The Dutch food safety authority NVWA has warned of widespread breaches in the use of crop protection products in the country’s tomato greenhouses. The regulator told NU.nl that growers are regularly failing to comply with legal requirements and several have been fined following inspections.

NVWA inspectors visited dozens of tomato growers and found repeated misuse of hydrogen peroxide, a cleaning agent used to flush water pipes in greenhouses to prevent the build-up of fungi and bacteria.

Some growers use a version containing added silver to prolong its effect. While this product is legal, the rules require pipes to be emptied and rinsed before clean water is allowed to reach the plants.

Authority inspectors found that some greenhouses were continuously flushing water mixed with hydrogen peroxide and silver through the irrigation system.

Tomatoes from those sites were labelled “possibly unsafe”, not because residues were found, but because the food safety risks of the added silver have not been fully assessed.

The NVWA subsequently tested the tomatoes and found no traces of hydrogen peroxide or silver, meaning the produce could be sold.

The agency, however, described the violations as “very worrying” and said there were “many breaches of biocide legislation”.