A method for characterising cook loss and water holding capacity in heat treated cod (Gadus morhua) muscle

The currently available methods for measuring water holding capacity (WHC) have been developed for raw material characterisation and have been applied to processed (cooked) muscle samples. The intrinsic shortcoming of the methods is that they do not allow rapid and uniform heating, which make them unsuitable for investigating the kinetics of cook loss and WHC. A new method and associated equipment (sample cups) for rapid and uniform heating that allows studying cook loss, water holding capacity and texture of fish samples was developed. After heating and cooling of samples in the sample cup it is feasible to gravimetrically determine the cook loss with a standard deviation within 30% of the total cook loss for minced samples. Both intact and coarsely minced muscle of farmed cod was used to investigate the abilities and limitations of the method with respect to WHC.     

Detection of quantitative trait loci affecting lameness and leg conformation traits in Danish Holstein cattle

Lameness is an important factor for culling animals. Strong legs and feet improve herd life of dairy cows. Therefore, many countries include leg and feet conformation traits in their breeding programs, often as early predictors of longevity. However, few countries directly measure lameness related traits to include these in a breeding program. Lameness indices in 3 different lactations and 5 leg conformation traits (rear legs side view, rear legs rear view, hock quality, bone quality, and foot angle) were measured on granddaughters of 19 Danish Holstein grandsires with 33 to 105 sons. A genome scan was performed to detect quantitative trait loci (QTL) based on the 29 autosomes using microsatellite markers. Data were analyzed across and within families for QTL affecting lameness and leg conformation traits. A regression method and a variance component method were used for QTL detection. Two QTL each for lameness in the first [Bos taurus autosome (BTA); BTA5, BTA26] and second (BTA19, BTA22) lactations were detected. For the 5 different leg conformation traits, 7 chromosome-wise significant QTL were detected across families for rear legs side view, 5 for rear legs rear view, 4 for hock quality, 4 for bone quality, and 1 for foot angle. For those chromosomes where a QTL associated with 2 different traits was detected (BTA1, BTA11, BTA15, BTA26, and BTA27), a multitrait-1-QTL model and a multitrait-2-QTL model were performed to characterize these QTL as single QTL with pleiotropic effects or distinct QTL.     

Undesired phenotypic and genetic trend for stillbirth in Danish Holsteins

The primary aim of this study was to evaluate the phenotypic and genetic trends for stillbirth in Danish Holsteins. Trends of calving difficulty and calf size were also evaluated. The second aim was to compare predicted transmitting abilities (PTA) of sires for stillbirth using a linear and a threshold model. Direct and maternal genetic effects were modeled by fitting correlated additive genetic effects of the sire and the maternal grandsire (MGS). For both the calf and the dam, covariates of breed proportions of Holstein-Friesian (HF) and the heterozygosity between HF and the original Danish Black and White (ODBW) were included. Records from 1.8 million first-calving Danish Holstein cows calving from 1985 to 2002 were used. In this period, the overall frequency of stillbirth increased from 0.071 to 0.090. An unfavorable genetic trend of stillbirth was found for both the direct and maternal effect. The background for the genetic trends was an intense use of HF sires as sires of sons, which increased the proportion of HF genes to 94% in the Danish Holstein calves born in 2002. The effect of the imported HF genes was higher direct effects of calf size, calving difficulty, and stillbirth compared with the ODBW genes. The maternal effect of stillbirth was poorer for HF than for ODBW even though HF had a better maternal calving performance than ODBW. The threshold and the linear models showed almost similar predictions of transmitting abilities of sires.     

Characterization of volatiles from cultured dairy spreads during storage by dynamic headspace GC/MS

The effect of storage time and storage temperature on the formation of volatile compounds in dairy spreads was investigated. Dairy spreads were stored for 10 weeks at -18, 5 and 20 °C, respectively, and analyzed after 0, 38, 54 and 67 days of storage. By means of a dynamic headspace GC/MS method using Tenax traps the dairy spreads were analyzed for volatile aromatic compounds. 61 components were identified and their relative content was followed during the storage period. Among these were four alcohols, 17 aldehydes, four esters, ten alkanes, 11 ketones and six lactones. A general increase in the concentration of most of the volatile compounds during storage was found. The content of volatile compounds in dairy spreads stored at -18 °C was nearly constant or showed a rather low increase in the content during the storage period. Storage at higher temperatures (5 and 20 °C) resulted in an increase in the content of most of the volatiles after 40 days of storage. The profiles obtained were subjected to multivariate data analysis to determine the volatiles potentially responsible for oxidized off-flavors in dairy spread. The volatiles were divided into three groups: one correlated with storage temperature and 5 °C, one with storage time and 20 °C and the last with storage time alone. Most of the volatiles were found in the highest concentration after storage at 20 °C, but the content of some volatiles was highest after storage at 5 °C.     

Formation of biogenic amines in herring and mackerel

The formation of biogenic amines (histamine, cadaverine, putrescine and spermidine) was followed during vacuum packed storage at 2 °C or 10 °C in the scombroid fish mackerel and in the non-scombroid fish herring. Also the changes in the content of free amino acids and in the organoleptic and microbiological qualities were followed.At 10 °C the amine contents were 2–20 times higher at the time of rejection as compared with samples stored at 2 °C. In herring and mackerel similar amounts of histamine were accumulated, whilst cadaverine was formed at much higher levels in mackerel compared with herring. The high contents of cadaverine in mackerel can possibly explain why mackerel and not herring are often implicated in incidents of scombortoxic poisoning.

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Bildung von biogenen Aminen im Hering

Zusammenfassung Die Bildung von biogenen Aminen (Histamin, Cadaverin, Putrescin und Spermidin) wurde während der Lagerung bei 2 °C oder 10 °C, vacuumverpackt, in Makrelen und Hering verfolgt, ebenso die Veränderungen im Gehalt an freien Aminosäuren und der sensorischen bzw. mikrobiologischen Eigenschaften.Bei 10 °C war der Amingehalt 2- bis 20mal höher als bei den Proben bei 2 °C. Beim Hering und der Makrele haben sich die Histaminmengen gleichermaßen angehäuft, wahrend sich Cadaverin in der Makrele viel starker gebildet hatte als im Hering. Der hohe Gehalt an Cadaverin in der Makrele kann möglicherwerise erklären, warum Makrelen und nicht die Heringe an Vergiftungen beitragen.

     

Migration of formaldehyde and melamine monomers from kitchen- and tableware made of melamine plastic

Migration of one or both formaldehyde and/or melamine monomers was found in seven of ten tested melamine samples bought on the Danish market. The samples were a bowl, a jug, a mug, a ladle, and different cups and plates. No violation of the European Union-specific migration limits for melamine (30 mg kg^-1) and formaldehyde (15 mg kg^-1) was found after three successive exposures to the food stimulant 3% acetic acid after 2 h at 70°C. To investigate the effects of long-term use, migration tests were performed with two types of cups from a day nursery. Furthermore, medium-term use was studied by ten successive exposures of a plate to 3% acetic acid for 30 min at 95°C. The results indicate that continuous migration of formaldehyde and melamine takes place during the lifetime of these articles. The molar ratio of released formaldehyde to melamine was seen to decrease from 12 to about 5. This indicates that, first, the migration of residual monomers is most important, but in the long-term, breakdown of the polymer dominates. Two CEN methods were used to determine the concentration of monomers: a spectrophotometric method for formaldehyde and a UV-HPLC method for melamine.     

In Search of the "Ideal" Pear (pyrus spp.): Results of a Multidisciplinary Exploration

Preference mapping with 10 pears identified 3 segments among New Zealand consumers. While 1 segment preferred ripe European cultivars, another rejected only the seedling with strong off‐flavors. A 3rd segment combined the 2 former segments, but also rejected 2 hybrid samples. Survey responses to the question “To me, the ideal pear is ?” from a 2nd consumer sample confirmed the general preference for juicy and sweet pears, the key characteristics of ripeness. A separate appearance evaluation revealed 4 segments based on color and shape. Combining information from several sources resulted in suggestions for new breeding directions for pears, while highlighting the importance of appearance and the need for more extensive measurements.     

Effect of imputing markers from a low-density chip on the reliability of genomic breeding values in Holstein populations

The purpose of this study was to investigate the imputation error and loss of reliability of direct genomic values (DGV) or genomically enhanced breeding values (GEBV) when using genotypes imputed from a 3,000-marker single nucleotide polymorphism (SNP) panel to a 50,000-marker SNP panel. Data consisted of genotypes of 15,966 European Holstein bulls from the combined EuroGenomics reference population. Genotypes with the low-density chip were created by erasing markers from 50,000-marker data. The studies were performed in the Nordic countries (Denmark, Finland, and Sweden) using a BLUP model for prediction of DGV and in France using a genomic marker-assisted selection approach for prediction of GEBV. Imputation in both studies was done using a combination of the DAGPHASE 1.1 and Beagle 2.1.3 software. Traits considered were protein yield, fertility, somatic cell count, and udder depth. Imputation of missing markers and prediction of breeding values were performed using 2 different reference populations in each country: either a national reference population or a combined EuroGenomics reference population. Validation for accuracy of imputation and genomic prediction was done based on national test data. Mean imputation error rates when using national reference animals was 5.5 and 3.9% in the Nordic countries and France, respectively, whereas imputation based on the EuroGenomics reference data set gave mean error rates of 4.0 and 2.1%, respectively. Prediction of GEBV based on genotypes imputed with a national reference data set gave an absolute loss of 0.05 in mean reliability of GEBV in the French study, whereas a loss of 0.03 was obtained for reliability of DGV in the Nordic study. When genotypes were imputed using the EuroGenomics reference, a loss of 0.02 in mean reliability of GEBV was detected in the French study, and a loss of 0.06 was observed for the mean reliability of DGV in the Nordic study. Consequently, the reliability of DGV using the imputed SNP data was 0.38 based on national reference data, and 0.48 based on EuroGenomics reference data in the Nordic validation, and the reliability of GEBV using the imputed SNP data was 0.41 based on national reference data, and 0.44 based on EuroGenomics reference data in the French validation.     

Genetic correlations between pathogen-specific mastitis and somatic cell count in Danish Holsteins

The aim of this study was to estimate genetic correlations (r_a) between 2 lactation average somatic cell count (LASCC) traits and 6 different mastitis traits in 226,482 first-parity Danish Holstein cows that calved between 1998 and 2008. The LASCC traits were defined from 5 to either 170 d (LASCC_170) or 300 d (LASCC_300) after calving, and the mastitis traits were unspecific mastitis (all mastitis treatments, both clinical and subclinical, regardless of the causative pathogen) and mastitis caused by either Streptococcus dysgalactiae, Escherichia coli, coagulase-negative staphylococci (CNS), Staphylococcus aureus, or Streptococcus uberis. Variance components were estimated using bivariate threshold-Gaussian models via Gibbs sampling. The posterior means of r_a between LASCC_170 and the mastitis traits were greatest for unspecific mastitis (r_a = 0.71), followed by CNS, Strep. dysgalactiae, Strep. uberis, and E. coli (r_a = 0.54 to 0.69) and were lowest for Staph. aureus mastitis (r_a = 0.44). The genetic correlation between LASCC_300 and the mastitis traits were generally smaller (r_a = 0.47 to 0.69). Caution should be taken when interpreting the results, however, because some posterior density intervals for r_a were large (between 0.14 and 0.47 units). Phenotypically, Staph. aureus is known to be associated with high SCC and especially with subclinical mastitis through chronic infections, so the low r_a between Staph. aureus mastitis and LASCC, compared with r_a for the other pathogens, was not expected. Subclinical cases are usually submitted to dry cow therapy (not included in the present study), not treated at all, or wrongly recorded as clinical cases. Thus, the incidence of Staph. aureus mastitis is likely too low, and the genetic correlation between Staph. aureus mastitis and LASCC may therefore be underestimated in the present study. The results for the remaining pathogens were as expected, smallest for E. coli and larger but similar for Strep. dysgalactiae, Strep. uberis, and CNS. Selection for lower LASCC is expected to decrease the incidence of pathogen-specific mastitis, especially for Strep. uberis, Strep. dysgalactiae, and CNS and, to a lesser extent, for Staph. aureus and E. coli. Data recording should preferably be improved, and economic weights for the pathogen-specific mastitis traits should be estimated before implementing an udder health index that includes pathogen-specific mastitis traits.