ASPERGILLUS-PARASITICUS NRRL-2667 GROWTH AND AFLATOXIN SYNTHESIS AS AFFECTED BY CALCIUM CONTENT AND INITIAL SPORE LOAD IN SINGLE PEANUTS

Mycelial growth of Aspergillus parasiticus NRRL 2667 and aflatoxin pro duction on Florunner peanuts grown under different calcium supplementa tion levels (CSL) (550, 1,100, 2,200 and 4,400 kg gypsum/ha) with init ial spore loads of 10(2), 10(4) and 10(6) spores/g were investigated. Growth at 25-degrees-C for 0, 4, 7 and 14 days was determined by viabl e plate counts on Aspergillus flavus/parasiticus agar (AFPA) medium. I rrespective of the initial spore load, maximum growth of 10(8) to 10(9 ) CFU/g was attained after 14 days except for the 4,400 kg/ha Ca-suppl emented nuts on which the maximum populations were one log less. Aflat oxins B1 and G1 concentrations measured by thin layer chromatography ( TLC) ranged from 0-3460 mug/g and 0-3740 mug/g, respectively. Toxin pr oduction was highest in single peanuts with CSL of 2,200 kg/ha. A redu ction of 50% or higher was observed as CSL was increased to 4,400 kg/h a.