DNA‐Based Methods for the Identification of Commercial Fish and Seafood Species

ABSTRACT: The detection of species substitution has become an important topic within the food industry and there is a growing need for rapid, reliable, and reproducible tests to verify species in commercial fish and seafood products. Increases in international trade and global seafood consumption, along with fluctuations in the supply and demand of different fish and seafood species, have resulted in intentional product mislabeling. The effects of species substitution are far‐reaching and include economic fraud, health hazards, and illegal trade of protected species. To improve detection of commercial seafood fraud, a variety of DNA‐based techniques have been developed, including Multiplex PCR, FINS, PCR‐RFLP, PCR‐RAPD, PCR‐AFLP, and PCR‐SSCP, which are all based on polymorphisms in the genetic codes of different species. These techniques have been applied in the differentiation of many types of fish and seafood species, such as gadoids, salmonids, scombroids, and bivalves. Some emerging technologies in this field include the use of real‐time PCR, lab‐on‐a‐chip, and DNA microarray chips. In this review article, the major DNA‐based methods currently employed in the authentication of commercial fish and seafood species are discussed and future trends are highlighted. Examples of commercial applications and the use of online database resources are also considered.     

Risk‐Benefit Analysis of Seafood Consumption: A Review

Abstract: Seafood, defined here as marine and freshwater fish and shellfish, is recognized as a healthy food choice because it is a low‐fat protein source that provides long‐chain omega‐3 fatty acids important for early development along with eye and heart health. However, seafood is also known to contain certain contaminants, such as methylmercury and persistent organic pollutants, which can have harmful effects on human health and development. In order to limit exposure to contaminants while maximizing the benefits of seafood consumption, a number of quantitative and qualitative risk‐benefit analyses have been conducted for seafood consumption. This review paper provides a brief background on risk‐benefit analysis of foods, followed by a discussion of the risks and benefits associated with fish consumption. Next, risk‐benefit analyses are reviewed in an historical context. While risk‐benefit analysis consists of three main elements (that is, assessment, management, and communication), this review will primarily focus on risk‐benefit assessments. Overall, most studies have found that the benefits far outweigh the risks among the general population, especially when a variety of fish is consumed at least twice per week. However, for certain populations (for example, pregnant women and young children) a more targeted approach is warranted in order to ensure that these groups consume fish that are low in contaminants but high in omega‐3 fatty acids. The potentially harmful unintended consequences of risk‐benefit communication on the general population and certain groups are also discussed.     

Application of DNA‐Based Methods to Identify Fish and Seafood Substitution on the Commercial Market

ABSTRACT: Fish and seafood substitution has become an important concern in domestic and international marketplaces, in part due to increased international trade, per capita seafood consumption, and production of processed foods. In many cases, seafood substitution is a form of economic deception, where highly prized species are substituted with those of lesser value. To prevent illegal species substitution, a number of DNA‐based methods have been developed to detect fish and seafood species in commercial products. These methods, along with common gene targets, have been reviewed previously in this journal. The current article is meant to build upon earlier discussions by providing a comprehensive review of the application of these DNA‐based methods to the discovery of fish and seafood substitution on the commercial market. Popular food uses, potential substitution cases, and peer‐reviewed research articles published to date are discussed for all major species groups of concern, including flatfish, gadoids, scombroids, salmonids, percoids, sturgeons, sharks, eels, and bivalves. The use of DNA‐based methods to monitor commercial whale meat products is also reviewed.     

Intervention Strategies for Reducing Vibrio Parahaemolyticus in Seafood: A Review

Vibrio parahaeomolyticus, a natural inhabitant in estuarine marine water, has been frequently isolated from seafood. It has been recognized as the leading causative agent for seafoodborne illness all over the world. Numerous physical, chemical, and biological intervention methods for reducing V. parahaeomolyticus in seafood products have been investigated and practiced. Each intervention method has distinct advantages and disadvantages depending on the processing needs and consumer preference. This review provides a comprehensive overview of various intervention strategies for reducing V. parahaeomolyticus in seafood with an emphasis on the efficiency of bacterial inactivation treatments and the changes in sensory qualities of seafood. In the meantime, reported researches on alternative technologies which have shown effectiveness to inactivate V. parahaemolyticus in seawater and other food products, but not directly in seafood are also included. The successful applications of appropriate intervention strategies could effectively reduce or eliminate the contamination of V. parahaeomolyticus in seafood, and consequently contribute to the improvement of seafood safety and the reduction of public health risk.     

Phenolic Compounds and Plant Phenolic Extracts as Natural Antioxidants in Prevention of Lipid Oxidation in Seafood: A Detailed Review

Lipid oxidation is the principal cause of quality loss in seafood, which is known to contain high amounts of polyunsaturated fatty acids. Such quality deterioration, associated with the development of off‐flavor as well as lowering of nutritive value, can be retarded by incorporation of additives having antioxidative properties. The use of synthetic antioxidants has long been practiced in retarding lipid oxidation. However, due to the potential health concerns of synthetic antioxidants, polyphenolic compounds, which are found in different plants and their manufactured by‐products, have been used as an alternative natural antioxidants to retard lipid oxidation in different seafood systems. Both pure phenolic compounds and crude plant phenolic extracts have been successfully used in delaying oxidation in fish muscle, fish oil, and fish oil‐in‐water emulsions. This article reviews in detail the phenolic antioxidants and their natural sources as well as focuses on the role of pure phenolic compounds and crude plant phenolic extracts on the prevention of lipid oxidation in different seafood systems.     

Tocopherols in Seafood and Aquaculture Products

Fish products contain various nutritionally beneficial components, namely, ω3-polyunsaturated fatty acids (ω3-PUFA), minerals, and vitamins. Particularly, tocopherols (α-, β-, γ-, and δ-tocopherol) can be provided by seafood and aquaculture products. Hence, this review shows the various aspects of tocopherols in seafood and aquaculture products. For tocopherol determination in these products, HPLC methods coupled with diode array detection in the UV area of the spectrum or fluorescence detection have been shown as sensitive and accurate. These newest methods have helped in understanding tocopherols fate upon ingestion by seafood organisms. Tocopherols pass through the intestinal mucosa mainly by the same passive diffusion mechanism as fats. After absorption, the transport mechanism is thought to consist of two loops. The first loop is dietary, including chylomicrons and fatty acids bound to carrier protein, transporting lipids mainly to the liver. The other is the transport from the liver to tissues and storage sites. Moreover, tocopherol levels in fish organisms correlate with diet levels, being adjusted in fish body depending on diet concentration. For farmed fish species, insufficient levels of tocopherols in the diet can lead to poor growth performance or to nutritional disease. The tocopherol quantity needed as a feed supplement depends on various factors, such as the vitamer mixture, the lipid level and source, the method of diet preparation, and the feed storage conditions. Other ingredients in diet may be of great importance, it has been proposed that α-tocopherol may behave as a prooxidant synergist at higher concentrations when prooxidants such as transition metals are present. However, the antioxidant action of tocopherols outweighs this prooxidant effect, provided that adequate conditions are used. In fact, muscle-based foods containing higher levels of tocopherol show, for instance, higher lipid stability. Besides, tocopherols are important not only from the nutritional point of view but also from the physiological one, since they are involved in many metabolic processes in the human organism. Moreover, synergistic interactions with selenium and ascorbic acid have been reported. It deserves attention that there is evidence tocopherols taken with food can prevent heart disease, while no such evidence was found for α-tocopherol as supplement. From this perspective, eating fish is advisable, since, for instance, a 100 g serving of salmon may provide nearly 14% of recommended dietary allowance.     

Roles of Starch in Surimi Seafood: A Review

Surimi seafood is a cooked gel product that utilizes fish protein from surimi to produce seafood analog products. Starch is the second most important ingredient used in the manufacture of surimi seafood due to its water holding ability and capacity to partially replace fish proteins while maintaining desired gel characteristics at a reduced cost. Typically, starch is added to surimi seafood formulations at 4–12%. Functional properties of surimi seafood to control wetness, stickiness, and/or thermal stability upon different storage and serving temperatures have been extensively studied using modified starches. There is a great need to review the role of starches in various applications of surimi seafood.     

Microbial Inactivation and Electron Penetration in Surimi Seafood During Electron Beam Processing

Electron penetration and microbial inactivation by electron beam (e‐beam) in surimi seafood were investigated. Dose map revealed that 1‐ and 2‐sided e‐beam could efficiently penetrate 33‐ and 82‐mm thick surimi seafood, respectively. Modeling of microbial inactivation by e‐beam demonstrated that 2‐sided e‐beam may control Staphylococcus aureus if the surimi seafood package is thinner than 82 mm. The D_e‐beam value for S. aureus was 0.34 kGy. An e‐beam dose of 4 kGy resulted in a minimum of a 7‐log and most likely a 12‐log reduction of S. aureus. Microbial inactivation was slower when frozen samples were subjected to e‐beam.     

HACCP在禽肉、水产品加工中的应用

<正> HACCP作为一种新型的食品安全预防控制体系,已在全球范围内得到了广泛的应用,并被验证为至今为止最为有效的食品安全控制方法。纵观HACCP的发展历程,由于禽肉和水产品的风险较高在美国率先立法,强制在这些行业贯彻HACCP体系。 HACCP的新颖与先进之处在于它不是以往以检验为目的的传统型控制方法,而是以预防性为出发点,通过对食品链全过程危害的分析、识别和控制,达到最终有效控制食品安全的目的。     

Rapid Detection of Chemical Hazards (Toxins,Dioxins, and PCBs) in Seafood

Among the various hazards occurring in fish and seafood chemical hazards and in particular toxins (ciguatera, scombroid fish poisoning, paralytic shellfish poisoning, neurotoxic (brevetoxic) shellfish poisoning, puffer fish poisoning, diarrhetic shellfish poisoning) have an important place in food poisoning cases. On the other hand, some of the chemical hazards are often due to the pollution of the environment (heavy metals, dioxins, polychlorinated biphenyls, and halogenated aromatic hydrocarbons) and their detection is neither rapid nor facile. As a result there was a great need for developing new rapid and effective methods toward the chemical hazards determination mainly because of their high toxicity. The aim of this review is to provide the information about the new up-to-date detection techniques (Immunological, Chemical and Biochemical, and Molecular assays) in conjunction with detection limits. The latter is made possible by means of inclusion of seven comprehensive and, in most case cases, very extended tables. A reference is also made on the risk characterization of toxins as regards their importance to food contamination or poisoning.     

Occurrence of Listeria Monocytogenes in a Serbian Salmon and Seafood Processing Line During 2013

The objective of this study was to examine the occurrence of L. monocytogenes in a selected fish and seafood processing line. Results showed that during 2013, 12.4%, 8.3% and 2.3% of fish, seafood salads and environmental swabs were positive for L. monocytogenes. All positive food samples showed a contamination level below 100 CFU/g. Environmental swabs from surface of slicing and trimming tables, slicing machines, fish filleting and trimming knives, belt glazer and working table were positive for L. monocytogenes. Therefore, strict attention must be paid to cleaning and disinfection to control the level of L. monocytogenes.     

Methicillin‐Resistant Staphylococcus aureus in Raw Meats and Prepared Foods in Public Hospitals in Salvador,Bahia, Brazil

This study investigated the presence of methicillin‐resistant Staphylococcus aureus (MRSA) in raw meat and fish and foods prepared from them for patient consumption in public hospitals in Salvador, Bahia, in northeastern Brazil. A total of 114 samples of raw meat and fish (chicken, n = 30; beef, n = 30; pork, n = 24; and fish, n = 30) and 63 samples of prepared foods (made with chicken, n = 15; beef, n = 15; pork, n = 15; and fish, n = 18) were collected from the kitchens of 10 different hospitals. Of the 114 investigated raw meat and fish samples, 28.1% were positive for MRSA, which comprised 23.3% beef, 23.3% chicken, 37.5% pork, and 30% fish samples. Of the prepared foods, 9.5% were positive for MRSA, which comprised 5.6% chicken products, 6.7% pork products, and 22.2% fish products. MRSA contamination was not detected in prepared beef dishes. A statistical analysis showed no association between the presence of MRSA and the type of raw food (P > 0.05). The high prevalence of MRSA among the raw foods tested and the presence of the microorganism in prepared foods emphasizes the necessity of enforcing hygienic practices within hospital kitchens.     

Seafood safety: Knowledge,attitudes, self-reported practices and risk perceptions of seafood workers

The aims of this study were to assess the knowledge, attitudes and self-reported practices regarding seafood safety and the risk perception of seafood-borne diseases among seafood workers and to study the relationships among these variables. This study was cross-sectional, and the data collection was conducted using questionnaires administered through face-to-face interviews with 193 seafood workers in Brazil. Of these workers, 49.8% handled fish on fishery boats (Fishery Workers, FWs) and 50.2% were seafood handlers in two seafood warehouses (Seafood Warehouse Workers, SWWs). A minority of the seafood workers (33.7%) had participated in at least one food-safety training session. The knowledge and attitudes scores of the SWWs were higher than the scores of the FWs. However, no difference was observed between the self-reported practice scores of the SWWs and FWs. The mean level of risk perception score of the SWWs was higher than that of the FWs; nevertheless, both groups were classified as having an average risk perception of seafood-borne diseases. The risk perception score was correlated with the knowledge and attitude scores in both groups. Multiple linear regression analysis showed that the attitude score and the age of the worker were related to the self-reported practice scores of both groups. These results showed the need for immediate actions to improve the knowledge, attitudes, and practices regarding food safety and handling to ensure the production of seafood that is safe for consumption.     

The Expanding Role of Traceability in Seafood: Tools and Key Initiatives

In the last decade, a range of drivers within the seafood sector have incentivized the application of traceability to issues beyond food safety and inventory management. Some of the issues motivating the expanded use of traceability within the global seafood sector include: increased media attention on the legal and social risks within some seafood supply chains, governmental traceability requirements, private‐sector sustainability commitments, and others. This article begins with an overview of these topics in the seafood industry, and why many nongovernment organizations (NGOs), companies, and government actors have turned to traceability as a tool to address them. We discuss how traceability connects to key requirements of environmental sustainability and social responsibility. Later, we review the range of traceability services, tools, software solutions, and the due diligence measures that are currently being leveraged within the seafood sector. The paper concludes with a discussion of several NGO‐ and industry‐led traceability initiatives that are examples of seafood traceability improvements.     

水产品过敏原的研究现状和展望

水产品作为人类食物的重要来源之一,其市场和消费群体不断扩大。与此同时,由水产品引发的食物过敏也日益增多,在联合国粮农组织公布的八大类过敏食物中,水产品就占了两大类。水产品过敏原有小清蛋白(Parvalbumin)、鱼卵蛋白(如鲑鱼的硫酸鱼精蛋白)和胶原蛋白(Collagen)、原肌球蛋白(Tropomyosin,TM)、精氨酸激酶(Arginine kinase)、肌球蛋白轻链(Myosin light chain)、肌钙结合蛋白(Sarcoplasmic calcium binding pro-tein)、血蓝蛋白亚基(Hemocyanin subunits)等。基于此,本文重点概述了国内外水产品过敏原及其加工脱敏技术的研究现状,以及今后水产品过敏原研究的发展趋势。     

Challenges in the Traceability of Seafood

The increasing global trade of foods and animal feeds have to be channelled in right directions to guarantee product safety, transparency and the protection of consumer health. According to this fact the European Regulation (EC) No 178/2002 lays down the common principle for implementing traceability systems in product supply chains. However, seafood is a highly perishable food item which is increasingly global traded so that a lot of particular conditions and difficulties more have to be taken into account compared to other food products. This review discusses the relevant regulations for traceability in seafood and gives a survey about the most important analysis techniques for characterizing seafood.     

High-pressure processing of fish and shellfish products: Safety,quality, and research prospects

Seafood products have been one of the main drivers behind the popularity of high-pressure processing (HPP) in the food industry owing to a high demand for fresh ready-to-eat seafood products and food safety. This review provides an overview of the advanced knowledge available on the use of HPP for production of wholesome and highly nutritive clean label fish and shellfish products. Out of 653 explored items, 65 articles published during 2016–2021 were used. Analysis of the literature showed that most of the earlier work evaluated the HPP effect on physicochemical and sensorial properties, and limited information is available on nutritional aspects. HPP has several applications in the seafood industry. Application of HPP (400–600 MPa) eliminates common seafood pathogens, such as Vibrio and Listeria spp., and slows the growth of spoilage microorganisms. Use of cold water as a pressure medium induces minimal changes in sensory and nutritional properties and helps in the development of clean label seafood products. This technology (200–350 MPa) is also useful to shuck oysters, lobsters, crabs, mussels, clams, and scallops to increase recovery of the edible meat. High-pressure helps to preserve organoleptic and functional properties for an extended time during refrigerated storage. Overall, HPP helps seafood manufacturers to maintain a balance between safety, quality, processing efficiency, and regulatory compliance. Further research is required to understand the mechanisms of pressure-induced modifications and clean label strategies to minimize these modifications.     

Challenges in the Traceability of Seafood

The increasing global trade of foods and animal feeds have to be channelled in right directions to guarantee product safety, transparency and the protection of consumer health. According to this fact the European Regulation (EC) No 178/2002 lays down the common principle for implementing traceability systems in product supply chains. However, seafood is a highly perishable food item which is increasingly global traded so that a lot of particular conditions and difficulties more have to be taken into account compared to other food products. This review discusses the relevant regulations for traceability in seafood and gives a survey about the most important analysis techniques for characterizing seafood. Received: September 17, 2007     

Microbiological and Sensorial Quality Assessment of Ready-to-Cook Seafood Products Packaged under Modified Atmosphere

ABSTRACT:  The effects of modified atmosphere packaging (MAP) (30:40:30 O₂:CO₂:N₂ and 5:95 O₂:CO₂) on the quality of 4 ready-to-cook seafood products were studied. In particular, the investigation was carried out on hake fillets, yellow gurnard fillets, chub mackerel fillets, and entire eviscerated cuttlefish. Quality assessment was based on microbiological and sensorial indices determination. Both packaging gas mixtures contributed to a considerable slowing down of the microbial and sensorial quality loss of the investigated seafood products. Results showed that sensorial quality was the subindex that limited their shelf life. In fact, based primarily on microbiological results, samples under MAP remained acceptable up to the end of storage (that is, 14 d), regardless of fish specie. On the other hand, results from sensory analyses showed that chub mackerel fillets in MAP were acceptable up to the 6th storage d, whilst hake fillets, yellow gurnard fillets, and entire cuttlefish became unacceptable after 10 to 11 d. However, compared to control samples, an increase in the sensorial shelf life of MAP samples (ranging from about 95% to 250%) was always recorded.
Practical Application: Modified atmosphere packaging (MAP) is an inexpensive and uncomplicated method of extending shelf life of packed seafood. It could gain great attention from the fish industrial sector due to the fact that MAP is a practical and economic technique, realizable by small technical expedients. Moreover, there is great attention from the food industry and retailers to react to the growing demand for convenience food, thus promoting an increase in the assortments of ready-to-cook seafood products.     

First report of methicillin‐resistant Staphylococcus aureus in tank cultured dusky kob (Argyrosomus japonicus), and evaluation of three phenotypic methods in the detection of MRSA

This study was conducted to ascertain the occurrence of methicillin‐resistant Staphylococcus aureus (MRSA) in marine finfish (Argyrosomus japonicus) harvested from the wild and two re‐circulatory aquaculture systems, and evaluating the reliability of three phenotypic methods in the detection of methicillin resistance. A total of 120 dusky kob fish were sampled for S. aureus detection using conventional methods and confirmed by polymerase chain reaction (PCR) targeting the nuc gene. Methicillin resistance was determined by molecular detection of the mecA gene. Using mecA as the defining standard, the specificities and sensitivities of cefoxitin disc diffusion, oxacillin screen agar, and growth of S. aureus on Brilliance MRSA II Agar were evaluated. A total of 321 presumptive S. aureus isolates were recovered by culture, out of which 202 (62.9%) were confirmed by PCR. Of these, 33 (16.3%) strains were mecA positive while 169 (83.7%) were mecA negative. The sensitivities and specificities of MRSA detection was 93.9 and 91.7%, 81.8 and 92.3%, and 87.9 and 94.1% for cefoxitin disc, oxacillin screen agar test, and Brilliance MRSA II agar, respectively. This is so far the first report of MRSA in dusky kob aquaculture in South Africa. In the absence of molecular techniques, cefoxitin disc diffusion test is recommended along with any other phenotypic method to improve MRSA detection from samples of veterinary origin.

Practical implications

Methicillin‐resistant Staphylococcus aureus currently presents one of the greatest challenges for medical research worldwide, as well as is one of the most important causes of bacteria gastroenteritis due to preformed toxins in foods. There is a dearth of knowledge on marine foods as carriers/sources of MRSA infection. There are also major discrepancies obtained with MRSA detection methods, making effective detection of this pathogen complicated. The results from this study show that healthy aquaculture fish are reservoirs of MRSA, thus it is necessary to regularly monitor marine foods. Cefoxitin disc diffusion test is recommended as the preferred method for detection of MRSA from fish/food samples where molecular methods are lacking.