Effect of different fruit components, aeration and cold storage at 5°C on the germination of ascospores ofNeosartorya fischeri

Abstract

Germination is the process by which a spore is transformed from a dormant state of metabolic activity to one of high activity. Effects of different fruit components, aeration and cold storage at 5°C on the germination of ascospores of Neosartorya fischeri after heat treatment were investigated by measuring rate and percentage germination and outgrowth of fungal biomass. Some activated spores reverted back to dormancy after 12 and 24h of storage at 5°C. Ascospores germinated easily in acetate buffers. Germination of ascospores was retarded in medium containing citric acid and sugars. Ascospores cultured under low aeration showed no signs of germination. Different food components and growth conditions have varying effects on germination of ascospores. The findings of this study can be used in the fruit industry to predict the effect of some fruit components on the germination of heat-resistant ascospores. The impact of cold storage on ascospores, which may be activated by heat schedules used to manufacture some types of fruit products, will help in determining the best storage conditions for enhanced shelf life to be adopted immediately after heat treatment. These findings also help to determine for how long a fruit juice is safe at room temperature after production before mycotoxin synthesis by heat-resistant fungi sets in.