Food contaminants

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Food safety

Terms
Foodborne illness
HACCP
Critical control point
Critical factors
FAT TOM
pH
Water activity (Wa)
Pathogens
Clostridium botulinum
E. coli
Hepatitis A
Norovirus
Parasitic infections
Blastocystis
Cryptosporidiosis
Trichinosis

Food contamination refers to the presence in food of harmful chemicals and microorganisms which can cause consumer illness. This article addresses the chemical contamination of foods, as opposed to microbiological contamination, which can be found under Foodborne illness. A separate issue is genetically modified food, or the presence in foods of ingredients from genetically modified organisms, also referred to as a form of food contamination.^[1]

Impact

The impact of chemical contaminants on consumer health and well-being is often apparent only after many years of prolonged exposure at low levels (e.g. cancer). Chemical contaminants present in foods are often unaffected by thermal processing (unlike most microbiological agents). 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 crops and reduce costs. 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 are:

Air: radionuclides (¹³⁷Caesium, ⁹⁰Strontium), polycyclic aromatic hydrocarbons (PAH).

Water: arsenic, mercury.

Soil: cadmium, nitrates, perchlorates.

Polychlorinated biphenyls (PCB) , dioxins, and polybrominated diphenyl ethers (PBDE) are ubiquitous chemicals, which are present in air, water, soil, and the entire biosphere.

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, phytohaemagglutinin, pyrrolizidine alkaloids, grayanotoxin, mushroom toxins, scombrotoxin (histamine), ciguatera, shellfish toxins (see shellfish poisoning), tetrodotoxin, among many others.

Banned pesticides, carcinogens

There are many cases of banned pesticides or carcinogens found in foods.

• Greenpeace exposed in 2006 in China that 25% of surveyed supermarkets agricultural products contained 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.Fruits were also tested in this investigation. Tangerines, strawberries and Kyofung grapes samples were found contaminated by banned pesticides, including the highly toxic Methamidophos. These fruits can also be found in Hong Kong market.^[2] 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.^[3]

• Even Quality Assurance International, a USDA certified organization, in July 2008 QAI had mistakenly certified as organic powdered ginger produced in China, which tests showed was contaminated with the banned pesticide Aldicarb. ^[4]

• News of Formaldehyde, a carcinogen was found in Vietnamese national dish, Pho, broke in 2007 Vietnam food scare. Vegetables and fruits were also found to have banned pesticides. "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," thundered the Thanh Nien daily. "Why didn't anyone tell us?"^[5] The carcinogen in Asian sauces is 3-MCPD and its metabolite 1,3-DCP, which has been an ongoing problem before 2000 affecting multiple continents.

• 2005 Indonesia food scare, carcinogenic formaldehyde was added as a preservative to noodles, tofu, salted fish, and meatballs.

• 2008 Chinese milk scandal.

Hair in food

Many people consider hair in food to be particularly unpleasant, however there are certain risks to be considered such as choking and repulsion induced vomiting. There are also considerations of contaminants on the hair itself such as waxes or other hair products that may cause problems.^[6] It is claimed sometimes that it does not usually pose any serious health risk,^[7][8] but in other cases it is claimed that it does pose a health risk.^[9]

For example, people working in the food industry are required to cover their hair.^[10][11] Also, when people are served food which contains hair in restaurants or cafes, people may complain to the manager.^[12] Despite this, it is not valid ground to sue the restaurant in the United States^[13] but in the United Kingdom it breaks the regulations of the UK Food Safety Act 1990 and is known to cause food poisoning^[14] and people can sue for this.^[15] In one case a supermarket considered banning a man with a beard working there.^[16] In such cases there exists protection for food workers who have facial hair, which is called 'snood'.^[17]

The cause of people's disgust with hair in food could be that hair is not easily digestible and is the wrong shape for being processed in the body. Hair in food was often a common cause of complaint from people eating food, before the introduction of complete capture hairnets.^[18]

Also, sometimes protein from human hair is actually used as a food ingredient,^[19] in bread and other such similar products. Such use of human hair in food is forbidden in Islam.^[20] Historically in Judaism finding hair in food was a sign of bad luck.^[21]

Processing contaminants

Processing contaminants are generated during the processing of foods (e.g. heating, fermentation). They are absent in the raw materials, and are formed by chemical reactions between natural and/or added food constituents during processing. The presence of these contaminants in processed foods can not be entirely avoided. However, technological processes can be adjusted and/or optimized in order to reduce the levels of formation of processing contaminants. Examples are: nitrosamines, polycyclic aromatic hydrocarbons (PAH), heterocyclic amines, histamine, acrylamide, furan, benzene, trans fat, monochloropropanediol (MCPD), semicarbazide, 4-hydroxynonenal (4-HNE), and ethyl carbamate. There is also the possibility of metal chips from the processing equipment that requires metal detection. In many conveyor lines, the line will be stopped, or when weighing the product with a Check weigher, the item can be rejected for over- or underweight as well as detection of very small pieces of metals.

Emerging food contaminants

While many food contaminants have been known for decades, the formation and presence of certain chemicals in foods has been discovered relatively recently. These are the so-called emerging food contaminants, e.g. acrylamide, furan, benzene, perchlorate, perfluorooctanoic acid (PFOA), monochloropropanediol (MCPD), 4-hydroxynonenal and (4-HNE).^{[citation needed]}

Safety and regulation

Acceptable Daily Intake (ADI) levels and tolerable concentrations of contaminants in individual foods are determined on the basis of the "No Observed Adverse Effect Level" (NOAEL) in animal experiments, by using a safety factor (usually 100). The maximum concentrations of contaminants allowed by legislation are often well below toxicological tolerance levels, because such levels can often be reasonably achieved by using good agricultural and manufacturing practices.

The establishment of ADIs for certain emerging food contaminants is currently an active area of research and regulatory debate.

References

See also

• Food safety
• Bad Bug Book from the US Food and Drug Administration

External links

• Office of Food Additive Safety at the US Food and Drug Administration's website
• Chemical Risks in Food from the World Health Organization
• Briefing on GM Food Contamination
• Pesticides and Chemical Contaminants from the US Food and Drug Administration's website