Chlorate may be present as a by-product in chlorine-containing disinfectants authorized for the production of drinking water.
Chlorate may be present in food from the use of chlorinated water for processing and disinfection of food processing equipment. The most affected food groups are fruits and vegetables.
However, drinking water is the main source of dietary chlorate, possibly contributing up to 60% of chronic chlorate exposure in infants.
Chlorate in fresh produce
Chlorate (ClO3) is a substance formed as a by-product when chlorine, chlorine dioxide, or hypochlorite are used for disinfection of drinking water, water for food production or processing, and cleaning surfaces of equipment that come into contact with food.
The opinion of a panel of scientists from the European Food Safety Authority (EFSA) and routine monitoring of chlorate in agricultural products was that chlorate levels in drinking water and food were too high and could negatively affect iodine absorption in humans, especially among infants and children.
Allowed concentrations
The EU’s general approach is to avoid stipulating an MRL for chlorate concentrations in water used for irrigation and food processing. This is in order not to further complicate an already complex web of legislation relating to drinking and process waters.
Control of chlorate concentrations moves to the next level of food production and processing, including fresh fruit and vegetables. Crops grown in water treated with chlorine-based disinfectant can accumulate chlorate within the crop tissue. This has led to a number of elevated chlorate concentrations above the MRL in crops.
However, although MRLs for products exist in 2020/749, there are also some tolerances. For example, food that has been in contact with products containing legal concentrations of chlorate residues, or that contains ingredients with such residues (such as processing aids or drinking water, used in accordance with the respective legal requirements).
The burden of proof regarding the level of such additional contributions lies with food business operators.
Current legal background
In June 2023, EFSA published a statement deriving toxicological maximum limits for the acute and chronic risks of chlorate in food. According to EFSA, a tolerable daily intake (TDI) of 3 µg/kg body weight is considered safe.
Until the maximum limits are valid for the whole EU, food must be monitored in accordance with Article 14 of the Basic Regulation (EC) No 178/2002 for safety reasons.
To this end, EFSA has deduced a maximum daily intake amount (acute reference dose ARfD) of 36 µg/kg of body weight. This will apply without any variability factor. For baby foods, a maximum residue limit of 0.01 mg/kg continues to apply.
On the other hand, a number of Coca-Cola products were withdrawn from the market in the UK. This happened after the company’s bottling partner said it had identified “elevated levels” of a chemical called chlorate.
Cans of Coca-Cola Original Taste, Coca-Cola Zero Sugar, Diet Coke and Sprite Zero sent to cafes and restaurants are being recalled. As well as the 6x250ml Appletiser multipacks sent to UK supermarkets.
The UK recall comes after Coca-Cola products were pulled from shelves in Belgium, Luxembourg and the Netherlands days ago.
The higher levels of chlorate were discovered during routine testing at the company’s production facility in Ghent, Belgium. Coca-Cola said that only five product lines had been sent to Britain at the time and had already been sold. It added that it had “alerted the authorities”.
The effects of chlorate on humans when taken in excess include nausea, vomiting, diarrhoea. As well as limiting the blood’s ability to absorb oxygen.
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