Shelf life study of some Nigerian fruit juices inoculated with ascospores of Neosartorya spp.

Mango, orange and pineapple juices containing various concentrations of sucrose were dispensed in 100 ml volumes into 100 ml conical flasks with stoppers. Each juice in a flask was inoculated with ascospores of one local isolate of either Neosartorya fischeri, N. fischeri var. spinosa or N. quadricincta to a final concentration of 120-140 ascospores/ml of juice, and then pasteurized at 80 degrees C for 30 min. A set of 36 inoculated flasks with 12 controls was stored at 4-5 degrees C and two sets, one protected with 100 mg/l sodium benzoate, were stored at room temperature (25-28 degrees C). A shelf life study was carried out on all the juices for 64 days. Only fruit juices stored at 4-5 degrees C and those containing sodium benzoate stored at room temperature were protected from spoilage by these fungi for 64 days. Addition of sucrose at levels of 9% to mango juice, 30% to pineapple juice and 31.5% to orange juice significantly (p = 0.05) protected ascospores from inactivation during cold storage.