Reduction of feed-contaminating mycotoxins by ultraviolet irradiation: an in vitro study

Ultraviolet (UV) germicidal irradiation has been applied to the sterilization of agricultural products including stored grain for foodstuffs or animal feed. Although UV treatment is known to be effective for killing pathogenic moulds that contaminate the surface of grain, it remains unclear how and to what extent such irradiation is able to eliminate mycotoxins, the fungal metabolites that have adverse effects on human and animal health. We evaluated in vitro the effects of mild (intensity = 0.1 mW cm(-2) at 254 nm UV-C) and strong (24 mW cm(-2)) UV irradiation on two feed-contaminating mycotoxins, zearalenone (ZEN) and deoxynivalenol (DON). When exposed to mild irradiation, the levels of ZEN and DON (both 30 mg kg(-1) initially) were reduced as irradiation time increased, and became undetectable at 60 min. Strong UV irradiation also reduced the mycotoxin levels in the same time-dependent manner, but more rapidly. It was therefore confirmed in vitro that UV irradiation is effective at reducing the levels of ZEN and DON. The present study provides preliminary data for establishing a practical method of using UV irradiation to reduce mycotoxin contamination in grain intended for use in feed.