AACC International - 2011 Meeting Abstract - Mycotoxin test kit validation for high-aflatoxin samples

Meeting Abstract - Poster Presentation

Mycotoxin test kit validation for high-aflatoxin samples
S. Y. Dai (1), K. LEE (1), J. Balthrop (1), W. Li (1), T. J. Herrman (1)
(1) Texas A&M University, College Station, TX, U.S.A.
Cereal Foods World 56:A37

Five commercial mycotoxin test kits were validated, including Aflatest from Vicam, Romer kit from the Romer Lab, Charm kit from Charm, Neogen Veratox, and Neogen Veratox AST. Three chemists evaluated three reference samples of naturally occurring aflatoxin contaminated ground corn. Each chemist analyzed seven samples per mycotoxin test kit for each of the three reference samples. The reference samples were also subject to HPLC analysis methodology (21 times per reference sample), yielding official results of 59, 306, and 901 ppb. The data were analyzed using SAS general linear model (GLM) procedures to explore whether significant differences were observed between test kits and chemists for the three aflatoxin levels. The percent relative difference for each aflatoxin measurement was calculated by subtracting the official (HPLC) value from the test kit value, dividing the difference by the average official value. All test kits met the GIPSA acceptable limits, which allow the maximum relative standard deviation (RSD) for the 100-ppb sample to be 16%. There was no observed significant main effect for chemist; however, a significant three-way interaction and two-way interactions were observed for test kit, aflatoxin level, and chemist (P < 0.01). The Romer and Neogen AST displayed no significant difference with HPLC results in percent relative difference at the three aflatoxin levels while the Charm and Aflatest results for the highest level (901 ppb) of aflatoxin were significantly different from HPLC results. Ideally, all test kits, with the proper dilution procedure, should give consistent results for different aflatoxin levels. However, it is tricky to figure out which step is critical for each individual kit. As the validation was done in a well-controlled laboratory environment, bigger variations would be expected in the real field practice.