This was the message from Central Science Laboratory's (CSL's) Food Science Group representative Stewart Reynolds.
Speaking at a British Carrot Growers' Association (BCGA)/HDC carrot technical seminar at Peterborough last week, he said that 10 years ago 0.05mg/kg was as low as residue analysts needed to go.
"Laboratories are driven by regulations to find lower levels in foods," he said. "Modern multi-residue methods mean that 0.01mg/kg is now routinely achievable for the majority of pesticides in most commodities. What is the limit for detection for pesticide residues? The answer is there are no limits. It's how much you want to spend."
Reynolds said there was a large variation in the quality of data coming from laboratories offering pesticide residues analysis but that proficiency tests - an external quality assurance assessment - were a good guide to laboratory performance. "Reported residue data must not be regarded as absolute values - there will be an associated measurement of uncertainty but with good labs that uncertainty will be small."
He added that an EC regulation was harmonising MRLs across the EU. Where no MRLs have been established, the regulation will set a default value of 0.01mg/kg, the same level as is set by the EU for residues in baby food.
BCGA chairman Martin Evans said carrot growers had recently lost many pesticides with which they were familiar and were entering a period of uncertainty with new chemistry, which made the sector "particularly vulnerable".