PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Shellfish”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1975

The quantitative bacteriology of some commercial bivalve shellfish entering British markets.

Incidents of non-specific illness associated with the consumption of oysters have highlighted the lack of published information on the bacteriology of shellfish suitable for consumption. Investigations showed that the majority of molluscan shellfish entering English markets conform to the accepted standard of less than 5 Escherichia coli/ml. tissue. The numbers of E. coli were related to the sanitary quality of the growing area but no relation could be established between numbers of E. coli and coliforms, faecal streptococci or Clostridium welchii. The numbers of non-specific bacteria varied considerably but shellfish from sources associated with non-specific illness yielded relatively high counts at 37 degrees C. The results showed that there was no justification for a standard based on total plate counts, which often exceeded 10(6)/g. Such a standard would have to be coupled with spoilage or the incidence of non-specific illness. The relation between the numbers of non-specific bacteria growing at 20 and 37 degrees C. appears to be a useful measure for assessing the likelihood that raw shellfish are a public health risk.

Animals↗
PubMed1977

Ionic bonding, the mechanism of viral uptake by shellfish mucus.

An investigation was conducted to determine the processes involved in the contamination of shellfish by viruses. Results of binding-release studies show that the process involves the attachment of viruses to mucus secreted, and then ingested, by shellfish during feeding. Analysis of the mucus-virus bond involved selective degradation of the mucus and use of chemical agents to block carboxyl and sulfate groups on the mucus. Results obtained indicate that the attachment of virus to mucus is primarily ionic and involves the binding of viral particles to sulfate radicals on the mucopolysaccharide moiety of shellfish mucus.

Enterovirus↗
PubMed1978

Analytical methodology for the determination of Kepone residues in fish, shellfish, and Hi-Vol air filters.

The recent discovery of the pollution of the environment with Kepone has resulted in a tremendous interest in the development of residue methodology for the compound. Current multiresidue methods for the determination of the common organochlorinated pesticides do not yield good quantitative analytical results for Kepone. The extracting solvents are usually of insufficient polarity to extract Kepone from the various media. This article describes some of the recently developed methodology for Kepone in air filters, finfish, finfish livers and entrails, shellfish, and archival oyster samples. The finfish and archival oyster samples were Soxhlet extracted using diethyl ether/petroleum ether (1:1 v/v) as the extracting solvent. The finfish livers and entrails were macerated in a Duall tissue grinder containing acetonitrile followed by partitioning of the Kepone into benzene. Shellfish samples were analyzed after extracting the sample with acetonitrile and partitioning the Kepone into benzene. The Hi-Vol air samples were extracted with methanol/benzene (1:1 v/v). The coextracting contaminants were removed by micro-Florisil column chromatography and/or acid digestion. The procedural recovery of Kepone from fortified samples averaged 82%.

Air↗
PubMedDate not supplied

[Paralytic shellfish poisoning (author's transl)].

Different diseases as viral or bacterian gastro-enteritis, Tiphoid, viral hepatitis can come from shellfishes. Less known is the shellfish poisoning although recent outbreaks took place in Spain, France, England, Morocco. Toxic poisoning is caused by a poison produced by dinoflagelates of plankton which get developped in shells and make them dangerous, even cooked, to be eaten. A respiratory failure can result from this neurotropic poison.

Adult↗
PubMed1978

Gas-liquid chromatographic determination of kepone residues in finfish, shellfish, and crustaceans.

Finfish, shellfish, and crustacean samples are extracted with isopropanol and benzene; the extract is filtered and then concentrated. The extract, dissolved in hexane, is treated with oleum and extracted with aqueous alkali. The aqueous phase is acidified and extracted with petroleum ether-ethyl ether (1 + 1). The Kepone residue is determined by electron capture gas-liquid chromatography (GLC). Recoveries obtained by 8 laboratories from 15 species of finfish fortified at 0.02-0.23 ppm ranged from 37 to 107% with a mean +/- relative standard deviation of 79.4 +/- 14.5%. For oysters fortified at 0.01-0.10 ppm, recoveries range from 63 to 129% with a mean of 78.8 +/- 20.8%. For crustaceans fortified at 0.05-0.26 ppm, recoveries ranged from 52 to 110% with a mean of 78 +/- 16.4%. The approximate limits of quantitation for finfish and for shellfish and crustaceans are 0.02 and 0.05 ppm, respectively, under the GLC conditions used in this study.

Animals↗
PubMed1976

High-pressure liquid chromatography of benzo(a) pyrene and benzo (ghi) perylene in oil-contaminated shellfish.

A high-pressure liquid chromatographic procedure is described for the determination of benzo(a) pyrene and benzo(ghi) perylene. These polynuclear aromatics are extracted with acetonitrile and partitioned into petroleum ether, the petroleum ether is removed, and the residue is saponified. The compounds are purified and isolated by passing the residue through a silica gel column and a high-pressure liquid chromatographic column, and detected by their ultraviolet absorption. Recoveries of standards through the procedure averaged 104%.

Benzopyrenes↗
PubMed1979

Human enteroviruses in oysters and their overlying waters.

The presence of enteroviruses in oysters and oyster-harvesting waters of the Texas Gulf coast was monitored over a period of 10 months. Viruses were detected in water and oyster samples obtained from areas both open and closed to shellfish harvesting. Viruses were detected periodically in waters that met current bacteriological standards for shellfish harvesting. No significant statistical relationship was demonstrated between virus concentration in oysters and the bacteriological and physiochemical quality of water and shellfish. Viruses in water were, however, moderately correlated with total coliforms in water and oysters and with fecal coliforms in oysters. Total coliforms in water were realted to total coliforms in sediment were related only to total coliforms in sediment. Among the physiochemical characteristics of water, turbidity was related statistically to the organic matter content of water and to fecal coliforms in water. There was a marked effect of rainfall on the bacteriological quality of water. Of a total of 44 water samples, 26 yielded virus in concentrations from 4 to 167 plaque-forming units per 100-gallon (ca. 378.5-liter) sample. Of a total of 40 pools of 10 to 12 oysters each, virus was found in 14 pools at a concentration of 6 to 224 plaque-forming units per 100 g of oyster meat. On five occasions, virus was found in water samples when no virus could be detected in oysters harvested from the same sites. This study indicates that current bacteriological standards for determining the safety of shellfish and shellfish-growing waters do no reflect the occurrence of enteroviruses.

Animals↗
PubMed2026

Culture of infectious human norovirus isolated from live contaminated oysters.

Human noroviruses are a major cause of foodborne outbreaks worldwide. Filter-feeding shellfish, such as oysters, can bioaccumulate these viruses in their digestive tissue when grown in sewage-impacted coastal areas and are often implicated in norovirus foodborne outbreaks. Despite the high sensitivity of current molecular assays, these methods for norovirus detection in shellfish fail to distinguish between infectious and non-infectious particles. Assessing norovirus infectivity in shellfish remains a challenge due to the lack of suitable isolation methods that maintain capsid integrity. In this study, a protocol for isolating infectious norovirus from oyster tissues, based on chloroform-butanol elution and polyethylene glycol concentration (CB-PEG), was optimized for the recovery of human norovirus GI and GII. While CB-PEG method recovered various norovirus GI and GII genotypes, it was less efficient at the genomic level than a protocol based on proteinase K elution (adapted from ISO 15216) and showed genotype-dependent viral recovery rates. By optimizing the flocculation step, we improved the method's compatibility with human intestinal enteroid (HIE) cultures. Using this approach, we successfully quantified infectious norovirus GII.3 titers recovered from artificially-contaminated live oysters. Interestingly, infectious virus was better isolated following a freezing step of the digestive tissues, with titers ranging from 13 to 40 TCID50/mL for positive samples. In conclusion, this study established an optimized methodological approach for the relative quantification of infectious norovirus GII.3 in shellfish, paving the way for future research on viral persistence and inactivation strategies in this foodstuff.

Norovirus↗
PubMed1978

Thermal treatment and infectivity of hepatitis A virus in human feces.

The susceptibility of white-lipped marmoset monkeys (Saguinus sp) to human hepatitis A virus (HAV) provides a system for evaluation of thermal inactivation of HAV in feces and contaminated shellfish. Intramuscular or oral administration of HAV derived from feces of four patients with acute hepatitis A induced hepatitis in 28--100% of the inoculated marmosets. A 10% (w/v) fecal pool (GBG-BM) prepared from two patients (GBG and GBM) induced hepatitis in marmosets (2/4 with 1 ml; 2/2 with 3 ml) when given orally as a 1 : 3 dilution. A HAV-baby food raw oyster mixture fed to fasted marmosets induced hepatitis in 1/4 and seroconversion in 2/4 animals. Two groups of oysters were injected with HAV (concentrated 3 : 1 by centrifugation of the GBG-BM pool); one group was treated at 140 degrees F for 19 minutes and the other served as an untreated control. In animals fed the untreated inoculum, 4/6 developed hepatitis and 6/6 seroconverted, whereas of those fed the heat-treated inoculum 1/7 developed hepatitis and 2/7 seroconverted. These data suggest that pasteurization methods could be developed that would eliminate shellfish-associated hepatitis A and retain the palatability of the shellfish.

Animals↗
PubMed1978

The functional characteristics conserved in tropomyosins.

1. Tropomyosin, one of the regulatory proteins in muscle contraction, was prepared from chickens, rabbits, frogs, shrimps, and shellfish, and conserved characteristics were studied using an enzymological technique. 2. All tropomyosins tested, irrespective of their sources, were found to have the ability to mediate the inhibitory activity of rabbit troponin toward rabbit Mg2+-activated actomyosin ATPase (Mg2+-ATPase) activity in the absence of Ca2+ ions. 3. The effect of tropomyosin on the Mg2+-ATPase activity in the presence of Ca2+ ions varied, depending on the source, and this variation appeared to reflect the evolutionary course of this protein. 4. Tropomyosin from shellfish adductor muscle had the ability to bind to rabbit skeletal muscle troponin and actin. This ability is also considered to be a basic characteristic of tropomyosin which has been conserved during evolution.

Actins↗
PubMed1977

Electron capture gas chromatographic determination of Kepone residues in environmental samples.

The pollution of the environment with Kepone (decachlorooctahydro-1,3,4-metheno-2H-cyclobuta[cd]pentalen-2-one) by an industrial manufacturer of the pesticide resulted in the contamination of several terrestrial media, including biological life, near the entry of the insecticide into the ecosystem. The substrata investigated and for which residue methodology was developed included river sediment, soil, water, shellfish, and finfish. Rigorous extraction techniques utilizing the Soxhlet apparatus and the Polytron tissue homogenizer were required for complete removal of Kepone from the samples. Finfish tissue was the most difficult to analyze. For this type of substratum, a preliminary cleanup by gel permeation chromatography was required to remove most of the lipid material followed by a micro Florisil column elution to eliminate polychlorinated biphenyls (PCB'S). Cleanup of shellfish and other environmental samples was accomplished with a micro Florisil column only. Electron capture gas chromatography was used to analyze the sample extracts. Recoveries of Kepone from fortified samples averaged 84% or greater.

Animals↗
PubMed1975

Uptake and elimination of poliovirus by West Coast oysters.

Accumulation of poliovirus Lsc-2ab by West Coast oysters was determined by using a stationary seawater system, and depuration was determined by using both stationary and free-flow systems. Results indicate that these shellfish have the same pattern of accumulation and localization of viruses as do East Coast species. However, uptake appeared to occur more rapidly than described for East Coast shellfish. There appeared to be a gradual diffusion of virus from the digestive area into the body. Depuration was found to occur more rapidly and completely under free-flow conditions than in a stationary system.

Animals↗
PubMed1979

Influences of oyster or clam feeding on lipid metabolism in rats.

Rats were fed on three kinds of diets for two weeks: (I) basal diet, (II) containing 0.1% cholate and (III) containing 0.1% cholesterol and 0.1% cholate. Each dietary group was further divided into subgroups to whose diet was added 0, 5 or 10% (dry weight) of minced oyster (Callocorchina) or clam (Tapes japonica). The serum and liver cholesterol levels of the rats fed the basal diet were reduced by feeding oyster or clam. The serum and liver triglyceride levels of all dietary groups were lowered markedly by feeding oyster or clam. The activities of glucose-6-phosphate dehydrogenase, malic enzyme and acetyl-CoA carboxylase were markedly reduced in the basal groups fed oyster or clam. These effects were observed in 5 and 10% shellfish feeding. These shellfish may be considered hypolipidemic foods.

Acetyl-CoA Carboxylase↗