For aflatoxin analysis, a 50 g sample of maize was ground in a coffee grinder, and three subsamples (0.5 g) were extracted overnight in 2 mL of acetonitrile. The extracts were filtered (4 mm × 0.45 μm Iso-Disc Filter, Supelco, Bellefonte, PA) before injection into a Shimadzu HPLC (Shimatzu Scientific Instruments, Inc. Kyoto, Japan) equipped with an analytical C18 column (5 μm, 4.6 mm × 150 mm, Alltech Econosphere), a post-column PHRED (Aura Industries, New York, NY), and a Shimadzu fluorometer (360 nm excitation and 440 nm emission). The mobile phase consisted of water, acetonitrile, and methanol (68:24:8, v:v:v). Aflatoxin B1 was quantified by comparing peak areas with a standard (Sigma Chemical Co., St. Louis, MO) over a range of 1–100 ng aflatoxin B1/ml.