Ironically, the gas is being touted as a fumigant alternative in response to an international treaty banning the use of ozone-layer harming chemicals currently used to rid food storage facilities of insects. When ozone is used for killing grain insects, it lasts for a very short period of time without damaging the environment or the grain, the Purdue scientists report in the January issue Journal of Stored Products Research.
"Ozone has a very short half-life and we're using relatively low dosages, but enough to kill an insect," said Linda Mason, Purdue entomology associate professor and co-author of the study. "The chemicals currently used can kill everything in and around the grain bin, including people. With ozone, we're not generating ozone at deadly concentrations, and we have better control over it when it's present."
Purdue's Post Harvest Grain Quality Research team began its studies in response to the 1987 Montreal Protocol, an international agreement to prohibit substances deemed dangerous to the Earth's ozone layer. One such substance is methyl bromide, commonly used against crop pests in the soil and in grain storage facilities. Beginning in 2005, it no longer will be available.
A replacement for chemical fumigants is imperative because insects not only eat the grain, they defecate on it causing development of fungi, primarily Fusarium and Aspergillus. These fungi can release potentially deadly mycotoxins that can cause illness in most livestock and have been linked to some forms of human cancer. In humans, approximately 76 million cases of food-borne disease occur annually in the United States, according to the Centers for Disease Control and Prevention.