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Pervasive Listeria monocytogenes is common in the Norwegian food system and is associated with increased prevalence of stress survival and resistance determinants
Get PDFTo investigate the diversity, distribution, persistence, and prevalence of stress survival and resistance genes of Listeria monocytogenes clones dominating in food processing environments in Norway, genome sequences from 769 L. monocytogenes isolates from food industry environments, foods, and raw materials (512 of which were sequenced in the present study) were subjected to whole-genome multilocus sequence typing (wgMLST), single-nucleotide polymorphism (SNP), and comparative genomic analyses. The data set comprised isolates from nine meat and six salmon processing facilities in Norway collected over a period of three decades. The most prevalent clonal complex (CC) was CC121, found in 10 factories, followed by CC7, CC8, and CC9, found in 7 factories each. Overall, 72% of the isolates were classified as persistent, showing 20 or fewer wgMLST allelic differences toward an isolate found in the same factory in a different calendar year. Moreover, over half of the isolates (56%) showed this level of genetic similarity toward an isolate collected from a different food processing facility. These were designated as pervasive strains, defined as clusters with the same level of genetic similarity as persistent strains but isolated from different factories. The prevalence of genetic determinants associated with increased survival in food processing environments, including heavy metal and biocide resistance determinants, stress response genes, and inlA truncation mutations, showed a highly significant increase among pervasive isolates but not among persistent isolates. Furthermore, these genes were significantly more prevalent among the isolates from food processing environments compared to in isolates from natural and rural environments (n = 218) and clinical isolates (n = 111) from NorwaypublishedVersio
Utnyttelse av restråstoff fra makrell og sild, ekstraksjon av fosfolipider - Faglig sluttrapport
Get PDFI prosjektet er det studert egnethet til restråstoff fra filetering av makrell og sild til ekstraksjon av fosfolipider. Makrellavskjær er funnet lite egnet sammenlignet med sild og spesielt umoden silderogn. Konsentrasjon av fosfolipider på tørrstoffbasis kan økes ved å foreta en varmebehandling og pressing/separasjon for fjerning av olje (triglyserider) i samfengt restråstoff. Det er utviklet en prosessoppskrift for kostnadseffektiv ekstraksjon av fosfolipider basert på etanolekstraksjon av spraytørket umoden silderogn. Fremgangsmåten gir høyt utbytte av lipidekstrakt med >65 % fosfolipider og 31 % n-3 PUFA. Optimale betingelser er funnet å være 11,3 % vann i etanolfasen med ingen effekt av temperatur i området 20-60 °C. Direkte ekstraksjon av våt rogn gir 25 % lavere utbytte sammenlignet med spraytørket rogn. Ekstraktet har en lys farge, lavt oksidasjonsnivå og nivå av uønskede forbindelser godt under gjeldende grenseverdier. Effekt på viskositet ved tilsetting av raffinert makrellolje er dokumentert. Forsøk på stabilisering av lipidekstraktet har ikke dokumentert effekt av tilsetting av naturlige tokoferoler eller rosmarinekstrakt. Rapporten gir også en oversikt over patenter med relevans for den anvendte teknologi.Utnyttelse av restråstoff fra makrell og sild, ekstraksjon av fosfolipider - Faglig sluttrapportpublishedVersio
The Effect of Buffer Towing on Quality Aspects of Frozen and Thawed Atlantic Cod (Gadus Morhua)
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Hvordan håndteres avrenning fra ferskfisktransport i andre fiskenasjoner, en komparativ studie av Irland, Island og Færøyene
Get PDFDet ble gjennomført en komparativ studie hos villfiskforedlere, lakseslakteri, transportbyrå og tilsynsmyndigheter i Irland, Island og Færøyene der man diskuterte problemstillingen rundt avrenning fra lastebiler som transporterer fersk fisk på is. Disse tre landene ble valgt, siden de har både fangst av villfisk, samt har oppdrett av laks. I tillegg representerer de land innenfor og utenfor EU. Det var til dels store forskjeller mellom hvilket fokus dette fenomenet hadde i de tre landene. I Irland var det tilnærmet ingen oppmerksomhet knyttet til avrenning, der hverken publikum eller myndigheter gav det noen oppmerksomhet. På Island var det forbud mot å la det renne ut på veien, og det var påbudt for lastebiler som transporterte fersk fisk å ha montert oppsamlingstanker på lastebilene. De hadde derimot ikke noe ordnet system på hvor tankene skulle tømmes, og det var heller ikke mye fokus på fra myndighetenes side på at dette ble overholdt. Tilsynelatende førte dette til at mange ikke lukket ventilen på oppsamlingtanken. På Færøyene var det forbud og krav til oppsamling for laksetransport. Dette skyldes frykt for smitte av ILA til villfisk i færøyske vassdrag. Til forskjell fra Island, så har de organisert oppsamling, og vannet desinfiseres før det slippes ut.Hvordan håndteres avrenning fra ferskfisktransport i andre fiskenasjoner, en komparativ studie av Irland, Island og FærøyenepublishedVersio
Reproductive biology of lumpfish (Cyclopterus lumpus): a key to successful selective breeding
Get PDFA detailed description of lumpfish reproductive biology has been described in terms of gonadal development using histological analysis and physiology using sex steroid development. This knowledge of basic reproductive biology of lumpfish has adopted by our industry partners in their breeding activities in their facilities. Our results demonstrated that spawning of lumpfish can be shifted using photomanipulation to spawn different times of the year and spawning can also be synchronized by increasing the temperature prior to ovulation. This means that lumpfish broodstock can be photomanipulated to spawn different times of the year. Compressing the natural photoperiod resulted in temporal shifts in levels of sex steroids and advanced gonad development, leading to earlier spawning. This knowledge has been currently implemented by our industry partners AquaGen and Namdal Rensefisk. Further, a non-invasive method for gender identification of lumpfish at smaller size (less than 50 g) using ultrasound technology has been developed in Cyclobreed project and the accuracy of this method is more than 90%. This is a huge benefit and important tool for the breeding companies, in this case our industrial partner AquaGen, in maintaining a proper sex ratio (increased females) in their breeding program. Currently AquaGen has implemented this tool in their breeding program for lumpfish.Reproductive biology of lumpfish (Cyclopterus lumpus): a key to successful selective breedingpublishedVersio
Low-cost, mass-producible nanostructured surface on flexible substrate with ultra-thin gold or silver film for SERS applications
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Global economic drivers in the development of different industrial hubs in the European Arctic
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Effect of Citric Acid Cross Linking on the Mechanical, Rheological and Barrier Properties of Chitosan
Get PDFIn this study, acetic acid (AA-2% w/v), a combination of acetic acid and citric acid (AA-1% w/v + CA-1% w/w), and three different concentrations of citric acid (CA-2, 4 and 6% w/w) were used to create chitosan solution. The FTIR analysis showed the presence of residual CA in all the CA-containing samples where no trace of AA was observed. The tensile strengths of the CA-containing samples were lower than the AA samples. Whereas the values for the elongation at break of the CA samples were higher than the AA samples, which kept increasing with an increasing CA content due to the plasticizing effect from residual citric acid. The elongation at break values for 4 and 6% CA-containing samples were 98% higher than the AA samples. The samples prepared with CA showed shorter LVE regions that reduced with an increasing CA concentration compared to the AA samples. Different acid concentrations did not have a large effect on the gelation time. However, CA-containing samples showed higher viscosities as compared to the AA-containing solution, which increased with an increasing CA content. The water vapour transmission rates of the CA-containing samples were lower than the others. All the chitosan solutions suppressed the growth of the two test strains, and none of the variants reached an abs 600 nm at 0.2.Effect of Citric Acid Cross Linking on the Mechanical, Rheological and Barrier Properties of ChitosanpublishedVersio
Raman and near Infrared Spectroscopy for Quantification of Fatty Acids in Muscle Tissue—A Salmon Case Study
Get PDFThe aim of the present study was to critically evaluate the potential of using NIR and Raman spectroscopy for prediction of fatty acid features and single fatty acids in salmon muscle. The study was based on 618 homogenized salmon muscle samples acquired from Atlantic salmon representing a one year-class nucleus, fed the same high fish oil feed. NIR and Raman spectra were used to make regression models for fatty acid features and single fatty acids measured by gas chromatography. The predictive performance of both NIR and Raman was good for most fatty acids, with R2 above 0.6. Overall, Raman performed marginally better than NIR, and since the Raman models generally required fewer components than respective NIR models to reach high and optimal performance, Raman is likely more robust for measuring fatty acids compared to NIR. The fatty acids of the salmon samples co-varied to a large extent, a feature that was exacerbated by the overlapping peaks in NIR and Raman spectra. Thus, the fatty acid related variation of the spectroscopic data of the present study can be explained by only a few independent principal components. For the Raman spectra, this variation was dominated by functional groups originating from long-chain polyunsaturated FAs like EPA and DHA. By exploring the independent EPA and DHA Raman models, spectral signatures similar to the respective pure fatty acids could be seen. This proves the potential of Raman spectroscopy for single fatty acid prediction in muscle tissue.Raman and near Infrared Spectroscopy for Quantification of Fatty Acids in Muscle Tissue—A Salmon Case StudypublishedVersio
Gelation and network structure of acidified milk gel investigated at different length scales with and without addition of iota-carrageenan
Get PDFThis work investigated the formation of acid milk gel at different length scales with and without the addition of iota-carrageenan (IC) (0.5% w/w) during incubation at 30 °C, using bulk rheology and syringe compression test at the macroscopic level, passive particle tracking (particle diameter 0.3 μm and 1.0 μm) at the microscopic level and pulsed field gradient (PFG)-NMR with poly(ethylene oxide) (PEO) at the molecular level. IC induced the early formation of the gel network in the sample as demonstrated by the progressive G′ and G″ increase (where G′ > G″) in the macroscopic measurement. When repeatedly compressed at the developing stage, the formed gel network in the IC sample reassociated into non-native colloidal structures unable to contain the serum phase, which also occurred without IC but at later incubation stage. The increased PEO diffusion at 30 min in PFG-NMR reflected the emerging casein-casein network and its extensive rearrangement occurring at the molecular level in both samples. This corresponded with the mean square displacement of the probe particles with IC at 30 min but not without IC, indicating that IC altered the length scale of the network rearrangements occurring at the molecular level to be detected at the microscopic level in the particle tracking. The size-dependent particle behaviors in the particle tracking demonstrated a high degree of IC-induced network heterogeneity that continued to develop even at late incubation stage, on contrary to the drastic compaction of the formed network observed in the sample without IC.Gelation and network structure of acidified milk gel investigated at different length scales with and without addition of iota-carrageenanpublishedVersio