Green Agro Control present at HortiContact 2022

We will be present at the HortiContact in Gorinchem on 10, 11 and 12 May.
You can find us at booth number J138.
Feel free to drop by to get acquainted or make an appointment with Ines van Marrewijk at


HortiContact is the annual meeting place for professionals in greenhouse horticulture. For three days you will find the latest innovations here, you can gain new knowledge during workshops and discover the most diverse solutions.


May 10, 2022 1:00 PM – 9:00 PM
May 11, 2022 1:00 PM – 9:00 PM
May 12, 2022 1:00 PM – 9:00 PM


Event Hall Gorinchem
Franklinweg 2
4207 HZ Gorinchem


Groen Agro Control at the Fruit Logistica 2022 fair

From April 5 to 7 you can visit us at stand B-7 in hall 3.2 of Fruit Logistica in Berlin.
During this fair, product manager Michel Witmer will inform visitors of the fair about the services that Groen Agro Control has to offer.

The laboratory manager Hassan el Khallabi is also present for substantive questions about measuring residues of plant protection products in fruit and vegetable products. Thirdly, you can also meet the colleagues of Groen Agro Control Peru. We look forward to welcoming you to our booth B-7 in hall 3.2. Groen Agro Control welcomes you with refreshing drinks.

Listeria and ToBRFV in the fruit and vegetable trade

Listeria and ToBRFV are hot topics for growers, suppliers and the AGF trade alike. Michel Witmer, Product Manager at Groen Agro Control, is happy to tell you more about it based on his experience with the Fruit & Vegetables trade and food sector.

Although Michel does not have direct contact with growers, the crates have to be cleaned properly to remove bacteria or viruses, for example. Groen Agro Control advises on this based on the PCR tests they perform.
“There are companies that clean professionally for third parties. They have to clean and, at the request of their customers, validate the absence of certain micro-organisms, usually viruses. What we do is periodically or upon request sample crates. There are not just one or two, but dozens of them.
If virus particles are found, then you know that the cleaning is not good and that adjustments must be made to the process. At the request of the customer, Groen Agro Control tests for the presence of viruses and they can also reveal any imperfections in the cleaning process.
Michel has no direct contact with growers’ organisations, but he is certainly not unfamiliar with the world of crate washers. In the past, he regularly visited companies in the food industry to check the crate washers for dosage of cleaning agents and disinfectants. The hygiene of the machine was also checked and discussed with the clients.


ToBRFV is a persistent virus, Michel has noticed. “You would think, that bit of DNA, some hot water over it and you’re done, but it’s not like that. It’s a matter of finding the ideal combination of various factors: chemistry, temperature, time and concentration of the agent.” In other words, the Circle of Sinner must be complete.
Michel explains how this works using a recognisable example. “Think of the old-fashioned washing-up bowl. You put a drop of Dreft in it, hot water, a dirty plate and a washing-up brush. You can’t get the grease off with cold water. So you either have to scrub harder or wash longer to get the dirt off the plate. If you raise the temperature, you don’t have to scrub as hard and you’re done faster. So in that way you actually have to validate your cleaning process.”

The ToBRFV puzzle

The tomato virus has been on everyone’s mind for over a year now. ToBRFV is making headlines in various parts of the world. “There are still many countries in and outside Europe that are suffering from it,” points out Michel. How should we solve the puzzle?
“Very good hygiene at the grower’s is important, and they have to keep a close eye on the germination material they start with. The tricky thing is that it cannot be seen.”
A possible solution is to develop resistant germination material, but even that does not offer 100 per cent certainty. “You can always get new viruses with modifications and other properties. Just look at COVID, which now also has an English and South African variant. Who says that’s not possible with other viruses?” So hygiene is the crux.

And how do you prevent Listeria?

Michel’s help is also regularly requested in preventing Listeria infections. Listeria is a very common microorganism. “Because it can make people sick, it’s important that it’s not present in the end product.
Sometimes companies have a positive result, without knowing where exactly it comes from. Then Michel can come along for advice. The whole process is checked to look for problem cases.
The problem with Listeria is that it is a persistent micro-organism. “At a temperature of between zero and five degrees, it can still grow. That is a temperature at which other bacteria cannot grow. So you have to pay extra attention to cold spots and places where condensation forms.” If you work in production every day, you sometimes fail to see the problematic spots, such as conveyor belts, yourself. Michel can help with an extra pair of eyes.
He makes an inventory of the production process and then advises a company on what it can do to clean it. A layer of biofilm on a pipe, for example, is an excellent breeding ground for Listeria. “It’s comfortable there and can grow in the meantime. If Listeria does get into the product through water or condensation, you can come across another contamination in the microbiological analyses of your end product. It’s like a raisin infection – it’s not distributed homogeneously.”
With Michel’s help, a company can pick out those unwanted currants. “That’s what I like to do: make customers happy by solving problems.”

For more information please contact Michel WitmerGroen Agro Control, Distributieweg 1 – 2645 EG Delfgauw, phone 015 2572511

Date of publication: Fri 5 Feb 2021
Author: Annet Breure

Photography: Martin van der Marel

Groen Agro Control wish everyone a Merry Christmas and a successful 2020

The management and staff of Groen Agro Control wish everyone a Merry Christmas and a special, enterprising, inspiring and successful 2020.

We are closed on 30th of May & 10th of June

Due to Ascension Day, on 30th of May, we will be closed. On Friday, 31st of May, we will be pleased to help you from 08:00.

On Monday 10th of June we will be closed as well, due to Whitsun.

Happy 2019

Today, December 31st, we are open until 15:00.
On January 1st we will be closed. From January 2nd the opening hours will be as usual, 08:00 – 17:30.
On behalf of our team we wish you a happy New Year!

Christmas 2018

We are closed during Christmas (25 & 26th of december) and on the 1st of January. We wish you a Merry Christmas and a Happy New Year!