Post-portem migration of Anisakis spp. larvae from viscera into muscle of Eurpean anchovy (Engraulis encrasicolus L.) stored at 0, 4 and 22 ºC

Accidental ingestion of nematode larvae from genus Anisakis Dujardin, 1845, have been identified to cause a variety of health problems form allergic responses (hypersensitivity reactions to Anisakis spp. allergens) to anisakidosis (gastric or intestinal infections by live larvae). The occurrence of some Anisakis spp. larvae in the musculature of different fish species is inevitable ; however contradictory reports have been published regarding post-mortem migration of nematode larvae from viscera to fillet and it is yet unknown what triggers the migration. It is believed that this migration occurs in fatty fish after elongated storage when the deterioration of viscera has already begun. In this study, the post-mortem migration of Anisakis spp. larvae in anchovy stored at different temperatures was monitored, and the obtained results were correlated to sensory evaluation. Anchovies were stored at 0, 4 and 22 oC, and its viscera (visual inspection) and fillets (artificial enzymatic digestion procedure) were inspected for nematode larvae at specific time intervals. The migration of larvae was observed in samples stored at 0 and 4 oC, on fifth and third day of storage, respectively. On day seven of storage nematode prevalence (%) in the muscle rose from zero to 9.50 (at 0 oC) and to 23.10 (at 4 oC). In anchovies stored at 22 oC no post-mortem migration was observed after four days of storage regardless of advanced spoilage process observed. These findings showed that postmortem migration is postponed at 0 oC thus emphasize the importance of adequate storage temperatures.