Residues in food
Residues in food refer to pollutants that get from the soil and water into plant-based foods as well as from animal feed or through treatment with veterinary drugs. They arise from industry or agriculture. While residues find their way into the food through conscious entry, in contrast to this, contaminants from the environment get into the food without human intervention.
The German Chemicals Act requires a toxicological test on at least two animal species for every substance with a production over 1 ton per year . In the Food and Feed Code Section 8 , Section 9 , Section 10 , Section 14 , Section 15 , the protection of the consumer is ensured through maximum quantity regulations. The quantities are in the ppm range (mg active ingredient per kg food) or ppb range (mg active ingredient per t food). A complete absence (zero tolerance) is often not possible, since with today's sensitive analytical possibilities almost any substance can be detected anywhere.
Agriculture
As with food additives, a toxicological test is required for agricultural auxiliaries before approval. Here, too, a substance must be included in a positive list before use. In the EU, plant protection law applies in accordance with Regulation (EC) No. 396/2005, as amended by Regulation (EC) No. 1107/2009 (Plant Protection Products Regulation) . Based on the experiments on short-term and chronic toxicity, limit values are derived and consumer exposure and health risk are assessed. The aim is to ensure that approved plant protection products should not have any harmful effects on human health after proper use.
Pesticides
In Germany, the pesticide maximum amount regulation applies to residues in food . In the context of the official food control in the sense of consumer protection , about 400 substances are checked. In Switzerland the "Ordinance of the FDHA on the maximum levels for pesticide residues in or on products of plant and animal origin" applies to the same.
A conventional farming without the use of pesticides is unthinkable today, although it is proven to be damaging to the natural balance between pests and their natural enemies or destroy. These are necessary for automated cultivation, otherwise there is a risk of a crop loss of over 30 percent. Efforts are being made to use substances that are completely degraded before harvest. In previous years, however, mainly organochlorine compounds were used that are not or only incompletely metabolized. Its great persistence led to its distribution all over the world, so that considerable amounts can now also be detected in breast milk . One of the few chlorine compounds still permitted is quintozen , which is used in the greenhouse cultivation of lettuce , chicory and cucumber and as a seed treatment agent.
An exemplary pesticide is lindane , which is found in meat products. The class of phosphoric acid esters includes parathion , ethion and malathion as well as dimethoate , mevinphos , bromophos and chlorfenvinphos . They act as cholinesterase inhibitors at the synapses of the insects . They are preferably used in fruit and vegetable cultivation because they are quickly broken down into non-toxic metabolites, which is why general waiting times must be observed. However, even in small doses, they are fatal to humans and can be absorbed through the respiratory tract and skin. Therefore, suitable protective measures must be taken when applying.
In viticulture, inorganic fungicides such as elemental sulfur and copper salts are used, and in the area of organic fungicides, mainly derivatives of N , N -dimethyldithiocarbamic acid , which act against various types of mold and powdery mildew .
2,4-dichlorophenoxyacetic acid and trichlorophenoxyacetic acid , which were used in high doses as a total herbicide for defoliation during the Vietnam War , became known worldwide . Their toxicity against warm-blooded animals is low, but the by-product 2,3,7,8-tetrachlorodibenzodioxin (TCDD, also Seveso poison after the chemical disaster) is one of the most toxic substances known, which is characterized by its strong teratogenic effect and also in the Exhaust gases from waste incineration plants can be found. Pentachlorophenol is a similar compound that is used to protect wood, textiles and leather against bacteria and fungi. It is transferred to edible mushrooms and pork and is carcinogenic.
The most powerful pesticides include the pyrethrins , cinerins and neonicotinoids , which are used as contact and food poisons against insects and lower, cold-blooded animals. Higher mammals and birds hardly suffer any damage.
In Germany in 2008, around 5% of the fruit and vegetable samples examined by the official controls were suspected of improper use. In about 2% of the cases, non-approved active ingredients were found, in about 3% there was no approval for the approved active ingredient in the culture. Only about 14% of the samples with non-approved active ingredients were complained about because the maximum amount was exceeded. The most common samples with unapproved residues include peppers (38.7%, possibly often incorrectly declared as German goods), beans with pods (15.5%), kale (14.1%), culinary herbs (11.5%) , Zucchini (10.4%), gooseberries (9.0%), lamb's lettuce (8.0%), rocket (7.7%), blackberries (6.3%), pears (5.9%).
In fresh vegetables and spices from Asia, which were imported into Switzerland between 2012 and 2015, 4 percent of the samples exceeded the acute reference dose.
Veterinary drugs
A number of different preparations with pharmacological effects can be used in animal husbandry. The most important are:
Antibiotics are mainly used in animal fattening. For example, they can be added to the feed. However, no active ingredients may be used that are used in human medicine to prevent the development of resistance in pathogens. The drugs are used either preventively or in acute diseases of the animals. Another positive side effect of some antibiotics is that parts of the microorganisms in the intestine are also combated, which can lead to better utilization of the feed, so that the feed consumption is reduced. These active ingredients are called performance enhancers and their use in the EU has not been permitted since 2006.
The main hormones used are sex hormones. These have estrogenic , androgenic or gestagenic effects and are used especially as fattening aids. They cause increased protein formation and better feed utilization. In the European Union, the use of hormones in food-producing animals is prohibited. Also no meat treated with hormones may be imported.
Anti- thyroid drugs are thiourea derivatives that affect the thyroid function. In doing so, they inhibit the synthesis of the hormone thyroxine . In the animal fattening stage, this leads to a sometimes strong weight gain of the animals. However, this is mainly due to increased water retention, which has a negative effect on the meat quality.
Since animals are exposed to increased stress, especially during transport, sedatives such as neuroleptics , benzodiazepines or beta-blockers can be used. These meanwhile play a rather subordinate role, since after the administration of the active substances a prescribed waiting time has to be observed before the animals can be slaughtered. Sedatives are therefore not very useful when being transported to the slaughterhouse. In addition, less stress-prone animals have now been bred, which makes the use of sedatives obsolete.
Antiparasitic drugs can be used to combat or prevent harmful parasites. A distinction can be made between endoparasites such as worms, flukes and toxoplasms, and ectoparasites (mites, fleas and ticks). They can have a direct or indirect negative impact on the health of the animals (e.g. through the transmission of diseases). In the case of worm infestations, anthelmintics such as avermectins or benzimidazoles are suitable . Some antiparasitic drugs are also used as pesticides in agriculture. For example, fipronil is used both in agriculture against ants and in veterinary medicine against fleas and mites.
Beta agonists are also performance enhancers. With high doses, they should produce a better meat / fat ratio. The effect is based on the excitation of the β-receptors on the heart and the smooth muscles. Typical representatives are Clenbuterol and Salbutamol , which were also used in doping in sports. Animals treated with beta agonists must not be used for food production.
In general, the use of veterinary medicinal products is strictly regulated and often linked to certain requirements, such as compliance with waiting times before slaughter.
Consumer awareness
According to a Eurobarometer survey, consumers rate the health risks of food residues in the form of chemicals more strongly than bacterial contamination or nutritional problems. If respondents are allowed to indicate specific problems, pesticide residues in fruits, vegetables and grain products lead; Antibiotics, hormones in meat products; cloning animals to produce food or pollutants like mercury in fish or dioxins in pork. In comparison, the bacterial contamination of food is taken less seriously. Fewer respondents also worried about diet-related risks such as weight gain or about an unbalanced diet.
Web links
Individual evidence
- ↑ U. Banasiak, B. Michalski, R. Pfeil, R. Solecki: Plant protection products and their residues, aspects of consumer safety in the context of new EU regulations , Federal Health Gazette - Health Research - Health Protection , Volume 53, Number 6, 567-576, doi : 10.1007 / s00103-010-1068-1 .
- ↑ a b c d e f g h i j k l m n o W. Baltes, R. Matissek: Food chemistry, residues in food , Springer textbook, 2011, 329–350, doi : 10.1007 / 978-3-642- 16539-9_12
- ↑ a b c d e f Thomas Kühn, Manfred Kutzke: Pocket book for food chemists, Environmentally relevant residues , Springer, 2006, 379–417, doi : 10.1007 / 3-540-28220-3_16
- ↑ Ordinance of the EDI on the maximum levels for pesticide residues in or on products of plant and animal origin. In: admin.ch . Retrieved February 6, 2020 .
- ↑ Peter Brandt: Evaluation of the data on pesticide residues from food monitoring with regard to the occurrence of unauthorized active substances in samples of German origin National reporting to the EU National Residue Control Plan (NRKP) and Import Residue Control Plan (ERKP) report on official feed control, reports on food safety 2008, BVL reports , Volume 4, 4, 2010, doi : 10.1007 / 978-3-0346-0205-1 .
- ↑ Pesticides in fresh vegetables and spices from Asia. Federal Food Safety and Veterinary Office , June 2016, accessed on December 1, 2019 .
- ↑ a b c d e f g h i W. Frede: Handbuch für Lebensmittelchemiker , Springer, 2010, 376–403, doi : 10.1007 / 978-3-642-01685-1
- ↑ EFSA press release: New research on consumer awareness in the EU of food risks .