Inactivation of Anisakis simplex Allergens in Fish Viscera by Acid Autolysis

The evisceration of infested species on board commercial fleets and the throwing of viscera into the sea, as is mostly the case for hake, is common practice for reducing the occurrence of Anisakis in fishery products. Moreover, the high levels of infestation and the lack of technically and economically feasible solutions hinder the possibility of recovering viscera with other fish processing byproducts as raw material for feed without the risk of transmission of allergens to humans, with the subsequent risk for public health. The aim of this work was to study the fate of Anisakis simplex allergens during 11 days of silage of infested hake (Merluccius merluccius) viscera, as a potential method for eliminating this risk. While the viscera were almost completely liquefied, an increase in the allergenicity of the soluble fraction was observed, which decreased only slightly after day 9. As we are aware of the resistance of parasite allergens to gastrointestinal enzymes, silage was also analyzed after 12 and 15 months. While the lower molecular weight fragments of Anisakis proteins are fully digested, some larger fragments with potential allergenicity resisted autolysis after long silage periods, but they were present in a very low concentration. The study concludes that there is the potential of silage as a method for recovering fish viscera infested with Anisakis.