Shellfish For Human Consumption Research Articles

Sustainability of shellfish aquaculture in Montenegro-perspectives

Shellfish for human consumption is produced in excess of 15 million tons per year, accounting for roughly 14% of global marine aquaculture, with China being the largest producer (89% of world production). However, in the previous two decades, shellfish output in the European Union has been dropping. This review provides information about shellfish aquaculture in Montenegro, in Boka Kotorska Bay, where most farms belong to the group of small farms. Shellfish production in this bay is constantly increasing. Thus, with minor deviations, the production of shellfish increased from 156 tonnes, as was produced in 2012, to 246 tonnes produced in 2020. However, despite the constant growth of production, statistical data indicate that every year a large amount of shellfish is imported, and there is a need for greater production in the country. The shellfish production capacity in Montenegro is still lower than expected, despite the great potential for development. Aquaculture?s development potential is in the areas of increasing production, modernising existing farms, automating production, strengthening the competitiveness and efficiency of the sector, introducing new species, better linking aquaculture with tourism and processing, marine spatial planning, promoting aquaculture products and branding products.

Occurrence of human e nterovirus in tropical fish and shellfish and their relationship with fecal indicator bacteria.

Aim:Human enteroviruses in fish and shellfish are a health concern worldwide. Human infections occur due to the consumption of raw or insufficiently cooked fish or shellfish. The objective of this study was to determine the occurrence of human enteric viruses belonging to Enterovirus (EV) group in seafood in Mumbai and to correlate their occurrence with the bacterial indicators of fecal contamination.Materials and Methods:Samples of fresh fish and shellfish collected from fish landing centers and retail fish markets were analyzed by virus concentration, nucleic acid extraction, and reverse transcription-polymerase chain reaction (RT-PCR). Bacterial indicators of fecal contamination were estimated by the most probable number technique. The relationship between the presence of virus and fecal indicators was determined by statistical analysis.Results:A total of 89 samples comprising of fish, shrimps, oysters, clams, and mussels were screened in this study. EV was detected in 32 (35.95%) samples, and all the virus-positive samples belonged to bivalve molluscan group. None of the finfish and crustacean shellfish samples was positive for the enteric viruses. Clams were found to be the most contaminated with 48.4% of the samples being positive for EV. The prevalence of enteric viruses in seafood samples showed a strong positive correlation with the bacteriological indicators of fecal contamination, suggesting that fecal coliform bacteria are good indicators of EVs in tropical seafood.Conclusion:The presence of EVs in seafood is a public health hazard. Increasing level of coastal water contamination from anthropogenic sources is the primary reason for the contamination of seafood with EVs. Continuous monitoring of coastal waters and seafood for enteric viruses will help to ensure the safety of fish and shellfish for human consumption.

Distribution of Diarrhetic Shellfish Toxins in Mussels, Scallops, and Ascidian.

Diarrhetic shellfish toxins (DST) are a group of phycotoxins that include Okadaic acid (OA) and structurally related toxins. In Japan, the regulatory limit of DST in shellfish for human consumption is a total OA equivalent of 0.16 mg per kg of edible tissue. Distribution and individual differences of DST in scallops collected in Aomori Prefecture were investigated. Fourteen to 20 individual scallops were divided into hepatopancreas, gonads, mantles, gills, adductor muscles, and the concentrations of diarrhetic shellfish poisoning (DSP) in each tissue were quantified by LC/MS/MS after hydrolysis. The dominant toxin in the scallops was Dinophysis toxin 1 (DTX1). More than 97% of the observed DTX1 in the scallop tissue was detected in the hepatopancreas and the average level of DTX1 was higher in mussels than the scallops. The number of individual scallops or mussels required to correctly reflect the DTX1 content of a sample group was estimated by resampling. In scallops, using 10 individuals fell within ± 20% of 30 individual's average with a probability of 99.8%. On the other hand, in the blue mussel, an average of 19 individuals fell within ± 20% of 30 individual's average with 98% probability. In addition, the analysis of the DST in ascidians collected from Miyagi Prefecture was carried out. The muscles, gills, hepatopancreas and intestines were analyzed. High concentration of both DTX1 and OA were detected in the hepatopancreas after hydrolysis. Low levels of DST were detected from other tissues, indicating that DST are primarily accumulated in the hepatopancreas in the ascidians.

Risk Assessment of Shellfish Toxins

Complex secondary metabolites, some of which are highly toxic to mammals, are produced by many marine organisms. Some of these organisms are important food sources for marine animals and, when ingested, the toxins that they produce may be absorbed and stored in the tissues of the predators, which then become toxic to animals higher up the food chain. This is a particular problem with shellfish, and many cases of poisoning are reported in shellfish consumers each year. At present, there is no practicable means of preventing uptake of the toxins by shellfish or of removing them after harvesting. Assessment of the risk posed by such toxins is therefore required in order to determine levels that are unlikely to cause adverse effects in humans and to permit the establishment of regulatory limits in shellfish for human consumption. In the present review, the basic principles of risk assessment are described, and the progress made toward robust risk assessment of seafood toxins is discussed. While good progress has been made, it is clear that further toxicological studies are required before this goal is fully achieved.

The development of a rapid method for the isolation of four azaspiracids for use as reference materials for quantitative LC–MS–MS methods

The azaspiracids are a family of lipophilic polyether marine biotoxins that have caused a number of human intoxication incidents in Europe since 1995 after consumption of contaminated shellfish (Mytilus edulis). Levels of azaspiracids in shellfish for human consumption are monitored in accordance with EU guidelines: only shellfish with less than 160 microg kg(-1) are deemed safe. The limited availability of commercially available standards for azaspiracids is a serious problem, because validated LC-MS methods are required for routine analysis of these toxins in shellfish tissues. The procedure described herein has been used for the separation and the isolation of four azaspiracid (AZA) toxins from shellfish, for use as LC-MS-MS reference materials. Five separation steps have been used to isolate azaspiracids 1, 2, 3, and 6. The purity of the toxins obtained has been confirmed by multiple mass spectrometric methods using authentic azaspiracid standards. The same techniques have been used for quantification of the toxins extracted. The isolation procedure involves several chromatographic purification techniques: solid-phase extraction (diol sorbent, 90% mass reduction, and 95 +/- 1% toxin recovery); Sephadex size-exclusion chromatography (87% mass reduction and up to 95 +/- 2% toxin recovery), Toyopearl HW size-exclusion chromatography (90% mass reduction and up to 92.5 +/- 2.5% toxin recovery), and semi-preparative LC (78 +/- 3% toxin recovery). The procedure effectively separates the toxins from the sample matrix and furnishes azaspiracid toxins (AZA1, AZA2, AZA3 and AZA6) of sufficient purity with an average yield of 65% (n = 5). Triple-quadrupole mass spectrometry was used for qualitative and quantitative monitoring of the isolation efficiency after each stage of the process. High-resolution mass spectrometric evaluation of the toxic isolated material in both positive and negative modes suggests high purity.

Marine Biotechnology: Realizing the Potential

Marine biotechnology is an applied science, the goal of which is to develop goods and services from marine organisms and processes. The new wave of marine biotechnology research began in the early 1980s and includes some significant success stories. A new drug to manage pain is commercially available, and a new cancer drug has been recommended for approval, the first from a fish-eating snail and the second from a mangrove tunicate. Enzymes from hydrothermal vent microbes are routinely used in PCR reactions, and marine-derived molecular probes are helping understand the molecular basis of disease processes. Advances in aquaculture biotechnology have resulted in more efficient production of finfish and shellfish for human consumption, and polyunsaturated fatty acids from marine microalgae are used as nutritional supplements for adults and infants. Rapid diagnostic tools have been developed to monitor toxins in the environment and in seafood, and genetic fingerprinting techniques are helping to control illegal trade of threatened marine species. In the future, multidisciplinary programs in oceans and human health should focus not only on microbial pathogens and harmful algal bloom toxins but also on discovery of new chemicals to prevent or treat human diseases. And the development of biological and biochemical sensors to detect pathogens, contaminants, and toxins and to monitor human and environmental health indicators in the marine environment should be a very high priority in the establishment of U.S. coastal ocean observing systems.

Levels and distribution of organochlorine pesticides in shellfish from Qiantang River, China

Various shellfish collected from different locations along the Qiantang River in 2006 were analyzed for the levels of 13 organochlorine pesticides (OCPs) in order to elucidate the status of OCPs pollution in shellfish for human consumption. Total concentrations of OCPs in shellfish ranged from 16.9 to 78.6 ng/g wet weight (ww), with HCHs (α-, β-, γ-, δ-HCH), DDTs ( p, p′-DDD, p, p′-DDE, p, p′-DDT, o, p′-DDD) and other OCPs (aldrin, diedrin, endrin, heptachlor and heptachlor epoxide) in the range of 3.33–13.2, 8.38–40.1 and 2.32–14.3 ng/g ww, respectively. The dominant OCPs in shellfish were p, p′-DDE among DDTs, β-HCH among HCHs and heptachlor epoxide among other OCPs. It is noticeable that higher OCPs biota-sediment accumulation factor (BSAF) occurred at site with high concentration of OCPs in sediments. The field bioconcentration factor (BCF) increased exponentially with the increase of K ow (octanol–water partition coefficients) of the OCPs. Concentrations of DDTs and HCHs in shellfish from Qiantang River kept at middle level compared with those from marine environment. The concentrations of DDTs in more than 50% of edible shellfish in this study were higher than the limit of 14.4 ng/g ww for human consumption recommended by US EPA (2000).

Heavy metals and arsenic in sediments, mussels and marine water from Murano (Venice, Italy)

This paper describes a study of the trace element distribution in sediments, marine water and mussel Mytilus galloprovincialis of the Venetian Lagoon around the Island of Murano, an island with a long tradition of glassmaking. Trace elements analysed include Fe, Mn, Zn, Cu, Cr, Pb, Ni, Ag and As. Sediments are contaminated with Zn, Cu, Ag, As and Pb, with levels in the <2 m fraction that are likely to cause adverse biological effects to marine organisms. The pelite (<63 μm) is the main carrier of heavy metals at most sites. However, the fine-grained and coarse sand on the southern coast of Murano accounts for a significant proportion of Fe, Mn, Zn, Cr, Ag, Ni and Pb. Most trace element concentrations found in soft tissue of mussels appear to be within recommended Italian and international guidelines for shellfish for human consumption, the only exception being relatively high As levels. The bioaccumulation of Ag and Cr is more pronounced in the shell of these organisms. In the marine water of the lagoon, trace elements are more enriched than in other areas of the Mediterranean, with particular reference to the dissolved labile species of Zn, Mn, As, Cu, Ni and Cr.

Recovery of the Marine Environment Following the Braer Spill, Shetland

ABSTRACT In January, 1993 on the southwest tip of Shetland the oil tanker Braer was wrecked, spilling 84,000 tonnes of crude oil and 1,500 tonnes of bunker oil into the sea. Heavy weather conditions dispersed almost all the oil into the surrounding water, producing oil-in-water concentrations near the wreck as high as 20,000 times background. Concentrations fell rapidly with time, regaining background values in 30–40 days. As surface slick formation was minimal and most seabirds were offshore at the time of the spill, seabird mortality was relatively light and seal and otter mortality was in single figures. Catching and marketing fish and shellfish for human consumption from the oil-contaminated area was prevented by the establishment of a Fishery Exclusion Zone. Oil concentrations in fish from this zone fell to background levels within 2 months of the spill. Shellfish were more severely affected, the most heavily contaminated regaining background levels within a year except for the sediment-dwelling Norway lobster, which still is contaminated. The impact on the intertidal habitat was minimal and most shores recovered within a year. Offshore benthic communities in contaminated sediments did not show evidence of being significantly stressed.

The effect of sewage on trace metal concentrations and scope for growth in Mytilus edulis aoteanus and Perna canaliculus from Wellington Harbour, New Zealand

Trace metal data are reported for Mytilus edulis aoteanus and Perna canaliculus, sampled monthly for 16 months from sites at varying distances away from a major municipal sewage outfall at the entrance to Wellington Harbour, New Zealand. The data indicate that the sewage outfall is the most likely input source of Ag, Cu, Pb, and Zn in this region, and that marine communities up to 3 km east and up to 750 m northwest of the outfall are periodically exposed to the effluent. However, only mussels within 750 m of the discharge point have elevated levels of potentially toxic metals and only M. edulis aoteanusfrom within 100 m of the outfall had higher concentrations of Pb and Zn than are permitted in shellfish for human consumption under N.Z. regulations. Scope for growth of both species, determined during a 3-month period, showed that the effluent adversely affected the physiological condition of these species at sites within 750 m of the discharge. Data for P. canaliculus from an uncontaminated area of Wellington Harbour transplanted into the effluent at increasing distances from the outfall and analysed for trace metals and scope for growth after 1, 2 and 3 months exposure, also indicated that trace metal levels and scope for growth in these mussels were affected by proximity to the outfall.