Efficacy of selected postharvest agrochemicals in reducing potato tuber soft rot caused by Pectobacterium carotovorum subsp. carotovorum in storage

The control of pectolytic bacteria (soft rot) is still a challenge in potato production worldwide. Consumer demands for more natural and less toxic alternative postharvest sanitizers has led the industry into developing different fresh produce sanitizers and preventative methods for potato soft rot. Foodprint^® and SporeKill^® were evaluated for their efficacy against the pectinolytic Gram negative bacterium, Pectobacterium carotovorum subsp. carotovorum (Pcc, Agro-255), the causal agent of potato tuber soft rot. The efficacy of the products was tested as a postharvest wash treatment on artificially infected potato tubers of cultivars ‘Mondial’ and ‘Fianna’ which were then stored at room temperature for a period of 35 days. Results showed that tubers of ‘Mondial’ are highly susceptible to soft rot (100% soft rot incidence) as compared to tubers of ‘Fianna’ (55% soft rot incidence). Foodprint^® and SporeKill^® reduced soft rot incidence by 43 and 17% on ‘Mondial’ potatoes and by 31 and 38% on ‘Fianna’ potatoes, respectively. This study concludes that the combination of a Pcc tolerant potato cultivar and an effective postharvest sanitizer can potentially reduce the incidence of postharvest soft rot by more than 70%.