Purdue University
Department of Botany and Plant Pathology Lilly Hall of Life Sciences
BP-5-22
Plant Disease central

Rapid Screening Methods for Aflatoxin in Corn
John Tuite and Donald H. Scott*

Aflatoxin B1, a liver toxin and carcinogen, may be produced by the fungi Aspergillus flavus and parasiticus as they grow on many agricultural products at certain conditions and temperatures. The present FDA administrative action guideline is 20 parts per billion (ppb) total aflatoxins for all products intended for feed or food. However, this guideline may be changed in the future depending upon whether the product is intended for human or animal use, and, possibly, categorized according to the age and species of animal to be fed. Young animals are more susceptible than older ones, and species of animals vary markedly in their susceptibility. Generally, mature cattle and sheep are the least affected. As afla-toxin is excreted in milk, a stringent consideration will be given for dairy cattle rations.

Methods of Detection

The blacklight technique (BLT) does not determine the presence of aflatoxin. How-ever, it is widely used to indicate the growth of the fungi that may have resulted in the
production of aflatoxin. Thus, the BLT is strictly a presumptive but useful test. Samples which give a positive blacklight reaction should be checked by a chemical assay procedure to determine the presence of aflatoxin.

Three chemical assay methods are used to determine the presence of aflatoxin in most grains and feeds: the minicolumn (MC), thin layer chromatography (TLC), and high pressure liquid chromatography (HPLC). These tests, except for HPLC, are described briefly in Table 1 along with their rec-commended use.

The blacklight and the minicolumn techniques are discussed in detail because of their adaptability to field use. Tie thin layer chromatography procedures are detailed in the Official Methods of Analysis of the Association of the Official Analytical Chemists (Chapter 26).

A partial list of firms that perform aflatoxin analyses by MC or TLC is available. See your local county Extension agent or write the Dept, of Botany and Plant Path-

Grateful thanks are given to Dr. Odette Shotwell, Dr. Leonard StolotT. and Dr. Charles Holaday for assistance in preparation of this manuscript.............................................................................................................. New 7/78

Cooperative Extension Work in Agriculture and Home Economics, State of Indiana Purdue Universityand U.S. Department of Agriculture Cooperating, H, G. Diesslin, Director, West Lafayette, Ind. Issued in furtherance of the Acts of May 8 and June 30, 1914. It is the policy of the Cooperative Extension Service of Purdue University that all persons shall have equal opportunity and access to its programs and facilities without regard to race, religion, color, sex or national origin.