XVI International Botanical Congess

Two toxigenic strains of Alternaria alternata (ATCC 56836 and ATCC 66868) were grown on surface-disinfected, fresh, ripe fruits and tested for the production of alternariol (AOL) and alternariol methyl ether (AME). Examined fruits included strawberries, red and green seedless grapes, concord grapes, red delicious, golden delicious and gala apples, and blueberries. After inoculation, fruits were incubated at 4?C, 10?C or room temperature (approximately 21?C) for up to three weeks. At weekly intervals, duplicate samples were analyzed for AOL and AME using HPLC. Results indicated that A. alternata and its metabolites were not a major problem in strawberries due to the presence of fast-growing molds like Rhizopus and Botrytis which outgrew and possibly inhibited Alternaria. Both strains showed limited growth on apples, although fast-growing molds were not present, and produced toxin only on the golden delicious and gala varieties, ranging from 0-4 ppm and 0-9 ppm for AOL and AME, respectively. Restricted growth without toxin production occurred in blueberries, whereas moderate growth and AOL (0-2366 ppm) and AME (0-1217) ppm) production took place in grapes.