Publications by authors named "Siv B Skeie"

This research paper addresses the hypothesis that substituting soybean meal with locally produced yeast protein from in barley-based concentrates for Norwegian Red (NR) dairy cows does not have adverse effects on milk fatty acid (FA) composition, rumen microbiota and sensory quality of milk. As soybeans also represent valuable protein sources for human consumption, alternative protein sources need to be investigated for animal feed. A total of 48 NR dairy cows were allocated into three feeding treatments, with the same basal diet of grass silage, but different concentrates.

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Spore-forming bacteria are the most complex group of microbes to eliminate from the dairy production line due to their ability to withstand heat treatment usually used in dairy processing. These ubiquitous microorganisms have ample opportunity for multiple points of entry into the milk chain, creating issues for food quality and safety. Certain spore-formers, namely bacilli and clostridia, are more problematic to the dairy industry due to their possible pathogenicity, growth, and production of metabolites and spoilage enzymes.

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The metaproteomics field has recently gained more and more interest as a valuable tool for studying both the taxonomy and function of microbiomes, including those used in food fermentations. One crucial step in the metaproteomics pipeline is selecting a database to obtain high-quality taxonomical and functional information from microbial communities. One of the best strategies described for building protein databases is using sample-specific or study-specific protein databases obtained from metagenomic sequencing.

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Background: Taste sensitivity has been reported to influence children's eating behaviour and contribute to their food preferences and intake. This study aimed to investigate the associations between taste sensitivity, eating behaviour, food frequency and BMI (Body Mass Index) in preadolescents.

Methods: Preadolescents' taste sensitivity was measured by detection threshold of sweetness (sucrose), sourness (citric acid), saltiness (sodium chloride), bitterness (caffeine, quinine), and umami (monosodium glutamate).

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Anaerobic spore-forming bacteria are a continuous threat to the dairy industry due to their ability to withstand processing conditions, such as those during heat treatment. These ubiquitous microorganisms have ample opportunity for multiple entry points into the milk chain, creating food quality and safety issues. Certain spore-formers, namely bacilli and clostridia, are more problematic due to their ability to spoil dairy products and pathogenicity.

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Article Synopsis
  • Streptococcus dysgalactiae (SD) is an emerging pathogen affecting both humans and animals, with two main subspecies: dysgalactiae (SDSD) and equisimilis (SDSE), though their genetic relationships are more complicated than previously thought.
  • * A study analyzed 156 genomes (78 from cows/sheep and 78 from other species), revealing that SDSD is a distinct group with little variation between host-associated isolates, while SDSE showed more genetic diversity linked to different hosts.
  • * Findings suggest that SD has adapted to multiple host species through horizontal gene transfer, leading to the emergence of lineage-specific virulence factors, but cross-species transmission is less common than expected.*
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This study aimed to investigate the production of acid-coagulated fresh cheese by using slightly acid diafiltered (DF) microfiltered (MF) casein concentrates (8% protein). Three different acidifying agents were tested during DF: carbon dioxide, lactic acid, and citric acid. Fresh cheese was manufactured using acid-DF casein concentrates, or casein concentrates DF with just water, and compared with cheese manufactured using MF casein concentrates without DF.

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Article Synopsis
  • The study investigates the impact of microbial contamination on dairy quality, emphasizing the importance of understanding variations in microbial composition at the farm level.
  • By analyzing milk from 37 farms over two years and weekly samples from five farms for up to 7 months, researchers identified that microbial changes are often driven by specific bacteria linked to mastitis.
  • Long-term shifts in milk microbiota were influenced more by environmental factors like weather and feeding practices rather than by farm-specific characteristics like milking systems or herd size.
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This study addresses the biodiversity of Bacillus cereus group population present along the value chain of milk for consumption. The B. cereus population did not grow and remained mainly unaltered during storage of milk at 4 °C while storage at a suboptimal temperature at 8 °C (representative of a broken cold chain) caused a major shift in its composition.

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Cheese made from microfiltration (MF) retentate may suffer from textural defects due to a high Ca concentration. The reduction of colloidal minerals by the acidification of milk before MF at pH below 6.0 has been well documented in the literature.

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Article Synopsis
  • * A study analyzed pasteurized milk samples from two dairies over a year, revealing that B. cereus is the most prevalent group in stored milk, with more genetic diversity at 8°C than at 4°C.
  • * The findings highlight that B. cereus populations in milk vary over time and between dairies, suggesting potential spoilage and health risks, and the new gene sequencing technique could help identify specific strains effectively.
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Microbial contamination of bovine raw milk often occurs at the farm. To acquire a deeper knowledge of the microbiota of farm tank milk, we studied milk from 45 farms situated in 2 geographical areas in Norway. Each farm was visited on 3 different occasions, with at least 2 wk between visits.

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Bovine milk contains a complex microbial community that affects the quality and safety of the product. Detailed knowledge of this microbiota is, therefore, of importance for the dairy industry. In this study, the bacterial composition of consumption milk was assessed during different stages in the production line and throughout the storage in cartons by using culturing techniques and 16S rRNA marker gene sequencing.

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The objective of this study was to investigate how ceramic membrane pore size and filtration temperature influence the protein fractionation of skim milk by cross flow microfiltration (MF). Microfiltration was performed at a uniform transmembrane pressure with constant permeate flux to a volume concentration factor of 2.5.

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Droplet digital PCR (ddPCR) is one of the newest and most promising methods for the detection and quantification of molecular targets by PCR. Here, we optimized and used a new ddPCR assay for the detection and quantification of the Bacillus cereus group in milk. We also compared the ddPCR to a standard qPCR assay.

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The demand for whey protein is increasing in the food industry. Traditionally, whey protein concentrates (WPC) and isolates are produced from cheese whey. At present, microfiltration (MF) enables the utilization of whey from skim milk (SM) through milk protein fractionation.

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Here, we present the draft genome of Enterococcus hirae INF E1, found as a contaminant in cultured milk and studied for its ability to metabolize milk fat globule membrane glycoconjugates.

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