Antigenicity and viability of anisakis larvae infesting hake heated at different time-temperature conditions

Abstract

Heat treatments (40 to 94°C, 30 s to 60 mitt) were applied to different batches of Anisakis simplex L3 larvae isolated from hake ovaries and viscera to study the effect of heat on the viability of the larvae measured as mobility, emission of fluorescence under UV light, and changes in color after staining with specific dyes, and on A. simplex antigenic proteins. The aim was to determine the lowest time-temperature conditions needed to kill the larvae to avoid anisakiasis in consumers, and to evaluate whether high temperature modifies the antigenicity of A. simplex extracts. Heating at 60°C for 10 min (recommended by some authors) was considered unsafe, as differences in viability between batches were found, with some larvae presenting spontaneous movements in one batch. At higher temperatures (≥70°C for ≥1 min), no movement of the larvae was observed. Antigenic protein Ani s 4 and A. simp/ex crude antigens were detected in the larvae heated at 94 ± 1 °C for 3 min. This indicates that allergic symptoms could be provoked in previously sensitized consumers, even if the larvae were killed by heat treatment.