Residue levels of a key chemical used to maintain the quality of stored potatoes continue to fall – but more data is needed, says a cross-industry body. The Chlorpropham Residues Monitoring Group (CRMG) submitted its second-year draft report to the Health and Safety Executive’s Chemical Regulation Division towards the end of last year.
The group says the report provides new evidence on chlorpropham (CIPC) residues in potatoes stored during the 2024/25 season – helping to inform an annual review of the temporary Maximum Residue Level (tMRL), which is currently set at 0.35mg/kg.
The CRMG report is based on residue data submitted by growers, store managers and supply chain partners. It is seen as key in helping to ensure potato stores with a history of CIPC can still be used – ensuring capacity for the UK potato industry.
In total, some 156 sample results were received from potato stores with a known history of CIPC use. Of these, 21 samples (13.5%) contained detectable CIPC residues, all of which were well within the temporary maximum limit, says the CRMG.
CIPC was effectively banned as a sprout suppressant in 2020 due to toxicity concerns. While residue levels continue to decline, the provisional data mirrors Year One patterns, reinforcing the need for the temporary limit, says the CRMG. Without the temporary limit, many stores would exceed the standard detection threshold and be taken out of use. This would put significant pressure on the UK’s storage infrastructure and supply chain resilience.
Challenge
CRMG chairman Adrian Cunnington said: “It is hard to overstate the challenge if we lost our storage capacity – it would be devastating for the industry.
“We are watching residues come down year-on-year, but the biggest challenge remains getting enough samples. It is imperative that we continue to collect and submit residue data if we are to maintain our supply base for years to come.”
The CRMG is now calling on the industry to support a third season of sampling. It says this will help to underpin the 2025/26 submission to the Chemical Regulation Division – and help ensure storage capacity.
Vital evidence
Growers and store managers already collecting multi-residue data are urged to submit chlorpropham results from crops stored for at least 60 days. All analysis must be conducted by a UKAS-accredited laboratory.
This evidence is seen vital to demonstrate the continued need for a temporary limit. Without sufficient data, stores with a CIPC history remain at risk of being taken out of use, said Mr Cunnington.
“We are asking growers to help build an accurate national picture of residue levels across stores with a CIPC history. By contributing their data, growers will help ensure the industry can continue to use vital storage capacity safely and responsibly.”