Disinfestation of Barley Using Microwave Energy

Abstract

Barley is one of the major crops grown in Canada, and it is used in malting, feed, and food industries. Disinfestation of harvested barley using microwaves can be an alternative for chemical methods used to kill insects. A pilot-scale industrial microwave system operating at 2.45 MHz was used in this study to determine the mortality of three common stored-grain insects namely Tribolium castaneum, Cryptolestes ferrugineus and Sitophilus granarius. Barley samples of 50 g each at 14, 16, and 18% moisture content (wet basis) were infested with adult insects. The samples were then exposed to microwave energy at four different power levels 200, 300, 400, and 500 W for two exposure times of 28 and 56 s. Complete (100%) mortality was achieved for all the three adult insects at 500 W for an exposure time of 28 s and at 400 W for an exposure time of 56 s. The mortality of T. castaneum was 12, 52, 87, and 100% at 200, 300, 400, and 500 W, respectively for 28 s exposure time. Similar results were obtained for the other two insects. There was no significant difference in the mortality of insects at 14, 16, and 18% m.c. Germination tests were conducted for the samples treated at various power levels and exposure times and germination of seeds decreased with an increase in power level or exposure time or both.