Fungicide Residue Degradation in Hot Water Treated Apple

The study elucidated the effect of hot water treatment (HWT) on fungicide residue degradation in apple. Residues were measured by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) during cold storage after HWT (48, 50, 52 and 54 °C for 2, 3, 4 and 5 min) of fruits. The developed method for the mixture of six fungicides (azoxystrobin, carbendizim, dithianon, difenconazole, hexaconazole, tebuconazole) was validated for linearity, specificity, selectivity, accuracy and precision using SANTE (SANTE/2020/12682) guidelines. The results of recovery ranged from 75.18 to 119.17% with 4.19–12.72% relative standard deviation. Increasing HWT temperature and duration yielded a significant reduction in residues (90–98%) in terms of processing factor. HWT of apple at 48 °C/5 min and 50 °C/2 min yielded acceptable quality fruits along with maximum reduction in fungicide residues. Fungicide reduction followed linear relationship and first-order rates. Azoxystrobin and hexaconazole dissipated at a lower rate than dithianon, difenoconazole, carbendazim and tebuconazole.