Effect of microwave, frying and boiling on lettuce contaminated with microcystins.

Microcystins inevitably exist in crops by irrigating, potentially threatening food safety. To assess thermal treatment on the fate of microcystins, we evaluated effect of routine cooking practice (microwave, frying and boiling) on health risk of lettuce that was previously exposed to 20, 50 and 100 μg·L-1 microcystins before harvesting. All 3 cooking methods decreased the concentration of microcystins in lettuce, and the decreased degree caused by boiling (43.73%) was largest, followed by frying (40.28%) and microwave (37.71%). Moreover, the results of in vitro digestion coupled with Caco-2 cell model revealed that the three cooking methods decreased the bioaccessibility and bioavailability of microcystins in lettuce. Furthermore, all three cooking methods with the subsequent digestion process alleviated the cytotoxicity of microcystins to viability of human liver (HL-7702) cells by decreasing lactate dehydrogenase. Taken together, routine cooking could be one of simple ways to protect human health from microcystins in food.