Detection of disease in stored potatoes by volatile monitoring

The feasibility of early disease detection in potato storages by the monitoring of volatiles was investigated usingErwinia carotovora as a model storage pathogen (soft rot) in both laboratory and commercial site tests. Volatiles were collected by cryogenic air liquefaction and concentrrated on Tenax-GC adsorbent. Analyses by gas chromatography and mass spectroscopy identified acetone, ethanol, and 2-butanone being produced in abnormal concentrations during host-soft rot incubations in a controlled environment. Preliminary comparisons between diseased and normal commercial bins at different storage sites (two cultivars) indicated soft rot infection also created abnormally high concentrations of the above three volatiles, with most notable differences in 2-butanone concentrations. The criteria of selection for volatiles for possible use as incipient disease indicators are discussed in terms of the composite rate of pathogenic destruction within a potato pile. Additional volatiles identified from potatoes inoculated withE. carotovora include: acetaldehyde, methyl acetate, ethyl acetate, propanethiol, hydrogen sulfide, methyl sulfide, methyl disulfide, n-propanol, and isobutanol.