Aflatoxin Production Correlated with Nitrification in<i>Aspergillus Flavus</i>Group Species

Abstract

Of 51 Aspergillus flavus group isolates, 46 oxidized peptone in a nitrification (NF) medium producing an average of 90 mg NO3-N/l. Only two of 27 isolates representing nine other groups of Aspergilli formed nitrate and the quantity was nearly an order of magnitude lower. Within the A. flavus group, nitrate production was highest in strains of A. parasiticus and A. flavus and nitrification by aflatoxigenic strains was significantly higher (122.7 ± 9.3 mg N03-N/1) than that produced by non-toxigenic strains (50.8 ± 16.0 mg NO3-N/l) of the same two species. Although nitrate formation in certain isolates was affected by prior soil culture, the average yield in NF medium of all A. flavus group isolates was the same whether the spore inoculum was obtained from soil or artifical medium.