NR AXKT
AU De Pascalis,A.; Cardone,F.; Berardi,V.; Valanzano,A.; Graziano,S.; Abdel-Haq,H.; Heinz,V.; Buchow,R.; Mathys,A.; Beekes,M.; Knorr,D.; Meyer,R.; Pocchiari,M.; Brown,P.
TI High Pressure/Temperature Inactivation of TSE Agents in Specified Risk Materials
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Epidemiology, Risk Assessment and Transmission P04.81
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB
Specified Risk Materials (SRM) include those parts of ruminant animals, such as brain, spinal cord and cranial nerves that represent a potential risk for transmission of transmissible spongiform encephalopathy (TSE) agents. European Union legislation excludes SRM from the human and animal food chain, but in view of a possible future use of these products, an efficient process of decontamination is required. In previous studies we proved that ultra-high pressure/temperature (HPT) treatments can reduce TSE infectivity in meat food up to a million fold. In the present study we investigate the reliability and the efficiency of these treatments for TSE infectivity removal from rendered SRM.
Rendered and desiccated SRM was rehydrated and spiked with high or low amounts of infectivity from mouse-adapted bovine spongiform encephalopathy (mBSE, strain 6PB1) or hamster-adapted scrapie (strain 263K). The samples were sealed in plastic bags and were pressurized for 5 minutes at 690 and 1000 MPa at increasing temperatures from 121 to 145°. The efficiency of decontamination was evaluated by the reduction of the pathological prion protein (PrPres) by western blot and by infectivity bioassay.
HPT treatments at 690 or 1000 MPa removed 1 log of PrPres from SRM samples spiked with high mBSE or scrapie infectivity. The removal of PrPres was higher at higher temperatures regardless of the pressure and was comparable for both strains. The reliability of these results was demonstrated by the study of replicate samples for which we observed a constant removal of 0.5 logs in eight replicate preparations. The effect of the different HPT treatments on high mBSE infectivity was also tested by the mouse bioassay. All inoculated mice developed disease, with incubation periods that become longer with increasing temperature. Surprisingly, the samples processed at 690 MPa produced longer incubation periods compared to the 1000 MPa samples. Finally, SRM spiked with a low dose of mBSE infectivity was exposed to 690MPa at 134°, in order to investigate the possibility of reducing infectivity below the level of bioassay detectability. Infectivity was not totally eliminated from the two samples analysed.
These results indicate that HPT treatment can produce a reproducible but limited reduction of TSE infectivity spiked into rendered SRM. The limited reduction compared to HPT treatment of processed meat products may be due to the prior desiccation of the SRM before HPT treatment.
AD A. De Pascalis, F. Cardone, V. Berardi, A. Valanzano, S. Graziano, H. Abdel-Haq, M. Pocchiari, Istituto Superiore di Sanità, Cell Biology and Neurosciences, Italy; V. Heinz, R. Buchow, A. Mathys, D. Knorr, Technische Universität Berlin, Food Biotechnology and Food Process Engineering, Germany; M. Beekes, Robert Koch Institut, P-24 Transmissible Spongiform Encephalopathies, Germany; R. Meyer, Washington Farms, USA; P. Brown, USA
SP englisch
PO Schottland