AFLATOXIN CONTENT OF SINGLE PEANUT KERNELS IN COMMERCIAL LOTS AND IN KERNELS ARTIFICIALLY INFECTED WITH ASPERGILLUS-PARASITICUS

During peanut processing, further removal of aflatoxin-contaminated ke rnels from electronically sorted and unblanched commercial lots was ac hieved by color sorting of the kernels after light roasting and deskin ning. A modified procedure for efficient recovery of aflatoxin from an individual kernel in a small-scale system was applied for analysis of discolored kernels sampled over 3 consecutive years in Taiwan. The hi ghest and average aflatoxin contents in 60 kernels sampled each year w ere 1,930 and 150 ppb in 1994, 4,040 and 160 ppb in 1995, and 410 and 32 ppb in 1996, respectively. In 1994, 1995, and 1996, 66.7, 85.0 and 61.7%, respectively, of the kernels tested contained aflatoxins; 16.7, 13.3, and 6.7% contained 50 to 100 ppb and 16.7, 15.0, and 10.0% cont ained more than 100 ppb. Enhanced aflatoxigenic mold infection and afl atoxin production were monitored in peanut kernels artificially inocul ated with Aspergillus parasiticus at various inoculum concentrations a nd incubated under 100% relative humidity at 28 degrees C or at ambien t temperature for various periods. In all cases, aflatoxin content dev iated tremendously from kernel to kernel. The highest aflatoxin conten t observed in a single kernel was 945,000 ppb. In uninoculated kernels incubated in the same conditions, the growth of naturally occurring m ycoflora was observed; the highest aflatoxin content was 5,190 ppb.