A food contaminant is a harmful chemical or microorganism present in food, which can cause illness to the consumer.
The impact of chemical contaminants on consumer health and well-being is often apparent only after many years of processing and prolonged exposure at low levels (e.g., cancer). Unlike food-borne pathogens, chemical contaminants present in foods are often unaffected by thermal processing. Chemical contaminants can be classified according to the source of contamination and the mechanism by which they enter the food product.
Agrochemicals
Agrochemicals are chemicals used in agricultural practices and animal husbandry with the intent to increase crop yields. Such agents include pesticides (e.g., insecticides, herbicides, rodenticides), plant growth regulators, veterinary drugs (e.g., nitrofuran, fluoroquinolones, malachite green, chloramphenicol), and bovine somatotropin (rBST).
Environmental contaminants
Environmental contaminants are chemicals that are present in the environment in which the food is grown, harvested, transported, stored, packaged, processed, and consumed. The physical contact of the food with its environment results in its contamination. Possible sources of contamination and contaminants common to that vector include: Air: radionuclides (caesium-137, strontium-90), polycyclic aromatic hydrocarbons (PAH) Water: arsenic, mercury Soil: cadmium, nitrates, perchlorates Packaging materials: antimony, tin, lead, perfluorooctanoic acid (PFOA), semicarbazide, benzophenone, isopropylthioxanthone (ITX), bisphenol A Processing/cooking equipment: copper or other metal chips, lubricants, cleaning and sanitizing agents Naturally occurring toxins: mycotoxins, phytohemagglutinin, pyrrolizidine alkaloids, grayanotoxin, scombrotoxin (histamine), ciguatera, shellfish toxins (see shellfish poisoning), tetrodotoxin, among many others.
Pesticides and carcinogens
There are many cases of banned pesticides or carcinogens found in foods. Greenpeace exposed in 2006 that 25% of surveyed supermarkets in China stocked agricultural products contaminated with banned pesticides. Over 70% of tomatoes that tested were found to have the banned pesticide Lindane, and almost 40% of the samples had a mix of three or more types of pesticides. Tangerine, strawberry, and Kyofung grape samples were also found contaminated by banned pesticides, including the highly toxic methamidophos. Greenpeace says there exists no comprehensive monitoring on fruit produce in the Hong Kong as of 2006. In India, soft drinks were found contaminated with high levels of pesticides and insecticides, including lindane, DDT, malathion and chlorpyrifos. Formaldehyde, a carcinogen, was frequently found in the common Vietnamese dish, Pho, resulting in the 2007 Vietnam food scare. "Health agencies have known that Vietnamese soy sauce, the country's second most popular sauce after fish sauce, has been chock full of cancer agents since at least 2001", reported the Thanh Nien daily. "Why didn't anyone tell us?" The carcinogen in Asian sauces is 3-MCPD and its metabolite 1,3-DCP, which has been an ongoing problem affecting multiple continents. Vietnamese vegetables and fruits were also found to have banned pesticides. The 2005 Indonesia food scare, where carcinogenic formaldehyde was found to be added as a preservative to noodles, tofu, salted fish, and meatballs. In 2008 Chinese milk scandal, melamine was discovered to have been added to milk and infant formula which caused 54,000 babies to be sent to the hospital. Six babies died because of kidney stones related to the contaminant.
Hair in food
There is a heavy stigma attached to the presence of hair in food in most societies. There is a risk that it may induce choking and vomiting, and also that it may be contaminated by toxic substances. Views differ as to the level of risk it poses to the inadvertent consumer.
In most countries, people working in the food industry are required to cover their hair because it will contaminate the food. When people are served food which contains hair in restaurants or cafés, it is usual for them to complain to the staff.
There are a range of possible reasons for the objection to hair in food, ranging from cultural taboos to the simple fact that it is difficult to digest and unpleasant to eat. It may also be interpreted as a sign of more widespread problems with hygiene. The introduction of complete-capture hairnets is believed to have resulted in a decrease in incidents of contamination of this type.