An Analytical Survey of Aflatoxins in Tissues from Swine Grown in Regions Reporting 1988 Aflatoxin-Contaminated Corn
Abstract A joint project was undertaken by the Food Safety and Inspection Service (FSIS) and the Agriculture Research Service branches of the U.S. Department of Agriculture to determine the presence of aflatoxins in the U.S. meat supply during a drought year. In 1988, high incidences of aflatoxins occurred in corn grown in regions of the Midwest, Southeast, and South. Six states were identified as having serious aflatoxin contamination in their corn crop: Virginia, North and South Carolina, Texas, Iowa, and Illinois. Swine liver and pillars of diaphragm (muscle) tissues were sampled by federal FSIS inspectors in plants located in these states. A worstcase sampling plan was conducted. Samples were taken in January 1989 from hogs fed corn soon after harvest and in April 1989 from hogs fed corn originally stored and then fed in the spring. A modification of the official AOAC method for the thin-layer chromatography (TLC) determination of aflatoxins in animal tissue was used to permit quantitation by LC with fluorescence detection. The official AOAC TLC confirmation of identity method was used to confirm all positive samples with B1 concentrations >0.04 ppb and M1 concentrations >0.1 ppb. Sixty samples in the January group and 100 samples in the April group were assayed. Concentrations of aflatoxins B1 and M1 in the first group of pig livers ranged from 0.04 to 0.06 ppb. The identity of aflatoxin Bi was confirmed in all positive samples. Aflatoxin M1 could not be confirmed in any of the positive liver samples because the method was insufficiently sensitive for this aflatoxin. No positive muscle samples were found. In the second set, 9 positive livers were determined with B1 concentrations from 0.01 to 0.24 ppb and M1 concentrations from 0.03 to 0.44 ppb. Two samples contained M1 only. None of the corresponding muscle samples contained aflatoxins. Of the 12 positive samples, 5 were from Iowa, 4 from South Carolina, 2 from North Carolina, and 1 from Illinois. Aflatoxins were not detected in any of the samples from Texas or Virginia. One sample from North Carolina contained more than 0.5 ppb total aflatoxins. Blind recovery studies were conducted by including an artificially contaminated liver sample for every 6 samples assayed, and 1 uncontaminated liver sample for every 18 samples. Recoveries of aflatoxins B1, d , and M1 were 71.8%, 73.2%, and 69.8% respectively.
