Effects of storage, processing and proteolytic digestion on microcystin-LR concentration in edible clams

Food Chem Toxicol. 2014 Apr:66:217-23. doi: 10.1016/j.fct.2014.01.041. Epub 2014 Jan 31.

Abstract

Accumulation of microcystin-LR (MC-LR) in edible aquatic organisms, particularly in bivalves, is widely documented. In this study, the effects of food storage and processing conditions on the free MC-LR concentration in clams (Corbicula fluminea) fed MC-LR-producing Microcystisaeruginosa (1×10(5) cell/mL) for four days, and the bioaccessibility of MC-LR after in vitro proteolytic digestion were investigated. The concentration of free MC-LR in clams decreased sequentially over the time with unrefrigerated and refrigerated storage and increased with freezing storage. Overall, cooking for short periods of time resulted in a significantly higher concentration (P<0.05) of free MC-LR in clams, specifically microwave (MW) radiation treatment for 0.5 (57.5%) and 1 min (59%) and boiling treatment for 5 (163.4%) and 15 min (213.4%). The bioaccessibility of MC-LR after proteolytic digestion was reduced to 83%, potentially because of MC-LR degradation by pancreatic enzymes. Our results suggest that risk assessment based on direct comparison between MC-LR concentrations determined in raw food products and the tolerable daily intake (TDI) value set for the MC-LR might not be representative of true human exposure.

Keywords: Bioaccessibility; Clams; Food processing; Food storage; Microcystin-LR; Proteolytic digestion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bivalvia / chemistry*
  • Chromatography, Liquid
  • Marine Toxins
  • Microcystins / analysis*
  • Proteolysis
  • Seafood / analysis*
  • Spectrometry, Mass, Electrospray Ionization

Substances

  • Marine Toxins
  • Microcystins
  • cyanoginosin LR