Analysis Karanjin

In response to recent demand from major supermarket chains and consolidators, we have introduced the active ingredient Karanjin into our multi-residue screening.

There is currently no authorisation of Karanjin in the EU, so an MRL of 0.01 mg/kg is applied. Because there is a lot of attention for Karanjin, we have set up a method and can now analyse it with the GC-MSMS method. From this week on, we will analyse Karanjin in the screening method. Here is some more information about the method and component.


Regarding the legal status, the active substance is currently not registered as a pesticide in the EU. Therefore, the application of a default MRL of 0.01 mg/kg would be acceptable.
The legal evaluation of the active substance in organic farming also raised questions, as e.g. the use of plant extracts (as foliar fertilisers or plant enhancers) is in principle allowed in organic farming.
With regard to toxicological evaluation, there is currently no known ARfD or ADI (Acceptable Daily Intake) value against which the values obtained in case of detection can be assessed.
However, the fact that the origin, biological or chemical, cannot be distinguished has led the distribution chains, as in the case of Matrine, to decide to prevent the importation of fruit and vegetables containing residues of this active substance in order to protect consumers, while the legal situation is being clarified.

What is Karanjin?

Karanjin is a furanoflavonol, a kind of flavonoid. Flavonoids are a broad group of nitrogen-free organic compounds that are widespread in the plant kingdom. It is obtained from the seeds of the karanja tree, a tree that grows wild in India. Karanjin is an acaricide (against ticks and mites) and also a general insecticide. The effect of this substance in the soil is that it reduces the conversion of Ammonium to Nitrate.

This substance can now also be analysed by Groen Agro Control and is included in the multi-residue screening LC-MSMS and GC-MSMS.

Do you want to check your product for Karanjin or other harmful substances?
Please contact us and consult our colleague Michel Witmer.


Ethylene oxide analysis

Do you need Ethylene Oxide analysis urgently?
Report within a few days possible, ask for the conditions.

The analysis of Ethylene Oxide in sesame seeds

In recent months there have been several batches of contaminated sesame seeds found in the EU with India as country of origin. In these batches, an increased level of Ethylene Oxide was found. In India, Ethylene Oxide is used as a disinfectant on sesame seed. The use of Ethylene Oxide is not permitted in the EU and this substance has an MRL of 0.05 mg/kg for sesame seeds.

Mid October 2020, a recall action of contaminated sesame seed lots was started by the NVWA. This has created a strong demand in the recent period for the analysis of Ethylene Oxide in sesame seeds and products containing sesame seeds.

During the first weeks, our residue lab was flooded with samples of sesame seeds or products in which sesame seeds are processed (oil or crackers). Initially, this analysis was outsourced to one of our partner laboratories, but due to the long waiting time (up to 5 weeks), we set up this analysis ourselves.

After two weeks, the validation process was completed and we started analysing for the customers. Initially with an LOQ of 0.02 mg/kg of product. By further optimisation of this analysis we can now also achieve an LOQ of 0.01 mg/kg. This means that we can now also support the biological sector with this analysis. Our method is also suitable for other products like cereals.

Want to check your product for ethylene oxide or other harmful substances?
Please contact us and discuss with our colleague Michel Witmer.

Groen Agro Control joins Normec Group

Over the past 25 years Groen Agro Control has built a fine company that supports clients with analyses and advice. In order to ensure continuity and growth of our company, we have chosen to join the Normec Group as from March 2nd 2021. We are pleased to have been able to take this step in order to embark on new developments together.

The Normec Group is a Dutch company with similar core values that offers a total package in the field of quality testing, analyses, safety and inspections throughout the food sector. By becoming part of the Normec Group we are able to offer excellent services and high-quality expertise in the agro and food sector.

We’d like to point out that nothing will change for you as our customer. You can continue to count on the same expertise, quality and personal service and you will keep the same contact persons at Groen Agro Control. We are convinced that by joining the Normec Group we are able to offer even better services.

We place great value on personal contact and clear communication. If there are any further questions, we are always available for further assistance.

Kind regards,
Bert van Tol

Contact people for your sector are:
Horticulture and grower associations – Ines van Marrewijk
Fruit and vegetable Trade and Food Industry – Michel Witmer
Arable farming and grassland – Joke de Geus
Peru – Andrea Pro
Other countries – Han van der Put

Underground water system; we know a lot (and a lot we don’t)

Ines van Marrewijk of Groen Agro Control likes to get to the bottom of unusual questions from growers. If there is a solution to a grower’s problem, Ines knows where to find it.

Bacteria unknown

The search for the right methods to measure bacteria in the water requires attention. “Are you looking for a specific pathogenic species such as Agrobacterium or for generally occurring bacteria?” explains Ines. “For example, it could be growth of anaerobic bacteria at low oxygen levels. This is not often tested and should be specifically asked for. Anaerobic and aerobic bacteria surround themselves with a layer of slime that causes biofilm in pipes, among other things. The addition of cleaning agents prevents most biofilm in the pipes themselves. But in dead ends, couplings or rough parts, fouling and germs often remain persistent.  A change of composition in water can sometimes cause the growth of bacteria and also yeasts to suddenly ‘explode’.”

What exactly that is for bacteria is often not immediately clear. “An example: For many years, Groen Agro Control named certain root growth ‘beaded roots’ and yet another image ‘thick roots’. Both appear to have a bacterial cause. It is not yet known that many bacteria can be harmful to plant and/or root growth. We now know more, but by no means everything. The bacterium Ralstonia was also such an ‘unknown factor’ when it suddenly turned up in roses and anthurium, which had not previously been described as a disease in those crops worldwide.”

DNA sequence

One of the advantages that Groen Agro Control has recently acquired to give the identification of bacteria a boost is the new technique of Next Generation Sequencing. By means of DNA sequencing, different variants within a virus, bacteria or fungus can be distinguished. In this way, different genetic variants of viruses, for example, can be better monitored. “Or we can do quality control on microbiological products. This way you can check that the product only contains what it should. The genetic information from drain water or roots can be used to map the microbiological composition. Both beneficial and harmful bacteria, fungi and viruses are detected.

By using sequencing in this way, you don’t focus on just one organism, but immediately see ‘all the micros’ in such a sample. “That sequencing machine has initially been purchased for virus research, after which we will see what has priority. For each purpose, the method will first have to be validated so that high-quality results are obtained from practical samples.”

Solving problems

At Groen Agro Control, the focus with micro is on monitoring cultivation and also on solving problems in the sector. For example, we prevent growth problems in cultivation and at growers through regular analysis of the water. “If you measure a few hundred thousand bacteria per millilitre in ‘clean water’ via germination numbers, that is really too much, certainly for cuttings and seedlings. Then the bacteria get in the way of good rooting, possibly resulting in growth damage.”

Improving resilience is also a key to better water that the company holds. “The magic word ‘resilient’ in analyses requires looking at both good and harmful micros.  With more extensive germ counts, you not only get to see the general fungi and bacteria in the water, but also the germ counts of plant diseases and, if desired, of benign fungi in package ‘Germ Count Resilient’.

“We then look not only at pathogens but also at antagonists – fungi and bacteria that help plants rather than hinder them, such as Trichoderma. You have to do such measurements at a certain frequency to get a good picture of the situation on a farm. As with a UV disinfector, it is not a question of measuring once, you have to keep monitoring.”

Water and ToBRFV

Finally, Ines zooms in on the connection between water and ToBRFV or other water-borne viruses.  According to her, this is still quite a blind spot on farms, mainly because of the complex water system. In principle, water is not the most dangerous factor in the spread of the dreaded tomato virus. During cultivation, the most dangerous factor is juice-on-juice spread. “But during the crop rotation, the risk of water and the drain water system is much higher. You often have to make a 500% effort in hygiene to get 99% results in virus free. Unfortunately, you sometimes only know whether you have succeeded in removing 100% of the virus after it turns out that the new crop remains clean.”

Hygiene and the establishment of protocols is a specialism of Groen Agro Control and Ines also accompanies growers on the farm because hygiene remains customised work.

For more information: Ines van Marrewijk, productmanager bij Groen Agro Control, Distributieweg 1 – 2645 EG Delfgauw, phone 015 2572511

Publication date:
Author: Annet Breure


First step in lowering MRL overshoot is understanding the whole process

Every fruit and vegetable trader has to deal with it at some point, some more than others: the exceeding of the permitted MRL value on fruit and vegetables and this leads irrevocably to the destruction of the product. Exceeding the MRL often has various causes. Michel Witmer, product manager for foodstuffs at Groen Agro Control, therefore gives the advice to his clients in the AGF to draw up a top five list of products with which they have the most problems. “From that point, they can start working towards improvement and thus fewer MRL violations on fruit and vegetables, thus limiting recalls.”

For 25 years, Groen Agro Control has had a specialised laboratory for analysing chemical and microbiological constituents on fruit and vegetables. “Based on those analyses, we as a company can also give advice on how things can be done differently. After all, many factors play a role when it comes to an MRL violation: When did pesticides end up in the fruit? During cultivation, after harvest or during transport in the container and do the various parties communicate with each other about the permitted value for the end customer? It also happens that such pesticides are sometimes applied by accident. Think of a grower who uses water from the river downstream that has been polluted by another grower upstream.”

Talking to the grower

Michel ziet vooral dat overzees fruit uit Afrika, Zuid-Amerika en Azië soms een te hoog pesticiden gehalte hebben. “Het is daar soms moeilijker om goed contact te houden met de telers die producten verbouwen voor de Europese markt. Zeker als hier in Europa de regels weer veranderen met nog strengere eisen rond de MRL in producten. Neem als voorbeeld straks het nieuwe Pomelo-seizoen. Daarvoor zijn de regels weer veranderd voor gebruik van Chloorpyrifos, maar of een Chinese teler dan gelijk zijn manier van telen gaat aanpassen is maar de vraag. Of wat dacht je van een voorbeeld dichter bij huis: Chloorprofam in aardappelen en uien waarvan het gebruik sinds dit jaar verboden is in de EU.”


Michel says that Groen Agro Control can give advice on adjusting the programmes. “We look for instance at the use of alternatives in crop protection products and the application at a certain moment in the cultivation. In addition, we often see that different pesticides are used on one product with exactly the same effect. We see that happen a lot on strawberries. The biggest gain for many AGF importers is to pass on MRL changes to their suppliers in time.

“The MRL is a fixed maximum value that is set for the use of certain pesticides and the legislation seems to become stricter every year. The European Commission often announces a further tightening six months in advance, giving growers the chance to reduce their doses or look for alternatives. However, the retail sector in Europe applies even stricter requirements on these residues and these also differ per chain. For us, the work would be easier if the retail sector were more transparent about their specifications so we can better inform the sector and the laboratories about the steps to take.

For more information please contact Michel Witmer, product manager at Groen Agro Control, Distributieweg 1 – 2645 EG Delfgauw, phone 015 2572511

Date of publication: Thu 3 sep 2020
Author: Thom Dobbelaar

Photography: Martin van der Marel

Groen Agro Control puts focus on compost analyses

This week Groen Agro Control received the green light from the Council for Accreditation to perform analyses on organic waste streams such as compost, organic waste, green waste and sewage sludge. The laboratory received the accreditation to perform analyses on nutrients and heavy metals in products that are useful for the soil and have to comply with laws and regulations. These analyses are carried out at our laboratory in Delfgauw. Composting companies and producers of organic waste streams take samples themselves or can have them taken for a fee by Groen Agro Control or through Van de Meerakker Service BV.

Accreditation is the degree of purity of analyses issued by the Council for Accreditation to ensure that customers can blindly trust that the quality of the analyses is in order. To prevent the application of products to the soil from leading to contamination or exceeding legally permitted levels of nitrogen and phosphate, composters have them analysed first. The levels can be passed on to the Rijksdienst voor Ondernemend Nederland (RVO) at their request. This way, the product is registered and the sale takes place in a responsible way.

Groen Agro Control is investing in these analyses because they believe that circular agriculture is the future.  Compost has good properties as a soil improver. An additional advantage is that the quantities of nitrogen and phosphate in compost count for half the application norms that apply to the use of fertilisers in agriculture.

Not all waste streams qualify as soil improvers. Some waste products could pose a danger due to high concentrations of undesirable compounds. In addition to the analyses they perform for composting facilities, they also assist organisations that want to have their waste products tested in order to be approved as usable raw materials for agricultural applications.

More information about the accreditation of compost analyses can be found on our website.

You can also contact Joke de Geus, product manager agriculture and grassland. Or call +31(0)15 257 25 11

Flexible scope for accredited analyses of pesticides in fresh produce and grain

After a positive assessment study by the Dutch Accreditation Council (RvA), the residue laboratory of Groen Agro Control has obtained a flexible scope for the analysis of residues of pesticides in food, animal feed, products derived of plants and water.

Starting from today, the following pesticide residues are also measured under accreditation:

Residue Screening LC-MSMS in Fresh Produce: Bensulfuron-methyl, Dimethirimol, Etoxazole, Fenbutatin Oxide, Buturon, Flupyridafurone, Isouron, Oxasulfuron, Quinoclamine, Terbuthylazine

Polar pesticides in Fresh produce and Grain: Ethephon, Fosetyl, Phosphorous acid, AMPA, Glyphosate, Glufosinate

The new analysis lists for fruit and vegetables and grain are available on our website, the newly accredited substances are also marked with a Q.

ARfD – calculation according to the EFSA PRIMo model version 3.1

Since the 12th of October 2020, Groen Agro Control calculates and reports the ARfD percentage (ARfD value) for the Netherlands with the EFSA PRIMo model 3.1. The Acute Reference Dose (ARfD) is an estimate of the amount of a pesticide in food that a person can ingest within 24 hours without significant health effects. The depletion of the ARfD value is always given as a percentage of the ARfD value.

Previously, the national models were used to calculate the ARfD percentage, in the Netherlands the NESTI model. Recently, the calculation method of the ARfD percentage has been harmonized within the European Union. The calculation model within the European Union is the EFSA PRIMo model (current version 3.1). For the Netherlands, RIVM has also published a list of associated processing factors that are included in the calculation. The calculation of the ARfD with the PRIMo model with processing factors is also used when testing against the requirements of Dutch retailers. For other countries within the EU, the PRIMo model is used without the processing factors.

If you have any questions about this change in the method for the ARfD calculation, please contact your account manager or our specialists from the Pesticide residue laboratory.


Groen Agro Control Peru SAC will attend the 2020 Expoalimentaria trade show

Groen Agro Control Perú SAC is participating in this new version of 2020 Expoalimentaria trade show: Virtual Expoalimentaria from September 30th to November 15th

Virtual Expoalimentaria is a commercial platform which has been created in order to display and promote important products within the food, beverage, machinery, services, containers and packaging sectors for the food industry. It will be used as meeting point for the key operators of distribution, retail, catering industry and specialized channel in the Peruvian and international market.

Be free to visit us and know more of our services: or contact by email for any request.

Groen Agro Control Peru obtained accreditation for the analysis of residues of crop protection products

Our colleagues in Lima have been working on the validation of the analysis methods for residues of pesticides. The Dutch Board of Accreditation (RvA) recently evaluated these efforts and awarded accreditation to our methods of analysis. Starting from the 7th of September the residue analyses on fruit and vegetables and grains that are carried out by our laboratory in Peru are performed under this accreditation.

If you wish to use the analyses of Groen Agro Control Peru, please contact us via