Pesticide residues in conventionally grown and organic New Zealand produce

Abstract

A study was carried out to determine the prevalence and concentrations of pesticide residues in conventionally grown and organic produce (bananas, broccoli, grapes, lettuce, potatoes, tomatoes, wine). Sampling was stratified, with organic produce being over-sampled, when available. All food samples were analysed, as received, by a multi-residue pesticide residue screen. Residues were found in 130 of 307 conventionally grown food samples (42%) and in nine of 41 organic food samples (22%), including six of eleven (55%) organic tomato samples. Only four organic samples (9.8%) contained multiple residues, while 24% of conventionally grown food samples contained multiple residues. Nine conventionally grown food samples (2.6%) contained pesticide residues that exceeded the maximum residue limit (MRL). Where direct comparisons were possible between conventionally grown and organic produce, the mean concentration of residues was usually lower in the organic produce, but was generally higher than would be expected from spray drift or other adventitious sources. While the presence of these residues does not represent a significant risk to human health, their presence is inconsistent with consumer expectations for organic produce.