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Dr. Trond Løvdal
Nofima – Norwegian Institute of Food, Fisheries and Aquaculture Research, Dept. of Process Technology, Richard Johnsens gate 4, N-4021, Norway

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0 Food Microbiology
0 Food Safety
0 Food-borne pathogens and spoilage bacteria
0 Sustainable industrial vegetable food processing technologies
0 Hygiene in food processing plants

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Food-borne pathogens and spoilage bacteria

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Communication
Published: 16 June 2021 in Hygiene
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Listeria monocytogenes is a food-borne bacterium that give rise to the potentially life-threatening disease listeriosis. Listeriosis has been mandatorily notifiable in Norway since 1991. All clinical L. monocytogenes isolates are sent to the Norwegian Institute of Public Health (NIPH) for typing. Since 2005 Multi-Locus Variable number tandem repeats Analysis (MLVA) has been used for typing but was recently replaced by whole genome sequencing using core genome Multi-Locus Sequence Typing (cgMLST). In the present study, L. monocytogenes isolates collected at salmon processing plants in Norway in 2007 (n = 12) and 2015 (n = 14) were first subject to MLVA. Twelve clinical L. monocytogenes isolates with matching MLVA profile and sampling time were selected from the strain collection at NIPH. Twenty-one isolates from the salmon processing plants and all clinical isolates (n = 12) were whole genome sequenced and compared using cgMLST and in silico detection of virulence genes. cgMLST revealed four pairs of environmental–human isolates with ≤10 allelic differences over 1708 genes, indicating that they may be assigned as clonal, with the implication that they are descended from the same recent ancestor. No relevant difference in carriage of virulence genes was found between environmental or human isolates. The present study shows that L. monocytogenes strains that genetically resemble contemporary isolates from human listeriosis circulate in Norwegian salmon slaughterhouses, and carry the same virulence genes.

ACS Style

Trond Løvdal; Lin Brandal; Arvind Sundaram; Umaer Naseer; Bjørn Roth; Bjørn Lunestad. Small-Scale Comparative Genomic Analysis of Listeria monocytogenes Isolated from Environments of Salmon Processing Plants and Human Cases in Norway. Hygiene 2021, 1, 43 -55.

AMA Style

Trond Løvdal, Lin Brandal, Arvind Sundaram, Umaer Naseer, Bjørn Roth, Bjørn Lunestad. Small-Scale Comparative Genomic Analysis of Listeria monocytogenes Isolated from Environments of Salmon Processing Plants and Human Cases in Norway. Hygiene. 2021; 1 (1):43-55.

Chicago/Turabian Style

Trond Løvdal; Lin Brandal; Arvind Sundaram; Umaer Naseer; Bjørn Roth; Bjørn Lunestad. 2021. "Small-Scale Comparative Genomic Analysis of Listeria monocytogenes Isolated from Environments of Salmon Processing Plants and Human Cases in Norway." Hygiene 1, no. 1: 43-55.

Research note
Published: 15 April 2021 in BMC Research Notes
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Objectives The study aims to generate the whole genome sequence of L. monocytogenes strain S2542 and to compare it to the genomes of strains RO15 and ScottA. In addition, we aimed to compare gene expression profiles of L. monocytogenes strains S2542, ScottA and RO15 after high-pressure processing (HPP) using ddPCR. Results The whole genome sequence of L. monocytogenes S2542 indicates that this strain belongs to serotype 4b, in contrast to the previously reported serotype 1/2a. Strain S2542 appears to be more susceptible to the treatment at 400 MPa compared to RO15 and ScottA strains. In contrast to RO15 and ScottA strains, viable cell counts of strain S2542 were below the limit of detection after HPP (400 MPa/8 min) when stored at 8 °C for 24 and 48 h. The transcriptional response of all three strains to HPP was not significantly different.

ACS Style

Ilhan Cem Duru; Florentina Ionela Bucur; Margarita Andreevskaya; Anne Ylinen; Peter Crauwels; Leontina Grigore-Gurgu; Bahareh Nikparvar; Tone Mari Rode; Pia Laine; Lars Paulin; Trond Løvdal; Christian U. Riedel; Nadav Bar; Daniela Borda; Anca Ioana Nicolau; Petri Auvinen. The complete genome sequence of Listeria monocytogenes strain S2542 and expression of selected genes under high-pressure processing. BMC Research Notes 2021, 14, 1 -6.

AMA Style

Ilhan Cem Duru, Florentina Ionela Bucur, Margarita Andreevskaya, Anne Ylinen, Peter Crauwels, Leontina Grigore-Gurgu, Bahareh Nikparvar, Tone Mari Rode, Pia Laine, Lars Paulin, Trond Løvdal, Christian U. Riedel, Nadav Bar, Daniela Borda, Anca Ioana Nicolau, Petri Auvinen. The complete genome sequence of Listeria monocytogenes strain S2542 and expression of selected genes under high-pressure processing. BMC Research Notes. 2021; 14 (1):1-6.

Chicago/Turabian Style

Ilhan Cem Duru; Florentina Ionela Bucur; Margarita Andreevskaya; Anne Ylinen; Peter Crauwels; Leontina Grigore-Gurgu; Bahareh Nikparvar; Tone Mari Rode; Pia Laine; Lars Paulin; Trond Løvdal; Christian U. Riedel; Nadav Bar; Daniela Borda; Anca Ioana Nicolau; Petri Auvinen. 2021. "The complete genome sequence of Listeria monocytogenes strain S2542 and expression of selected genes under high-pressure processing." BMC Research Notes 14, no. 1: 1-6.

Journal article
Published: 15 April 2021
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The study aims to generate the whole genome sequence of L. monocytogenes strain S2542 and to compare it to the genomes of strains RO15 and ScottA. In addition, we aimed to compare gene expression profiles of L. monocytogenes strains S2542, ScottA and RO15 after high-pressure processing (HPP) using ddPCR. The whole genome sequence of L. monocytogenes S2542 indicates that this strain belongs to serotype 4b, in contrast to the previously reported serotype 1/2a. Strain S2542 appears to be more susceptible to the treatment at 400 MPa compared to RO15 and ScottA strains. In contrast to RO15 and ScottA strains, viable cell counts of strain S2542 were below the limit of detection after HPP (400 MPa/8 min) when stored at 8 °C for 24 and 48 h. The transcriptional response of all three strains to HPP was not significantly different.

ACS Style

Ilhan Cem Duru; Florentina Ionela Bucur; Margarita Andreevskaya; Anne Ylinen; Peter Crauwels; Leontina Grigore-Gurgu; Bahareh Nikparvar; Tone Mari Rode; Pia Laine; Lars Paulin; Trond Løvdal; Christian U Riedel; Nadav Bar; Daniela Borda; Anca Ioana Nicolau; Petri Auvinen. The complete genome sequence of Listeria monocytogenes strain S2542 and expression of selected genes under high-pressure processing. 2021, 14, 137 .

AMA Style

Ilhan Cem Duru, Florentina Ionela Bucur, Margarita Andreevskaya, Anne Ylinen, Peter Crauwels, Leontina Grigore-Gurgu, Bahareh Nikparvar, Tone Mari Rode, Pia Laine, Lars Paulin, Trond Løvdal, Christian U Riedel, Nadav Bar, Daniela Borda, Anca Ioana Nicolau, Petri Auvinen. The complete genome sequence of Listeria monocytogenes strain S2542 and expression of selected genes under high-pressure processing. . 2021; 14 (1):137.

Chicago/Turabian Style

Ilhan Cem Duru; Florentina Ionela Bucur; Margarita Andreevskaya; Anne Ylinen; Peter Crauwels; Leontina Grigore-Gurgu; Bahareh Nikparvar; Tone Mari Rode; Pia Laine; Lars Paulin; Trond Løvdal; Christian U Riedel; Nadav Bar; Daniela Borda; Anca Ioana Nicolau; Petri Auvinen. 2021. "The complete genome sequence of Listeria monocytogenes strain S2542 and expression of selected genes under high-pressure processing." 14, no. 1: 137.

Research article
Published: 12 February 2021 in BMC Genomics
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Background High-pressure processing (HPP) is a commonly used technique in the food industry to inactivate pathogens, including L. monocytogenes. It has been shown that L. monocytogenes is able to recover from HPP injuries and can start to grow again during long-term cold storage. To date, the gene expression profiling of L. monocytogenes during HPP damage recovery at cooling temperature has not been studied. In order identify key genes that play a role in recovery of the damage caused by HPP treatment, we performed RNA-sequencing (RNA-seq) for two L. monocytogenes strains (barotolerant RO15 and barosensitive ScottA) at nine selected time points (up to 48 h) after treatment with two pressure levels (200 and 400 MPa). Results The results showed that a general stress response was activated by SigB after HPP treatment. In addition, the phosphotransferase system (PTS; mostly fructose-, mannose-, galactitol-, cellobiose-, and ascorbate-specific PTS systems), protein folding, and cobalamin biosynthesis were the most upregulated genes during HPP damage recovery. We observed that cell-division-related genes (divIC, dicIVA, ftsE, and ftsX) were downregulated. By contrast, peptidoglycan-synthesis genes (murG, murC, and pbp2A) were upregulated. This indicates that cell-wall repair occurs as a part of HPP damage recovery. We also observed that prophage genes, including anti-CRISPR genes, were induced by HPP. Interestingly, a large amount of RNA-seq data (up to 85%) was mapped to Rli47, which is a non-coding RNA that is upregulated after HPP. Thus, we predicted that Rli47 plays a role in HPP damage recovery in L. monocytogenes. Moreover, gene-deletion experiments showed that amongst peptidoglycan biosynthesis genes, pbp2A mutants are more sensitive to HPP. Conclusions We identified several genes and mechanisms that may play a role in recovery from HPP damage of L. monocytogenes. Our study contributes to new information on pathogen inactivation by HPP.

ACS Style

Ilhan Cem Duru; Florentina Ionela Bucur; Margarita Andreevskaya; Bahareh Nikparvar; Anne Ylinen; Leontina Grigore-Gurgu; Tone Mari Rode; Peter Crauwels; Pia Laine; Lars Paulin; Trond Løvdal; Christian U. Riedel; Nadav Bar; Daniela Borda; Anca Ioana Nicolau; Petri Auvinen. High-pressure processing-induced transcriptome response during recovery of Listeria monocytogenes. BMC Genomics 2021, 22, 1 -20.

AMA Style

Ilhan Cem Duru, Florentina Ionela Bucur, Margarita Andreevskaya, Bahareh Nikparvar, Anne Ylinen, Leontina Grigore-Gurgu, Tone Mari Rode, Peter Crauwels, Pia Laine, Lars Paulin, Trond Løvdal, Christian U. Riedel, Nadav Bar, Daniela Borda, Anca Ioana Nicolau, Petri Auvinen. High-pressure processing-induced transcriptome response during recovery of Listeria monocytogenes. BMC Genomics. 2021; 22 (1):1-20.

Chicago/Turabian Style

Ilhan Cem Duru; Florentina Ionela Bucur; Margarita Andreevskaya; Bahareh Nikparvar; Anne Ylinen; Leontina Grigore-Gurgu; Tone Mari Rode; Peter Crauwels; Pia Laine; Lars Paulin; Trond Løvdal; Christian U. Riedel; Nadav Bar; Daniela Borda; Anca Ioana Nicolau; Petri Auvinen. 2021. "High-pressure processing-induced transcriptome response during recovery of Listeria monocytogenes." BMC Genomics 22, no. 1: 1-20.

Journal article
Published: 02 July 2020 in BMC Genomics
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Background High pressure processing (HPP; i.e. 100–600 MPa pressure depending on product) is a non-thermal preservation technique adopted by the food industry to decrease significantly foodborne pathogens, including Listeria monocytogenes, from food. However, susceptibility towards pressure differs among diverse strains of L. monocytogenes and it is unclear if this is due to their intrinsic characteristics related to genomic content. Here, we tested the barotolerance of 10 different L. monocytogenes strains, from food and food processing environments and widely used reference strains including clinical isolate, to pressure treatments with 400 and 600 MPa. Genome sequencing and genome comparison of the tested L. monocytogenes strains were performed to investigate the relation between genomic profile and pressure tolerance. Results None of the tested strains were tolerant to 600 MPa. A reduction of more than 5 log10 was observed for all strains after 1 min 600 MPa pressure treatment. L. monocytogenes strain RO15 showed no significant reduction in viable cell counts after 400 MPa for 1 min and was therefore defined as barotolerant. Genome analysis of so far unsequenced L. monocytogenes strain RO15, 2HF33, MB5, AB199, AB120, C7, and RO4 allowed us to compare the gene content of all strains tested. This revealed that the three most pressure tolerant strains had more than one CRISPR system with self-targeting spacers. Furthermore, several anti-CRISPR genes were detected in these strains. Pan-genome analysis showed that 10 prophage genes were significantly associated with the three most barotolerant strains. Conclusions L. monocytogenes strain RO15 was the most pressure tolerant among the selected strains. Genome comparison suggests that there might be a relationship between prophages and pressure tolerance in L. monocytogenes.

ACS Style

Ilhan Cem Duru; Margarita Andreevskaya; Pia Laine; Tone Mari Rode; Anne Ylinen; Trond Løvdal; Nadav Bar; Peter Crauwels; Christian U. Riedel; Florentina Ionela Bucur; Anca Ioana Nicolau; Petri Auvinen. Genomic characterization of the most barotolerant Listeria monocytogenes RO15 strain compared to reference strains used to evaluate food high pressure processing. BMC Genomics 2020, 21, 1 -14.

AMA Style

Ilhan Cem Duru, Margarita Andreevskaya, Pia Laine, Tone Mari Rode, Anne Ylinen, Trond Løvdal, Nadav Bar, Peter Crauwels, Christian U. Riedel, Florentina Ionela Bucur, Anca Ioana Nicolau, Petri Auvinen. Genomic characterization of the most barotolerant Listeria monocytogenes RO15 strain compared to reference strains used to evaluate food high pressure processing. BMC Genomics. 2020; 21 (1):1-14.

Chicago/Turabian Style

Ilhan Cem Duru; Margarita Andreevskaya; Pia Laine; Tone Mari Rode; Anne Ylinen; Trond Løvdal; Nadav Bar; Peter Crauwels; Christian U. Riedel; Florentina Ionela Bucur; Anca Ioana Nicolau; Petri Auvinen. 2020. "Genomic characterization of the most barotolerant Listeria monocytogenes RO15 strain compared to reference strains used to evaluate food high pressure processing." BMC Genomics 21, no. 1: 1-14.

Preprint content
Published: 13 May 2020
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Background: High pressure processing (HPP; i.e. 100 - 600 MPa pressure depending on product) is a non-thermal preservation technique adopted by the food industry to decrease significantly foodborne pathogens, including Listeria monocytogenes, from food. However, susceptibility towards pressure differs among diverse strains of L. monocytogenes and it is unclear if this is related to their genomic content. Here, we tested the barotolerance of 10 different L. monocytogenes strains, from food and food processing environments and widely used reference type strains, to pressure treatments with 400 and 600 MPa. Genome sequencing and genome comparison of the tested L. monocytogenes strains were performed to investigate the relation between genomic profile and pressure tolerance.Results: None of the tested strains were tolerant to 600 MPa. A reduction of more than 5 log10 was observed for all strains after 1 minute 600 MPa pressure treatment. L. monocytogenes strain RO15 showed no significant reduction in viable cell counts after 400 MPa for 1 minute and was therefore defined as barotolerant. Genome analysis of so far unsequenced L. monocytogenes strain RO15, 2HF33, MB5, AB199, AB120, C7, and RO4 allowed us to compare the gene content of all strains tested. This revealed that the three most pressure tolerant strains had more than one CRISPR system with self-targeting spacers. Furthermore, several anti-CRISPR genes were detected in these strains. Pan-genome analysis showed that 10 prophage genes were significantly associated with the three most barotolerant strains.Conclusions: L. monocytogenes strain RO15 was the most pressure tolerant among the selected strains. Genome comparison suggests that there might be a relationship between prophages and pressure tolerance in L. monocytogenes.

ACS Style

Ilhan Cem Duru; Margarita Andreevskaya; Pia Laine; Tone Mari Rode; Anne Ylinen; Trond Løvdal; Nadav Bar; Peter Crauwels; Christian Riedel; Florentina Ionela Bucur; Anca Ioana Nicolau; Petri Auvinen. Complete genome of the barotolerant Listeria monocytogenes RO15 strain and comparison with other strains isolated from food and food processing environments. 2020, 1 .

AMA Style

Ilhan Cem Duru, Margarita Andreevskaya, Pia Laine, Tone Mari Rode, Anne Ylinen, Trond Løvdal, Nadav Bar, Peter Crauwels, Christian Riedel, Florentina Ionela Bucur, Anca Ioana Nicolau, Petri Auvinen. Complete genome of the barotolerant Listeria monocytogenes RO15 strain and comparison with other strains isolated from food and food processing environments. . 2020; ():1.

Chicago/Turabian Style

Ilhan Cem Duru; Margarita Andreevskaya; Pia Laine; Tone Mari Rode; Anne Ylinen; Trond Løvdal; Nadav Bar; Peter Crauwels; Christian Riedel; Florentina Ionela Bucur; Anca Ioana Nicolau; Petri Auvinen. 2020. "Complete genome of the barotolerant Listeria monocytogenes RO15 strain and comparison with other strains isolated from food and food processing environments." , no. : 1.

Journal article
Published: 27 June 2019 in Foods
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There is a large potential in Europe for valorization in the vegetable food supply chain. For example, there is occasionally overproduction of tomatoes for fresh consumption, and a fraction of the production is unsuited for fresh consumption sale (unacceptable color, shape, maturity, lesions, etc.). In countries where the facilities and infrastructure for tomato processing is lacking, these tomatoes are normally destroyed, used as landfilling or animal feed, and represent an economic loss for producers and negative environmental impact. Likewise, there is also a potential in the tomato processing industry to valorize side streams and reduce waste. The present paper provides an overview of tomato production in Europe and the strategies employed for processing and valorization of tomato side streams and waste fractions. Special emphasis is put on the four tomato-producing countries Norway, Belgium, Poland, and Turkey. These countries are very different regards for example their climatic preconditions for tomato production and volumes produced, and represent the extremes among European tomato producing countries. Postharvest treatments and applications for optimized harvest time and improved storage for premium raw material quality are discussed, as well as novel, sustainable processing technologies for minimum waste and side stream valorization. Preservation and enrichment of lycopene, the primary health promoting agent and sales argument, is reviewed in detail. The European volume of tomato postharvest wastage is estimated at >3 million metric tons per year. Together, the optimization of harvesting time and preprocessing storage conditions and sustainable food processing technologies, coupled with stabilization and valorization of processing by-products and side streams, can significantly contribute to the valorization of this underutilized biomass.

ACS Style

Trond Løvdal; Bart Van Droogenbroeck; Evren Caglar Eroglu; Stanislaw Kaniszewski; Giovanni Agati; Michel Verheul; Dagbjørn Skipnes. Valorization of Tomato Surplus and Waste Fractions: A Case Study Using Norway, Belgium, Poland, and Turkey as Examples. Foods 2019, 8, 229 .

AMA Style

Trond Løvdal, Bart Van Droogenbroeck, Evren Caglar Eroglu, Stanislaw Kaniszewski, Giovanni Agati, Michel Verheul, Dagbjørn Skipnes. Valorization of Tomato Surplus and Waste Fractions: A Case Study Using Norway, Belgium, Poland, and Turkey as Examples. Foods. 2019; 8 (7):229.

Chicago/Turabian Style

Trond Løvdal; Bart Van Droogenbroeck; Evren Caglar Eroglu; Stanislaw Kaniszewski; Giovanni Agati; Michel Verheul; Dagbjørn Skipnes. 2019. "Valorization of Tomato Surplus and Waste Fractions: A Case Study Using Norway, Belgium, Poland, and Turkey as Examples." Foods 8, no. 7: 229.

Journal article
Published: 30 January 2019 in Food Control
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This paper presents the development and experimental testing of the effectiveness of a robotic cleaning system for fish processing plants. The processing of fish introduces a substantial risk of bacterial contamination, which can cause the spoilage of fish and pose a threat to consumers’ health. Good operational hygiene and precautions, in addition to regular cleaning of the processing plants, are necessary for the reduction of the risk of contamination. The state-of-the art cleaning techniques currently include manual cleaning operations of fish processing plants. The experiments of robotic cleaning presented in this paper were performed in two rounds. First, a test using a conventional low-cost industrial robot mounted on a vertical linear axis was used. As the results from this test seemed promising, a second robotic system was built aiming at a more industrialized version. This system consisted of a serial manipulator, tailored for the task, mounted on a horizontal transportation system, and a comparison was conducted between the cleaning performed by human operators and that performed by the robotic system. An electrical stunner with a connected conveyor belt, which is a typical installation for salmon processing plants, was experimentally inoculated with a cocktail of fish-spoilage bacteria that were allowed to develop a biofilm. Back-to-back cleaning trials with biofilms of Pseudomonas fluorescens, Pseudomonas putida, and Photobacterium phosphoreum confirmed that the industrialized robotic prototype performed equally well or better than the conventional manual cleaning procedure currently used in the industry. The results demonstrate that a robotic system can deliver satisfactory results in the cleaning of fish processing plants, thereby minimizing the potential for the spread of contamination. The proposed robotic concept allows for an automated cleaning system, reduced human labor, increased profitability for the industry, and better stability of the cleaning process.

ACS Style

Lars Andre Langøyli Giske; Emil Bjørlykhaug; Trond Løvdal; Ola Jon Mork. Experimental study of effectiveness of robotic cleaning for fish-processing plants. Food Control 2019, 100, 269 -277.

AMA Style

Lars Andre Langøyli Giske, Emil Bjørlykhaug, Trond Løvdal, Ola Jon Mork. Experimental study of effectiveness of robotic cleaning for fish-processing plants. Food Control. 2019; 100 ():269-277.

Chicago/Turabian Style

Lars Andre Langøyli Giske; Emil Bjørlykhaug; Trond Løvdal; Ola Jon Mork. 2019. "Experimental study of effectiveness of robotic cleaning for fish-processing plants." Food Control 100, no. : 269-277.

Journal article
Published: 01 January 2019 in Procedia CIRP
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ACS Style

Lars Andre Langøyli Giske; Tommy Benjaminsen; Ola Jon Mork; Trond Løvdal. Visualization Support for Design of Manufacturing Systems and Prototypes – Lessons Learned from Two Case Studies. Procedia CIRP 2019, 81, 512 -517.

AMA Style

Lars Andre Langøyli Giske, Tommy Benjaminsen, Ola Jon Mork, Trond Løvdal. Visualization Support for Design of Manufacturing Systems and Prototypes – Lessons Learned from Two Case Studies. Procedia CIRP. 2019; 81 ():512-517.

Chicago/Turabian Style

Lars Andre Langøyli Giske; Tommy Benjaminsen; Ola Jon Mork; Trond Løvdal. 2019. "Visualization Support for Design of Manufacturing Systems and Prototypes – Lessons Learned from Two Case Studies." Procedia CIRP 81, no. : 512-517.

Research article
Published: 19 September 2018 in Journal of the Science of Food and Agriculture
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BACKGROUND There is a fast increase in the number of seaweed farms in the Western World, and it is crucial for these companies and their customers to have standardized methods for quality assessment and optimization. The aim of this study was to adapt known methods for food quality determination for analysis of seaweed quality, including color, texture and microbiology, and discuss optimal heat treatments for the popular macroalgae Saccharina latissima and Alaria esculenta. RESULTS The development of a desirable, green color during heating was highly specific to species, freezing history and part of the thallus. The resilience and its thermostability was also species dependent. Low microbial numbers (1 – 3 log cfu/g) for total aerobic count, psychrotrophic bacteria, and spore‐forming bacteria were found, but Bacillus spp. were isolated. No enterococci, coliforms, pathogenic vibrios, nor Listeria monocytogenes were detected. CONCLUSION The employed methods were able to describe clearly the physical and microbial quality of A. esculenta and S. latissima, as well as the quality change during processing. Based on the results, optimal cooking for a minimum of 15 minutes at 95 °C was suggested for S. latissima. Fresh and frozen A. esculenta showed the greenest color after heating for a few seconds (5 – 9 s) at a high temperature (> 85 °C). If a higher heat load is needed for achieving safe and stable food products, using fresh and not frozen A. esculenta is highly recommended, as fresh specimens remain green even after 15 minutes at 95 °C. This article is protected by copyright. All rights reserved.

ACS Style

Marthe J Blikra; Trond Løvdal; Mette R Vaka; Irja S Roiha; Bjørn Tore Lunestad; Cecilie Lindseth; Dagbjørn Skipnes. Assessment of food quality and microbial safety of brown macroalgae (Alaria esculentaandSaccharina latissima). Journal of the Science of Food and Agriculture 2018, 99, 1198 -1206.

AMA Style

Marthe J Blikra, Trond Løvdal, Mette R Vaka, Irja S Roiha, Bjørn Tore Lunestad, Cecilie Lindseth, Dagbjørn Skipnes. Assessment of food quality and microbial safety of brown macroalgae (Alaria esculentaandSaccharina latissima). Journal of the Science of Food and Agriculture. 2018; 99 (3):1198-1206.

Chicago/Turabian Style

Marthe J Blikra; Trond Løvdal; Mette R Vaka; Irja S Roiha; Bjørn Tore Lunestad; Cecilie Lindseth; Dagbjørn Skipnes. 2018. "Assessment of food quality and microbial safety of brown macroalgae (Alaria esculentaandSaccharina latissima)." Journal of the Science of Food and Agriculture 99, no. 3: 1198-1206.

Articles
Published: 07 February 2017 in Journal of Aquatic Food Product Technology
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The effects of a commercial lactate salt formulation—containing potassium lactate (KL) and potassium acetate (KA)—and liquid smoke (LS) on the growth of selected lactic acid bacteria (LAB; Carnobacterium maltaromaticum, Carnobacterium inhibens, Lactococcus lactis, Lactobacillus curvatus, and Enterococcus faecalis), fish spoilage bacteria (Photobacterium phosphoreum, Pseudomonas putida, and Vibrio vulnificus), and Listeria innocua, were examined in a tryptic soy broth model system at 20ºC based on BioScreen data. The most pronounced inhibition effect on growth of bacteria was seen in the presence of 6% KL + 0.4% KA, used either combined with LS or alone. Only a minor inhibition effect on growth was found in the presence of LS alone. The only exception was Lactobacillus curvatus, which grew quite well in the presence of LS compared to control medium. The growth of Vibrio vulnificus was prevented in 6% KL + 0.4% KA, and significantly inhibited in the presence of 3% KL + 0.2% KA. When V. vulnificus was grown in NaCl, KA, and KL + KA, it was observed that KL + KA had a better inhibition effect than sodium salt within the same concentration range.

ACS Style

Aparna Saha; Sveinung Birkeland; Trond Løvdal. The Effect of K-Lactate Salt and Liquid Smoke on Bacterial Growth in a Model System. Journal of Aquatic Food Product Technology 2017, 26, 192 -204.

AMA Style

Aparna Saha, Sveinung Birkeland, Trond Løvdal. The Effect of K-Lactate Salt and Liquid Smoke on Bacterial Growth in a Model System. Journal of Aquatic Food Product Technology. 2017; 26 (2):192-204.

Chicago/Turabian Style

Aparna Saha; Sveinung Birkeland; Trond Løvdal. 2017. "The Effect of K-Lactate Salt and Liquid Smoke on Bacterial Growth in a Model System." Journal of Aquatic Food Product Technology 26, no. 2: 192-204.

Journal article
Published: 01 August 2015 in Food Control
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ACS Style

Trond Løvdal. The microbiology of cold smoked salmon. Food Control 2015, 54, 360 -373.

AMA Style

Trond Løvdal. The microbiology of cold smoked salmon. Food Control. 2015; 54 ():360-373.

Chicago/Turabian Style

Trond Løvdal. 2015. "The microbiology of cold smoked salmon." Food Control 54, no. : 360-373.

Journal article
Published: 21 July 2014 in Journal of Food Science
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A total of 18 farmed turbot (Scophthalmus maximus) were slaughtered over 4 successive weeks in November 2012 and stored in polystyrene boxes with ice until analyzed. The fish were stored between 1 and 22 d and presented to a taste panel and further analyzed for quality index method (QIM), microbiological analysis by real‐time quantitative PCR (qPCR), taste, pH, color by computer imaging, protein denaturation with differential scanner calorimeter (DSC), texture hardness, and shear force. Results show small, but significant changes in physical and visual attributes such as texture and color. No gaping was observed. Only small changes in texture were observed explained by lack of myosin denaturation. The fillets became more white and yellow during storage, whereas the major changes occurred during the 1st week. A panel evaluating QIM and taste could not distinguish major differences in appearance and taste and over 15 d storage period, but were able to quantify the age by smell. Analysis of microorganisms on the epidermis displayed growth of Carnobacterium maltaromaticum, potentially inhibiting growth of other spoilage bacteria. Fish stored for 22 d were rejected by the taste panel caused by a stale smell and taste, but not bitter or rancid. It is concluded that turbot has a shelf life of at least 16 d.

ACS Style

Bjorn Roth; Lene Kramer; Aase Vorre Skuland; Trond Løvdal; Sigurd Øines; Atle Foss; Albert Kjartansson Imsland. The Shelf Life of Farmed Turbot ( Scophthalmus maximus ). Journal of Food Science 2014, 79, 1 .

AMA Style

Bjorn Roth, Lene Kramer, Aase Vorre Skuland, Trond Løvdal, Sigurd Øines, Atle Foss, Albert Kjartansson Imsland. The Shelf Life of Farmed Turbot ( Scophthalmus maximus ). Journal of Food Science. 2014; 79 (8):1.

Chicago/Turabian Style

Bjorn Roth; Lene Kramer; Aase Vorre Skuland; Trond Løvdal; Sigurd Øines; Atle Foss; Albert Kjartansson Imsland. 2014. "The Shelf Life of Farmed Turbot ( Scophthalmus maximus )." Journal of Food Science 79, no. 8: 1.

Journal article
Published: 14 September 2013 in Molecular Biotechnology
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Eight putative consistently expressed genes in Carnobacterium maltaromaticum and Lactobacillus curvatus, and nine in Listeria innocua, were examined for their potential as references for the normalization of gene expression. Expression stability of candidate reference genes was evaluated under growth conditions of low (5 °C) and moderately high (40–42.5 °C) temperatures, and high salt (≥3 % NaCl) using the geNormplus and NormFinder algorithms. Under temperature stress, both algorithms ranked elongation factor Tu (Tuf) as the most stably expressed gene in C. maltaromaticum. In L. curvatus, at similar conditions, geNormplus identified Tuf and 6-phosphogluconate dehydrogenase (6PGDH) as suitable for normalization, while NormFinder identified phenylalanyl-tRNA synthase and recombinase A as the best pair. In L. innocua grown under the same temperatures, geNormplus ranked 6PGDH, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and Tuf as the top three most stable references, whereas NormFinder identified GAPDH and 6PGDH as suitable for normalization, with Tuf ranked as number six. There was less consistency between algorithms in the salt stress experiment. No gene was identified that exhibited such a constant level of expression as to outperform the other candidates under both experimental conditions. This study underlines the need for normalizing bacterial gene expression using multiple carefully selected references.

ACS Style

Trond Løvdal; Aparna Saha. Reference Gene Selection in Carnobacterium maltaromaticum, Lactobacillus curvatus, and Listeria innocua Subjected to Temperature and Salt Stress. Molecular Biotechnology 2013, 56, 210 -222.

AMA Style

Trond Løvdal, Aparna Saha. Reference Gene Selection in Carnobacterium maltaromaticum, Lactobacillus curvatus, and Listeria innocua Subjected to Temperature and Salt Stress. Molecular Biotechnology. 2013; 56 (3):210-222.

Chicago/Turabian Style

Trond Løvdal; Aparna Saha. 2013. "Reference Gene Selection in Carnobacterium maltaromaticum, Lactobacillus curvatus, and Listeria innocua Subjected to Temperature and Salt Stress." Molecular Biotechnology 56, no. 3: 210-222.

Journal article
Published: 07 November 2012 in Antonie van Leeuwenhoek
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The time/temperature profiles experienced by spores on the track from their natural sporulation environment to consumable food products may be highly diverse. Temperature has been documented as an important factor that may activate spores, i.e. potentiates spores to germinate. There is, however, limited knowledge about the relationship between the expected temperature history and the subsequent germination characteristics of bacterial spores. We show here that the germination rate of five different Bacillus spore populations, represented by strains of Bacillus cereus, Bacillus weihenstephanensis, Bacillus pumilus, Bacillus licheniformis and Bacillus subtilis could be increased following 1 week storage at moderately elevated temperatures, 30–33 °C, compared to spores stored at 3–8 °C. The results imply that spores contamination routes to foods, specifically the temperature history, could be highly relevant data in predictive modeling of food spoilage and safety. Activation at these moderately elevated temperatures may be a native form of spore activation in their natural habitats, knowledge that also could be useful in development of decontamination strategies for mildly heated foods.

ACS Style

Irene Stranden Løvdal; Per Einar Granum; Jan Thomas Rosnes; Trond Løvdal. Activation of Bacillus spores at moderately elevated temperatures (30–33 °C). Antonie van Leeuwenhoek 2012, 103, 693 -700.

AMA Style

Irene Stranden Løvdal, Per Einar Granum, Jan Thomas Rosnes, Trond Løvdal. Activation of Bacillus spores at moderately elevated temperatures (30–33 °C). Antonie van Leeuwenhoek. 2012; 103 (3):693-700.

Chicago/Turabian Style

Irene Stranden Løvdal; Per Einar Granum; Jan Thomas Rosnes; Trond Løvdal. 2012. "Activation of Bacillus spores at moderately elevated temperatures (30–33 °C)." Antonie van Leeuwenhoek 103, no. 3: 693-700.

Journal article
Published: 12 March 2012 in Phytochemistry
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High concentrations of phenolics have been shown to play a role in plant resistance to pathogens. One way to obtain increased phenolic concentrations in plant tissues is to limit mineral nitrogen (N) availability; however, over long periods, this treatment will have a negative effect on plant growth. The aim of our study was to determine the effect of repeated short-term N limitations on plant growth and phenolic metabolism in leaves. Tomato plants (Solanum lycopersicum, cv. Pixie) were subjected to two successive 10-day N-limitation periods (0.15 mM NO3−, 0.01 mM NH4+), followed by periods of full nutrient supply (15 mM NO3−, 1.2 mM NH4+). Additionally, other plants were subjected to either of these two limitation periods, and a set of control plants was given a full nutrient supply during the entire period. The phenolic metabolism was monitored by measuring the leaf concentrations of chlorogenic acid, three flavonol glycosides (quercetin and kaempferol derivatives) and two major anthocyanins, together with the expression of eight structural genes and three transcription factors of the phenylpropanoid pathway. The relative growth rate of the plants decreased during the N-limitation periods but was restored as soon as N was resupplied. Each N-limitation period resulted in an up-regulation of the phenolic biosynthetic pathway, as demonstrated by an increase in the leaf phenolic concentration and an up-regulation of the related genes. The genes in the phenolic pathway were down-regulated immediately when N was resupplied; however, the leaf concentrations of several phenolics, particularly flavonol glycosides, were maintained at significantly higher levels than in the control plants for up to 17 days after the end of the first limitation. The amplitude of the increase in leaf phenolic concentration did not depend on the number of N-limitation periods to which the plant was subjected, which indicates that the plants did not acclimate to nitrogen limitation. Successive N-limitation periods resulted in additive increases in flavonol glycoside concentrations.

ACS Style

Romain Larbat; Kristine M. Olsen; Rune Slimestad; Trond Løvdal; Camille Bénard; Michel Verheul; Frédéric Bourgaud; Christophe Robin; Cathrine Lillo. Influence of repeated short-term nitrogen limitations on leaf phenolics metabolism in tomato. Phytochemistry 2012, 77, 119 -128.

AMA Style

Romain Larbat, Kristine M. Olsen, Rune Slimestad, Trond Løvdal, Camille Bénard, Michel Verheul, Frédéric Bourgaud, Christophe Robin, Cathrine Lillo. Influence of repeated short-term nitrogen limitations on leaf phenolics metabolism in tomato. Phytochemistry. 2012; 77 ():119-128.

Chicago/Turabian Style

Romain Larbat; Kristine M. Olsen; Rune Slimestad; Trond Løvdal; Camille Bénard; Michel Verheul; Frédéric Bourgaud; Christophe Robin; Cathrine Lillo. 2012. "Influence of repeated short-term nitrogen limitations on leaf phenolics metabolism in tomato." Phytochemistry 77, no. : 119-128.

Short communication
Published: 31 May 2011 in Journal of Microbiological Methods
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The combination of propidium monoazide (PMA) and quantitative real-time PCR (qPCR) significantly overestimated the fraction of viable Listeria innocua as compared to plate counts and confocal fluorescence microscopy. Our data imply that PMA-qPCR must be used with caution as an analytical tool for the differentiation between viable and dead bacteria.

ACS Style

Trond Løvdal; Maria Befring Hovda; Benny Björkblom; Simon Moller. Propidium monoazide combined with real-time quantitative PCR underestimates heat-killed Listeria innocua. Journal of Microbiological Methods 2011, 85, 164 -169.

AMA Style

Trond Løvdal, Maria Befring Hovda, Benny Björkblom, Simon Moller. Propidium monoazide combined with real-time quantitative PCR underestimates heat-killed Listeria innocua. Journal of Microbiological Methods. 2011; 85 (2):164-169.

Chicago/Turabian Style

Trond Løvdal; Maria Befring Hovda; Benny Björkblom; Simon Moller. 2011. "Propidium monoazide combined with real-time quantitative PCR underestimates heat-killed Listeria innocua." Journal of Microbiological Methods 85, no. 2: 164-169.

Journal article
Published: 30 April 2010 in Phytochemistry
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Tomato plants (Solanum lycopersicum, cv. Suzanne) were subjected to complete nutrient solution or a solution without nitrogen (N), and placed at different temperatures and light conditions to test the effects of environment on flavonoids and caffeoyl derivatives and related gene expression. N depletion during 4–8 days resulted in enhanced levels of flavonoids and caffeoyl derivatives. Anthocyanins showed pronounced increased levels when lowering the growth temperature from 24 °C to 18 °C or 12 °C. Flavonol levels increased when the light intensity was increased from 100 μmol m−2 s−1 PAR to 200 μmol m−2 s−1 PAR. Synergistic effects of the various environmental factors were observed. The increase in content of quercetin derivatives in response to low temperatures was only found under conditions of N depletion, and especially at the higher light intensity. Expression of structural genes in the phenylpropanoid and flavonoid pathways, PAL (phenylalanine ammonia lyase), CHS (chalcone synthase), F3H (flavanone 3-hydroxylase), and FLS (flavonol synthase) increased in response to N depletion, in agreement with a corresponding increase in flavonoid and caffeoyl content. Expression of these structural genes generally also increased in response to lower temperatures. As indicated through expression studies and correlation analysis, effects of N depletion were apparently mediated through the overall regulators of the pathway the MYB transcription factor ANT1 (ANTHOCYANIN 1) and SlJAF13 (a bHLH transcription factor orthologue of petunia JAF13 and maize RED genes). A PAL gene (PAL6) was identified, and correlation analysis was compatible with PAL6 being an actively expressed gene with function in flavonoid synthesis.

ACS Style

Trond Løvdal; Kristine M. Olsen; Rune Slimestad; Michel Verheul; Cathrine Lillo. Synergetic effects of nitrogen depletion, temperature, and light on the content of phenolic compounds and gene expression in leaves of tomato. Phytochemistry 2010, 71, 605 -613.

AMA Style

Trond Løvdal, Kristine M. Olsen, Rune Slimestad, Michel Verheul, Cathrine Lillo. Synergetic effects of nitrogen depletion, temperature, and light on the content of phenolic compounds and gene expression in leaves of tomato. Phytochemistry. 2010; 71 (5-6):605-613.

Chicago/Turabian Style

Trond Løvdal; Kristine M. Olsen; Rune Slimestad; Michel Verheul; Cathrine Lillo. 2010. "Synergetic effects of nitrogen depletion, temperature, and light on the content of phenolic compounds and gene expression in leaves of tomato." Phytochemistry 71, no. 5-6: 605-613.

Journal article
Published: 21 July 2009 in Planta
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The bHLH transcription factors EGL3 (ENHANCER OF GLABRA3) and its close homologue GL3 (GLABRA3) are important regulators of the anthocyanin pathway in Arabidopsis thaliana, and together with TTG1 (a WD40 repeat protein) and MYB transcription factors regulate specific genes in the pathway. In response to nitrogen depletion, the MYB genes PAP1/PAP2 (production of anthocyanin pigment 1/2) and GL3 are strongly induced, and anthocyanin synthesis is activated in seedlings and rosette stage plants. In this study we show that anthocyanins accumulate in both wild type and egl3, but not in gl3 loss-of-function mutants when depleted of nitrogen. Several structural genes of flavonoid metabolism including CHS (chalcone synthase), FLS1 (flavonol synthase 1) and ANS (anthocyanidin synthase) were induced in response to nitrogen depletion in wild type as well as in the egl3 and gl3 mutants. Strikingly, in the gl3 mutant DFR (dihydroflavonol-4-reductase) transcript level was only 2% of the levels in wild type or egl3 mutant. Hence, low expression of DFR appears to be the bottleneck preventing anthocyanin synthesis in the gl3 mutant. The specific effect on DFR, but not ANS is compatible with involvement of the MYBL2 inhibitor.

ACS Style

Dugassa N. Feyissa; Trond Løvdal; Kristine M. Olsen; Rune Slimestad; Cathrine Lillo. The endogenous GL3, but not EGL3, gene is necessary for anthocyanin accumulation as induced by nitrogen depletion in Arabidopsis rosette stage leaves. Planta 2009, 230, 747 -754.

AMA Style

Dugassa N. Feyissa, Trond Løvdal, Kristine M. Olsen, Rune Slimestad, Cathrine Lillo. The endogenous GL3, but not EGL3, gene is necessary for anthocyanin accumulation as induced by nitrogen depletion in Arabidopsis rosette stage leaves. Planta. 2009; 230 (4):747-754.

Chicago/Turabian Style

Dugassa N. Feyissa; Trond Løvdal; Kristine M. Olsen; Rune Slimestad; Cathrine Lillo. 2009. "The endogenous GL3, but not EGL3, gene is necessary for anthocyanin accumulation as induced by nitrogen depletion in Arabidopsis rosette stage leaves." Planta 230, no. 4: 747-754.

Journal article
Published: 15 April 2009 in Analytical Biochemistry
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We examined eight putative consistently expressed genes—actin (ACT), β-tubulin, elongation factor 1α (EF1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), phosphoglycerate kinase (PGK), ribosomal protein L2 (RPL2), ubiquitin (UBI), and a catalytic subunit of protein phosphatase 2A (PP2Acs)—for their potential as references for the normalization of gene expression in tomato leaves. Expression stability of candidate reference genes was tested during growth conditions of nitrogen (N) starvation, low temperature, and suboptimal light. The geNorm algorithm, using reciprocal cross-validation among a larger group of candidate references, was applied for this purpose. The widely used reference genes GAPDH and PGK were top ranked during light stress but poorly ranked during N and cold stress. In contrast, EF1 was top ranked during N and cold stress but poorly ranked during light stress. The novel references RPL2 and PP2Acs, as well as the traditional references ACT and UBI, appeared to be stably expressed when looking at the data set as a whole. No gene was identified that exhibited such a constant level of expression as to outperform the other candidates under all experimental conditions. Thus, the results highlight the need for normalizing gene expression in tomato using the geometric average of multiple carefully selected reference genes.

ACS Style

Trond Løvdal; Cathrine Lillo. Reference gene selection for quantitative real-time PCR normalization in tomato subjected to nitrogen, cold, and light stress. Analytical Biochemistry 2009, 387, 238 -242.

AMA Style

Trond Løvdal, Cathrine Lillo. Reference gene selection for quantitative real-time PCR normalization in tomato subjected to nitrogen, cold, and light stress. Analytical Biochemistry. 2009; 387 (2):238-242.

Chicago/Turabian Style

Trond Løvdal; Cathrine Lillo. 2009. "Reference gene selection for quantitative real-time PCR normalization in tomato subjected to nitrogen, cold, and light stress." Analytical Biochemistry 387, no. 2: 238-242.