Unwanted companions

Challenges in organic farming at A.Vogel

Environment and philosophy

Cheryl Vincelette
Andrea Pauli

04 May 2021

Environmental pollution, the plant's own toxins, harmful companion plants - in the cultivation and processing of medicinal plants, one cannot be careful enough to be able to deliver a really high-quality medicinal product in the end. Which is why the laboratory at A.Vogel has played a very important role in the manufacturing process from the very beginning.

Even before processing, the raw material is tested for ingredients, purity parameters and contaminants in accordance with the current state of scientific knowledge and applicable official regulations. When it comes to contaminants, the A.Vogel laboratory team led by Reto Brunschwiler, Head of Quality Control, relies first and foremost on their colleagues from the Cultivation Department: "They do their job very well, our data shows that". Unwanted companion plants are therefore identified before and during the harvest in the fields in Roggwil TG (keyword: meticulous weeding) and then immediately determined in the laboratory. Why is this so important?

A sharp look at contaminants

Let's take the example of pyrrolizidine alkaloids (short: PA). Difficult word, insidious effect: PAs are plant compounds that, when ingested, can damage our health, especially the liver. Whether ragwort, coltsfoot or viper's bugloss: PAs have been identified in about 350 plant species worldwide. The unintentional harvesting of PA-containing plant parts and seeds ("weeds") can then also lead to the introduction of these sensitive substances into medicinal products. It is therefore important to identify problem plants containing PA in good time: "Each incoming batch of plants is carefully checked to see if it contains known companion plants that carry the toxin, explains Gabriela Rohr, Head of Quality Management.
The crux of the matter with PA-containing plants is: The aim of organic farming, apart from not using herbicides, is to promote biodiversity. "For crop management, companion plants are important and not all bad," Rohr notes. "The advantage with us is that we process fresh plants, so we can tell what's medicinal and what's a companion plant right from the harvest cart," says Reto Brunschwiler. This is an important criterion, for example in comparison with manufacturers who purchase crushed medicinal plants (and thus possibly a pig in a poke). Risk-minimising measures with regard to PA are important not only for health reasons: "They also ensure that we don't have to throw away contaminated batches," Brunschwiler points out.
"To date, we have carried out 220 risk analyses of a wide range of plants and products that are important to us, so we know where the problem plants are," explains Gabriela Rohr. Of course, this knowledge is also passed on to the contractual partners who grow medicinal plants for A.Vogel. "Especially with Hypericum (St. John's wort), we know we have to look closely, as the similar-looking ragwort is a potential problem," Rohr said.

Examination for companion plants after harvest of Hypericum (St. John's wort)

Heavy metals well under control

There is relative confidence with regard to heavy metals: "They are avoidable, the input of such substances is easily controllable," according to Reto Brunschwiler's experience. At present, mercury, arsenic, cadmium and lead are the focus of particular attention. Appropriate measures are: Stop fertilising in time, self-control of compost, meticulous examination of wild collection. Special attention is also paid to the soil: "It can be problematic if the soil is loosened with sand, then you have to check exactly where this sand comes from," Gabriela Rohr emphasizes.
A.Vogel's laboratory also sometimes arranges soil tests for heavy metals. "We analyse at least one batch per supplier per year to check if there are any residues," reports the Head of Quality Management. The medicinal plant suppliers/contract farmers also appreciate this. "They are of course interested in such data, because the analyses are quite expensive and a farmer doesn't just order that for himself," Rohr knows. The contractual partners also like to present the expensive analysis results as monitoring data during their own annual organic inspection.

Problematic pesticides

What's tricky are the pesticides: Even if you are devoted to organic farming - if gardeners or farmers use so-called pesticides (fungicides, herbicides, insecticides) in the surrounding area, they can unintentionally end up in A. Vogel's fields and affect the medicinal plants through the water cycle. This is called cross-contamination - because cultivation does not take place under a protective cover, but usually in the open air.
A.Vogel has contracted various laboratories that test for 500 to 600 pesticides. Reto Brunschwiler always checks that the methods used are suitable and that the limits applied are correct. Together with the Quality Management of A.Vogel, he then interprets the results of the external laboratories. "In this way, we have ensured a large degree of coverage with regard to possible contamination," explains the Head of Quality Control.


Gabriela Rohr, Head of Quality Management, Diploma in Pharmacy, Dr. sc.nat. ETH, with A.Vogel since 2000

Reto Brunschwiler, Head of Quality Control, Bachelor of Life Science (B.sc.) Biological Chemistry, with A.Vogel since 2015

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