Khapra beetle larvae can destroy a significant proportion of unprotected grain stores due to their “dirty eating” behavior, e.g., their feeding habit where the beetle eats only a little of a single grain before moving on to others. The khapra beetle is difficult to control and can survive nearly anywhere they are protected from cold temperatures. This insect, which prefers low-moisture foods, is smaller than a grain of rice (three millimeters or less than an eighth-of-an-inch long). Khapra beetle contamination in food products presents a food safety concern as the hairs associated with larvae and cast skins are potential allergen and respiratory hazards, particularly for young children. The threat was driven home in 1953 when khapra beetles were discovered in California, resulting in a 13-year, $15-million eradication effort. This invasive insect species poses a considerable threat to U.S. agriculture and natural resources — making it imperative that khapra beetles are detected and their introduction throughout global trade pathways prevented. To address the khapra beetle issue, scientists at the Edgewood Chemical Biological Center are helping the Department of Homeland Security’s Science and Technology Directorate and the U.S. Department of Agriculture’s Animal Plant Health Inspection Service’s Plant Protection Quarantine find an easier and more effective way to inspect bulk food supplies for khapra beetles. In a project funded by the DHS S&T Seedling Program, Edgewood researchers, in partnership with iSense LLC, are studying the use of colorimetric sensor arrays, or CSAs, to detect this invasive species in shipping containers. These inexpensive, disposable sensors, manufactured by iSense, are approximately one square inch in size (about the size of a postage stamp) and spotted with 73 dyes which change color in response to various vapors coming in contact with the CSAs from the sample. Samples are not identified by any single spot color change, but instead by the combination of color changes across multiple spots forming a “fingerprint” that can be used to identify compounds found in a sample. Edgewood researchers envision a solution where an inexpensive, disposable reader could be placed within a crate before shipment and then later queried by a smart phone to allow inspectors at the port of destination to assess food security and quality without ever having to open the container. So far, researchers have been able to distinguish between the warehouse beetle-infested and non-infested grain based on the response of the CSAs to the VOCs (volatile organic compounds) present in the headspace above the grain. The group expects to complete its first round of testing by this fall.