How pesticide findings on organic food can be explained

Some customers buy organic food precisely because it is important to them that there is not the slightest trace of a pesticide on it. But that does happen sometimes. In spring, for example, the German laboratory of Ökotest magazine found traces of glyphosate in organic chickpeas.

Usually, these are minor traces below the limits set by the authorities for conventional products. There are no maximum levels for organic products, because organic agriculture works according to rules that do not allow chemical-synthetic pesticides in the first place.

Evaluation of European and Swiss studies

Mirjam Schleiffer, Ursula Kretzschmar and Bernhard Speiser from the Swiss Research Institute of Organic Agriculture have investigated why traces of pesticides are occasionally found on organic fruit and vegetables. For this purpose, they evaluated Swiss and European studies. The European studies showed a similar picture to the Swiss: pesticide contamination was found in 44 percent, i.e. almost half of the conventional samples, and in six percent of the organic samples.

The data from Switzerland also showed that organic fresh products were on average 35 times less contaminated and that they were significantly less likely to be contaminated multiple times. The fact that impurities are found is due, on the one hand, to ever finer measurement and analysis methods, the researchers write. On the other hand, they are mainly absorbed from the environment or during processing and packaging.

Whether pesticide-contaminated food endangers health is disputed. Authorities point to limit values that are usually complied with. But consumer protectionists and critical scientists say that long-term effects have not yet been sufficiently investigated. In particular, it is unclear what the effects of the combination of different pesticides are.

30 per cent of all pesticides found in organic food were residues of natural pesticides such as pyrethrin, which is extracted from a chrysanthemum species, or neem extract, spinosad, which is based on metabolic products of a soil bacterium, or copper. These may be used to a limited extent in organic farming, but the industry is making efforts to reduce their use.

5 percent of the contamination was due to organochlorine pesticides such as DDT or hexachlorobenzene, pesticides that are now banned everywhere but are still found in many soils.

About half of the findings were distributed among various chemically-synthesised pesticides that are used in conventional agriculture, processing or storage, but are not permitted in the organic sector. Investigations by the inspection bodies had shown that in the rarest cases it was the producers themselves who had used synthetic chemical pesticides without authorisation.

Drift is a common problem

According to the scientists, the fact that pesticides get onto organic food is often due to drift from conventionally farmed fields. Contamination also occurs when conventional and organic processors share machines, warehouses and containers. Be it that machines or containers were not cleaned carefully enough, be it that it is not even possible to clean without residues.

The FIBL scientists point out that the organic industry is also making efforts to reduce traces of pesticide contamination: among other things, with hedges to keep out drift from conventionally managed fields, through elaborate cleaning or separate facilities.

Related links (German):

FIBL study Pesticide residues on organic foods

Ecomonitoring Baden-Württemberg 2019