How to limit cook loss when preparing cod (Gadus morhua): The constraints of temperature and time

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On the use of pulsed electric field technology as a pretreatment to reduce the content of potentially toxic elements in dried Saccharina latissima

Seaweeds, like sugar kelp, are increasingly popular for food production, but their application is often limited by the content of iodine and other potentially toxic elements (PTEs). Boiling and blanching are efficient in reducing the iodine content (-38-94%), but are energy demanding processes and could therefore be too expensive for viable commercial applications. Pulsed electric field (PEF) processing is gaining interest for commercial processing of seaweeds, aiming to reduce the energy demand for the pre-treatment. In this work, two conditional settings (energy levels: 2.7 and 14.4 kJ/kg) of PEF were evaluated as pretreatments prior to drying of sugar kelp, and compared to no pretreatment and freezing/thawing at −20/4 °C. Both PEF treatments reduced the iodine content significantly, by approximately 40%, compared to no pretreatment. Similarly, the content of mercury was reduced by approximately 19%. Freezing prior to drying did not significantly alter the content of PTEs in dried kelp. The energy input associated with PEF processing was <10% of the calculated input for traditional processing. These findings are promising as the industry is looking into rapid, non-destructive processing methods for reducing the energy requirements associated with drying and preservation, while improving the safety of products.publishedVersio

Thaw rigor in Atlantic salmon (Salmo salar) fillets, as affected by thawing rate and frozen storage time

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Effects of capture-related stress and pre-freezing holding in refrigerated sea water (RSW) on the muscle quality and storage stability of Atlantic mackerel (Scomber scombrus) during subsequent frozen storage

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Predicting liquid loss of frozen and thawed cod from hyperspectral imaging

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Food Microstructure and Fat Content Affect Growth Morphology, Growth Kinetics, and Preferred Phase for Cell Growth of Listeria monocytogenes in Fish-Based Model Systems

Food microstructure significantly affects microbial growth dynamics, but knowledge concerning the exact influencing mechanisms at a microscopic scale is limited. The food microstructural influence on Listeria monocytogenes (green fluorescent protein strain) growth at 10°C in fish-based food model systems was investigated by confocal laser scanning microscopy. The model systems had different microstructures, i.e., liquid, xanthan (high-viscosity liquid), aqueous gel, and emulsion and gelled emulsion systems varying in fat content. Bacteria grew as single cells, small aggregates, and microcolonies of different sizes (based on colony radii [size I, 1.5 to 5.0 μm; size II, 5.0 to 10.0 μm; size III, 10.0 to 15.0 μm; and size IV, ≥15 μm]). In the liquid, small aggregates and size I microcolonies were predominantly present, while size II and III microcolonies were predominant in the xanthan and aqueous gel. Cells in the emulsions and gelled emulsions grew in the aqueous phase and on the fat-water interface. A microbial adhesion to solvent assay demonstrated limited bacterial nonpolar solvent affinities, implying that this behavior was probably not caused by cell surface hydrophobicity. In systems containing 1 and 5% fat, the largest cell volume was mainly represented by size I and II microcolonies, while at 10 and 20% fat a few size IV microcolonies comprised nearly the total cell volume. Microscopic results (concerning, e.g., growth morphology, microcolony size, intercolony distances, and the preferred phase for growth) were related to previously obtained macroscopic growth dynamics in the model systems for an L. monocytogenes strain cocktail, leading to more substantiated explanations for the influence of food microstructural aspects on lag phase duration and growth rate. IMPORTANCE Listeria monocytogenes is one of the most hazardous foodborne pathogens due to the high fatality rate of the disease (i.e., listeriosis). In this study, the growth behavior of L. monocytogenes was investigated at a microscopic scale in food model systems that mimic processed fish products (e.g., fish paté and fish soup), and the results were related to macroscopic growth parameters. Many studies have previously focused on the food microstructural influence on microbial growth. The novelty of this work lies in (i) the microscopic investigation of products with a complex composition and/or structure using confocal laser scanning microscopy and (ii) the direct link to the macroscopic level. Growth behavior (i.e., concerning bacterial growth morphology and preferred phase for growth) was more complex than assumed in common macroscopic studies. Consequently, the effectiveness of industrial antimicrobial food preservation technologies (e.g., thermal processing) might be overestimated for certain products, which may have critical food safety implications.acceptedVersio

Thermal inactivation of Listeria monocytogenes in the Shaka agitated reciprocal retort: Influence of food matrix rheology and fat content

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Nye metoder for bedre holdbarhet og mer miljøvennlig transport av lakseprodukter, faglig sluttrapport

Resultatene i dette prosjektet viser at det er fullt mulig å senke klimautslippet knyttet til transport av norsk laks. Ved å gå over til eksport av fryst laks med båt til markeder som i dag får fersk fisk transportert med fly, eller eksportere subkjølt laks til markeder som betjenes med enten lastebil eller fly, så kan man få store reduksjoner i klimautslipp. Subkjølt laks til Europa har også blitt vist å kunne gi store innsparinger i transport- og emballasjekostnader. Videre er det vist at laks som fryses og tines riktig har kvalitetsegenskaper som er sammenlignbare med fersk laks. Markedsundersøkelsene viste at overgangen til fryst og tint laks ikke nødvendigvis er enkel. Det ble pekt på en preferanse for fersk laks i USA og Japan, samt at forbrukerne ikke var villig til å betale like mye for frossen som fersk laks. Det finnes imidlertid et segment forbrukere som ønsker laks med lavt karbonavtrykk, og dette segmentet er interessant å se videre på.publishedVersio