Evaluation of the application period on glyphosate residue contamination in coffee beans

The impairment of productivity and harvest of coffee beans by weeds is more accentuated when the infestation occurs between the flowering and fruiting periods of the coffee plant. However, controlling these plants with herbicides, such as glyphosate, can result in crop contamination and accumulation of the herbicide in coffee beans through the drift during application. In this sense, this work sought to determine the stage of development of the coffee crop at which the application of the herbicide glyphosate does not result in the contamination of coffee beans. Glyphosate was applied in lower doses in 5 different stages of the coffee plant, from bean formation to maturation (cherry beans), with one application per plant for each stage evaluated, in addition to the controls, which did not receive herbicide application. After complete maturation, the grains were harvested, pulped, dried, and analyzed by LC-MS/MS to determine the concentration of glyphosate. Herbicide residues were detected in four of the five selected stages, at concentrations lower than the LOQ (0.5 mg kg^-1), but were not detected in the cherry maturation stage. These results indicate the translocation of the herbicide and accumulation in the grains, compromising the quality of the commercialized grains.