Authors:Mykola Sysyn, Ulf Gerber, Olga Nabochenko, and Vitalii Kovalchuk
The analysis of track based inertial measurements for common crossing fault detection and prediction is presented in the paper. The measurement of spatial acceleration in common crossing spike and impact position during overall lifecycle are studied regarding to rolling surface fatigue degradation. Two approaches for retrieving the relation of inertial parameters to common crossing lifetime are proposed. The first one is based on the statistical learning method - t-SNE algorithm that helps to find out similarities in measured dataset. The second one is a mechanical approach that handles the data with a fatigue and contact models. Both approaches allow the significant improvement of the common crossing fault detection as well as its early prediction.
Authors:Á. Belák, M. Kovács, Zs. Hermann, Á. Holczman, D. Márta, S. Stojakovič, N. Bajcsi, and A. Maráz
Psychrotrophic Pseudomonas species P. fluorescens, P. fragi and P. lundensis were found as predominant bacteria of chicken meat stored at chill temperature, which showed high level of molecular diversity, while isolates of the psychrotrophic yeasts Candida zeylanoides, Metschnikowia pulcherrima, Rhodotorula glutinis and Rhodotorula mucilaginosa formed clusters of high level similarity within the different species as revealed by RAPD-PCR analysis.Combination of multiplex PCR and sequencing of the rpoB gene resulted correct identification of the Pseudomas isolates, while the routine diagnostic tests led to improper identification in case of half of the isolates, which indicated the extended biochemical and physiological heterogeneity of the food-borne pseudomonads. Majority of P. fluorescens and P. lundensis isolates were strong protease and lipase producers, while P. fragi strains were week or negative from this respect. Proteolytic and lipolytic activities of the isolated yeast strains were species specific and protease production was less frequent than lipolytic activities.
Authors:E. Szanics, B. Devreese, and J. Van Beeumen
Examination of heat shock and PR (“pathogenesis-related”) proteins is of special interest in food science. Many food allergens have a similar or the same structure as PR proteins, which are produced in the plants as a response to pathogenesis or certain environmental stresses. The protein set of the psychrophilic bacterium Shewanella hanedai was studied by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Gel patterns from control and heat-treated bacteria were evaluated by PDQUEST software. The differentially expressed proteins were excised from the gel and digested by trypsin. The tryptic peptides were analysed by nanoflow LC-MS/MS. On the basis of amino acid sequences obtained by this method, the proteins were identified by similarity searching in the protein database. Using this proteomic approach a heat shock and a 50S ribosomal protein were identified as the major heat induced proteins in Shewanella hanedai.
The authors determined the location of the critical point for conduction heated food, involving simplified heat-treatment process. Infinite and finite cylinders have been investigated. Analytical method was applied to compute symmetrical temperatures. The spatial co-ordinates of the critical point were found by searching for the minimum of equivalent time (F-value), as microbial survival is the greatest in the critical point. The introduction of a z-value related dimensionless temperature enabled to extend similarity conditions for F-values. The locations of the critical points of species or attributes with diverse z-values differed in the same process. The most important factor influencing the critical point’s location was the difference between heating and initial food temperatures divided by the z-value. When this difference was sufficiently great, the critical point approached the geometric centre, but reached it only for the infinite cylinder. Decreasing difference shifted it towards the surface either along the axis, or in the median plane.
Authors:N. Orbán, A. Kiss, M. Drávucz, L. Gál, and S. Orbán
Nine phenolic compounds (gallic acid, (+)catechin, vanillic and caffeic
acid, p-coumaric acid, resveratrol, myricetin, quercitrin and quercetin)
of fourteen Eger (Hungarian) young red wines were investigated using
high-performance liquid chromatography in order to obtain data on the 2003
vintage. The grapes were harvested at different sites of the wine-district,
vinified with same technology, but stored under different conditions (glass
holder or 5-10 years old oak barrel). Same varietal wines originating from
different sites of Eger wine-region showed considerable alterations in some
phenolic components, and we found distinction in polyphenol content of
different varietal wines originating from the same harvesting site. Cluster
analysis was performed to acquire information about the similarity among the
measured wines. Our study provides new data of polyphenol composition for Eger
(Hungary) pure varietal red wines, and the results contribute to better identification
of Hungarian red wines on the basis of geographical location.
Authors:K. Skowron, K. Grudlewska, D. Lewandowski, P. Gajewski, A. Reśliński, and E. Gospodarek-Komkowska
L. monocytogenes poses a serious threat to public health, since most cases of listeriosis are connected with eating contaminated food. L. monocytogenes is often detected both in fresh and frozen vegetables.
The aim of this study was to evaluate the antibiotic susceptibility and ability to form biofilm of L. monocytogenes strains isolated from frozen vegetable mixtures in Poland.
Ninetynine genetically different strains were found among 100 isolates of L. monocytogenes. Among the 99 strains, 80 (80.8%) were susceptible to all tested antibiotics. Nineteen (19.2%) strains were resistant to one or more antibiotics. From this group of L. monocytogenes strains, most strains were resistant to erythromycin (16; 16,1%), penicillin (15; 15.1%), meropenem (12; 12.1%), cotrimoxazole (12; 12.1%), and ampicillin (3; 3.1%). According to the obtained results, differences in intensity of biofilm, both between those isolated in successive years and in the particular year, were observed. Performed analysis showed statistically insignificant faint negative correlation (r=–0.088) between the number of antibiotics to which strains were resistant and the intensity of biofilm formation by them.
Food contamination with L. monocytogenes poses a threat to consumers, therefore it is necessary to monitor their antibiotic susceptibility, ability to form biofilm, and genetic similarity, in order to evaluate the strains persistence time in plant.
Total polyphenol content and in vitro antioxidant properties were investigated in five lager and three dark beers. The average concentration of total polyphenols in lager and dark beers was 376 and 473 mg l -1, respectively. All samples exhibited strong hydrogen-donating property and reducing power in a concentration-dependent manner. Beers also showed copper(II)-chelating ability and antioxidant property in Randox TAS measurement. The differences of polyphenol content and antioxidant characteristics between lager and dark beers were statistically not different. Antioxidant properties were dependent on the total polyphenol content of beers. The concentration of polyphenols and antioxidant properties except for chelating ability of beers measured in the same in vitro test system was very similar to those characteristics of white wine, while the extent of chelating ability of beers showed similarity to that of red wines. Studies evaluating the relative benefits of wine versus beer versus spirits suggest that moderate consumption of any alcoholic beverage is associated with lower rates of cardiovascular disease. Although beers have antioxidant capacity like white wines with having half the alcoholic content of wines, beers should be good sources of antioxidant polyphenols, and moderate consumption as a part of a well-balanced diet cannot be criticised either medically or socially and may have a beneficial effect on reducing oxidative disorders.