Detection of Total Ergot Alkaloids in Cereal Flour and in Bread by a Generic Enzyme Immunoassay Method

J AOAC Int. 2018 May 1;101(3):618-626. doi: 10.5740/jaoacint.17-0346. Epub 2017 Oct 2.

Abstract

Four sets of polyclonal antibodies against ergot alkaloids ergometrine, ergotamine, α-ergocryptine, and ergocornine were produced and characterized in a competitive direct or indirect enzyme immunoassay (EIA). Standard curve LODs were 0.03 ng/mL (ergometrine EIA) to 2.0 ng/mL (ergocornine EIA). Three EIAs were highly specific, whereas the ergometrine EIA had a broad specificity pattern and reacted, albeit weakly, with all seven major ergot alkaloids and their epimeric forms. Using the ergometrine EIA, a generic test system was established in which total ergot alkaloids are quantified by a standard curve for a toxin mixture composed of three alkaloids that matched the ergot alkaloid composition in naturally contaminated rye and wheat products. Sample extraction with acetonitrile-phosphate-buffered saline at pH 6.0 without further cleanup was sufficient for EIA analysis. The LODs for total ergot alkaloids were 20 ng/g in rye and wheat flour and 14 ng/g in bread. Recoveries were 85-110% (RSDs of 0.1-11.7%) at a concentration range of 50-1000 ng/g. The total ergot alkaloid EIA was validated by comparison with HPLC-fluorescence detection. Although some under- and overestimation by the total ergot alkaloid EIA was observed, it was suitable for the reliable identification of positive samples at 10-20 ng/g and for the determination of total ergot alkaloids in a concentration range between 100 and 1000 ng/g.

Publication types

  • Editorial

MeSH terms

  • Animals
  • Antibodies / immunology
  • Bread / analysis*
  • Bread / microbiology
  • Edible Grain / chemistry*
  • Edible Grain / microbiology
  • Ergot Alkaloids / analysis*
  • Ergot Alkaloids / immunology
  • Flour / analysis*
  • Flour / microbiology
  • Food Contamination / analysis*
  • Immunoenzyme Techniques / methods*
  • Limit of Detection
  • Rabbits

Substances

  • Antibodies
  • Ergot Alkaloids