Kinetics of adsorption and desorption of aflatoxin B-1 by viable and nonviable bacteria

Y K Lee, H El-Nezami, C A Haskard, Silvia Gratz, K Y Puong, S Salminen, H Mykkanen

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The reactions involved in the binding (adsorption) and release (desorption) of aflatoxin B-1 (AFB(1)) to and from the surface of bacteria were investigated. Viable and heat-killed Lactobacillus rhamnosus GG, L. rhamnosus LC-705, and Propionibacterium freudenreichii subsp. shermanii JS were incubated in phosphate-buffered saline containing variable concentrations (0.0017 to 13.3 mug/ml) of AFB(1). The relationship between the bacterial surface hydrophobicity and the AFB(1) adsorption affinity was also investigated. A linear relationship was observed between the specific rate of AFB(1) adsorption and the AFB(1) concentration for all bacteria. The nature of desorption of adsorbed AFB(1) was investigated by repetitive aqueous washes. A linear relationship was observed between the natural log value of the concentration of AFB(1) adsorbed and the number of washes for all bacteria studied. The desorption constants were strain-dependent and were lower for heat-killed bacteria than for viable bacteria. Heat treatment appears to alter the surface properties of the bacteria rather than expose new adsorption sites. No correlation was found between the hydrophobicity and the AFB(1) adsorption affinity.

Original languageEnglish
Pages (from-to)426-430
Number of pages5
JournalJournal of Food Protection
Issue number3
Publication statusPublished - Mar 2003


  • lactic-acid bacteria
  • rhamnosus strain GG
  • binding-properties
  • dairy strains
  • mycotoxins
  • ability
  • milk

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