Postharvest treatments for the reduction of mancozeb in fresh apples

The objective of this study was to determine the effectiveness of chlorine, chlorine dioxide, ozone, and hydrogen peroxyacetic acid (HPA) treatments o n the degradation of mancozeb and ethylenethiourea (ETU) in apples. This st udy was based on model experiments at neutral pH and temperature. Fresh app les were treated with two different levels of mancozeb (1 and 10 mug/mL). S everal of the treatments were effective in reducing or removing mancozeb an d ETU residues on spiked apples. Mancozeb residues decreased 56-99% with ch lorine and 36-87% with chlorine dioxide treatments. ETU was completely degr aded by 500 ppm of calcium hypochlorite and 10 ppm of chlorine dioxide at a 1 ppm spike level. However, at a 10 ppm spike level, the effectiveness of ETU degradation was lower than observed at 1 ppm level. Mancozeb residues d ecreased 56-97% with ozone treatment. At 1 and 3 ppm of ozone, no ETU resid ue was detected at 1 ppm of spiked mancozeb after both 3 and 30 min. RPA wa s also effective in degrading the mancozeb residues, with 44-99% reduction depending on treatment time and HPA concentrations. ETU was completely degr aded at 500 ppm of HPA after 30 min of reaction time. These treatments indi cated good potential for the removal of pesticide residues on fruit and in processed products.