Evaluation of 146 pesticides in peels, mesocarp, and seeds of thirty-five cultivars of apples (Malus domestica Borkh.) grown under the same edaphoclimatic region

In order to help optimize pesticide management and application strategies, we analyzed pesticide residues in thirty commercial and five regional apple cultivars from the same edaphoclimatic region in Portugal. Each sample was carefully divided into peel, pulp (mesocarp), and seeds. Analytical assessments were carried out utilizing a QuEChERS technique followed by LC-MS/MS, with 146 pesticide as targets. Regional cultivars tested confirmed for six different pesticide residues, ranging in concentrations from 0.01 to 1.46 mg/kg. However, there were nineteen compounds in the commercial samples, with concentrations ranging from 0.01 to 0.212 mg/kg. The comparison of 21 cultivars under controlled conditions improves the interpretation of residue data by establishing a clear correlation between the active substances sprayed and their presence in the fruit. Residues were predominantly concentrated in peel and seed fractions, while mesocarp tissues generally presented lower contamination levels, suggesting limited penetration of several compounds into the edible portion of the fruit. Differences in tissue distribution were associated with cultivar characteristics and physicochemical properties of the pesticides, particularly lipophilicity. The results obtained allow us to understand the distribution of pesticide residues in specific apple tissues and highlight the importance of residue monitoring systems to promote consumer safety and sustainable agricultural practices.