SURVIVAL OF CONIDIA OF ASPERGILLUS-FLAVUS IN DRIED FOODS

The survival of conidia of Aspergillus flavus in dried processed foods with water activities (aw) of 0.78 or less was monitored over 48 weeks at 21°C. Aspergillus differential medium (ADM) containing 30 μg/ml of tetracycline and ADM containing 50 μg/ml of streptomycin sulfate and 10 μg/ml of 2,6-dichloro-4-nitroanaline (botran) were compared for their ability to recover viable conidia from foods. The survival of conidia at aw 0.32 to 0.78 varied greatly among foods, the rate and extent of death of conidia being enhanced with increasing aw. The rate of destruction of conidia was more rapid in most acid foods in the range pH 6.81 to 3.75 but no effect of pH on survival was demonstrated in corn meal acidified with citric acid. The two ADM were judged to be equally acceptable as selective agars for supporting colony formation by A. flavus. © 1979.