Chlorine reactions with food compounds and possible risks
What it found
Chlorine and chlorine dioxide react with fats, proteins and carbohydrates in food, and can leave chlorine behind in flour, shrimp and meat.
The health risks of these reaction products are unknown.
What they found
Animal and lab studies
Chlorine sticks to fats
In lab tests, chlorine and chlorine dioxide reacted with fatty acids, and more chlorine was taken up by fats with more double bonds. Free fatty acids took up more chlorine than their methyl esters.
Chlorine in flour
When flour was treated with radioactive chlorine gas, 99% of the chlorine either reacted with flour components or was used up in oxidation and chlorination reactions. The lipids extracted from the flour contained significant amounts of chlorine.
Chlorine in shrimp
Shrimp dipped in a hypochlorous acid solution took up chlorine, and 75% of that was found in the edible portion. Most of the chlorine in the edible part was in the form of chloride ions.
Animal feeding studies
Rats fed chlorinated flour at commercial levels in a long-term study did not develop any pathological lesions, and their body and organ weights were the same as controls. In other rat studies, high doses of chlorinated flour or chlorinated lipids reduced growth and increased liver and kidney weights.
Mutation tests
In lab tests, reaction products from mixing aqueous chlorine with various lipids or tryptophan did not cause mutations in the Ames Salmonella test. However, the authors note that other reaction products were not tested and the test may not catch all effects.
Chloroform in chicken
Low levels of chloroform were found in chicken carcasses treated with chlorine or chlorine dioxide solutions. The highest level was 447 ppb in carcasses dipped in water with 50 mg/L of aqueous chlorine.
What the authors conclude
“At this time, it is too early to assess the risks of using chlorine compounds in foods.”
Also in their conclusions
- They say that at this time it is too early to assess the risks of using chlorine compounds in foods.
- They advise that to determine the risks, the amounts of chlorine used, the reactivity with food chemicals, the reaction products and their toxicities, and consumer exposure levels must all be examined.
- They hope to have an answer in the near future.
How it was done
The authors wanted to review what is known about how chlorine and chlorine dioxide react with food components, because little was known about the nature of these reactions and the possible toxicity of the products formed.
They reviewed published studies on the reactions of chlorine gas, aqueous chlorine and chlorine dioxide with model food compounds like fatty acids, amino acids and carbohydrates, and with foods such as flour, shrimp and meat. They also included some of their own preliminary lab tests on whether reaction products cause mutations in bacteria.
What it can’t tell you
- This is a review of lab and animal studies. It cannot show what happens in people who eat foods treated with chlorine.
- The health risks of the chlorinated products found in food are unknown, so no link to human health effects can be made.
- The animal studies used doses of chlorinated compounds much higher than would be expected from the food supply.
The paper
- Title
- Reactions of aqueous chlorine and chlorine dioxide with model food compounds
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Animals and lab studies
- Summarised from
- Full text
- Cite
- Fukayama MY, Tan H, Wheeler WB, Wei CI (1986). Reactions of aqueous chlorine and chlorine dioxide with model food compounds. Environmental health perspectives. doi:10.1289/ehp.8669267Free full textPubMed 3545804DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error