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PubMed1999

Seafood-associated disease outbreaks in New York, 1980-1994.

BACKGROUND: Seafood-associated disease outbreaks in New York were examined to describe their epidemiology and to identify areas for prevention and control efforts. METHODS: We reviewed reports submitted to the New York State Department of Health (NYSDOH) of seafood-associated outbreaks occurring from January 1, 1980, through December 31, 1994. RESULTS: During 1980-1994, 339 seafood-associated outbreaks were reported, resulting in 3959 illnesses, 76 hospitalizations, and 4 deaths. During this period, seafood-associated outbreaks accounted for 19% of all reported foodborne outbreaks and 10% of foodborne illnesses. Shellfish, the most frequently implicated seafood item, accounted for 64% of seafood outbreaks, followed by finfish (31% of outbreaks). Of the 148 seafood-associated outbreaks with a confirmed etiologic agent, Norwalk virus and scombrotoxin were the most frequently identified agents: Norwalk virus accounted for 42% of outbreaks and 42% of illnesses, and scombrotoxin accounted for 44% of outbreaks and 19% of illnesses. Three of the 4 seafood-associated deaths were caused by Clostridium botulinum; the remaining death was caused by Vibrio vulnificus. CONCLUSIONS: Reducing the number of seafood outbreaks will require continued and coordinated efforts by many different agencies, including those involved with water quality; disease surveillance; consumer education; and seafood harvesting, processing, and marketing. New York's foodborne disease surveillance data highlight potential areas on which to focus prevention efforts, including: (1) commodities and associated pathogens causing the largest number of seafood-associated outbreaks and illnesses, namely shellfish-associated viral gastroenteritis and finfish-associated scombroid fish poisoning, and (2) venues at which seafood were most frequently consumed in reported outbreaks, such as commercial food establishments and catered events.

Disease Outbreaks↗

PubMed2002

Flow system for fish freshness determination based on double multi-enzyme reactor electrodes.

A double reactor system for the determination of fish and shellfish freshness using the freshness indicator, K-value (K=[(HxR+Hx)/(ATP+ADP+AMP+IMP+HxR+Hx)]x100), was developed, where ATP, ADP, AMP, IMP, HxR and Hx are adenosine triphosphate, adenosine diphosphate, adenosine monophosphate, inosine monophosphate, inosine and hypoxanthine, respectively. The system consisted of a pair of enzyme reactors with an oxygen electrode positioned close to the respective reactor. The enzyme reactor (I) was packed with nucleoside phosphorylase and xanthine oxidase immobilized simultaneously on chitosan beads (immobilized enzyme A). Similarly, the enzyme reactor (II) was packed with immobilized enzyme A and immobilized enzyme B (co-immobilized alkaline phosphatase and adenosine deaminase). Moreover, this reactor consisted of two layers, the enzyme A and enzyme B (1:1). A good correlation was obtained between K values, which were determination by the proposed system and by the HPLC method. One assay could be completed within 5 min. The signal for the determination of K value of fish and shellfish was reproducible within 2.3%. The long-term stability of the enzyme reactors was evaluated at 30 degrees C for 28 days.

Adenosine Deaminase↗

PubMed2003

Immunostimulation in crustaceans: does it really protect against infection?

There is a growing need to control, prevent or minimise the devastating effects of disease in crustacean culture without recourse to toxic chemicals or antibiotics. In keeping with approaches to disease control in fish and higher mammals, interest is developing in compounds that confer protection and/or enhance immune reactivity to likely pathogens in shellfish (sometimes, erroneously, referred to as as "shellfish vaccines"). The agents currently under scrutiny for crustaceans include glucans, lipopolysaccharides and killed bacterial cells. They are thought to act as "immuno-stimulants" because of their known effects on the crustacean immune system in vitro. A number of papers are now appearing in the literature claiming to demonstrate their positive impact on immunity and immunity and disease resistance. This review article considers the problem of disease and its control in crustacean farming, describing the types of capability in cultured species. Analysis of the validity of the results of many of the published studies raises questions about the value of these compounds for cost-effective control of infection in aquaculture, especially for long lasting protection in both adults and juveniles. This review further discusses the potential risks to the wellbeing of the stock animals from repeated use of these agents and makes the case for rigorous testing of putative stimulants, at the gene, protein and functional levels, as well as for the need to consider alternative strategies and approaches to disease control.

Adjuvants, Immunologic↗

PubMed1982

Studies on the growth of Vibrio cholerae biotype eltor and biotype classical in foods.

The growth of Vibrio cholerae biotype eltor and biotype classical was studied in a range of cooked foods, shellfish and raw vegetables, incubated at 22 degrees, 30 degrees and 37 degrees C. Both biotypes grew in all cooked foods but growth was not demonstrated on raw shellfish. The organism multiplied on some vegetables to levels of the order of 10(6)/g. The classical biotypes of V. cholerae showed a longer lag period than the eltor biotype in some foods particularly when incubated at 22 degrees C. The eltor biotypes reached a higher level in the stationary phase than the classical biotypes.

Asia↗

PubMed2005

Listeria spp. in the coastal environment of the Aqaba Gulf, Suez Gulf and the Red Sea.

Listeria monocytogenes is an important pathogen which causes an infection called listeriosis. Because of the high mortality rate (~30%) associated with listeriosis, and the widespread nature of the organism, it is a major concern for food and water microbiologists since it has been isolated from various types of foods, including seafood, as well as from the aqueous environment. To investigate the prevalence of this pathogen in the Aqaba Gulf (12 sites), Suez Gulf (14 sites) and Red Sea (14 sites), 200 water samples (collected during five sampling cruises in 2004), 40 fresh fish samples and 15 shellfish samples were analysed using the enrichment procedure and selective agar medium. All water samples were also examined for the presence Listeria innocua which was the most common of the Listeria spp. isolated, followed by L. monocytogenes, with a low incidence of the other species. During the whole year, the percentage of Listeria spp. and L. monocytogenes in 200 water samples was 20.5% (41 samples) and 13% (26 samples) respectively. In fresh fish (40 samples) it was 37% (15 samples) and 17.3% (7 samples) and in shellfish (15 samples) 53% (8 samples) and 33% (5 samples) respectively. In water samples, there was an association between the faecal contamination parameters and the presence of the pathogen; however, water salinity, temperature, dissolved oxygen and pH did not influence the occurrence of this bacterium. These results may help in the water-quality evaluation of the coastal environments of these regions.

Animals↗

PubMedDate not supplied

Preparation and characterization of domoic acid-protein conjugates using small amount of toxin in a reversed micellar medium: application in a competitive enzyme-linked immunosorbent assay.

With the aim of producing novel antibodies to domoic acid (DA), an original, rapid, and simple procedure for preparing minute amount of hapten-protein conjugates was developed. The amide-bond-generating mixed anhydride method of Erlanger was performed using 0.32-0.64 micromol of DA in a reversed micellar medium allowing strong carrier haptenization as determined by spectrophotometric measurement. Bovine serum albumin (BSA) and ovalbumin (OVA) conjugates were, respectively, used for immunization of BALB/c mice and antibody screening by enzyme-linked immunosorbent assay (ELISA). Specific polyclonal antibodies were produced upon multiple injections of (DA)(17)-BSA conjugate administered by three different routes: (i) intraperitoneal (i.p.), (ii) intraperitoneal + subcutaneous (i.p. + s.c.), (iii) footpad (f.p.). The i.p. route induced antisera of higher titer (1:350000) than did the other protocols (approximately 1:72900) and was selected throughout further experiments. Using a competitive ELISA format with a peroxidase immunoconjugate and a chromogenic substrate, no significant cross-reactivity was observed with glutamic acid, aspartic acid and kainic acid (KA), a structural analogue of DA. The sensitivity of this assay could be enhanced by 1 order of magnitude by using a beta-galactosidase immunoconjugate with a fluorogenic substrate while preserving DA specificity. The calculated dissociation constant (K(D)) for the interaction of the antibodies with free DA was 5 x 10(-)(7) M (chromogenic assay) and 5 x 10(-)(8) M (fluorogenic assay). Using the optimized assay the limit of detection (LOD) and the limit of quantitation (LOQ) in the ELISA buffer were 1.4 and 3 ng/mL, respectively. Moreover this assay was found applicable for measuring DA levels in spiked mussel extracts pre-cleaned through a solid-phase extraction column, as a very good correlation (r(2) = 0.96) was observed between the actual amounts of DA added and amounts detected by ELISA. Thus, accurate determinations of DA in clean extracts could be achieved between 2 and 180 ng/mL in spiked samples which corresponds to 0.02-1.8 microg/g of original mussel tissue. Owing to the regulation limits of 20 microg DA/g of shellfish tissue, these extraction and assay procedures should provide a useful complement to the standard HPLC analytical technique currently employed in monitoring DA in shellfish tissue.

Animals↗

PubMed2003

Polychlorinated naphthalenes in foods: estimated dietary intake by the population of Catalonia, Spain.

Concentrations of polychlorinated naphthalenes (PCNs) were measured in foodstuffs randomly acquired in seven cities of Catalonia, Spain. A total of 108 samples, belonging to 11 food groups (vegetables, tubers, fruits, cereals, pulses, fish and shellfish, meat and meat products, eggs, milk, dairy products, and oils and fats), were analyzed by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). The levels of tetra-, penta-, hexa-, and hepta-CNs, those of octachloronaphthalene, and the mean sum concentration of tetra-octa-CN were determined. The highest concentration of total PCNs was found in oils and fats (447 pg/g), followed by cereals (71 pg/g), fish and shellfish (39 pg/g), and dairy products (36 pg/g). In general, tetra-CN was the predominant homologue in all food groups except for fruits and pulses, which had greater proportions of hexa-CNs. The dietary intake of total PCNs was subsequently determined. For calculations, recent data on consumption of the selected food items were used. Intake of PCNs was estimated for five population groups of Catalonia: children, adolescents, male and female adults, and seniors. When the dietary intake of total PCNs was expressed in nanogram per kilogram of body weight per day, it was age-dependent, with the highest and lowest values corresponding to children (1.65) and seniors (0.54), respectively. The largest contribution to the daily PCNs intake came from oils and fats and from cereals. The result of the current study is the first published report concerning human exposure to PCNs through the diet.

Adolescent↗

PubMed2001

Isolation and structural determination of DTX-6, a new okadaic acid derivative.

Diarrhetic shellfish poisoning is an illness caused by toxins accumulated in shellfish and produced by dinoflagellates, mainly of the Dinophysis and Prorocentrum genera. This paper reports the isolation and spectroscopic structural elucidation of a new compound, DTX-6 (2), an ester derivative of okadaic acid (OA) (1), isolated from an artificial culture of strain PLV2 of Prorocentrum lima.

Animals↗

PubMed2001

Enteric virus contamination of foods through industrial practices: a primer on intervention strategies.

Hepatitis A and E viruses, rotaviruses, Norwalk-like caliciviruses, and astroviruses are among the enteric viruses known to cause food- and waterborne illness. These viruses are spread by the fecal-oral route and are a major cause of morbidity and mortality worldwide. Foods may be contaminated at any time pre- or post-harvest; however, many outbreaks are associated with foods handled by infected restaurant workers. Produce may be contaminated by improper irrigation or fertilization practices, by the hands of infected pickers or processors, or as the result of adulteration during any stage of handling. Outbreaks have been commonly associated with foods which are served raw or only lightly cooked, such as molluscan shellfish, fruits and vegetables, and salads or products contaminated after cooking like frosted bakery products. The farming, shellfish, processing, transportation, and restaurant industries must maintain vigilance to reduce outbreaks of enteric virus illness. Intervention strategies to enhance product safety include increased industry and consumer education; changes in industrial practices, product management, and processing technologies; worker immunizations; and the development of improved monitoring tools for the detection of enteric viruses in foods.

Caliciviridae Infections↗

PubMed1996

High-performance liquid chromatographic methods for determination of marine biotoxins.

Paralysing and diarrhetic shellfish poisonings (PSP and DSP) are important intoxications caused by the consumption of shellfish, mainly bivalve molluscs, contaminated by certain species of toxic dinoflagellates present in the marine phytoplankton. Their appearance and massive reproduction take place in some periods of the year, causing the phenomenon commonly known as 'red tide'. This causes significant problems to health and to the economy of the Galician region. The AOAC mouse bioassay is the most commonly used method of analysis for these toxic compounds, being the official method in most countries. Owing to the lack of sensitivity and selectivity of the biological assay, HPLC methods were developed as an alternative methodology. In this paper work carried out on the improvement of the chromatographic conditions in order to achieve accurate information about the PSP and DSP compounds present in the studied samples is reported.

Animals↗

PubMed2001

cDNA cloning and molecular identification of the major oyster allergen from the Pacific oyster Crassostrea gigas.

BACKGROUND: Shellfish is one of the most common food allergens. Despite the recent cloning and molecular identification of the major heat stable crustacean allergens in shrimp, lobster and crab, there have been no similar studies on molluscs to which a significant portion of populations allergic to shellfish are also hypersensitive. Recent biochemical evidence suggests that tropomyosin is also an allergen in molluscs, but data on the molecular cloning, nucleotide sequencing, expression and IgE binding to mollusc tropomyosin are lacking. OBJECTIVE: This study was undertaken to clone, identify and determine the primary structure of a major IgE-reactive mollusc allergen in oyster at the DNA and protein level. METHODS: We constructed an expression cDNA library from the Pacific oyster Crassostrea gigas. This library was screened for IgE binding clones using sera from 15 subjects with a well-documented history of type I hypersensitivity reactions to oysters. An IgE reactive clone was selected and sub-cloned into plasmids for nucleotide sequence determination and expression in E. coli. RESULTS: We identified a 1.3-kb cDNA designated as Cra g 1.03. Expression of Cra g 1.03 in plasmid vector pGEX produced a 59-kDa recombinant fusion protein reactive to the IgE antibodies from patients with oyster allergies but not non-allergic controls. Cra g 1.03 has an open reading frame of 233 amino acids and demonstrates marked similarity in amino acid composition and peptide sequence with mollusc and crustacean tropomyosins. Absorption of oyster allergic sera with Cra g 1.03 totally removed IgE reactivity to oyster extract. Moreover, absorption of allergic sera with recombinant shrimp tropomyosin (Met e 1), lobster tropomyosin (Pan s 1) and crab tropomyosin (Cha f 1) removed most of the IgE reactivity to Cra g 1.03. CONCLUSION: Cra g 1.03 is the first oyster allergen identified at the molecular level. Nucleotide and amino acid comparison shows that this protein is the oyster tropomyosin.

Allergens↗

PubMed2000

Influence of environmental factors on virus detection by RT-PCR and cell culture.

The effects of clay, humic acid, u.v. light and shellfish tissue residues on the detection of poliovirus type 2 from environmental samples by culture and RT-PCR were investigated. RT-PCR showed 10-100 times greater sensitivity for PV2 detection in the absence of sample contaminants than did culture by plaque assay in BGM cell monolayers. Bentonite clay (100-1000 mg l-1) and shellfish tissue residues reduced virus detection by plaque assay, but the effect of bentonite was mitigated by simple elution procedures. Bentonite clay, humic acid (5-150 mg l-1) and mussel tissue reduced virus detection by RT-PCR by between 1 and 8 logs, although this was mitigated in part by elution and Sephadex filtration of extracts. Sephadex filtration of samples reduced culturable PV2 by 32-50%. Exposure of PV2 in water to u.v. light reduced culturability of PV2 but not detection by RT-PCR. This study demonstrates that virus detection in environmental samples is strongly influenced by naturally occurring substances and disinfection approaches. The accuracy of results of viral analyses of this nature should be carefully scrutinized with respect to sample constituents.

Animals↗

PubMed2003

Application of polymerase chain reaction for detection of Vibrio parahaemolyticus associated with tropical seafoods and coastal environment.

AIMS: To study the incidence of Vibrio parahaemolyticus in seafoods, water and sediment by molecular techniques vs conventional microbiological methods. METHODS AND RESULTS: Of 86 samples analysed, 28 recorded positive for V. parahaemolyticus by conventional microbiological method, while 53 were positive by the toxR-targeted PCR, performed directly on enrichment broth lysates. While one sample of molluscan shellfish was positive for tdh gene, trh gene was detected in three enrichment broths of molluscan shellfish. CONCLUSIONS: Direct application of PCR to enrichment broths will be useful for the rapid and sensitive detection of potentially pathogenic strains of V. parahemolyticus in seafoods. SIGNIFICANCE AND IMPACT OF THE STUDY: Vibrio parahaemolyticus is an important human pathogen responsible for food-borne gastroenteritis world-wide. As, both pathogenic and non-pathogenic strains of V. parahaemolyticus exist in the seafood, application of PCR specific for the virulence genes (tdh & trh) will help in detection of pathogenic strains of V. parahaemolyticus and consequently reduce the risk of food-borne illness.

Animals↗

PubMedDate not supplied

[Survival of the fattest: the key to human brain evolution].

The circumstances of human brain evolution are of central importance to accounting for human origins, yet are still poorly understood. Human evolution is usually portrayed as having occurred in a hot, dry climate in East Africa where the earliest human ancestors became bipedal and evolved tool-making skills and language while struggling to survive in a wooded or savannah environment. At least three points need to be recognised when constructing concepts of human brain evolution : (1) The human brain cannot develop normally without a reliable supply of several nutrients, notably docosahexaenoic acid, iodine and iron. (2) At term, the human fetus has about 13 % of body weight as fat, a key form of energy insurance supporting brain development that is not found in other primates. (3) The genome of humans and chimpanzees is <1 % different, so if they both evolved in essentially the same habitat, how did the human brain become so much larger, and how was its present-day nutritional vulnerability circumvented during 5-6 million years of hominid evolution ? The abundant presence of fish bones and shellfish remains in many African hominid fossil sites dating to 2 million years ago implies human ancestors commonly inhabited the shores, but this point is usually overlooked in conceptualizing how the human brain evolved. Shellfish, fish and shore-based animals and plants are the richest dietary sources of the key nutrients needed by the brain. Whether on the shores of lakes, marshes, rivers or the sea, the consumption of most shore-based foods requires no specialized skills or tools. The presence of key brain nutrients and a rich energy supply in shore-based foods would have provided the essential metabolic and nutritional support needed to gradually expand the hominid brain. Abundant availability of these foods also provided the time needed to develop and refine proto-human attributes that subsequently formed the basis of language, culture, tool making and hunting. The presence of body fat in human babies appears to be the product of a long period of sedentary, shore-based existence by the line of hominids destined to become humans, and became the unique solution to insuring a back-up fuel supply for the expanding hominid brain. Hence, survival of the fattest (babies) was the key to human brain evolution.

Animals↗

PubMed2000

The marine toxin domoic acid may affect the developing brain by activation of neonatal brain microglia and subsequent neurotoxic mediator generation.

Amnesic shellfish poisoning, one of the shellfish poisoning syndromes, is caused by the marine diatom toxin domoic acid (DOM). While in adult rats, mice, monkeys and humans DOM poorly penetrates the blood-brain barrier, DOM has been shown to be very toxic to fetal in newborn mice, because the blood-brain barrier is incomplete during neurodevelopment. This fact may explain why neonates show a higher sensitivity to neurotoxins like DOM as compared to adult animals. Mechanistic studies on DOM's neurotoxicity have mainly concentrated on the investigation of DOM's effect on neuronal tissue. Recent studies have shown that glia is also involved in DOM's neurotoxicity to the adult as well as the developing nervous system. The scientific literature strongly supports the hypothesis that the microglia may play a critical role in mediating DOM's neurotoxic effects. However, the effect of DOM on microglia has not been systematically investigated. The literature supporting our hypothesis is presented and discussed.

Animals↗

PubMed1975

Lack of secondary intoxification by red tide poison in the American lobster Homarus americanus.

Lobsters are able to feed on shellfish which are toxic with PSP (paralytic shellfish poisoning from Gonyaulax tamarensis) with no apparent harm to themselves, and no measurable assimilation of the poison into their tissues. Lobsters consumed food containing in excess of 1000 mug PSP. There was no impairment of respiration (oxygen consumption) measurable two to three hours after feeding, and no PSP measured in the meat of the claws and tail 48 to 120 hours after feeding. The only PSP was in the guts and contents which were measured 48 hours after feeding began.

Aging↗

PubMed2001

Exposure assessment of dioxins/furans consumed in dairy foods and fish.

Dioxins/furans are ubiquitous environmental contaminants whose primary route of human exposure occurs via the consumption of fatty foods of animal origin. The US FDA conducted a market basket survey of dairy products and commercial fish and shellfish to obtain data on levels of 17 dioxin/furan congeners (2, 3, 7, 8-congeners) in the US. The dairy products sampled included various cheeses (American, cheddar, Swiss, cottage), ice cream, yogurt, butter, and milk. The finfish and shellfish (molluscs and crustacea) sampled are those marine species consumed in the greatest amounts and include canned tuna, shrimp, cod, blue crab, and oysters. Catfish was sampled because it is the dominant aquaculture species. Samples were collected in 1995/96 and analysis for 17 dioxin/furan congeners was performed by high-resolution gas chromatography following extraction and clean-up. Limits of detection (LOD) and quantitation (LOQ) for each congener in each food were reported. Point estimates of exposure were calculated using a 3-day (1-day diary plus 2-day recall) food consumption survey for eaters-only and for the general population (USDA/CSFII, 1989-92). Toxicity equivalency factors (TEFs) developed by the World Health Organization (1997) were used to derive overall dioxin/furan toxicity equivalents (TEQ) for each sample food. Mean estimates of TEQ exposure for each food were derived using five values for non-detects (ND = 0; ND = 1/2 LOD or LOQ, ND = LOD or LOQ) on both a total sample and eaters-only basis. Using zero and the LOD provide lower and upper bounds on the range of estimated exposure, respectively. The bounds on mean dioxin intakes (pg/person/day) calculated for consumers of specific foods were estimated as follows (using zero or LOD for non-detects): butter (0.5-11), cheese (1.6-3.2), ice cream (4-19), yogurt (0.8-28), catfish (148-150), fish (other than catfish) (0.03-9), crustacea (32-35), mollusks (16.1-16.6), and shrimp (0.09-4.5). Exposure estimates derived by the five ND-methods are strongly dependent on the LOD and LOQ and represent upper bound estimates of exposure. Uncertainty in the exposure estimates is reduced with refinements in the analytical method.

Adolescent↗

PubMed2003

Food safety implications of the distribution of azaspiracids in the tissue compartments of scallops (Pecten maximus).

Azaspiracids, a new class of shellfish toxins, have been implicated in several recent incidents of human intoxications following the consumption of mussels (Mytilus edulis). A study was undertaken to examine the distribution of azaspiracid poisoning (AZP) toxins in scallops (Pecten maximus) and individual shellfish were dissected into five tissue fractions for the determination of toxin composition. Separation of the predominant azaspiracids, AZA1-3, was achieved using reversed-phase liquid chromatography with detection by positive electrospray multiple tandem mass spectrometry. The AZP toxin composition was determined in the adductor muscle (meat), gonad (roe), hepatopancreas (digestive glands), mantle and gill of scallops. Substantial differences in the AZP toxin levels between tissue compartments were observed and toxins were concentrated predominantly, about 85%, in the hepatopancreas. There was also a significant variation in the total toxin levels between individual scallops from the same sample batch and the RSD was 60% (n = 9). Interestingly, although all three AZP toxins were present in phytoplankton and mussels, AZA3 was not detected in the scallop samples examined. It was concluded that to improve food safety, only the adductor muscle and gonad of scallops should be permitted for sale to the public.

Animals↗