involves reviewing scientific data and studies in order to evaluate risks associated with certain hazards. It involves four steps: hazard identification, hazard characterisation, exposure assessment and risk characterisation. is large.

EFSA’s scientific advice was requested to support decision-makers in the Commission and Member States who are re-examining existing measures to limit consumer exposure to chlorate in food. When considering efforts to reduce chlorate residues in food, besides the toxicological aspects of these residues, the impact on microbiological food safety should also be taken into account. EFSA did not, however, evaluate these aspects as part of this risk assessment.

• Scientific opinion on risks for public health related to the presence of chlorate in food  

During the development of this scientific opinion, EFSA and Germany’s Federal Institute for Risk Assessment (BfR) were involved in a continuous dialogue regarding their respective risk assessments of chlorate in food.

• Joint EFSA/BfR document on chlorate risk assessment(199.29 KB)