Enzyme-linked immunosorbent assay of aflatoxins B1, B2, and G1 in corn, cottonseed, peanuts, peanut butter, and poultry feed: collaborative study.
A direct competitive enzyme-linked immunosorbent assay (ELISA) screening method for aflatoxins at 20 ng/g was studied by 12 collaborators. Test samples of peanut butter were extracted by blending with methanol-water-hexane (55 + 45 + 100) and heating the test extracts on a steam bath; test samples of the other commodities were extracted by blending with methanol-water (80 + 20). All test extracts were filtered and the filtrates were diluted with buffer to a final methanol concentration of less than 30%. Each diluted filtrate was applied to a cup containing a filter with immobilized polyclonal antibodies specific to aflatoxins B1, B2, and G1. Aflatoxin B1-peroxidase conjugate was added, the cup was washed with water, and a mixture of hydrogen peroxide and tetramethylbenzidine was added. The test sample was judged to contain greater than or equal to 20 ng aflatoxins/g when, after exactly 1 min, no color was observed on the filter; when a blue or gray color developed, the test sample was judged to contain less than 20 ng aflatoxins/g. All collaborators correctly identified naturally contaminated corn and raw peanut positive test samples. No false positives were found for controls containing less than 2 ng aflatoxins/g. The correct responses for positive test samples spiked at levels of 10, 20, and greater than or equal to 30 ng aflatoxins/g (the ratio of B1:B2:G1 was 10:1:3) were 52, 86, and 96%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Trucksess
M W
MW
Food and Drug Administration, Division of Contaminants Chemistry, Washington, DC 20204.
Stack
M E
ME
Nesheim
S
S
Park
D L
DL
Pohland
A E
AE
D016604:Aflatoxin B1; D000348:Aflatoxins / Q000032:analysis*; D000821:Animal Feed / Q000032:analysis; D010367:Arachis / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D003368:Gossypium / Q000032:analysis; D007202:Indicators and Reagents; D003313:Zea mays / Q000032:analysis
D000348:Aflatoxins; D007202:Indicators and Reagents; C027955:aflatoxin G1; C029753:aflatoxin B2; D016604:Aflatoxin B1