In 1964, William Horowitz published the history of the Association of Official Agricultural Chemists (AOAC), of which he was the chief executive officer (Horwitz 1964). At that time the AOAC had existed for 80 years and had ventured very little beyond its stated purpose of validating and publishing standardized methods of analysis for substances important to agriculture and the public health through a highly structured system of interlaboratory testing and review. In the ensuing quarter of a century, however, the AOAC not only changed its name to Association of Official Analytical Chemists but also underwent a striking expansion and transformation. The highlights of that transformation are the subject of this account.

Association of official analytical chemists: 1964-1988

SUMMARY
Aspergillus flavus is an opportunistic pathogen of crops. It is important because it produces aflatoxin as a secondary metabolite in the seeds of a number of crops both before and after harvest. Aflatoxin is a potent carcinogen that is highly regulated in most countries. In the field, aflatoxin is associated with drought-stressed oilseed crops including maize, peanut, cottonseed and tree nuts. Under the right conditions, the fungus will grow and produce aflatoxin in almost any stored crop seed. In storage, aflatoxin can be controlled by maintaining available moisture at levels below that which will support growth of A. flavus. A number of field control measures are being utilized or explored, including: modification of cultural practices; development of resistant crops through molecular and proteomic techniques; competitive exclusion using strains that do not produce aflatoxin; and development of field treatments that would block aflatoxin production.

Taxonomy: Aspergillus flavus Link (teleomorph unknown) kingdom Fungi, phyllum Ascomycota, order Eurotiales, class Eurotiomycetes, family Trichocomaceae, genus Aspergillus, species flavus.

Host range: Aspergillus flavus has a broad host range as an opportunistic pathogen/saprobe. It is an extremely common soil fungus. The major concern with this fungus in agriculture is that it produces highly carcinogenic toxins called aflatoxins which are a health hazard to animals. In the field, A. flavus is predominantly a problem in the oilseed crops maize, peanuts, cottonseed and tree nuts. Under improper storage conditions, A. flavus is capable of growing and forming aflatoxin in almost any crop seed. It also is a pathogen of animals and insects. In humans it is predominantly an opportunistic pathogen of immunosuppressed patients.

Useful websites: http://www.aspergillusflavus.org, http://www.aflatoxin.info/health.asp, plantpathology.tamu.edu/aflatoxin, http://www.aspergillus.org.uk

Aspergillus flavus: the major producer of aflatoxin

When an animal eats "spoiled" or "rotten" food of any kind, it runs a largely unknown risk (except in the case of grains) of being injured by toxins or microbe-produced antibiotics, getting food wi...

Why Fruits Rot, Seeds Mold, and Meat Spoils

Aflatoxin B1: A review on metabolism, toxicity, occurrence in food, occupational exposure, and detoxification methods.

Aflatoxin in food and feed: occurrence, legislation and inactivation by physical methods

Determination of Aflatoxins in Agricultural Products: Use of Aqueous Acetone for Extraction

Subsamples of a given lot of peanuts may vary greatly in aflatoxin content due to extreme variability in the degree of contamination of individual kernels. A micro method, adapted from the aqueous acetone procedure recently proposed by Pons and Goldblatt for the determination of aflatoxins in cottonseed products, was developed to permit accurate determination of aflatoxins in individual kernels and kernel sections. Use of this procedure permitted the topographic distribution of aflatoxins within single kernels to be mapped and indicated that the toxins are not uniformly distributed within contaminated kernels, even when the kernel contains a high level of aflatoxins. Although wrinkling or discoloration sometimes indicated that a kernel was contaminated, this type of physical damage was not found to be a reliable indication of aflatoxin content. Also it was noted that a few apparently sound and mature kernels contained high levels of aflatoxins.

Alva F. Cucullu

Papers

Determination of Aflatoxins in Agricultural Products: Use of Aqueous Acetone for Extraction

Determination of aflatoxins in individual peanuts and peanut sections

Synthesis of versicolorin A by a mutant strain of Aspergillus parasiticus deficient in aflatoxin production

Biosynthesis of aflatoxin B1. Conversion of versicolorin A to aflatoxin B1 by Aspergillus parasiticus.

Destruction of aflatoxins in peanuts during dry and oil roasting