The evaluation of high hydrostatic pressure effects on bovine blood constituents and the microbial survival

Ceylan, Çağatay
The main objective of this study was to investigate the effects of high hydrostatic pressure on the stability of blood constituents for the purpose of an effective reduction of viral and bacterial count. The effect of HHP treatment on the several blood constituents were analyzed at different HHP levels at 25 0C for 5 minutes. The bovine blood as the model material was separated into two major parts; namely, serum and blood cells by centrifugation. Erythrocytes were found to be mostly stable up to 220 MPa pressure treatment displaying only surface modifications, but the cells lose their morphology at 350 MPa. White Blood Cells and platelets were found to be more sensitive, being degraded at around 110 MPa pressures putting an upper limit for the HHP treatment for the whole blood. But serum components and parameters studied showed much higher stability up to 220 MPa pressure level. The HHP treated blood cells were analyzed by FTIR spectroscopic technique and found to be stable in the macromolecular level. HHP treated proteins display only minimal changes in their secondary structures shown by the artificial neural network and curve fitting studies. Changes in the lipid bands indicated the changes in the membranes of the blood cells. In the microbiologic part of the study, Listeria innocua was found to be more stable than Bovine Herpes Virus type 1 as the model bacterium and virus respectively and their inactivation levels were compared with that of blood constituents.


High hydrostatic pressure induced inactivation kinetics of e. coli o157:h7 and s. aureus in carrot juice and analysis of cell volume change
Pilavtepe, Mutlu; Alpas, Hami; Department of Food Engineering (2007)
The main objective of this study was to determine the pressure induced inactivation mechanism of pressure-resistant Escherichia coli O157:H7 933 and Staphylococcus aureus 485 in a low acid food. Firstly, inactivation curves of pathogens were obtained at 200 to 400 MPa at 40ºC in peptone water and carrot juice. First-order and Weibull models were fitted and Weibull model described the inactivation curves of both pathogens more accurately than first-order model, revealing that food systems could exhibit eithe...
Extracellular recombinant human growth hormone production by pichia pastoris
Orman, Mehmet Ali; Çalık, Pınar; Department of Chemical Engineering (2007)
In this study, the effects of bioprocess operation parameters on recombinant human growth hormone (rhGH) production by P. pastoris were systematically investigated. In this frame, first, for the extracellular expression and purification of human growth hormone by recombinant P. pastoris the cDNA of hGH, fused with a polyhistidine tag and also fused with a target site for the Factor Xa protease in which cleavage produces a mature N- and C- termini of rhGH, was cloned into pPICZαA plasmid and the constructed ...
Recombinant plasmid-based quantitative Real-Time PCR analysis of Salmonella enterica serotypes and its application to milk samples
Gokduman, Kurtulus; AVŞAROĞLU ERKAN, MÜRŞİDE DİLEK; Cakiris, Aris; Ustek, Duran; Gültekin, Güzin Candan (Elsevier BV, 2016-03-01)
The aim of the current study was to develop, a new, rapid, sensitive and quantitative Salmonella detection method using a Real-Time PCR technique based on an inexpensive, easy to produce, convenient and standardized recombinant plasmid positive control. To achieve this, two recombinant plasmids were constructed as reference molecules by cloning the two most commonly used Salmonella-specific target gene regions, invA and ttrRSBC The more rapid detection enabled by the developed method (21 h) compared to the ...
Characterization of extracellular beta-lactamases from penicillin G-resistant cells of Streptococcus thermophilus
Chirica, LC; Güray, Nülüfer Tülün; Gültekin, Güzin Candan; Bozoglu, F (International Association for Food Protection, 1998-07-01)
In this study, biochemical properties of two extracellular beta-lactamases produced by penicillin-resistant Streptococcus thermophilus cells were investigated. Both beta-lactamases showed specificity for penicillins but not for cephaloridins. The p-lactamases exhibited different affinities for penicillin G. The one with the higher molecular weight (F1) had a K(m) value of 3.44 mu M and a V(max), value of 8.33, mu mol/min/mg of protein, whereas the beta-lactamase with the lower molecular weight (FII) had a K...
First reference map for Phanerochaete chrysosporium proteome
Yıldırım, Volkan; Özcengiz, Gülay; Department of Biology (2006)
In this study, the soluble protein fraction of P. chrysosporium grown under standard conditions was analyzed by using 2D-PAGE approach and a 2-D reference map was constructed. 910 spots could be separated and detected on Coomassie-stained 2-D gels by the help of Delta2D image analysis software. 720 spots could be cut from the master gel and were subjected to MALDI-TOF MS analysis followed by MASCOT search. A total of 517 spots out of 720 were assigned to specific accession numbers from the P. chrysosporium ...
Citation Formats
Ç. Ceylan, “The evaluation of high hydrostatic pressure effects on bovine blood constituents and the microbial survival,” Ph.D. - Doctoral Program, Middle East Technical University, 2005.