Comparison of Aspergillus Differential Medium and Aspergillus flavus/parasiticus Agar for Enumerating Total Yeasts and Molds and Potentially Aflatoxigenic Aspergilli in Peanuts, Corn Meal and Cowpeas

Abstract

Aspergillus differential medium (ADM) and Aspergillus flavus/parasiticus agar (AFPA) were compared for enumerating total yeasts and molds as well as the A. flavus group in raw peanuts, corn meal and cowpeas. Colony counts were made after plates were incubated at 30 and 37°C; incubation times of 42–44 and 70–72 h were evaluated. Incubation at 30°C enhanced recovery of yeasts and molds compared to incubation at 37°C. Incubation for 42–44 h at 37°C on ADM or AFPA was optimum for detecting A. flavus in corn meal. Use of AFPA for detecting A. flavus/parasiticus may have some advantage over ADM, since orange-yellow color development of reverse colonies is quicker and more intense on AFPA.