DETECTION OF VIABLE ASCOSPORES OF NEOSARTORYA

Studies on 29 Neosartorya cultures showed that many ascospores, as enu merated in a haemocytometer, failed to produce colonies when cultured on agar media. Although the percent recoveries differed greatly betwee n spore crops, germination and outgrowth of most were stimulated by he at activation in grape juice for 30-60 min at 70-degrees-C. Most proba ble number and CFU counts were usually similar which indicated that lo w recoveries were not due to an inadequate incubation period or to the production of self-inhibitory compounds. Low percent recoveries did n ot affect the D values obtained in heat-resistance trials.