Abrin Toxin Stability in Complex Food Matrices

Introduction: Abrin is an extremely toxic ribosomal inactivating protein commonly found in the tropical plant, Abrus precatorius. Although abrin has not been documented in a bioterrorism event, it does not have an antidote, and its lethality, availability, and ease of dissemination make it a dangerous foodborne contaminate for bioterrorism activity. A clear understanding of the toxin’s stability in foods is necessary in order to determine its overall threat and the potential vulnerability in a variety of foods.

Purpose: This study’s objective was to determine the duration of abrin toxin stability in a variety of complex food matrices.

Methods: Hot dogs, liquid eggs, and infant formula were fortified at three levels in four sets at days 7, 5, 3, and 0. Fortifications for low levels were near the limit of detection for each matrix, and high level fortifications were one log higher. Samples were homogenized with GBS and extracted via centrifugation. The aqueous layers were removed and analyzed in triplicate, in accordance with the ELISA manufacturer’s instructions.  

Results: Calculated absorbance values indicated that at high fortification levels, significant toxin degradation occurs during the initial degradation phase (day 0-3) in hot dogs (62.7%), while significantly lower differences occurred in toxin stability for liquid eggs (20.4%) and infant formula (15.5%).  Between days 3 and 5, the differences between absorbance values decreased nearly half from those in the initial phase: hot dogs (33%), liquid eggs (10.6%), and formula (9.1%).  Absorbance values stabilized for foods analyzed after day 5.

Significance: The data generated from this study will be used for future proficiency testing purposes and may lend insight into the stability and degradation of abrin toxin, when introduced into a variety of matrices, for food biodefense purposes.