Application of stable isotope analysis to differentiate shrimp extracted by industrial fishing or produced through aquaculture practices.

Carbon and nitrogen stable isotope values were determined in Pacific white shrimp (Litopenaeus vannamei) with the objective of discriminating animals produced through aquaculture practices from those extracted from the wild. Farmed animals were collected at semi-intensive shrimp farms in Mexico and Ecuador. Fisheries-derived shrimps were caught in different fishing areas representing two estuarine systems and four open sea locations in Mexico and Ecuador. Carbon and nitrogen stable isotope values (13CVPDB and 15NAIR) allowed clear differentiation of wild from farmed animals. 13CVPDB and 15NAIR values in shrimps collected in the open sea were isotopically enriched (−16.99‰ and 11.57‰), indicating that these organisms belong to higher trophic levels than farmed animals. 13CVPDB and 15NAIR values of farmed animals (−19.72‰ and 7.85‰, respectively) partially overlapped with values measured in animals collected in estuaries (−18.46‰ and 5.38‰, respectively). Canonical discriminant analysis showed that when used separately and in conjunction, 13CVPDB and I5NAIR values were powerful discriminatory variables and demonstrate the viability of isotopic evaluations to distinguish wild-caught shrimps from aquaculture shrimps. Methodological improvements will define a verification tool to support shrimp traceability protocols.

Rastreabilidade em camarões marinhos utilizando a técnica dos isótopos estáveis do carbono e nitrogênio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Food quality awareness : cases from shrimp producers in Thailand and vegetable producers in Vietnam

The high number of import rejections of food commodities suggests that producers in exporting countries are not complying with established standards. To understand why this is the case, we explore the behavior of producers and consumers in developing countries. First, we examine the successful transformation of production practices adopted by shrimp producers in Thailand. In support of the dramatic change in practices, we observe an important role played by the public sector in providing a means to visualize chemical residues and to control processes upstream of the supply chain via a registration system and a traceability system called Movement Document. Furthermore, very active information sharing by the private sector contributes to the dissemination of useful technical and market information among producers. We also examine the knowledge and perceptions of consumers with respect to food safety in Vietnam. We find that consumers in Hanoi and Ho Chi Minh City behave differently toward the third-party certification VietGAP, probably owing to differences in the history of market mechanisms between the two cities.

Traceability : retracing law and public policy on measurement standards

This presentation outlines key aspects of public policy in broad terms insofar as they relate to establishment, implementation and compliance with legal measurement standards. It refers in particular to traceability of a legal measurement unit from its source in a single international standard as a compliance issue. It comments on accreditation of legal measurement and liability concerned with errors in measurement.

An RFID-based traceability system

Traceability system in the food supply chain is becoming more necessary. RFID and EPCglobal Network Standards are emerging technologies that bring new opportunities to develop the high performance traceability system. This research proposes the analysis, design, and development of the RFID and EPCglobal Network Standards based traceability system that adheres to the requirements of global food traceability in terms of completeness of traceability information. The additional components, including lot management system and electronic transaction management system, encourage the traditional system in order to fulfill the missing information. The proposed system was developed and applied in a rice supply chain. Results from experimentation showed that the additional components can significantly improve the completeness of traceability information. The collaboration between EPCglobal Network Standards and electronic transaction management system can improve the performances in RFID operations.

Desynchronization and Traceability Attacks on RIPTA-DA Protocol

Recently Gao et al. proposed a lightweight RFID mutual authentication protocol [3] to resist against intermittent position trace attacks and desynchronization attacks and called it RIPTA-DA. They also verified their protocol’s security by data reduction method with the learning parity with noise (LPN) and also formally verified the functionality of the proposed scheme by Colored Petri Nets. In this paper, we investigate RIPTA-DA’s security. We present an efficient secret disclosure attack against the protocol which can be used to mount both de-synchronization and traceability attacks against the protocol. Thus our attacks show that RIPTA-DA protocol is not a RIPTA-DA.

Molecular and functional characterizations of a Kunitz-type serine protease inhibitor FcKuSPI of the shrimp Fenneropenaeus chinensis

Serine proteinase inhibitors play important and diverse roles in biological processes such as coagulation, defense mechanisms, and immune responses. Here, we identified and characterized a Kunitz-type proteinase inhibitor, designated FcKuSPI, of the BPTI/Kunitz family of serine proteinase inhibitors from the hemocyte cDNA library of the shrimp Fenneropenaeus chinensis. The deduced amino acid sequence of FcKuSPI comprises 80 residues with a putative signal peptide of 15 amino acids. The predicted molecular weight of the mature peptide is 7.66 kDa and its predicted isoelectric point is 8.84. FcKuSPI includes a Kunitz domain containing six conserved cysteine residues that are predicted to form three disulfide bonds. FcKuSPI shares 44e53% homology with BPTI/Kunitz family members from other species. FcKuSPI mRNAwas expressed highly in the hemocytes and moderately in muscle in healthy shrimp. Recombinant FcKuSPI protein demonstrated anti-protease activity against trypsin and anticoagulant activity against citrated human plasma in a dose-dependent manner in in vitro assays.

B- and T-cell epitopes of tropomyosin, the major shrimp allergen

Seafood allergy is often encountered on ingestion of crustaceans such as shrimp, lobster, crab, and crayfish (1). On eating cooked shrimp, sensitive individuals experience a wide spectrum of reactions ranging from abdominal discomfort to anaphylaxis. The presence of cross-reacting heat-stable allergens in crustacean food was first recognized by Hoffman et al. (2) and Lehrer et al. (3). Subsequently, the major allergen was isolated and characterized from the shrimp species Paneaus indicus (Pen i 1) (4) and I? aztecm (Pen a 1) (5). Pen i 1 (originally designated Sa-TI) and Pen a 1, with mol. mass of 34 and 36 kDa, respectively, contain 301 and 312 amino-acid residues with a predominance of gluta- mate/glutamine and asparatate/asparagine.

A spatially explicit multi-competitor coexistence model of penaeid (shrimp) distribution on the Australian Great Barrier Reef

A spatially explicit multi-competitor coexistence model was developed for meta-populations of prawns (shrimp) occupying habitat patches across the Great Barrier Reef, where dispersal was localised and dispersal rates varied between species. Prawns were modelled as individuals moving to and from patches or cells according to pre-set decision rules. The landscape was simulated as a matrix of cells with each cell having a spatially explicit survival index for each species. Mixed species prawn assemblages moved over this simplified spatially explicit landscape. A low level of chronic random environmental disturbance was assumed (cyclone and tropical storm damage) with additional acute spatially confined disturbance due to commercial trawling, modelled as an increase in mortality affecting inter-specific competition. The general form of the results was for increased disturbance to favour good-colonising "generalist" species at the expense of good-competitor "specialists". Increasing fishing mortality (local patch extinctions) combined with poor colonising ability resulted in low equilibrium abundance for even the best competitor, while in the same circumstances the poorest competitor but best coloniser could have the highest equilibrium abundance. This mimics the switch from high-value prawn species to lower-value prawn species as trawl effort increases, reflected in historic catch and effort logbook data and reported anecdotaly from the north Queensland trawl fleet. To match the observed distribution and behaviour of prawn assemblages, a combination inter-species competition, a spatially explicit landscape, and a defined pattern of disturbance (trawling) was required. Modelling this combination could simulate not only general trends in spatial distribution of each of prawn species but also localised concentrations observed in the survey data

Additional records of the rock shrimp, Sicyonia australiensis Hanamura & Wadley, 1998 (Decapoda, Sicyoniidae) from eastern Australia, western central Pacific

This paper reports on the collection of S. australiensis from the continental shelf off southern Queensland, easter Australia, in the western Central Pacific, documenting for the first time the occurrence of the species outside of eastern Bass Strait.

Relationship between the Physicochemical Properties of Nonchitinolytic Listeria and Salmonella and Their Attachment to Shrimp Carapace

Listeria and Salmonella are important foodborne pathogens normally associated with the shrimp production chain. This study investigated the potential of Salmonella Typhimurium, Salmonella Senftenberg, and Listeria monocytogenes (Scott A and V7) to attach to and colonize shrimp carapace. Attachment and colonization of Listeria and Salmonella were demonstrated. Shrimp abdominal carapaces showed higher levels of bacterial attachment (P < 0.05) than did head carapaces. Listeria consistently exhibited greater attachment (P < 0.05) than did Salmonella on all surfaces. Chitinase activity of all strains was tested and found not to occur at the three temperatures (10, 25. and 37 degrees C) tested. The surface physicochemical properties of bacterial cells and shrimp carapace were Studied to determine their role in attachment and colonization. Salmonella had significantly (P < 0.05) more positive (-3.9 and -6.0 mV) cell surface charge than Listeria (-18 and -22.8 mV) had. Both bacterial species were found to be hydrophilic (<35%) when measured by the bacterial adherence to hydrocarbon method and by contact angle (theta) measurements (Listeria, 21.3 and 24.8 degrees, and Salmonella, 14.5 and 18.9 degrees). The percentage of cells retained by Pheryl-Sepharose was lower for Salmonella (12.8 to 14.8%) than it was for Listeria (26.5 to 31.4%). The shrimp carapace was found to be hydrophobic (theta = 74.5 degrees), and a significant (P < 0.05) difference in surface roughness between carapace types was noted. There was a linear correlation between bacterial cell Surface charge (r(2) = 0.95) and hydrophobicity (r(2) = 0.85) and initial attachment (P < 0.05) of Listeria and Salmonella to carapaces. However, the same properties Could not be related to subsequent colonization.

Prevalence, persistence and control of Salmonella and Listeria in shrimp and shrimp products: A review.

Shrimp are an important commodity in the international fisheries trade and there is an indication of an increase in worldwide consumption of this crustacean. Salmonella and Listeria have been isolated from shrimps and shrimp products on a regular basis since the 1980s. The continued reporting of the presence of these pathogens in fresh and frozen shrimps, and even in the lightly preserved and ready-to-eat products, indicates that the existing practices used by the manufacturers or processors are insufficient to eliminate these pathogens. This paper reviews the information available on Salmonella and Listeria in shrimp and makes recommendations on control options and avenues for future research in order to improve shrimp safety and quality.

Effects of secondary crops on bacterial growth and nitrogen removal in shrimp farm effluent treatment systems

Secondary crops provide a means of assimilating some effluent nitrogen from eutrophic shrimp farm settlement ponds. However, a more important role may be their stimulation of beneficial bacterial nitrogen removal processes. In this study, bacterial biomass, growth and nitrogen removal capacity were quantified in shrimp farm effluent treatment systems containing vertical artificial substrates and either the banana shrimp Penaeus merguiensis (de Man) or the grey mullet, Mugil cephalus L. Banana shrimp were found to actively graze biofilm on the artificial substrates and significantly reduced bacterial biomass relative to a control (24.5 ± 5.6mgCm−2 and 39.2 ± 8.7mgCm−2, respectively). Bacterial volumetric growth rates, however, were significantly increased in the presence of the shrimp relative to the control 45.2±11.3mgCm−2 per day and 22.0±4.3mgCm−2 per day, respectively). Specific growth rate, or growth rate per cell, of bacteria was therefore appreciably stimulated by the banana shrimp. Nitrate assimilation was found to be significantly higher on grazed substrate biofilm relative to the control (223±54 mgNm−2 per day and 126±36 mg Nm−2 per day, respectively), suggesting that increased bacterial growth rate does relate to enhanced nitrogen uptake. Regulated banana shrimp feeding activity therefore can increase the rate of newbacterial biomass production and also the capacity for bacterial effluent nitrogen assimilation. Mullet had a negligible influence on the biofilm associated with the artificial substrate but reduced sediment bacterial biomass (224 ± 92 mgCm−2) relative to undisturbed sediment (650 ± 254 mgCm−2). Net, or volumetric bacterial growth in the sediment was similar in treatments with and without mullet, suggesting that the growth rate per cell of bacteria in grazed sediments was enhanced. Similar rates of dissolved nitrogen mineralisation werefound in sediments with and without mullet but nitrificationwas reduced. Presence of mullet increased water column suspended solids concentrations, water column bacterial growth and dissolved nutrient uptake. This study has shown that secondary crops, particularly banana shrimp, can play a stimulatory role in the bacterial processing of effluent nitrogen in eutrophic shrimp effluent treatment systems.