STUDIES ON VACUUM-DRYING FOR THE PRESERVATION OF PLANT PATHOGENIC BACTERIA

A comparison of freeze-drying and vacuum-drying of plant pathogenic bacteria showed no short-term differences in survival. Storage long term with vacuum-drying suggests that this simpler method offers similar survival rates to freeze-drying. A modification of the procedure in which the condenser is by-passed in the latter stages of drying offers the prospect of achieving lower pressures which are not limited by the vapour pressure of ice.