International mycotoxin check sample program. Part I. Report on the performance of participating laboratories.

Three aflatoxin-contaminated samples, raw peanut meal, finished peanut butter, and white corn meal, were analyzed by 139 laboratories in 34 countries. Sufficient data were obtained to permit a statistical comparison of the performance of laboratories using the BF, CB, and Pons methods and those using high performance liquid chromatography for quantification. A raw peanut meal sample showed no significant differences among means for laboratories using the four methods, and a white corn meal sample showed only one such significant difference; however, a finished peanut butter sample containing less than 10 micrograms total aflatoxins/kg showed 10 significant differences among means for laboratories using the 4 methods considered.