A chromatographic approach for fluorescence reduction in liquid Raman analysis.

In this study a chromatographic approach for fluorescence reduction in liquid Raman analysis has been evaluated. The idea behind the approach is to apply a chromatographic separation step prior to Raman analysis in order to separate fluorescing compounds from other components of interest, thus facilitating better quantitative and qualitative analysis of the latter components. A real-time liquid-core Raman waveguide detector designed for chromatographic applications was used in the study, thus providing real-time chemical pretreatment of liquid samples for Raman analysis.

Use of multivariate statistics for 16S rRNA gene analysis of microbial communities.

Understanding dynamic processes and diversity in microbial communities is of key importance for combating pathogens and for stimulating beneficial bacteria. We have addressed these challenges utilising multivariate statistics for analyses of microbial community structures. We based our microbial community analyses on 16S rRNA gene data.

Rapid identification and classification of bacteria by 16S rDNA restriction fragment melting curve analyses (RFMCA).

The aim of this work was to evaluate restriction fragment melting curve analyses (RFMCA) as a novel approach for rapid classification of bacteria during food production. RFMCA was evaluated for bacteria isolated from sous vide food products, and raw materials used for sous vide production. We identified four major bacterial groups in the material analysed (cluster I-Streptococcus, cluster II-Carnobacterium/Bacillus, cluster III-Staphylococcus and cluster IV-Actinomycetales).

Raman spectra of biological samples: A study of preprocessing methods.

In this study preprocessing of Raman spectra of different biological samples has been studied, and their effect on the ability to extract robust and quantitative information has been evaluated. Four data sets of Raman spectra were chosen in order to cover different aspects of biological Raman spectra, and the samples constituted salmon oils, juice samples, salmon meat, and mixtures of fat, protein, and water. A range of frequently used preprocessing methods, as well as combinations of different methods, was evaluated.

Alignment-independent bilinear multivariate modelling (AIBIMM) for global analyses of 16S rRNA gene phylogeny.

Alignment-independent phylogenetic methods have interesting properties for global phylogenetic reconstructions, particularly with respect to speed and accuracy. Here, we present a novel multimer-based alignment-independent bilinear mathematical modelling (AIBIMM) approach for global 16S rRNA gene phylogenetic analyses. In AIBIMM, jackknife cross-validated principal component analyses (PCA) are used to explain the variance in nucleotide n-mer frequency data.

Multiplex real-time single nucleotide polymorphism detection and quantification by quencher extension.

Multiplex quencher extension (multiplex-QEXT) is a novel closed tube single-step method for detection and quantification of several single nucleotide polymorphisms (SNPs) simultaneously. The principle of multiplex-QEXT is that 5' reporter-labeled probes are 3' single-base-extended with TAMRA dideoxy nucleotides if the respective SNP alleles are present. TAMRA can serve as either an energy acceptor (quencher-based detection) or donor [fluorescence resonance energy transfer (FRET)-based detection] for a wide range of different reporter fluorochromes.

Raman and near-infrared spectroscopy for quantification of fat composition in a complex food model system.

Raman and near-infrared (NIR) spectroscopy have been evaluated for determining fatty acid composition and contents of main constituents in a complex food model system. A model system consisting of 70 different mixtures of protein, water, and oil blends was developed in order to create a rough chemical imitation of typical fish and meat samples, showing variation both in fatty acid composition and in contents of main constituents. The model samples as well as the pure oil mixtures were measured using Raman and NIR techniques.

16S rDNA analyses of the cyanobacterial microbiota through the water-column in a boreal lake with a metalimnic Planktothrix population.

The Planktothrix population in Lake Steinsfjord has attracted particular attention, due to the potential development of toxic blooms. This population is special in the sense that mass developments of Planktothrix occur in the metalimnion. We investigated the distribution of Planktothrix, as well as other cyanobacteria, through the water-column during a Planktothrix mass development at 10-16 m depth.

Explorative screening of complex microbial communities by real-time 16S rDNA restriction fragment melting curve analyses.

We have developed restriction fragment melting curve analyses (RFMCA), which is a novel method for the real-time analysis of microbial communities. The major advantage of RFMCA compared to, for example, terminal restriction fragment length polymorphism (T-RFLP) or temperature/denaturing gradient gel electrophoresis (TGGE/DGGE) is that the physical separation of DNA fragments is avoided. The RFMCA detection is done by melting point analyses in closed tube systems, which enables high-throughput applications.

Low-cost approaches to robust temperature compensation in near-infrared calibration and prediction situations.

The traditional way of handling temperature shifts and other perturbations in calibration situations is to incorporate the non-relevant spectral variation in the calibration set by measuring the samples at various conditions. The present paper proposes two low-cost approaches based on simulation and prior knowledge about the perturbations, and these are compared to traditional methods. The first approach is based on augmentation of the calibration matrix through adding simulated noise on the spectra.

Explorative multivariate analyses of 16S rRNA gene data from microbial communities in modified-atmosphere-packed salmon and coalfish.

Modified-atmosphere packaging (MAP) of foods in combination with low-temperature storage extends product shelf life by limiting microbial growth. We investigated the microbial biodiversity of MAP salmon and coalfish by using an explorative approach and analyzing both the total amounts of bacteria and the microbial group composition (both aerobic and anaerobic bacteria). Real-time PCR analyses revealed a surprisingly large difference in the microbial loads for the different fish samples.

Effects of carbon dioxide on yield, texture and microstructure of cooked ground beef.

The objective of the study was to find the effects of CO(2) gas on cooking loss, instrumental hardness and microstructural changes of ground beef heated to 70-83 °C. In two experiments, ground beef was stored for 4 days in 60% CO(2)/39.6% N(2)/0.

Rapid quantification of carotenoids and fat in Atlantic Salmon (Salmo salar L.) by Raman spectroscopy and chemometrics.

Raman spectroscopy (785 nm excitation) was used to determine the overall carotenoid (astaxanthin and cantaxanthin) and fat content in 49 samples of ground muscle tissue from farmed Atlantic salmon (Salmo salar L.). Chemically determined contents ranged from 1.

Commercial antioxidants control lipid oxidation in mechanically deboned turkey meat.

Effects of commercial rosemary antioxidants on oxidative stability of mechanically deboned turkey meat (MDTM) compared with Trolox C (vitamin E), ascorbic acid (vitamin C) and control without antioxidant were investigated. Antioxidants were added to meat at three levels. Thiobarbituric acid (TBA) assay and dynamic headspace gas chromatography were used to assess the effects of commercial antioxidants on lipid stability of MDTM during 7 months of frozen storage.

Increased speed and accuracy of single nucleotide polymorphism (SNP) quantification by quencher extension (QEXT).

Extract: Single nucleotide polymorphisms (SNPs) often represent allelic variants of genes. The differences between individuals within a species are mainly due to SNPs. SNPs are commonly used as genetic markers for genetic diseases and other phenotypic traits.

Real-time closed tube single nucleotide polymorphism (SNP) quantification in pooled samples by quencher extension (QEXT).

Quencher extension (QEXT) is a novel single step closed tube real-time method to quantify SNPs using reporters and quenchers in combination with primer extension. A probe with a 5'-reporter dye is single base extended with a dideoxy nucleotide containing a quencher dye if the target SNP allele is present. The extension is recorded from the quenching (reduced fluorescence) of the reporter dye.

Protocols for 16S rDNA array analyses of microbial communities by sequence-specific labeling of DNA probes.

Analyses of complex microbial communities are becoming increasingly important. Bottlenecks in these analyses, however, are the tools to actually describe the biodiversity. Novel protocols for DNA array-based analyses of microbial communities are presented.

Nondestructive measurement of light-induced oxidation in dairy products by fluorescence spectroscopy and imaging.

The purpose of this paper is to demonstrate the potential of solid-sample fluorescence spectroscopy in nondestructive assessment of light-induced oxidation in different dairy products such as Swiss cheese, cream cheese, and sour cream. Analytical and quantitative spectral properties of fluorescence were elucidated by use of principal component analysis with designed experiments involving different levels of air and light exposure. A significant reduction in fluorescence intensity at approximately 525 nm, and a corresponding increase in the region 415 to 490 nm as a result of illumination was observed on all the products.

Quality of comminuted sausages formulated from mechanically deboned poultry meat.

Comminuted sausages formulated with mechanically deboned poultry meat-MDPM (turkey or chicken, frame or neck) treated in different ways before production (vacuum packed MDPM or air packed skeletons deboned at production) and stored frozen for 6 or 18 weeks have been studied using a full-factorial design and chemical, physical and sensory analysis. MDPM was obtained from a Beehive separator. Comminuted sausages with MDPM from turkey frames, stored at -25 °C as skeletons, packed in air for 18 weeks developed marked rancid odour and flavour which could also be detected by thiobarbituric acid reactive substances (TBARS) and the concentration of volatile compounds.

Potentiation of the lethal effect of peroxygen on Bacillus cereus spores by alkali and enzyme wash.

Bacillus cereus present in pipes and heat-exchangers represents a potential quality problem for dairy industry. The peroxygen-containing disinfectants investigated had only negligible sporicidal effect when applied at the recommended in-use temperature and concentration. However, cleaning agents used before disinfection potentiated their lethal activity.

Sulfated glycosaminoglycans and collagen in two bovine muscles (M. Semitendinosus and M. Psoas major) differing in texture.

M. semitendinosus (ST) and M. psoas major (PM) were used as models for tough and tender meat to study a possible role of sulfated glycosaminoglycans (GAGs) for muscle tenderness.

The effect of evaporative air chilling and storage temperature on quality and shelf life of fresh chicken carcasses.

The effect of evaporative air chilling on quality of fresh chicken carcasses was compared with air chilling as reference method. Cooling efficiency and total heat loss were significantly higher for evaporative air chilling. The chilling method was of great importance for weight loss.

The storage life of beef and pork packaged in an atmosphere with low carbon monoxide and high carbon dioxide.

Ground beef, beef loin steaks and pork chops were packaged in modified atmospheres of 0.4% CO/60% CO(2)/40% N(2) and 70% O(2)/30% CO(2). In addition ground beef was packaged in clipped chub packs, beef loin steaks were vacuum packaged, and pork chops were packaged in an atmosphere of 60% CO(2)/40% N(2) with each pack containing an O(2) absorber.

Identification of pseudomonads from fresh and chill-stored chicken carcasses.

Results of carbon source assimilation tests (17 carbon compounds) led to 88% of pseudomonads from cold-stored chicken carcasses being assigned to one of 17 groups. Of these groups, 13 had combinations of properties identical to, or with readily recognizable degrees of similarity to those of published species/biovars. Two of the four groups having carbon assimilation patterns dissimilar to any known species had cellular fatty acid composition corresponding to Pseudomonas fluorescens, and two to Pseudomonas lundensis or Pseudomonas fragi.

Determination of endpoint temperatures in previously heat treated beef using reflectance spectroscopy.

Heat processing endpoint temperature affects several quality parameters of meat. The present paper focuses on using near-infrared and visual light reflectance spectroscopy at 400-2500 nm to determine the endpoint temperature in previously heated ground beef. Glass fibre filters with beef juice centrifuged from m.