"Anyone wanting to reduce residues must first understand the situation"

In recent months, media coverage has highlighted residues on ornamental crops and in potting soils. "We receive many questions about this and are conducting numerous tests," says Alexander van de Bilt, Business Developer at Eurofins Food & Feed Testing in Graauw. "The central question when a test result comes in is often: what exactly are we looking at, and what do these numbers mean? Unlike vegetables and fruit, there are no legal standards for ornamental plants and potting soil to compare the results against."

Eurofins Food & Feed is part of the international Eurofins network, which also includes Eurofins Agro in Wageningen. The two divisions work closely together on residue analyses in agricultural products.

"Samples such as vegetables, fruit or flowers that arrive in Wageningen are immediately forwarded to Graauw, where they are analysed using state‑of‑the‑art equipment," Van de Bilt explains. "In addition, we receive many samples directly in Graauw from companies, retailers or other Eurofins locations operating across many countries worldwide. Fun fact: we are one of the largest laboratories for residue analysis in agricultural products in Europe!"

800 substances, from pesticides to plant hormones
Eurofins tests for around 800 different substances, including pesticides, growth regulators and plant hormones. "We analyse samples in all kinds of matrices: from relatively simple ones like water and plant material, to complex materials such as potting soil," Van de Bilt says.

Most substances are analysed through a so‑called multi‑residue screening. For some substances, such as glyphosate, a separate single screening is required. This method is highly specific and tailored to the chemical properties of the substance to achieve the necessary sensitivity. "Our list of substances and analytical methods is continuously updated based on the latest insights and technologies."

Sampling is specialist work
According to Van de Bilt, everything starts with representative sampling. "Taking samples is specialist work. Retailers often have their own trained staff, but Eurofins also has accredited samplers who can carry this out professionally and in accordance with European guidelines. They need to consider, for example, the type of product and analysis, and prevent contamination of the sample."

Logic and guidelines for ornamental horticulture
For ornamental crops, there are still no standardised norms, but Eurofins is happy to help develop logic and solutions for residue risk management in the sector. "We support customers in drafting protocols and compiling positive or negative lists of substances for ornamental horticulture. This can be an important part of a jointly developed rationale," Van de Bilt explains.

"There are many ways to manage the risk of residues in ornamental crops, and I can imagine companies wanting to get started with this. With our expertise, we can make a valuable contribution to setting up such a system efficiently and effectively."

Measure first, then act
However, as long as there are no fixed residue standards for ornamental crops, water or potting soil, measurement is the first step. "Anyone wanting to reduce residues must first understand the situation," Van de Bilt states. "That begins with smart measurement and monitoring. Only then can we build a reliable and practical rationale for the responsible use of crop protection products in the ornamental sector—and strengthen trust throughout the chain, from grower to consumer. Only once you understand your own situation can you be a fully informed partner in the chain."

Finally, Van de Bilt emphasises: "Reducing pesticide use is crucial for the sector. The foundation lies in resilient cultivation systems, and healthy soil life plays a central role in this. In Wageningen, my colleagues are conducting extensive research into soil health and soil biology. This is incredibly important for understanding how plants or substrates can become more resilient against pathogens. Together with growers, we can work towards a healthier ornamental horticulture sector!"