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ABSTRACT: Inactivation of parasites in food by microwave treatment may vary due to differences in the characteristics of microwave ovens and food properties. Microwave treatment in standard domestic ovens results in hot and cold spots, and the microwaves do not penetrate all areas of the samples depending on the thickness, which makes it difficult to compare microwave with conventional heat treatments. The viability of Anisakis simplex (isolated larvae and infected fish muscle) heated in a microwave oven with precise temperature control was compared with that of larvae heated in a water bath to investigate any additional effect of the microwaves. At a given temperature, less time was required to kill the larvae by microwaves than by heated water. Microwave treatment killed A. simplex larvae faster than did conventional cooking when the microwaves fully penetrated the samples and resulted in fewer changes in the fish muscle. However, the heat-stable allergen Ani s 4 was detected by immunohistochemistry in the fish muscle after both heat treatments, even at 70°C, suggesting that Ani s 4 allergens were released from the larvae into the surrounding tissue and that the tissues retained their allergenicity even after the larvae were killed by both heat treatments. Thus, microwave cooking will not render fish safe for individuals already sensitized to A. simplex heat-resistant allergens.
Journal of food protection 12/2011; 74(12):2119-26. · 1.94 Impact Factor
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ABSTRACT: In this study, we researched the presence of anisakids in specimens of Merluccius merluccius caught in the area of Little Sole Bank, in the Northeast Atlantic, and found that 100% of the European hake examined were infected and showed high average values of abundance (976.88) and intensity (976.88). The larvae were identified in morphological terms as morphotype type I and in molecular terms as Anisakis simplex s.s via polymerase chain reaction (PCR) restriction fragment length polymorphism of the rDNA. The genetic variability of the A. simplex s.s population in the North Atlantic is notable, with at least two ribosomal and three mitochondrial haplotypes which are different from the specimen used as control, reflecting the diversity of this species, an aspect which has scarcely been studied to date. The cox-2 gene appears to be an interesting candidate for generating new genetic markers which can be applied to differentiate between A. simplex s.s and Anisakis pegreffii. We detected 11 fixed differences in this gene, and it also offers the advantage of being easily amplified by PCR. The high prevalence of infection by A. simplex s.s and the extremely high average intensity and abundance values can have significant repercussions on public health, especially among populations which regularly eat insufficiently cooked or raw fish and have a certain genetic predisposition; the genetic variability of the parasite could be another factor to take into account.
Parasitology Research 11/2010; 107(6):1399-404. · 2.15 Impact Factor
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ABSTRACT: Fish-borne parasitic zoonoses such as Anisakiasis were once limited to people living in countries where raw or undercooked fish is traditionally consumed. Nowadays, several factors, such as the growing international markets, the improved transportation systems, the population movements, and the expansion of ethnic ways of cooking in developed countries, have increased the population exposed to these parasites. Improved diagnosis technology and a better knowledge of the symptoms by clinicians have increased the Anisakiasis cases worldwide. Dietary recommendations to Anisakis-sensitized patients include the consumption of frozen or well-cooked fish, but these probably do not defend sensitized patients from allergen exposure. The aim of our work was to develop a sensitive and specific method to detect and quantify Anisakis simplex allergens in fish muscle and its derivatives. Protein extraction was made in saline buffer followed by preparation under acid conditions. A. simplex antigens were detected by IgG immunoblot and quantified by dot blot. The allergenic properties of the extracts were assessed by IgE immunoblotting and basophil activation test. We were able to detect less than 1 ppm of A. simplex antigens, among them the allergen Ani s 4, in fish muscle with no cross-reactions and with a recovery rate of 82.5%. A. simplex antigens were detected in hakes and anchovies but not in sardines, red mullets, or shellfish. We detected A. simplex allergens in cooked hakes and also in hake stock. We proved that A. simplex allergens are preserved in long-term frozen storage (-20 degrees C +/- 2 degrees C for 11 months) of parasitized hakes. Basophil activation tests have proven the capability of the A. simplex-positive fish extracts to induce allergic symptoms.
Foodborne Pathogens and Disease 08/2010; 7(8):967-73. · 2.26 Impact Factor
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ABSTRACT: Heat treatments (40 to 94°C, 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°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. simplex 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.
Journal of food protection 12/2009; 73(1):62-68. · 1.94 Impact Factor
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ABSTRACT: BACKGROUND: High pressure (HP) ranging from 100 to 350 MPa (1–15 min) was applied to Anisakis simplex larvae and parasitised hake (Merluccius merluccius) muscle. The aim of the study was to kill the larvae to prevent human anisakidosis, to evaluate the effect on A. simplex allergens and to minimally alter fish muscle quality.RESULTS: The larvae were killed at pressures ≥ 200 MPa and times ≥ 1 min, producing alterations in the larva body and ruptures in the cuticle when observed by scanning electron microscopy. Nevertheless, Ani s 4 and A. simplex crude antigens were recognised by immunoblotting and immunohistochemistry at all HPs assayed. Small changes in colour and texture were observed in fish muscle under all pressure/time conditions. Major changes were observed visually at 300 MPa, where the muscle appeared as slightly cooked. Apparent viscosity of muscle homogenates decreased significantly at longer times or higher applied pressure. No changes were detected at 200 MPa in the electrophoretic pattern of proteins treated with or without β-mercaptoethanol, suggesting that disulfide bonds were not formed.CONCLUSION: Application of HP at 200 MPa for up to 5 min would kill A. simplex larvae, avoiding infestation of the consumer and causing small changes in the hake muscle perceived sensorially. However, HP-treated A. simplex-parasitised fish would still be a potential hazard for consumers allergic to the larvae. Copyright © 2009 Society of Chemical Industry
Journal of the Science of Food and Agriculture 08/2009; 89(13):2228 - 2235. · 1.44 Impact Factor
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ABSTRACT: 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
Journal of the Science of Food and Agriculture 07/2009; 89(12):1997 - 2002. · 1.44 Impact Factor
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ABSTRACT: This article examines the viability of and the alterations to the larval cuticle and the pattern of the antigens released when live or frozen Anisakis simplex larvae were treated with acid and pepsin. The results showed that freezing did not greatly alter the larva body. If ruptures were observed, the antigen release to the incubation media was not enhanced, and most of the antigenic content was retained inside the bodies of the larvae. The immunoblotting assay demonstrated that most of the antigens released, including the allergen Ani s 4, were resistant to pepsin. Freezing killed the larvae, but their survival was not compromised by acid treatment or pepsin digestion when kept chilled. All these findings support recommendations about freezing fish for consumption raw or undercooked to prevent human infection by A. simplex larvae. However, our data show that the antigenicity of the larvae is preserved after freezing and may explain why some sensitized patients develop symptoms after ingestion of infested frozen fish.
Journal of food protection 01/2009; 71(12):2578-81. · 1.94 Impact Factor
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ABSTRACT: 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.
Journal of food protection 07/2008; 71(6):1273-6. · 1.94 Impact Factor
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ABSTRACT: Farmed Senegalese sole (Solea senegalensis) from two different cultivation areas in Spain and different rearing conditions were analyzed up to 28 days in order to establish
changes in the quality indices during ice storage and select the best ones to be used to calibrate a prototype designed for
rapid measurement of freshness in this species. The main indices measured were the degradation of adenosine-5′-triphosphate
and breakdown products, K-value, Torrymeter readings, trimethylamine oxide nitrogen (TMAO-N), TMA-N, TBA index and dielectric measurements. The main
differences observed were related to size, amount of TMAO-N, pH and fat content, which may be related to differences in the
rearing conditions. The most consistent index to measure changes in freshness was the K-value that showed a linear response with time during the shelf-life period, irrespectively of the differences of size and
composition of the fish in both batches. However, the dielectric response of the fish varied in the two batches in the pulse
amplitude. More work is needed in order to adjust the prototype for predicting the days in ice for this species.
European Food Research and Technology 05/2007; 225(2):225-232. · 1.57 Impact Factor
