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15 pages, 7 tables, 3 figures, Emerging risk identification is a priority for the European Food Safety Authority (EFSA). The goal of the Galician Emerging Food Safety Risks Network (RISEGAL) is the identification of emerging risks in foods produced and commercialized in Galicia (northwest Spain) in order to propose prevention plans and mitigation strategies. In this work, RISEGAL applied a systematic approach for the identification of emerging food safety risks potentially affecting bivalve shellfish. First, a comprehensive review of scientific databases was carried out to identify hazards most quoted as emerging in bivalves in the period 2016–2018. Then, identified hazards were semiquantitatively assessed by a panel of food safety experts, who scored them accordingly with the five evaluation criteria proposed by EFSA: novelty, soundness, imminence, scale, and severity. Scores determined that perfluorinated compounds, antimicrobial resistance, Vibrio parahaemolyticus, hepatitis E virus (HEV), and antimicrobial residues are the emerging hazards that are considered most imminent and severe and that could cause safety problems of the highest scale in the bivalve value chain by the majority of the experts consulted (75%). Finally, in a preliminary way, an exploratory study carried out in the Galician Rías highlighted the presence of HEV in mussels cultivated in class B production areas., This research was funded by Xunta de Galicia, grant number IN 607C 2017/04.

12 pages, 6 figures, 3 tables, The main aim of this study was to localise, identify and characterise the Listeria monocytogenes-harbouring bacterial communities present in food related premises via 16S rRNA gene metagenetic analysis. With this scope, 319 environmental samples coming from a wide variety of surfaces of fish (n = 120), meat (n = 80) and dairy industries (n = 119), were firstly analysed following ISO 11290–1 and ISO 11290–2 norms. Direct L. monocytogenes quantification was possible in 9 samples (2.8%) with values between 2.00 and 3.97 log CFU/cm2. After enrichment, an overall L. monocytogenes incidence of 12.54% (n = 40) was obtained, being samples from meat industry the most contaminated. Molecular serotyping assays showed that most of the isolates belonged to 1/2b-3b-7 subgroup, followed by 1/2a-3a and 1/2c-3c. These results combined with AscI and ApaI PFGE macrorestriction patterns, yielded 7 different L. monocytogenes clusters. Nevertheless, no clear ecological relationships could be stablished. High amounts of L. monocytogenes-associated psychrotrophic microbiota were obtained in all cases with values above 9 log CFU/cm2 in some cases. Metagenetic analysis of one representative sample per each food industry type (fish, meat, dairy) demonstrated that Actinobacteria (53.16%) was mostly present in the meat sample whereas Proteobacteria was the most representative phylum in dairy (69.58%) and fish (97.11%) samples. Subsequent operational taxonomic units (OTUs) analysis, showed a wide variety of taxa associated with L. monocytogenes such as spoilage-associated genera (e.g. Psyschromonas or Shewanella), lactic acid bacteria genera (e.g. Lactococcus or Lactobacillus) or pathogenic species such as Yersinia enterocolitica. It was thus demonstrated, that L. monocytogenes is capable to both survive with different bacteria in different ecological niches, highlighting once more the need for proper surveillance schedules so as to guarantee the safety of the food products, This research was financially supported by the Spanish Ministerio de Economía, Industria y Competitividad [SOLISTA, AGL2016-78549]

9 pages, 5 figures, 4 tables, In this work we develop a model describing the evolution of the adenosine triphosphate (ATP) degradation products, typically used as early indicators of fish quality loss, during storage and transport conditions. The model is constructed following a modular approach that includes essentially three mechanisms: (1) enzymatic transformation of inosine 5′-monophosphate (IMP), inosine (Ino) and hypoxanthine (Hx) with some reactions catalyzed by bacteria; (2) bacterial growth and (3) nucleotide diffusion through the food matrix. This approach allows us to combine the different underlying mechanisms to account for other fish species and conditions. We compare alternative mechanisms explaining the catalytic effect of Pseudomonas and Shewanella populations on the reaction linking IMP, Ino and Hx. The selection is carried out in terms of the Akaike Information Criteria. The predictive capabilities of the selected model are demonstrated with experiments, The authors acknowledge financial support from the Spanish Ministry of Science and Innovation (Projects ISFORQUALITY AGL2012-39951-C02-01 and RESISTANCE DPI2014-54085-JIN)

6 páginas, 5 tablas, 1 figura, The objective of this study was to evaluate the behaviour of small-sized (∼19 g/unit) Mediterranean mussels packaged hermetically with different proportions of oxygen in the interior of the package and stored at 2 °C and 7 °C. The most favourable conservation conditions (83% O2 and 2 °C) were compared with larger mussels (∼24 g/unit). On day 3 of storage with 20 %O2 at 2 °C, the concentration of volatile fatty acids in the intervalval fluid was double that for the mussels packaged with 83% O2 and this difference increased during storage. Higher temperatures produced a larger and more rapid accumulation of ammonium nitrogen with concentrations of 49 mg N/L on day 6. Lower concentrations were observed at the end of storage at 2 °C (27 mg N/L on day 9). From day 7, the increase of N-TVB measured in the intervalval fluid of the small mussels at 2 °C was more pronounced than in the larger mussels. The organoleptic evaluation, percentage mortality and microbial counts collectively indicated that a high quality product was maintained on day 8–9 at 2 °C with mussels packaged with 83% O2. Inadequate temperatures have a stronger negative impact on shelf life than low oxygen concentrations., This research was supported by European Project 2-05 AL, AquaGair

The effectiveness of packaging material on the shelf-life of fresh salmon (Salmo salar) derived from aquaculture has been studied using an atmosphere rich in carbon dioxide and low in oxygen (80% CO2, 5% O2, 15% N2). Multilayer materials with different permeability to the gases (with copolymers of ethylene-vinyl alcohol or of polyethylene) were used in the upper film and/or in the packaging tray. The effect of the material on the conservation of the salmon was determined on the basis of changes in the initial gas mixture and the quantification of chemical, microbiological, and sensory variables during storage. In general, the results show small differences between the two types of packaging and their influence on salmon conservation. The sensorial parameter mean values (color, odor, flavor and texture) were favorable to the low barrier material LB/LB at the end of the storage period (day 13) when the salmon in EVOH/LB was considered as rejected. Se ha estudiado la efectividad del material de envasado en l...

9 páginas, 7 tablas, 4 figuras, Hake (Merluccius merluccius) from the Galician inshore fishing fleet, has been used to study the effectiveness of sterile and ozonized water in the conservation of fresh fish. This water was used to wash the fish and to manufacture ice in flakes (Petfrost system). The fish is stored refrigerated in the holds of the boats for a period of up to 18 days. The fish samples came from five samples made at 17, 14, 12, 8 and 3 days from their capture to their arrival to port. Later, once on shore, they were kept refrigerated up 12 days at 2 C. The results of this new processing were compared with those obtained by the traditional method, which consists of using only sea water for the washing and the manufacture of the ice. The results obtained from the study of microbiological, chemical and sensorial variables indicate a greater stability and quality of the hake, as compared with the traditional method, when the new treatment is applied. The study of the five hake samples, from different dates after capture, demonstrated that hake treated with the combined Petfrost system was, in all cases, less deteriorated than the control. The Petfrost hake stored in the boat for 12, 8 and 3 days, once on shore, could last one week conserved in a refrigerated state without deteriorating to the level of unacceptability. For the same conditions, only the control sample with three days of storage on board would be acceptable., This research was supported by Empresa Peter Taboada (Pontevedra-Spain) and by the Xunta de Galicia, project (PGIDIT04TAL029E).

4 páginas, 4 figuras, 2 tablas, The objective of this study was the development of a method for the quantification of free fatty acids (FFA) using less aggressive reactants against the handler and the environment than those used in the classic method of Lowry and Tinsley. The modified procedure is a variation of the Lowry and Tinsley method employing cyclohexane in place of benzene. The use of benzene is prohibited in certain work processes and laboratories, and the competent authority in each country is actively promoting research into harmless or less harmful products that could replace benzene. A comparison with the traditional AOCS titration method for oil analysis was performed. FFA content in mackerel frozen at −10 °C was measured according to the three methods over a 12 month period. The results showed similar values, and good correlations were obtained, This research was supported by the Interministerial Commission of Science and Technology (CICYT) during the Research Project AGL2001-1355.

6 páginas, 1 tabla, 5 figuras, The aim of the present study was to design methods for the digestion of fish proteins from processing wastes, leading to new possibilities for little-used species or those generating a significant volume of residues. Residues of rayfish (Raja clavata) were used for the solubilisation of protein by hydrolysis treatment. The kinetics of hydrolysis was studied using rayfish enzymes, either by autolysis of the protein in a triturate of the raw material or by application of a multi-enzyme preparation previously extracted from the viscera of the species. Their effectiveness was compared with that of two commercial enzymes, papain and pepsin. Optimum conditions of hydrolysis and enzymatic activity for digestion with rayfish enzymes were ascertained. The yield of material and the efficiency of digestion in each of the hydrolysis processes are reported, This work was supported by Xunta of Galicia, project PGIDT PIN004.

5 páginas, 4 tablas, 2 figuras, The effects of lauric acid on pre-cooked products derived from minced cod or shrimp tails stored in the refrigerated state were studied. Lauric acid was employed either with or without modified atmosphere packaging (MAP:50% CO2:50% N2). Synergism between lauric acid and MAP on bacterial growth kinetics was found in pre-cooked minced fish products but not in precooked shrimp tail products. Sensory properties of both products received the highest scores when treated with lauric acid and packed under a modified atmosphere. Only samples subjected to combined treatment were commercially acceptable after 1 month of storage., This work was supported by CICYT (Inter-ministerial Committee of Science and Technology, project PETRI 95-0324-OP).

10 páginas, 5 tablas, 6 figuras.-- This is an open access article under the CC BY-NC-ND license, Fish quality has a direct impact on market price and its accurate assessment and prediction are of main importance to set prices, increase competitiveness, resolve conflicts of interest and prevent food wastage due to conservative product shelf-life estimations. In this work we present a general methodology to derive predictive models of fish freshness under different storage conditions. The approach makes use of the theory of optimal experimental design, to maximize data information and in this way reduce the number of experiments. The resulting growth model for specific spoilage microorganisms in hake (Merluccius merluccius) is sufficiently informative to estimate quality sensory indexes under time-varying temperature profiles. In addition it incorporates quantitative information of the uncertainty induced by fish variability. The model has been employed to test the effect of factors such as fishing gear or evisceration, on fish spoilage and therefore fish quality. Results show no significant differences in terms of microbial growth between hake fished by long-line or bottom-set nets, within the implicit uncertainty of the model. Similar conclusions can be drawn for gutted and un-gutted hake along the experiment horizon. In addition, whenever there is the possibility to carry out the necessary experiments, this approach is sufficiently general to be used in other fish species and under different stress variables, This work has been funded by the Spanish Ministry of Science and Innovation throughout project ISFORQUALITY (AGL2012-39951-C02-01) and by the CSIC throughout project CONTROLA (PIE201270E075)

The commercialization of live mussels is limited by their capacity to resist the adverse conditions associated with their removal from the natural environment. Packaging under modified atmospheres has been proposed as an alternative method for the stabilization of mussels and prolong shelf life. This study investigates how different concentrations of oxygen (20, 75 and 85%) influence the percentage mortality and quality of packaged Mediterranean mussels (Mytilus galloproviciallis) of different sizes (30 and 44 units/kg). In general, mussels packaged with oxygen-rich atmospheres had a higher organoleptic rating and lower percentage mortality. The decrease in pH of both the tissues and intervalval fluid was less pronounced in the larger mussels compared to the smaller mussels. Mussel size and packaging atmosphere also influenced the metabolic survival strategies. The smaller mussels produced more ammonium and volatile fatty acids, which decreased as initial oxygen increased. After 10 days of storage no consumption of glycogen was detected in any of the samples analyzed. The marketable period for the mussels, defined as a 20% mortality threshold, was reached earlier in the packages displaying a greater accumulation of acidic and basic metabolites.

9 páginas, Sous vide and other mild preservation techniques are increasingly demanded by consumers. However, spores often will survive in minimally processed foods, causing both spoilage and safety problems. The main objective of the present work was to solve an industrial spoilage problem associated with two sous vide products: mushrooms and shellfish salad. Bacillus subtilis and Bacillus licheniformis predominated as the most heat-resistant organisms isolated from mushrooms and shellfish salad, respectively. The combined effects of nisin and pediocin against resistance and germination of both Bacillus species were described by empirical equations. Whereas nisin was more effective for decreasing thermal resistance of B. subtilis spores, pediocin was more effective against B. licheniformis. However, a significant positive interaction between both biopeptides for decreasing the proportion of vegetative cells resulting from thermoresistant spores was demonstrated in later experiments, thus indicating the increased efficacy of applying high concentrations of both bacteriocins. This efficacy was further demonstrated in additional challenge studies carried out at 15°C in the two sous vide products: mushrooms and shellfish salad. Whereas no vegetative cells were detected after 90 days in the presence of bacteriocins, almost 100% of the population in nontreated samples of mushrooms and shellfish salad was in the vegetative state after 17 and 43 days of storage at 15°C, respectively

8 páginas, 3 figuras, 4 tablas, This study investigates the effectiveness of ozonated water and flake ice (combined Petfrost system) to increase the quality and stability of fresh megrim on fishing boats. The captured fish were washed, placed in plastic boxes, covered with flake ice and refrigerated at 2 °C for up to 2-weeks onboard and, thereafter, for 11 days onshore. The experiments employed sterile, filtered and ozonated water at a concentration of 2 ppm for washing the fish and making the flake ice. The results are compared with samples from a traditional treatment consisting of water and flake ice of marine origin. Fish were caught in four different hauls, which took 14, 12, 8 and 3 days in being landed. Subsequently, fish were stored for 1, 5, 7 and 11 days at 3 °C. The different treatments were evaluated using sensory, microbiological and chemical techniques. Fish treated with ozone always showed the best quality. Megrim treated with ozone was still suitable for consumption after 14 days on board, and megrim stored for 12, 8 and 3 days on board could be stored for a further five days in the ice state once landed with an acceptable quality. In contrast, control fish were not suitable for consumption if stored for longer than three days on board.The results indicate that treatment with water and ice flakes made from sterile and ozonated water maintains the quality of fresh megrim onboard fishing boats and upon arrival onshore, This research was supported by Empresa Peter Taboada (Pontevedra-Spain) and by the Xunta de Galicia, project (PGIDIT04TAL029E)

5 páginas, 5 tablas, 2 figuras.-- The original publication is available at www.springerlink.com, The stability of bivalve molluscs was studied in live mussels (Mytilus galloprovincialis) packaged under modified atmospheres. Studies of physical, chemical, microbiological and sensory parameters have detailed these changes in the live packaged mussels. The highest survival was achieved at high oxygen concentrations, i.e. 75%, in the absence of carbon dioxide. The improved storage conditions promote shelf life in 80% of the packaged mussels, reaching a storage life of 6 days when held at 2–3 C, whereas control molluscs packaged in air did not exceed 3–4 days when stored under the same conditions. Sensory analysis of cooked products from live mussels packaged under 75% oxygen:25% nitrogen were optimum throughout the period of storage. Secondly, the results for the most effective treatment were compared with those for an approximate 75–80% oxygen mixture achieved by applying partial vacuum to the packaging machine. This option employed only oxygen and decreased packaging time, which reduced mussel packaging stress by avoiding elevated vacuum conditions. It provided operational and economic advantage to commercial mussel packaging., This research was supported by AMEGROVE (O Grove-Spain) and by the Xunta de Galicia (project PGIDT01TIN21E).