Changes of various insecticides during in vitro human digestion.

This study was performed to determine the effects of in vitro human digestion on the concentrations of five insecticides, namely 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD), 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (DDE), bifenthrin, and fipronil. In vitro models included all the steps of human digestion, i.e., passage through the mouth, stomach, small intestine, and large intestine (with enteric bacteria). The concentrations of DDT and fipronil did not change (P > 0.05) until small intestinal digestion, whereas those of DDD, DDE, and bifenthrin decreased (P < 0.05) at each digestion step. The concentrations of all the insecticides decreased (P < 0.05) during the large intestinal digestion step with enteric bacteria, Lactobacillus sakei and Escherichia coli. In conclusion, the concentrations of all the tested insecticides decreased during all the steps of in vitro human digestion and were especially reduced by enteric bacteria during the large intestinal digestion step.