The objective of the present study was to establish whether exposure to temperatures of 55-70 °C results in eradication of the pathogen Clavibacter sepedonicus (Cs) in colonised potato tissue, in order to evaluate the efficiency of composting for disinfection of Cs-infected potato waste. Pre-sprouted potato tubers were inoculated and planted to produce Cs-colonised stem and tuber material. After incubation in temperature-controlled water baths, the infected potato tissue was analysed for the presence of culturable and pathogenic Cs. Additional experiments were performed with Cs-colonised potato stem tissue crushed and deaerated, thus simulating macerated stem tissue in the compost heap. To enable a comparison with bacterial cells that are not enclosed by their natural organic matrix, temperature treatments were applied to noninfected stem tissue crushed and deaerated, and spiked with freshly prepared Cssuspensions. Cs settled inside colonised potato tissue, as well as Cs present as Cssuspensions supplemented to potato tissue, was eradicated by exposure to heat, even after a treatment of 1 h at 55 °C, with the exception of one case in which the pathogen present in intact stem material escaped a treatment of 6 h at 60 °C, indicating that incidentally stems may provide niches in which the pathogen is protected against heat.
- Disinfection of potato waste ring rot
- Potato composting
- TaqMan assay