Each year in the United States, up to $500 million is lost to post-harvest insect infestations of grain. Furthermore, insect infestations have been linked to allergies and an increased risk for fungal infestation or food pathogen contamination, forcing millers to perform additional cleaning operations that destroy up to 3% of uninfested wheat. Stored grain insects are extremely difficult to detect and count in a sample of grain as immature insects are hidden inside the kernels.

Grain handlers and millers need to be able to rapidly detect the number of grain kernels with hidden insect infestations. If an accurate estimate of the number of insects can be made, grain managers can decide if the grain should be accepted or if it needs treatment to reduce the possibility of further insect damage.

Dr. Tom Pearson and Dan Brabec conceptualized and developed a novel system that enables rapid and accurate estimation of stored grain insects in wheat. The device operates on the basis of crushing wheat between two rotating rollers. An electrical circuit attached to the rollers monitors the electrical current traveling from one roller to the other as the wheat is crushed. If an insect is inside a kernel, it will be crushed and emit hemolymph (the circulatory fluid of certain invertebrates), which is highly conductive and causes a brief spike in the electrical current. Dr. Pearson then developed computer signal processing software to detect these spikes and count the number of live insects in a sample.

Technology for the device has been transferred to a large milling company, General Mills, and an instrument manufacturer, National Manufacturing, so that it is now widely available to other grain handlers, marketers and millers. The instrument is now part of National Manufacturing’s product line and is being tested, under Dr. Pearson’s supervision, for its applicability to rice, sorghum, barley and corn.