Despite advances in increased food production, microorganism-caused rot destroys half of the world’s harvested food. Plants emit a variety of volatile organic compounds into their surroundings, which can be monitored to detect plant disease early and prevent food loss.

A new study led by the Hebrew University of Jerusalem (HU) and Israel’s Agricultural Research Organization (Volcani Institute) details the success of a biological sensor for the early detection of hidden disease in potato tubers, one of Israel’s leading export industries with 700,000 tons produced annually.

Israeli farmers purchase European potatoes to plant in Israel. However, a small percentage of them carry disease within them, either visibly or invisibly, which causes rot and significantly reduces the quality of the potato. The collaboration between Hebrew University and Volcani is about to change that. They’ve created a sensor that detects disease and can be used to prevent it from spreading. Dr. Dorin Harpaz and her Ph.D. student Boris Veltman conducted the research, which will be published in the upcoming issue of Talanta, at HU’s Faculty of Agriculture, Food, and Environment, under the supervision of Dr. Evgeni Eltzov of the Volcani Institute. Dr. Sarit Melamed and Dr. Zipora Tietel of the Volcani Institute, as well as Dr. Leah Tsror of the Gilat Research Center, were part of the team.

The sensor is based on clever bioengineering and optics. When the sensor is placed near an infected potato, a bacterial compound within glows, with the intensity of the glow indicating the concentration and composition of the rot.

“The intensity of the light given off by the bacteria panel makes it possible to quickly and quantifiably analyze the characteristics of the disease, which the sensor can ‘smell,’ before the appearance of visible symptoms,” Eltzov declared.

In his turn, Harpaz added that the biosensor they’ve developed will help identify diseased potatoes that do not yet have any external indications and keep them away from healthy tubers, thus preventing the rot from developing or spreading to other healthy plants.

The bacteria panel was created by combining four genetically engineered bacteria that measure biological toxicity. The biological sensor detected disease before there was any visible trace in this study, causing the optical sensor to shine twice as brightly as the sensors in non-infected potatoes. Their capabilities were previously demonstrated in a study that used the sensors to detect toxicity in artificial sweeteners in sports supplements.

According to the researchers, early disease detection, before the potatoes are exported or replanted, provides a significant advantage to food growers.

“The biological sensor can be used to quickly and economically identify hidden rot in potatoes, facilitate better post-harvest management, and reduce food wastage — particularly important given the current global food crisis,” Harpaz concluded.