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XXVI Encontro Galego Portugués de Químlca, 16-18 de noviembre de 2022, Santiago de Compostela, Las algas marinas forman parte de la dieta humana en algunos países asiáticos desde la antigüedad. Recientemente, su uso está recibiendo un creciente interés en el mundo occidental debido a sus excelentes propiedades nutricionales, así como por su aporte en componentes con propiedades antimicrobianas, antioxidantes, antiinflamatorias y antitumorales [1,2]. Entre estas algas, Bifurcaría bifurcata destaca por su abundancia en las costas atlánticas de Portugal, Francia y España [3] así como por sus propiedades conservantes demostradas en diversos experimentos in vitro [4]. Este estudio se centra en la utilización de esta macroalga parda al objeto de mejorar la calidad de pescado comercializado en estados fresco y enlatado. Para ello, se utilizaron disoluciones acuosas de extractos de dicha alga para la elaboración del hielo utilizado como medio de conservación en refrigeración de gallo (Lepidorhombus whiffiagonis); los efectos de los extractos del alga sobre el desarrollo de la actividad microbiana y la alteración lipídica fueron analizados durante un periodo de conservación de 14 días. Por otra parte, los extractos de B. bifurcata fueron incluidos en el medio de cobertura empleado durante el enlatado de caballa atlántica (Scomber scombrus); después de tres meses de conservación del producto enlatado, se analizaron los efectos originados sobre la calidad del pescado. En lo que respecta al estudio de gallo refrigerado, se observó un marcado efecto inhibidor en el desarrollo de distintos grupos microbianos (aerobios, psicrótrofos, Enterobacterias, proteolíticos y lipolíticos), así como en la formación de ácidos grasos libres y compuestos fluorescentes. Por su parte, el experimento de enlatado de caballa reflejó un efecto inhibidor por parte del extracto de alga sobre la formación de compuestos fluorescentes y sobre el incremento de los parámetros L* y b* de color. Se concluye que ambas estrategias (inclusión en el hielo de refrigeración y en el medio de cobertura del enlatado) pueden significar un importante avance a la hora de retener la calidad de pescado fresco y enlatado respectivamente, Este trabajo fue financiado por la Xunta de Galicia (Galicia, España) a través del proyecto INNOVAPEMES (IN848D), 026-IN848D-2020-1119362

50th Conference of the Western European Fish Technologists Association, Rotterdam, Netherlands, 17th - 21st October 2022

4th International Caparica Conference in Antibiotic Resistance, Caparica, Portugal, 13th – 17th June 2021, Streptococcus spp. are among the main mastitis pathogens present in dairy products [1]. The major species involved in both clinical and subclinical mastitis are Streptococcus agalactiae, Streptococcus canis, Streptococcus dysgalactiae and Streptococcus uberis, which produce a variety of virulence factors that are involved in streptococcal pathogenicity. These include neuraminidase, pyrogenic exotoxin, and M protein, and in addition they might produce bacteriocins and antibiotic-resistance proteins [2]. Unjustifiable misuse of antimicrobials has led to an increase in antibiotic-resistant bacteria present in foodstuffs [3]. Identification of the mastitis-causing bacterial strain, as well as determining its antibiotic resistance and sensitivity is crucial for effective therapy. Classic culture-based methods used for the detection of pathogenic bacteria are time-consuming and laborious procedures. The present work focused on the LC–ESI–MS/MS (liquid chromatography–electrospray ionization tandem mass spectrometry) analysis of tryptic digestion peptides from mastitis-causing Streptococcus spp. isolated from milk. A total of 100 μg of protein extraction was digested with trypsin, cleaned on a C18 microSpinTM, and analyzed by LC-MS/MS. Proteomic data were processed by SEQUEST (Proteome Discoverer 1.4 package, Thermo Fisher Scientific) against bacteria in the UniProt/TrEMBL database. A total of 2706 non-redundant peptides belonging to 2510 proteins was identified and analyzed. Among them, 168 peptides were determined, representing proteins that act as virulence factors, toxins, anti-toxins, provide resistance to antibiotics that are associated with the production of lantibiotic-related compounds, or play a role in the resistance to toxic substances. Protein comparisons with the NCBI database allowed the identification of 134 peptides as specific to Streptococcus spp., while two peptides (EATGNQNISPNLTISNAQLNLEDKNK and DLWC*NM*IIAAK) were found to be species-specific to Streptococcus dysgalactiae. This proteomic repository might be useful for further studies and research work, as well as for the development of new therapeutics for the mastitis-causing Streptococcus strains

6 pages, 3 tables, This study focusses on the employment of a gelatine-based biofilm during fish refrigeration. In it, a Fucus spiralis protein hydrolysate (PH) is included in the biofilm and used as packaging system in European hake (Merluccius merluccius) slices during the refrigerated storage (up to 6 days at 4 ºC). A progressive quality loss can be observed in hake slices by increasing the storage time. However, comparison with control fish shows a partial inhibitory effect on microbial activity development (counts assessment of aerobes, psychrotrophs, Enterobacteriaceae, proteolytics, lipolytics and anaerobes) and lipid oxidation (determination of thiobarbituric acid and fluorescence indices) and hydrolysis (free fatty acids formation) in hake samples packaged in the alga-gelatine condition. A preservative effect resulting from the PH presence in the gelatine-based biofilm is concluded, this showing a quality and safety enhancement and a potential commercial value increase. Further research focused on the optimisation of the current biofilm preparation ought to be addressed., Thanks to Department of Research and Postgraduate in Food (University of Sonora, Hermosillo, Mexico) for the financial support of the internship of Dr. Daniela CastroEnríquez. This work was supported by the Consejo Superior de Investigaciones Científicas (CSIC, Spain; project PIE 201370E001).

7 pages, 2 tables, 1 figure, The current study represents an attempt to apply the alga Undaria pinnatifida for the quality enhancement of fish products. For it, ethanolic extracts of this alga were included in the icing system during the chilling storage of megrim (Lepidorhombus whiffiagonis). Lipid damage and microbial activity were analysed in megrim muscle after 0, 2, 6 and 9 days. An inhibitory effect (p < 0.05) on lipid hydrolysis (free fatty acids assessment) development could be observed as a result of the alga presence in the icing medium. In this study, a low formation of primary (i.e., peroxides) and secondary (thiobarbituric acid reactive substances) lipid oxidation compounds was inferred in both control and treated fish samples. However, determination of fluorescent compounds (tertiary lipid oxidation compounds) revealed lower average scores for treated megrim at advanced storage periods (6-9 days), so that a partial inhibition of lipid oxidation development could be concluded as a result of the presence of the alga extract in the icing medium. Compositional analyses revealed a polyphenol content of 11±1 mg gallic acid equivalent g-1 of lyophilised alga and an antioxidant capacity of 27 % (DPPH assay). Interestingly, aerobes, proteolytic and lipolytic bacteria growth was partly slowed down as compared to their control counterparts. Consequently, the proposed novel employment of U. pinnatifida can be considered a promising strategy to enhance seafood quality, This work was supported by the 2013 Cooperation Program “CONICET (Argentine)-CSIC (Spain)” and by the Project PIE 2013-70E001 (CSIC, Spain)

23 pages, Inhibition ofmicrobial activity in chilled fish was investigated. For it, an aqueous/ethanolic saponin-free quinoa extract was added to the icing system and applied to lean (megrim, Lepidorhombus whif.fiagonis; 0.03 and 0.12 g lyophilised quinoa/L icing solution) and fatty (Atlantic chub mackerel, Scomber eolias; 0.05 and 0.20 g lyophilised quinoa/L icing solution) fish. Microbial development was monitored for a 13-day chilled storage period by microbial and chemical indices. An inhibitory effect (p < 0.05) of the quinoa extracts present in the icing systems on microbial development in megrim (aerobe counts, pH and free fatty acid value) and mackerel (aerobe, psychrotroph, proteolytic and lipolytic counts; pH and free fatty acid values) was observed when considering the most concentrated presence of quinoa in the icing system. A novel icing system is proposed to obtain improvement in the quality ofboth lean and fatty fish species during commercialisation under chilled conditions, The work was supported by the Consejo Superior de Investigaciones Científicas (CSIC) (Spain) through Research Project 2013-70E001

Poster.-- 3º International Conference on Bio-antioxidants, 17-21 September 2019, Nessebar, Bulgaria

Poster.-- Congreso Nacional de Biotecnología Biotec, Vigo, 10-13 de junio de 2019, Classical and culture-based methods for pathogen identification and characterization of their biochemical properties are slow and labour-intensive. Molecular microbial diagnostic methods based on genomics and proteomics allow a faster and more effectively species identification. Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) has been used for the analysis of bacterial pathogen strain-specific diagnostic peptides allowing the characterization of bacterial strains. In this study, tryptic digestion peptides from mastitis producer Streptococcus spp. isolated from milk have been analysed by LC-ESI-MS/MS to search for specific biomarkers useful for a rapid identification of both, the bacterial species and the physiological and biochemical characteristics such as the expression of virulence factors including toxins, immune-modulatory factors, exoenzymes and so on. Thus, a total of 100 μg protein extraction was digested with trypsin, cleaned on a C18 microSpinTM, and then analysed by LC-MS/MS. Proteomic data was processed by SEQUEST (Proteome Discoverer 1.4 package, Thermo Scientific) against Bacteria in the UniProt/ TrEMBL database. Specific peptides from proteins such as bacteriophage proteins, toxins and M protein, were found and could be useful as specific biomarker peptides, This work was funded by the Spanish Ministry of Economy and Competitivity Project AGL2013-48244-R and by the European Regional Development Fund (ERDF) (2007-2013). Ana Gonzalez Abril pre-doctoral scholarships was funded by Xunta de Galicia and the European Union (European Social Fund - ESF)

Poster.-- 4th Meeting of Medicinal Biotechnology, Porto, May 17th 2019, Streptococcus includes numerous mastitis causing species, being responsible for high economic losses as well as human health issues Recently, new rapid molecular microbial diagnostic methods based on genomics and proteomics have been developed in order to achieve faster and more effectively species identification than classical and culture based methods which are labour intensive Liquid chromatography electrospray ionization tandem mass spectrometry (LC ESI MS/MS) has been used for the analysis of bacterial pathogen strain specific diagnostic peptides 1 2 As bacteriophages are high specific to their host pathogens, their nucleic acids, antibodies, phage display peptides ( and most recently phage’s receptor binding proteins ( have been studied as biosensor for pathogen detection 3 4 In addition, LC ESI MS/MS techniques have been employed for the identification and detection of bacterial bacteriophages 5 However, any study has been published for Streptococcus phage detection and identification by LC MS MS so far, This work was funded by the Spanish Ministry of Economy and Competitivity Project AGL 2013 48244 R and by the European Regional Development Fund ( 2007 2013 Ana Gonzalez Abril pre doctoral scholarships was funded by Xunta de Galicia and the European Union (European Social Fund ESF)

Poster.-- Congreso Nacional de Biotecnología Biotec, Vigo, 10-13 de junio de 2019, Some bacterial strains have the ability to decarboxylate specific amino acids producing biogenic amines (such as histamine from histidine). The detection of these strains having amino acid decarboxylase activity is important to lower the risk of biogenic amine in food products, especially histamine. Histamine is regulated in fish (lower than 100 mg/Kg-1, but it is generally recognized that the presence of other biogenic amines aggravate symptoms from histamine. Molecular methods for the detection of biogenic amine-producing bacteria in foods are based on the specific detection of decarboxylase genes by PCR allowing the detection before the biogenic amine is produced [1]. However, the difficulty is the availability of universal primers. Mass spectrometry [2] can provide a useful tool for the detection of strain-specific diagnostic decarboxylase peptides. In this study, proteins from biogenic amine producing strains were isolated, after tryptic digestion, the resulting peptides were analysed by LC-ESI-MS/MS (Liquid chromatography-electrospray ionizationtandem mass spectrometry). A total of 100μg protein extraction was digested with trypsin, cleaned on a C18 microSpinTM, following by LC-MS/MS analyse. Proteomic data was processed by SEQUEST (Proteome Discoverer 1.4 package, Thermo Scientific) against Bacteria in the UniProt/ TrEMBL database. MS data was analysed to identify the peptides from the amino acid decarboxylases and then compared to the GenBank database using the Blast tool (NCBI) to achieve peptide/protein identification. Thus, decarboxylase peptides were detected in studied strains that could be used as biomarkers in further studies, This work was funded by the Spanish Ministry of Economy and Competitivity Project AGL2013-48244-R and by the European Regional Development Fund (ERDF) (2007-2013). Ana Gonzalez Abril pre-doctoral scholarships was funded by Xunta de Galicia and the European Union (European Social Fund - ESF)

7 pages, 5 figures, Esta investigación se enfocó a un crustáceo actualmente infravalorado, la langostilla (Munida spp.), como potencial nueva fuente de nutrientes para consumo humano. El trabajo se centra en el estudio de su composición nutricional y de su variabilidad estacional, proponiéndose asimismo dos estrategias de comercialización en fresco y como producto congelado. A nivel composicional, debemos destacar su elevado contenido proteico, así como su interesante fracción lipídica, con un elevado contenido en constituyentes valiosos como ácidos grasos poliinsaturados (PUFA) y PUFA-ω3 y una buena proporción entre ácidos ω3 y ω6. El pre-tratamiento por inmersión en una solución de metabisulfito sódico permite extender la vida útil del producto fresco hasta el día 10. Asimismo, dicho pre-tratamiento, en combinación con la congelación, permite la retención de la calidad sensorial y nutricional del producto congelado hasta 10 meses. Este trabajo abre el camino a la comercialización de la langostilla como un producto nuevo, atractivo y nutritivo para el consumo humano., El desarrollo del estudio fue financiado por la Secretaría Xeral de I+D de la Xunta de Galicia (Galicia, España) a través del proyecto IN 841C 2012/82.

VII International Conference on Environmental, Industrial and Applied Microbiology - BioMicroWorld2017 (Madrid, Spain), Madrid (Spain), 18-20 October 2017, Numerous species of Bacillus genus are implicated in food poisoning and spoilage. Food safety is one of the most important public international concerns either for food industry, Institutions or for the consumer. Recently, new rapid molecular microbial diagnostic methods based on genomics and proteornics have been developed in order to achieve faster and more effectively methods for species detection and identification and even strain biotyping. [I]. Liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) has been used for the analysis of Bacillus cereus group-type strain-specific diagnostic peptides (2,3].). In this study, Bacillus tryptic digestion peptides have been analysed by LC-ESI-MS/MS to search for genus and/or species-specific biomarkers useful for a rapid Bacillus identification. A total of I 0Oμg protein extraction was digested with trypsin, cleaned on a C I 8 microSpinTM, following by LC-MS/MS analyse. The data was processed by SEQUEST (Proteome Discoverer 1.4 package, Thermo Scientific) against Bacteria in the UniProt/ TrEMBL database. The study and comparison of Bacillus resulting peptides with other genera and strains, led to the discovery of some Bacillus specific biomarker peptides, This work was funded by the Spanish Ministry of Economy and Competitivity Project AGL2013-48244-R and by the European Regional Development Fund (ERDF) (2007-2013). Ana Gonzalez Abril pre-doctoral scholarships was funded by Xunta de Galicia and the European Union (European Social Fund - ESF)

1 poster presented at the 47th West European Fish Technologists Association Conference, Aviva Stadium, Dublin, 9th-12th October 2017

8 páginas, 5 tablas, 2 figuras, [Background] An advanced strategy for chilled fish preservation, based on the inclusion in ice of an extract of jumbo squid (Dosidicus gigas) skin (JSS), is proposed. Aqueous solutions including acetic acid–ethanol extracts of JSS were tested at two different concentrations as icing media, with the effects on the quality evolution of chilled hake (Merluccius merluccius) being monitored., [Results] A significant inhibition (P < 0.05) of microbial activity (aerobes, psychrotrophs, Enterobacteriaceae, proteolytic bacteria; pH, trimethylamine) was obtained in hake corresponding to the icing batch including the highest JSS concentration. Additionally, fish specimens from such icing conditions showed an inhibitory effect (P < 0.05) on lipid hydrolysis development, while no effect (P > 0.05) was depicted for lipid oxidation. Sensory analysis (skin and mucus development; eyes; gills; texture; external odour; raw and cooked flesh odour; flesh taste) indicated a shelf life extension of chilled hake stored in ice including the highest JSS concentration., [Conclusion] A profitable use of JSS, an industrial by-product during jumbo squid commercialisation, has been developed in the present work, which leads to a remarkable microbial inhibition and a significant shelf life extension of chilled hake. In agreement with previous research, ommochrome pigments (i.e. lipophilic-type compounds) would be considered responsible for this preservative effect. © 2016 Society of Chemical Industry, This work was supported by the CONACYT-Mexico grant 154046, by the Consejo Superior de Investigaciones Científicas (CSIC) through the Research Project PIE 201370E001 and by the University of Sonora grant USO31302163

1 poster presented at the First International Conference on Bio-antioxidants, Natural bio-antioxidants – as a base for new synthetic drugs and food additives/supplements, 25-29 June 2017

1 poster presented at the First International Conference on Bio-antioxidants, Natural bio-antioxidants – as a base for new synthetic drugs and food additives/supplements, 25-29 June 2017

6 pages, 6 figures, CONACYT-Méjico (Proyecto 154046), Consejo Superior de Investigaciones Científicas (CSIC, España) (Proyecto 2013-70E001), Universidad de Sonora (Méjico) (USO31302163)

5 pages, 3 figures, 2 tables, For an effective food control and monitoring of foodborne pathogens, methods are required that are able to detect rapidly, precisely and quantitatively microbial contaminants in complex mixtures and directly in the food matrices. In the present study, we focused on this aim and searched for specific peptide biomarkers for the main histamine-producing bacterial species, potentially present in fish and seafood products. Such biomarkers could be targets for the identification of the corresponding species at low concentrations in a complex food matrix. The determination of possible candidate peptide biomarkers was carried out by ESI-LC-MS/MS analysis of the tryptic digests of the bacterial protein extracts. Previously, specific peaks detected by MALDI-TOF MS analysis were identified by database searches. The focus of the study was then given to those proteins and corresponding peptides that have been determined as specific by bioinformatics tools, such as BLAST and alignment of the protein sequences. Finally, the determined specific peptides have been studied in relation to their abundance, spectral quality and reproducibility, with the aim to evaluate their potential as biomarkers for bacterial identification in complex mixtures, This work was funded by the Project AGL2013- 48244-R from the Spanish Ministry of Economy and Competitiveness and by the European Regional Development Fund (ERDF) (2007-2013). The work of S. Caamaño Antelo is supported by the Otilia Millares Foundation

5 pages, 3 figures, The increase of foodborne diseases in the past years, especially emergent pathogens is a great concern for authorities, industry and consumers. It is important the early detection and identification of the microbiota in order to evaluate the safety of the product and avoid health issues and economic losses for either the producer or the distributor. Consequently, there is a critical need to develop rapid and sensitive methods for detection and accurate identification of food-borne pathogens. Our approach is the description of peptide/protein markers unique for a bacterial species, strain or genera. The identification of bacterial peptide/protein markers was performed after digesting the protein in solution and analyzing its tryptic peptides by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS), and subsequent analysis with database search software and comparison with amino acid sequences available in public databases (NCBI). Two peptides were found to be potentially useful for the detection of Staphylococcus aureus, This work was funded by the Spanish Ministry of Economy and Competitivity Project AGL2013-48244-R and by the European Regional Development Fund (ERDF) (2007-2013). The work of Sonia Caamaño Antelo is supported by the Otilia Millares Foundation

6 páginas, 4 figuras, Como resultado de la creciente demanda de productos marinos frescos de alta calidad, la tecnología de alimentos ha desarrollado una gran diversidad de estrategias novedosas de refrigeración que han contribuido al desarrollo continuado y a la innovación en el sector. En este trabajo se describe la actividad llevada a cabo en los últimos años en nuestro grupo de trabajo. En él, se desarrolló una estrategia nueva consistente en emplear como medio de refrigeración hielo preparado a partir de disoluciones acuosas incluyendo componentes conservantes naturales de distinta procedencia (extractos vegetales, ácidos orgánicos de pequeño tamaño y extractos de macroalgas), Los experimentos fueron financiados por la Secretaría Xeral de I+D de la Xunta de Galicia (Galicia, España) (Proyecto 10 TAL 018E), el Consejo Superior de Investigaciones Científicas (CSIC; Proyecto PIE 201370E001) y el Programa de Cooperación Hispano-Chileno “Universidad de Chile-Consejo Superior de Investigaciones Científicas (CSIC) (Proyecto 2004 CL 0038).

Presentación de la conferencia dictada en el Colloque QSPA, Qualité et Sécurité des Produits Aquatiques, Boulogne (France), 18 juin 2015

1 póster presentado al Colloque QSPA Qualité et Sécurité des Produits Aquatiques, Boulogne (France) 17-19 Juin 2015, Cette étude a été financée par la Secretaría Xeral de I+D de la Xunta de Galicia, project IN 841C 2012/62

11 páginas, 4 figuras, 2 tablas, The present study aims to compare two molecular technologies, 16S rRNA sequencing and MALDI-TOF MS, for bacterial species identification in seafood. With this aim, 70 reference strains from culture collections, including important seafood-borne pathogenic and spoilage bacterial species, and 50 strains isolated from commercial seafood products, were analysed by both techniques. Genomic analysis only identified the species of 50% of the isolated strains, proving to be particularly poor at identifying members of the Pseudomonas and Bacillus genera. In contrast, MALDI-TOF MS fingerprinting identified 76% of the strains at the species level. The mass spectral data were submitted to the SpectraBank database (http://www.spectrabank.org), making this information available to other researchers. Furthermore, cluster analysis of the peak mass lists was carried out with the web application SPECLUST and the calculated groupings were consistent with results determined by a phylogenetic approach that is based on the 16S rRNA sequences. However, the MALDI-TOF MS analysis demonstrated more discriminating potential that allowed for better classification, especially for the Pseudomonas and Bacillus genera. This is of importance with respect to the varying pathogenic and spoilage character at the intragenus and intraspecies level. In this sense, MALDI-TOF MS demonstrated to be a competent bacterial typing tool that extends phenotypic and genotypic approaches, allowing a more ample classification of bacterial strains., This work was funded by project 10PXIB261045PR from Xunta de Galicia and by project AGL2010–19646 from the Spanish Ministry of Science and Technology.

3 pages, 2 figures

9 páginas, 4 tabla, The efficacy of oregano and thyme essential oils (OEO and TEO, respectively) in the quality retention of a refrigerated (4 °C) squid (Loligo vulgaris) ring ready-to-eat (RTE) product was studied. Essential oils were added at different concentrations to the coating medium during processing. An inhibitory (P < 0.05) effect of OEO on the microbial activity (aerobes, anaerobes, Enterobacteriaceae, psychrotrophs) of the squid rings was observed, with a more pronounced effect as OEO concentration increased. The addition of OEO also led to an inhibitory (P < 0.05) effect on lipid oxidation, as determined by peroxide, thiobarbituric acid-reactive substance and interaction compound formation; however, no effect (P > 0.05) of the OEO concentrations on lipid oxidation development was detected. The addition of TEO did not lead to an inhibitory effect (P > 0.05) on the microbial activity of the refrigerated RTE squid, although a slight inhibitory (P < 0.05) effect on lipid oxidation was observed in the batches including the higher TEO concentrations.

13 páginas, 3 figuras, Matrix-assisted laser desorption/ionisation (MALDI) time-of-flight (TOF) mass spectrometry (MS) has proved to be an accurate, rapid and cost-effective technique for microbial identification in which the spectral fingerprint of an unknown strain can be compared to a database of spectra from reference strains. Most of the existing databases are private and often costly to access, and little spectral information is shared among researchers. The objective of the present communication is to introduce the SpectraBank database (http://www.spectrabank.org), which provides open access MALDI-TOF mass spectra from a variety of microorganisms. This work aims to familiarise readers with the SpectraBank database, from the sample preparation, data collection, and data analysis to how the spectral reference data can be used for microbial species identification. The database currently includes more than 200 MALDI-TOF MS spectra from more than 70 bacterial species and links to the freely available web-based application SPECLUST (http://bioinfo.thep.lu.se/speclust.html) to allow comparisons of the obtained peak mass lists and evaluate phyloproteomic relationships. The SpectraBank database is intended to be expanded by the addition of new spectra from microbial strains, obtained in our laboratory and by other researchers., This work was funded by project 10PXIB261045PR from Xunta de Galicia and by project AGL2010- 19646 from the Spanish Ministry of Science and Technology.

9 páginas, 6 tablas, The aim of this work was to evaluate a slurry ice (SI) packaging system on three bivalve species: clams (Venerupis rhomboideus), oysters (Ostrea edulis) and mussels (Mytilus galloprovincialis). Comparative analyses were performed on specimens caught in autumn and spring and compared to batches stored in conventional flake ice. Microbiological analysis of autumn specimens stored in SI showed significantly (P < 0.05) reduced numbers of mesophiles and psychrotrophs in all three species, as well as fewer Enterobacteriaceae in clams and oysters. Spring specimens also exhibited significantly (P < 0.05) lower microbial loads, with SI storage significantly (P < 0.05) improving the control of mesophiles, psychrotrophs and proteolytic bacteria in clams and oysters. Sensory analysis correlated well with microbial analyses, with a significantly (P < 0.05) better quality in terms of odour, taste, juiciness, appearance and shelf life. The SI packaging system evaluated in this work proved to be a valuable method for maintaining quality of these bivalve species., This work was supported by the Secretaría Xeral de I+D from the Xunta de Galicia (Galicia, Spain) through Research Project PGIDIT06TAL061E.

Quality loss inhibition in chilled blue whiting (Micromesistius poutassou) was investigated. For it, a natural organic acid-mixture including ascorbic, citric and lactic acids was applied in a two-step processing strategy: (i) as an aqueous dipping medium previous to chilling storage and, (ii) included in the flake ice employed as chilling system. As a result of the acid-mixture addition, a partial inhibition of microbial and biochemical mechanisms involved in the quality loss was obtained. Thus, aerobe and psychrotrophe counts in treated fish showed lower ranges (2.07–4.15 and 2.43–4.39 log CFU g−1, respectively) than control fish (2.64–5.83 and 2.30–5.30 log CFU g−1, respectively). Sensory analysis revealed that treated fish was still acceptable at the end of the experiment (day 9), while control fish was rejected at this time. Lipid hydrolysis (free fatty acid formation) proved to be more limiting of fish quality than lipid oxidation (peroxide and thiobarbituric acid-reactive substance formation)., This work was supported by the Secretaría Xeral de I+D from the Xunta de Galicia (Galicia, Spain) through the Research Project PGIDIT 08 TAL 038E.

24 pages

[EN] This study was aimed at investigating the effect of including a mixture of natural organic acids (citric, ascorbic and lactic) in the icing medium employed during the chilled storage of horse mackerel (Trachurus trachurus). To this end, two aqueous solutions including 0.005% and 0.020% (w/v) of each acid (P-1 and P-2 conditions, respectively) were employed as icing systems. The effects on lipid damage development in fish muscle were monitored for up to a 13-day storage period; complementary chemical quality and sensory acceptance analyses were carried out. According to peroxide and thiobarbituric acid reactive substance assessment, a slight inhibitory effect was concluded as a result of the acid mixture present in the chilling medium. At the same time, P-2-treated fish showed a longer shelf life than their counterparts belonging to P-1 and control conditions. No effect of the acid presence in the icing system could be outlined on the nucleotide degradation or the free fatty acid formation., [ES] Se estudió el empleo de hielo conteniendo una mezcla de ácidos orgánicos naturales (cítrico, ascórbico, láctico) como método de refrigeración en jurel (Trachurus trachurus). Para ello, se aplicó hielo incluyendo dos concentraciones (0.005 y 0.020 %; p/v) de cada ácido (condiciones P-1 y P-2, respectivamente). Se estudiaron los efectos producidos sobre el desarrollo de la alteración lipídica en el músculo de pescado conservado durante 13 días; asimismo, se realizaron análisis químicos complementarios de calidad y de aceptación sensorial. Como resultado de la presencia de los ácidos, se observó un pequeño efecto inhibidor de la formación de peróxidos y de sustancias reactivas con ácido tiobarbitúrico. Asimismo, las muestras correspondientes al tratamiento P-2 reflejaron un tiempo de vida útil mayor que las pertenecientes a las condiciones P-1 y control. La presencia de ácidos en el hielo no produjo diferencias en la degradación de nucleótidos ni en la formación de ácidos grasos libres., This work was supported by the Secretaría Xeral de I1D from the Xunta de Galicia (Galicia, Spain) through the Research Project PGIDIT 10 TAL 402001PR.