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Pollutants in food

by Josephine Andrews
Published: Last Updated on 376 views

Man cannot survive without food! However, there is always news of harmful substances in food . Find out here how antibiotics, pesticides, heavy metals and the like affect you and what tips you can use to protect yourself from the pollutants.

Pollutants: residue or contamination?

When it comes to pollutants in food, there are basically two types:


Contaminants are substances that accidentally got into food, i.e. were not intentionally added. These include mold toxins and heavy metals. They get into the products, for example, during processing, preparation, packaging or transport. Sometimes environmental pollution is also the cause of contaminated food – for example polluted farmland.


Residues come from substances that are specifically used in the production or storage of food. These include pesticides, veterinary medicines and fertilizers (nitrate).

Antibiotics and co.

Modern animal production cannot do without the use of so-called pharmacologically active substances such as antibiotics. Medicines must be used more intensively, especially in factory farming, because otherwise diseases could spread rapidly among the animals. However, residues or degradation products of these active substances can remain in the animal’s body.

The legislator therefore prescribes certain waiting times that must be observed before the treated pigs or cattle can be processed into food. But even after these periods have expired, tiny amounts of the active ingredients can often still be detected in the animal products.

Health hazard from antibiotics

Experts recommend keeping the use of antibiotics in animal husbandry to a minimum. Otherwise there is a risk that the germs will become insensitive (resistant) to the medication over time. The germs can pass on this ability to resist to bacteria that cause infections in humans. Here, too, antibiotics may no longer work.

There are some pharmacologically active substances that are banned in animal production but are sometimes detected in controls, for example the anti-inflammatory and analgesic phenylbutazone. This can cause a rare but dangerous form of anemia.

Tips to avoid antibiotics

  • Rarely eat offal: the liver and kidneys are sort of garbage chutes – they filter pollutants out of the body and therefore usually contain larger amounts of pharmacologically active substances than muscle meat.
  • In general: Eat a varied and balanced diet! Those who eat mostly animal-based foods may ingest more veterinary drug residues than those who frequently eat plant-based products.

dioxins and furans

Dioxins and furans are formed during combustion processes under certain conditions: the temperature is between 300 and 600 degrees. In addition to carbon, oxygen and hydrogen, chlorine is also present during combustion.

Humans primarily ingest dioxins and furans through milk and milk products. Meat and eggs follow in second place. To a lesser extent, the pollutants enter the body via plant-based foods such as vegetables, fruit, bread and baked goods.

Health hazard from dioxins and furans

The groups of dioxins and furans include many different compounds that differ in their toxicity. With many representatives, experts do not even know what acute or chronic damage they can cause in the human body.

So far, damage to the skin and liver has been the most well-known. In addition, some of the substances are carcinogenic and mutagenic.

Tips to avoid dioxins and furans

  • Dioxins and furans that adhere to the surface of plant foods can be largely removed by washing, rubbing and peeling.
  • High-fat animal foods are normally only slightly contaminated with dioxins. Experts say that there shouldn’t be any risk to health if the amounts consumed are normal and the diet is otherwise varied.

nitrate and nitrite

Nitrate is a nitrogenous compound that is formed in the soil when microorganisms break down organic, nitrogenous substances. In addition, nitrate enters the soil through the use of mineral fertilizers. Plants need the nitrate to grow. Different types of fruit and vegetables contain different amounts of nitrate, depending on the environmental and growing conditions. There are also plants that naturally store a lot of nitrate, for example rocket, lamb’s lettuce and lettuce.

Tomatoes, cucumbers and peas as well as fruit, cereals and potatoes, on the other hand, only have low nitrate levels. In areas with intensive use of fertilizers, higher nitrate levels can also be detected in drinking water. Last but not least, humans absorb nitrate and nitrite (also a nitrogen compound) from cured meat and sausage products.

Health hazard from nitrates and nitrites

Bacteria in the body (oral cavity, digestive tract) can convert nitrate into nitrite. Nitrosamines, some of which are highly carcinogenic, can form in the stomach. In addition, nitrite can convert the red blood pigment hemoglobin into what is known as methemoglobin, which can then no longer transport oxygen.

Adults can use enzymes to reverse this conversion. However, infants are only able to do this to a limited extent, which means that methemoglobin can accumulate in their blood. The result is the so-called blue addiction (cyanosis), which can be life-threatening under certain circumstances.

Tips to avoid nitrate and nitrite

  • Especially when it comes to leafy and root vegetables, only buy fresh produce that was harvested in months with strong light, i.e. when the varieties are in season. With increasing light irradiation, the nitrate content of the plants decreases. Leaf lettuce grown in a greenhouse in winter has a higher nitrate load than summer lettuce.
  • Organically grown vegetables generally have lower nitrate levels than conventional produce.
  • For leafy greens, remove the stalk, stalk, large leaf veins, and outer leaves. Blanching and cooking can further reduce the nitrate content.
  • Meat products made with nitrite curing salt should not be grilled or roasted. The reason: high temperatures favor the formation of nitrosamines.


The term pesticides (plant protection products) includes active ingredients against various harmful organisms such as insects (insecticides), weeds (herbicides), mites (acaricides) and fungi (fungicides). With their help, the food industry wants to avoid crop losses due to pest infestation or facilitate the cultivation of plants by eradicating weeds.

Plant protection products also include so-called growth regulators. These are substances that increase the yield of crops in different ways, improve their quality and make cultivation easier. For example, they ensure that the plants bear more fruit. In the case of potatoes, they prevent germination during storage.

Health hazard from pesticides

Pesticides are not only toxic to harmful organisms, but also to humans. How great the risk to our health is depends on several factors, such as the amount of pesticide ingested, the toxicity of the substance, body weight or how you came into contact with the pesticide – via the respiratory tract, skin or food, for example. In principle, pesticides can cause a wide range of damage in the body, such as changing the genetic material or promoting the development of cancer. This is especially true at higher doses, to which agricultural workers, for example, may be exposed.

However, it is not entirely clear how the consumption of small amounts of pesticides in the form of contaminated food affects the long-term. According to the current state of knowledge, experts assume that pesticide residues in food do not cause any verifiable damage to health. However, this has not been absolutely proven.

Tips to avoid pesticides

  • Reach for organic food, it is mostly free of pesticides.
  • Be careful with imported goods, these are often heavily contaminated with pesticides.
  • Shop for seasonal and local produce. Fruit and vegetables that are allowed to grow naturally and do not have to be stored or transported for long periods of time require fewer pesticides.
  • Wash fruit and vegetables thoroughly under running water and then rub them with a cloth, for example.
  • The labeling “untreated” (e.g. in the case of citrus fruits) only means that no peel treatment agents have been applied to the fruit after harvest. If you need the peel of lemons or oranges for a recipe, you should therefore use organic products.
  • For lettuce , remove the outer leaves.
  • Cooking vegetables also helps reduce pesticide residues.

mold toxins

Mold toxins (mycotoxins) are metabolic products of various types of fungi. These include, for example, aflatoxins, patulin and ochratoxins. Many of these toxins get into food if it is directly infected with mold: for example, moldy yoghurt, rotten fruit and grains or spices that are contaminated with mold and their toxins due to incorrect storage and processing.

Health hazard from mold toxins

Mycotoxins can cause both acute and chronic poisoning. For example, damage to the liver and kidneys and impairment of the nervous and immune systems are possible.

In addition, mycotoxins can cause cancer, damage genetic material and cause birth defects in unborn children. The greatest danger comes from aflatoxin B1 – it is extremely carcinogenic.

Tips to avoid mold toxins

  • Mold toxins are usually heat-stable, so they are not destroyed during cooking, roasting or roasting.
  • Beware of nuts that taste bitter or furry: spit them out immediately and dispose of the rest of the pack!
  • Discard spices that have passed their use-by date . Even if they look okay, they can contain mycotoxins.
  • It is only sufficient to generously cut away moldy areas for a few foods, such as bread or hard cheese.
  • If you throw moldy food in the trash can, you should take it out of the house as well. Otherwise fungal spores will escape every time you open the bucket, which will then spread throughout the house.
  • To prevent fungal infestation, you should always store food in a cool and dry place.
  • Clean the bread bin and refrigerator regularly with a 10% vinegar solution. This reduces mold growth.

heavy metals

As components of the earth’s crust, traces of heavy metals occur everywhere in nature, in the soil as well as in water and in plants. This means that the substances also find their way into the human food chain. In addition, heavy metals enter the body via the lungs: They are inhaled together with dust, exhaust gases and tobacco smoke.

Some heavy metals are vital for the body in small amounts, such as copper, zinc and iron. Other representatives, on the other hand, have no health benefits according to the current state of knowledge or are poisonous even in small doses. These include lead and mercury, for example.

Health hazard from heavy metals

The most dangerous heavy metals that can be found in food are lead, cadmium and mercury.


Lead accumulates in bones and teeth and primarily damages the nervous system, the blood-forming system, the kidneys and, in adults, the cardiovascular system. Possible consequences are, for example, reduced intelligence, learning and memory problems, anemia and kidney dysfunction. Lead exposure is particularly risky for children and pregnant women. In animal experiments, lead also caused cancer.


Cadmium is primarily stored in the kidneys, but also in other organs such as the liver, thyroid gland and bones. The body can hardly excrete the cadmium, so it accumulates. This primarily damages the kidneys and disrupts their function. Because smokers also absorb cadmium with tobacco smoke, their kidneys are usually exposed to additional cadmium exposure.


Mercury is mainly ingested through the consumption of fish and sea creatures – mostly in the form of organic mercury compounds. These are almost completely absorbed in the intestine. They cross the blood-brain barrier and accumulate in the brain and spinal cord.

The greatest damage from exposure to mercury therefore occurs in the nervous system. These include abnormal sensations, unsteady gait, speech and hearing disorders. Inorganic mercury compounds are hardly absorbed in the intestine. They accumulate mainly in the kidneys (functional disorders), but can also be detected in the liver, thyroid, brain and testicles under stress. Both organic and inorganic mercury compounds have shown carcinogenic effects in animal experiments.

Tips to avoid heavy metals

  • Fruit and vegetables should be washed thoroughly and peeled if necessary. Don’t use the outer leaves of lettuce.
  • Eat a maximum of 200 to 250g of wild mushrooms per week. Chanterelles, porcini & Co. store a lot of mercury and cadmium. Breeding mushrooms are less contaminated.
  • Do not use pottery (plates, cups, etc.) with glaze containing lead. If you are unsure whether lead was used in the manufacture of a ceramic vessel, do not use it in the kitchen or as a food base.
  • Anyone who consumes flaxseed regularly and over a longer period of time should not choose the ground version. Any cadmium it contains can then escape more easily and be absorbed by the body.

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