A pesticide is a substance or mixture of substances used for preventing, controlling, or lessening the damage caused by a pest. A pesticide may be a chemical substance, biological agent (such as a virus or bacteria), antimicrobial, disinfectant or device used against any pest. Pests include insects, plant pathogens, weeds, mollusks, birds, mammals, fish, nematodes (roundworms) and microbes that compete with humans for food, destroy property, spread or are a vector for disease or cause trouble. Many pesticides are poisonous to humans.
An important priority for farmers is to ensure that their products - whether vegetable or animal in origin - are produced in a safe manner. To comply with this, they are assisted by a wide variety of farm advisory services, providing advice on the correct use of fertilisers, pesticides and other products in crop and animal husbandry.
Chemicals such as pesticides or products used in animal health are subject to strict regulations. They undergo rigid testing procedures before they are accepted for registration by European or national authorities.
More than 800 pesticides are currently approved for use in Europe. The procedure for establishing if a new product merits registration is complex. It requires many toxicity and efficacy studies before initial field tests can be carried out. It also includes tests on the degradation of the product and its derivatives in the plant and in the environment. A product should benefit the plant or animal it is intended to help with no negative effect on other species, and should not leave any harmful residues at such levels to cause health risks in the plant or animal or in the soil or water.
3.1.2 Environmental contaminants
Environmental contaminants are chemicals 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) and polycyclic aromatic hydrocarbons (PAH)
- Water: arsenic, mercury
Soil: cadmium, nitrate, perchlorate
Air, water and soil: Polychlorinated biphenyls (PCB), dioxins and polybrominated diphenyl ether (PBDE)
Packaging materials: antimony, tin, lead, etc.
- Processing/cooking equipment: copper, lubricants, cleaning and sanitizing agents
- Naturally occurring toxins: mycotoxins, mushroom toxins, scombrotoxin (histamine), ciguatera, shellfish toxins, tetrodotoxin, etc.
Examples of environmental contaminants:
Dioxins are by-products of the manufacture of certain industrial chemicals and incineration or burning. Dioxins are environmental contaminants that persist in the environment for many years and can find their way onto and into foods.
In fish, polluted water is the main cause of dioxin contamination while other animals are mostly exposed to dioxins through the air. Dioxins settle on plants and feed, which are then eaten by animals. Dioxins concentrate in the fatty tissues of livestock and fish. More than 90% of human exposure occurs mainly through foodstuffs. Products of animal origin normally account for approximate 80% of the overall exposure.
Despite punctual incidents (e.g. Belgium, 1999), available data shows that the background exposure to dioxins of the European population has decreased over the last 10 years. The current EU policy on dioxins aims at further reducing the contamination levels of dioxins in the environment, feed and foodstuffs in order to ensure a higher level of public health protection.
188.8.131.52 Heavy metals
Other industrial pollutants include heavy metals such as mercury, lead and cadmium . Fish are especially vulnerable to environmental pollutants because waters can become contaminated from industrial discharges or accidental spillage. Recent reports of levels of mercury in large predatory fish such as swordfish have caused some European authorities to issue warnings that these fish should not be eaten by pregnant or lactating women or children due to the possibility of high levels of mercury. The fishing industry has responded by harvesting smaller sized deep-sea fish, which are unlikely to have a build-up of heavy metals. The EU has standards for mercury and other heavy metal contaminants in foods and the levels are routinely monitored.
Mycotoxins are toxins produced by certain fungi or moulds that grow on foods such as peanuts, tree nuts, corn, cereals, soybeans, animal feeds, dried fruits and spices. The toxins may be produced as crops grow or develop later during poor storage or handling. Mycotoxins can also enter the food chain via meat or other animal products such as eggs, milk and cheese as the result of livestock eating contaminated feed.
The actual effects they have on health depend on the amount and type of the mycotoxins ingested. For instance continuous intake of aflatoxin is thought to be associated with liver cancer in people affected by Hepatitis B. Other mycotoxins have been linked to kidney and liver damage.
Careful surveillance procedures and proper storage conditions of foods are important in helping to prevent the development of mycotoxins.
3.1.3 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. They include: acrylamide, furan, benzene, trans fat, etc.