Dairy products are considered as nutrient-dense foods and consumed by many people in western countries, as well as an increasing number of Asian people. Excessive and frequent application of pesticides on vegetables and fruits leads to a potential health hazard to consumers. The organophosphate insecticide chlorpyrifos has been reported to bind with human and bovine serum albumin. Thus, it is necessary to explore the interaction between food protein and chlorpyrifos. In this study, equilibrium dialysis and fluorescence spectra were used to demonstrate binding of milk proteins to chlorpyrifos. The amount of milk protein bound was 0.03 ± 0.01 mg/g. Moreover, the milk protein-chlorpyrifos complexes were stable at pH 3.5 to 9.5 and ion concentrations from 0.1 to 1.0 M. The amount of chlorpyrifos bound to milk proteins decreased to 50% after being in vitro digested by pepsin and trypsin. The results showed that the interaction between food proteins and the pesticide might partially remove the insecticide and reduce the concentration of pesticide absorbed into the blood and, thus, alleviate the corresponding toxicity.
