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PubMed1991

Occurrence of faecal bacteria, Salmonella and antigens associated with hepatitis A virus in shellfish.

An investigation was carried out over a one year period to examine jointly the occurrence of faecal bacteria, salmonella and the presence of antigens associated with the hepatitis A virus (HAV) in oysters (Crassostrea gigas), mussels (Mytilus edulis, Mytilus galloprovincialis) and cockles (Cerastoderma edule), taken from 8 shellfish farming areas or natural beds along the French coast. For the faecal coliforms (FC) and faecal streptococci (FS), statistical analysis of the 176 samples examined shows a statistically significant difference between sampling stations (F = 44.39 and F = 26.69 respectively, p less than 0.001): 4 of the 8 stations are more highly contaminated. Salmonella and antigens associated with HAV were detected in 5% and 1.7% respectively of the samples analysed. Frequency of isolation of salmonella is higher for the group of sampling stations where the mean levels of contamination by FC and FS are highest. The presence of HAV associated antigens was detected for the group of stations showing the lowest mean contamination levels. Taking all sample stations together, the percentage of isolation of salmonella differs significantly (chi 2 = 7.28, p less than 0.01) for the two classes of FC established on the basis of the threshold value (300 FC). There is no difference between the two classes of FS. For the HAV-associated antigens, detection percentages are similar for the two classes of results for FC and FS. Within each sampling station, considered independently, no particular correlation was found between the various viral and bacterial markers investigated.

Animals↗

PubMed1991

[11 cases of anaphylaxis caused by grand keyhole limpet (abalone like shellfish)].

We reported 11 cases of patients who developed moderate to severe anaphylactic reactions induced by the ingestion of grand keyhole limpet (GKL) and abalone. Specific IgE-mediated hypersensitivity to these shellfish was demonstrated by history, skin prick test, RAST and immunoblotting. The RAST inhibition technique revealed cross antigenicity between GKL, abalone and keyhole limpet hemocyanin. By immunoblotting analysis, the major antigens of GKL are shown in the MW range of about 38 Kd and 80 Kd.

Adolescent↗

PubMedDate not supplied

Comparison of microwave digestion with conventional wet ashing and dry ashing digestion for analysis of lead, cadmium, chromium, copper, and zinc in shellfish by flame atomic absorption spectroscopy.

A closed vessel microwave digestion procedure was developed for shellfish samples. This procedure was compared with wet and dry ash procedures for levels of lead, cadmium, chromium, copper, and zinc. Results obtained for microwave and conventional wet ash digestion were comparable. The dry ashing procedure produced results consistently lower than either of the other methods. Recoveries ranged from 80-92% for microwave and wet ashing procedures and 54-72% for the dry ashing procedure. Accuracy was also determined by analyzing lobster hepatopancreas marine reference material. Values for Pb, Cd, and Cr fell within the range specified for the reference material for all 3 digestion procedures; however, values were lower for Cu and Zn. Results of this study show that microwave digestion is comparable to wet ashing.

Animals↗

PubMedDate not supplied

Identification of Escherichia coli from shellfish and related environments by automicrobic system.

A total of 463 fecal coliform positive isolates obtained from shellfish and related samples gave typical Escherichia coli IMViC reactions. E. coli identifications for 458 (99%) of these isolates were confirmed using a combination of the Automicrobic System (AMS) and the API 20E system (reference system). The AMS (test system) identified 433 isolates as E. coli; the remaining 25 (5%) isolates were identified as E. hermanii by the test system and as E. coli by the reference system. Additional tests performed on the isolates identified as E. hermanii confirmed those AMS identifications to be incorrect.

Animals↗

PubMedDate not supplied

Rapid determination of methyl mercury in fish and shellfish: collaborative study.

A modification of the official AOAC method for determining methyl mercury in fish and shellfish was studied in 8 laboratories. Methyl mercury is isolated from homogenized, acetone-washed tissue by adding HCl and extracting into toluene the methyl mercuric chloride produced. The extract is analyzed for methyl mercuric chloride by electron capture gas chromatography. Collaborators determined methyl mercury in blind duplicate homogenates at 2 levels in tuna and at 1 level in swordfish and oysters. Collaborators also analyzed single homogenates of swordfish and oysters containing methyl mercury at a second level. Both fortified and unfortified tissues were analyzed. Methyl-bound mercury in the commodities ranged from 0.50 to 2.30 micrograms Hg/g. Reproducibility coefficients of variation ranged from 4 to 15%. Accuracy, measured by comparison to reference values, ranged from 92 to 101%. Recovery from fortified homogenates ranged from 86 to 98%. Reference values and unfortified levels were determined in the author's laboratory by replicate analysis of fortified and unfortified commodities. The method has been approved interim official first action.

Animals↗

PubMedDate not supplied

Rapid, semimicro method for determination of polycyclic aromatic hydrocarbons in shellfish by automated gel permeation/liquid chromatography.

A simple, rapid, easily automated method is described for the determination of polycyclic aromatic hydrocarbons (PAHs) in shellfish such as American lobster (Homarus americanus) and blue mussel (Mytilus edulis). PAHs are extracted from small amounts (1-8 g) of tissue by saponification in 1N ethanolic potassium hydroxide followed by partitioning into 2,2,4-trimethylpentane. This solution is evaporated just to dryness by rotary evaporation and the residue is dissolved in cyclohexane-dichloromethane (1 + 1) for gel permeation chromatography (GPC) on Bio-Beads SX-3. The GPC procedure is ideal as a screening method in the range 25-18 000 ng PAHs/g tissue. If individual PAH measurements are required, the appropriate GPC fraction is collected and PAHs are separated by reverse phase liquid chromatography (LC) with fluorometric detection. Individual PAHs at concentrations as low as 0.25-10 ng/g can be determined. Recoveries of added fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[e]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene, benzo[ghi]perylene, and indeno[1,2,3-cd]pyrene were quantitative, with relative standard deviations ranging from 0.0 to 16.9%.

Animals↗

PubMed1977

Survey of finfish and shellfish for volatile N-nitrosamines.

A variety of finfish and shellfish obtained on the local retail market were analyzed for 14 volatile N-nitrosamines by using a gas-liquid chromatographic method demonstrated to be sensitive to 10 ppb (microng/kg). A total of 78 samples (fresh, frozen, and canned), representing 26 varieties of fish, were analyzed. No nitrosamines were found.

Animals↗

PubMed1979

Paralytic shellfish poisoning. A report of 17 cases in Cape Town.

An outbreak of 17 cases of paralytic shellfish poisoning in humans occurred in Cape Town during May 1978. The clinical features were typical and no deaths occurred. Efforts to correlate the severity of disease with the amount of toxin ingested, to demonstrate a protective effect of alcohol, and to demonstrate the immunogenicity of the toxin proved unsuccessful. The regional ecological effects are described. Continued monitoring for the presence of toxic dinoflagellates must be conducted, and the dangers of the consumption of mussels from the Cape west coast should be widely publicized.

Bivalvia↗

PubMed1983

Electron capture gas-liquid chromatographic determination of methyl mercury in fish and shellfish: collaborative study.

A method for determining methyl mercury in fish and shellfish was collaboratively studied in 8 laboratories. Methyl mercury is isolated from acetone-washed, homogenized tissue by adding hydrochloric acid and extracting into benzene the methyl mercuric chloride that is formed. The benzene extract is concentrated and analyzed for methyl mercuric chloride by electron capture gas-liquid chromatography on 5% DEGS-PS treated with inorganic mercuric chloride solution. The quantitation limit for the method is 0.05 micrograms Hg/g. Each collaborator determined methyl mercury at 2 levels in blind duplicate samples of swordfish, tuna, oyster, and shrimp tissues. Both fortified and unfortified samples were analyzed. Methyl-bound mercury in the samples ranged from 0.15 to 2.48 micrograms Hg/g. The reproducibility coefficients of variation for the 8 samples ranged from 3 to 13%. The accuracy, measured by comparison to reference values, ranged from 99 to 120%. Reference values were determined in the Associate Referee's laboratory by replicate analyses of the fortified and unfortified samples. The method has been adopted official first action.

Animals↗

PubMed1981

Diseases from fish and shellfish ingestion.

Fish- and shellfish-acquired diseases are a common but often unrecognized group of food-borne illnesses with considerable epidemiologic importance. They present with a spectrum of gastrointestinal and neurologic symptoms, but the history of pertinent ingestion establishes the diagnosis. Treatment is generally supportive, and recovery with minimal or no residua is the rule. State and local health authorities should be notified of all suspected cases because of the frequent occurrence of multiple cases from one source.

Adult↗

PubMed1996

[Annual daily intakes of Hg, PCB and arsenic from fish and shellfish and comparative survey of their residue levels in fish by body weight].

We have been surveying toxic substances in food and foodstuffs and carrying out a total diet study on the intakes of various substances since 1979 in cooperation with local public institutes in Japan. In this paper, we report the daily intakes of mercury, PCB and arsenic from foods, and the relation between the concentrations of these substance in fish and the fish body weight. The intakes of mercury and arsenic were 6.9-11.0 micrograms/ man/day and 120-230 micrograms/man/day, respectively. The intakes of these substances remained on a stable level from 1979 to 1994. On the other hand, the intake of PCB decreased from 3.1 micrograms/man/day in 1979 to 0.9 microgram/man/day in 1994. Most of the intakes of mercury, PCB and arsenic were derived from the diet group "fish and shellfish". The level of mercury in fish increased with increasing fish body weight. For PCB and arsenic, there was no correlation between these concentrations in fish and the fish body weight, except that mackerel and croaker show a higher concentration of PCB when they are small. Arsenic shows almost a constant level in each fish regardless of their body weight.

Animals↗

PubMed1998

Determination of Na channel blockers in paralytic shellfish toxins and pufferfish toxins with a tissue biosensor.

The biosensor consisted of a sodium electrode and covered with the frog bladder membrane within a flow cell was tested for the estimation of tetrodotoxin (TTX) and saxitoxin (STX). This sensor was applied to detect very low amounts of the Na+ channel blockers, STX and TTX, in different shellfishes and swellfishes. A good agreement was obtained between TTX activities determined by mouse assay and amounts of Na+ channel blockers estimated by frog membrane sensor. The lowest level of TTX (fg) that can be determined by frog membrane sensor does not cause human poisoning. The channel blockers in short-necked clam, which was assumed to be STX, were monitored by this sensor continuously every week for one year. It was discovered that the STX content increased from July until September and then decreased from October until March. The biosensor proposed here may be used for the estimation of STX and TTX conventionally in the future.

Animals↗

PubMed1998

Oral toxicity in mice of algal toxins from the diarrheic shellfish toxin (DST) complex and associated toxins.

Mussel samples from four locations along the Norweigian coast were extracted by methods for diarrheic shellfish toxins (DST) and tested by chemical and biological methods, including histopathology. All samples had previously been found to be highly toxic in mice, with symptoms indicating the presence of non-diarrheagenic toxins in the mouse bioassay. Chemical analysis revealed that the DST okadaic acid (OA) and dinophysistoxin-1 (DTX1) were present each one in one sample, but only a minor part of the total toxicity could be attributed to these toxions. In the other two samples, OA and DTX1 were absent. Incubation of the mussel extracts from all four samples with freshly prepared hepatocytes indicated the presence of unknown toxin(s) which may not be classified within the DST complex. Purified mussel samples were given to baby mice both via intraperitoneal (i.p.) injections and by oral intubation. Oral toxicity was about 25-50 times lower than toxicity obtained by i.p. injections, a result in accordance with acute toxic properties of many toxins. Risk assessment of the unknown toxin(s) requires chemical identification, but the preliminary results obtained indicate a large margin of safety, based on the large amounts of mussel extracts necessary to yield toxic effects in the intestine and liver in experimental animals upon oral exposure versus human intake.

Administration, Oral↗

PubMed1994

Characteristics of paralytic shellfish poisoning toxins derived from short-necked clams (Tapes japonica) in Mikawa Bay.

A "red tide" bloom of Alexandrium tamarense occurred in Mikawa Bay in April 1991. In association with this, paralytic shellfish poisoning toxin was detected in short-necked clams by mouse bioassay. High performance liquid chromatography analysis demonstrated large quantities of the N-sulfocarbamoyl toxins, C1, and C2 (approximately 90% of the total toxins), whose latent potency was confirmed by treatment with boiling at low pH.

Animals↗

PubMed1994

Accumulation of paralytic shellfish toxins by surfclams, Spisula solidissima (Dillwyn, 1897) in the Gulf of Maine: seasonal changes, distribution between tissues, and notes on feeding habits.

Accumulation of paralytic shellfish poisoning (PSP) toxins by surfclams, Spisula solidissima, was studied over a period of two years at two inshore locations in southern Maine and at six stations on Georges Bank in the Gulf of Maine. Whole animals as well as individual tissues (siphon, mantle, digestive gland, foot, adductor muscle, gill) were analyzed for PSP-toxicity levels using the standard AOAC mouse bioassay. Analyses of gut contents were carried out on surfclams from both inshore and offshore locations to identify the type of particles ingested. Surfclams feed primarily on phytoplankton and detrital material characteristic of the overlying seawater and surface sediment. No evidence was found for any selection based on particle size or type. Elevated levels of PSP toxins were noted in surfclams from Georges Bank more than two years after initial toxification. Toxins were not evenly distributed among the various tissues of surfclams. Initially, maximum toxicity among surfclam tissues was found in digestive glands; however, subsequent analyses of samples collected later in the year indicated that toxicity in gill and mantle tissues had increased relative to initial values. No toxicity was detected in adductor muscles. Surfclams are characterized by a high variation in total toxin load among individual animals, with a tendency for decreasing variation as toxin levels increase. Archived data from the Main Department of Marine Resources revealed annual and seasonal patterns of toxin accumulation by surfclams, i.e., toxin accumulation is an annual event, with initial increases in toxicity usually occurring in early spring.

Animals↗

PubMed1992

Ionspray mass spectrometry of marine toxins. III. Analysis of paralytic shellfish poisoning toxins by flow-injection analysis, liquid chromatography/mass spectrometry and capillary electrophoresis/mass spectrometry.

Ionspray mass spectrometry has been used to monitor the purification of saxitoxin, the parent compound in the family of toxins responsible for paralytic shellfish poisoning (PSP), from a strain of the dinoflagellate Alexandrium excavatum. Quantitative results obtained by flow-injection analysis are compared to those obtained by high-performance liquid chromatography with post-column oxidation and fluorescence detection. The coupling of liquid chromatography and capillary electrophoresis with ionspray mass spectrometry is described for the separation of mixtures of PSP toxins and the highly potent pufferfish toxin tetrodotoxin. Tandem mass spectrometry is used to provide the structural information, and the ability to distinguish isomeric PSP toxins both chromatographically and mass spectrometrically is demonstrated.

Chromatography, High Pressure Liquid↗

PubMed1992

Ionspray mass spectrometry of marine toxins. IV. Determination of diarrhetic shellfish poisoning toxins in mussel tissue by liquid chromatography/mass spectrometry.

An improved liquid chromatographic/mass spectrometric (LC/MS) method utilizing gradient elution and ion-spray ionization is described for the sensitive determination of okadaic acid and dinophysistoxin-1, the principal toxins implicated in cases of diarrhetic shellfish poisoning. The method was used to confirm the presence of both toxins, together with a recently identified isomer of okadaic acid, dinophysistoxin-2, in various samples of cultivated blue mussels (Mytilus edulis) from Canadian and European waters. The method provided a mass detection limit of 0.4 ng for each toxin, thus allowing detection of 40 ng per g of whole mussel tissue (or approximately 10 ng/g if only the digestive glands were used in the assay). Quantitative results obtained by LC/MS were in good agreement with those obtained by derivatization and high-performance liquid chromatography with fluorescence detection.

Animals↗

PubMed1993

Characterization of the oxidation products of paralytic shellfish poisoning toxins by liquid chromatography/mass spectrometry.

Periodate oxidation of the toxins responsible for paralytic shellfish poisoning (PSP) yields fluorescent products that are useful for trace analysis by reversed-phase liquid chromatography. Some toxins are oxidized to the same product, while others are transformed to a mixture of products; in all cases, the products are too unstable to be isolated preparatively. A mobile phase containing heptafluorobutyric acid as an ion-pair agent was developed to improve compatibility with liquid chromatography/mass spectrometry (LC/MS) analysis. Several LC/MS techniques were investigated: chemical ionization with the moving belt interface, atmospheric-pressure chemical ionization, thermospray, continuous-flow fast-atom bombardment, and ion-spray. Only LC/ion-spray MS was able to provide spectra of the oxidized products. The products were characterized as purines resulting from: (a) breakage of the C4-C12 bond and aromatization of the remaining rings (loss of 4 hydrogens); (b) partial elimination of a carbamoyl or N-sulfocarbamoyl side-chain (this is promoted by the presence of an N-1-hydroxy group); and (c) partial hydrolysis of an N-sulfocarbamoyl side-chain to a carbamoyl group.

Gas Chromatography-Mass Spectrometry↗