Chemical contaminants of food

Chemical contamination of dietary intake
Chemical residues in food

Nature

Chemical contaminants of food are unwanted substances that enter food products during production, processing, packaging, or storage. These contaminants include pesticides, heavy metals, industrial chemicals, and residues from food contact materials. Their presence poses significant health risks, such as acute poisoning, chronic diseases, and developmental disorders. Chemical contamination is a global food safety problem, often resulting from environmental pollution, improper agricultural practices, or inadequate regulation. Monitoring and controlling chemical contaminants is essential to protect public health and maintain consumer confidence in the food supply.

Background

The global significance of chemical contaminants in food emerged in the mid-20th century, following incidents such as mercury poisoning in Minamata, Japan, and widespread pesticide residues detected in agricultural products. Heightened international concern grew with advances in analytical chemistry, revealing persistent organic pollutants and industrial chemicals in food chains worldwide. Subsequent food safety crises, including dioxin and melamine scandals, underscored the pervasive and transboundary nature of chemical contamination, prompting coordinated monitoring and regulatory responses.

Incidence

Contaminants of major concern include: aflatoxins; PCBs; toxic metals (lead, cadmium, mercury, tin); organochlorine pesticides (aldrin plus dieldrin, DDT complex, hexachlorocyclohexane, lindane, heptachlor and heptachlor epoxide, hexachlorobenzene, endrin and endosulfan); organophosphorous pesticides (diazinon, malathion, parathion methyl and fenitrothion).

The UK Working Party on Pesticide Residues reported that in 1991 there were chemical residues in 37% of the bread, milk and potatoes sampled; in 30% of the cereals; in 29% of the fruit and vegetables. Typically, 1 or 2% of foods sampled exceed their maximum residue level (MRL). The USA National Academy of Sciences found that the worst foods for residues are, in descending order, tomatoes, beef, potatoes, oranges, lettuces, applies, peaches, pork, wheat, soybeans, beans, carrots, chicken, corn and grapes. A consumer magazine survey found that 10-25% of "post-harvest" pesticides applied to the skin during storage had seeped into the flesh. Washing apples and potatoes left residues largely unaffected (many will not dissolve, others are inside the skin). Peeling removed about 85% of apple residues and 75-90% of those in potatoes, but it also removes up to a fifth of the product as well as important fibre and nutrients. Cooking often increases residues.

Claim

If the bodies of American consumers were sold as meat in the EEC/EU, they would be declared unfit for consumption because of the DDT contamination.

Counter-claim

The concern over chemical contaminants in food is vastly exaggerated and not an important problem at all. Modern food safety regulations and rigorous testing ensure that any trace chemicals present are far below harmful levels. Worrying about chemical contaminants distracts from more pressing issues like food insecurity and nutrition. The fear surrounding this topic is largely unfounded and only serves to create unnecessary panic among consumers.