Reduction of residual pesticide levels in meat through cooking. Optimisation of the method

Abstract

A chromatographic method was validated for the determination of eight organochlorine pesticides in raw and cooked beef. The extraction method used was a modified QuEChERS method. The method was linear within the range evaluated (0.01–2 mg/kg) with an R² greater than 0.9783. Precision values were less than 5.8 per cent and recovery rates ranged from 93.5 to 115.3 per cent. Following validation, 100 meat samples obtained from butchers and meet processing plants in the region were analysed. Several pesticides were present simultaneously in the same sample. Some pesticides exceeded the MRLs: 1 sample for α-HCH, 7 samples for β-HCH, and 15 samples for endrin. Different cooking methods were evaluated: grilling, oven cooking, and boiling. For grilling, it is recommended to cook at 100°C for 8 minutes, achieving reductions of between 88.4% and 100.0%. For oven cooking, 100°C for 20 minutes is recommended, achieving reductions of between 72.8% and 99.7%. Boiling was optimised using a Central Composite Design and Response Surface Methodology. The optimised method involved boiling for 18 minutes in 1.7 litres of water, achieving reductions of between 66.3% and 95.1%.