No abstract

Heat treatments (40 to 94 degrees Celsius, 30 s to 60 min) 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 degrees Celsius 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 (> or = 70 degrees Celsius for > or = 1 min), no movement of the larvae was observed. Antigenic protein Ani s 4 and A. simplex crude antigens were detected in the larvae heated at 94 + or - 1 degrees Celsius for 3 min. This indicates that allergic symptoms could be provoked in previously sensitized consumers, even if the larvae were killed by heat treatment.

Anisakis simplex is a fish parasite that is a public health risk to those consuming raw or poorly cooked marine fish and cephalopods because of the possibility of becoming infested with live larvae. In humans, penetration of the larvae into the gastrointestinal track can cause acute and chronic symptoms and allergic anisakiasis. Excretion and secretion products released by the larvae are thought to play a role in migration through the tissues and induce an immunoglobulin E-mediated immune response. The aim of this preliminary study was to detect parasite antigens and allergens in fish tissues surrounding the migrating larvae. Hake and anchovy fillets were artificially parasitized with Anisakis larvae and stored in chilled conditions for 5 days. Larvae were evaluated for fluorescence, fish muscle tissue was examined with transmission electron microscopy, and immunohistochemical reactions of two rabbit polyclonal antisera against a parasite crude extract and the allergen Ani s 4 were recorded. Larvae immediately migrated into the fish muscle, and no emission of bluish fluorescence was observed. Fish muscle areas in contact with the parasite showed disruptions in the structure and inclusion of granules within sarcomeres. Both parasite antigens and the Ani s 4 allergen were located in areas close to the larvae and where sarcomere structure was preserved. These findings indicate that parasite antigens and allergens are dispersed into the muscle and might cause allergic symptoms such as dyspnea, vomiting, diarrhea, urticaria, angioedema, or anaphylaxis in some individuals sensitive to A. simplex.

BACKGROUND: Some Anisakis simplex allergens, Ani s 4 among them, are reported to be resistant to freezing, heat and pepsin. However, the effect of conventional and microwave heating on live and frozen larvae, common conditions for fish preparation, and consecutive pepsin treatment have not been studied previously. In this study, live and frozen/thawed A. simplex larvae were subjected to conventional or microwave heating during time–temperature sufficient to kill live larvae, and digested with pepsin in the strong conditions used in fish inspection. The antigenicity of A. simplex in the larvae extracts and in the incubation media filtrates after all treatments was studied. RESULTS: The immunoblotting assay showed the presence of Ani s 4 in all the larvae extracts and all the incubation media filtrates. A. simplex crude antigens were detected in all conditions; nevertheless, differences were observed among treatments, with lower values detected in the filtrates obtained after the strong acidic pepsin treatment. CONCLUSION: The results indicate that ingestion of A. simplex larvae can cause allergy in consumers already sensitised to this allergen, even if the parasitised fish is consumed well‐cooked and after freezing in the recommended conditions selected for killing the larvae to avoid human anisakiasis. Copyright © 2009 Society of Chemical Industry