Resumen
Fungicides, including thiophanate-methyl, tebuconazole, pyraclostrobin, and difenoconazole, have been widely used as preservatives to control fungal diseases during pear storage. However, the metabolic capability of pear for exogenous compounds decreases at lower storage temperatures, leading to an increase in the risk of exposure to chemical preservatives. In this work, a sensitive and stable ultraperformance liquid chromatography?tandem mass spectrometry (UPLC?MS/MS) analytical method was established to investigate the dissipation dynamics and dietary intake risk of four chemical preservatives in pears under different conditions. The mean recoveries of the preservatives in pear samples ranged from 73.2% to 117.1%, with relative standard deviations of 0.5?7.2%. The dissipation half-lives (T1/2) of thiophanate-methyl, tebuconazole, pyraclostrobin, and difenoconazole in pears were 7.2?21.1 d and 31.6?173.3 d at storage temperatures of 25 °C and 4 °C, respectively. The results of dietary risk evaluation showed that the intake risk of preservatives in commercial pears was acceptable. However, some pears from commercial supermarkets still contained preservatives at amounts that exceeded the maximum residue limit (MRL) set by the Chinese government. This work provides a guideline for the risk evaluation of fruit preservatives on human health.