Volatiles as biomarker for detection of soft rot during potato storage

In Northern Europe, potatoes are harvested at the end of the summer period and kept in large storage facilities for many months. Depending on the agreed delivery time, the demand of the market and/or the quality during storage, potatoes are sold. Higher quality potatoes, delivered at agreed delivery time, or at a time of high market demand, will lead to a higher price and thus more profit for the potato grower. One of the important quality issues during storage is the development of rot, often caused by infection with bacteria belonging to the family of Pectobacteriaceae, causing soft rot (Pectobacterium and Dickeya species). Initial infection can spread to neighboring tubers and therefore trigger a wide infection. Such infections can start anywhere in a potato pile and are thus not always immediately visible, leading to extensive product losses. Respiration and volatile production of healthy, wounded and soft rot-infected potatoes were measured over time using GC and PTR-ToF-MS. We observed that both the respiration, as well as the production of specific volatiles increases significantly in potatoes infected by Pectobacterium polaris. This indicates that there is a potential to use the respiration and volatile-profile as biomarkers for early and remote detection of rot in potato. This would allow growers to take action by adjusting the storage regime to prevent further spread of infection and extend the storage of the healthy potatoes. Depending on the demand on the market, growers could also decide to bring batches showing no signs of infection to the market while the quality is still acceptable, thereby increasing profit for the grower.