Browsing by Subject "Thermal pressure hydrolysis with microwaves"

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Untersuchungen zur Inaktivierung von Prionen unter Verwendung einer Thermodruckhydrolyse mit Mikrowellen
(2022) Schöffler, Marie; Hölzle, Ludwig
The pathogens that cause TSE, known as prions, are infectious proteins that are responsible for a number of fatal neurodegenerative diseases in humans and animals. In the presented work, inactivation of category 1 and 2 meat mash contaminated with Scrapie 263 K and BSE 301 V were investigated as part of the project "PRIORITY 222887 Protecting the food chain from prions: shaping European priorities through basic and applied research". Category 1 material includes specific risk material that is produced at slaughter and poses a potential TSE risk. Currently this material has to be sterilised and incinerated according to European legislation and thus cannot be put to further use. We were looking for method which, on the one hand, prion proteins are safely inactivated and, on the other hand, a further material use of this inactivated material is made possible. This material could be used, for example, as a source of phosphorus or amino acids in fertilizers or as part of renewable energies such as biogas or biodiesel. Treatment with thermal pressure hydrolysis using microwaves was shown successful in inactivating category 1 and 2 meat mash contaminated with Scrapie 263 K at a temperature of 120°C and a treatment duration of 5 min. For complete inactivation of category 1 and 2 meat mash contaminated with BSE 301 V, a temperature of 120°C and a treatment duration of 10 min are required. Detection was carried out here exclusively by Western blotting. Since detection by Western blotting alone is not reliable, a bioassay was needed. The use of animals was not desired for various reasons, which is why an alternative was sought. With the help of in vitro amplification, the so-called Protein Misfolding Cyclic Amplification (PMCA), a method was found that can replace the bioassay. With PMCA, even small amounts of prions can be amplified identically in such a way that they can be detected by Western blotting. In subsequent inactivation experiments of peptone water spiked with Scrapie 263 K, which served as a meat pulp substitute, complete inactivation (at least 4-5 log10-step reduction) was achieved when treated in thermal pressure hydrolysis with microwaves at a treatment temperature of 120°C and for 15 min. In summary, the results of the work could show that thermal pressure hydrolysis with microwaves is suitable to ensure reliable inactivation of prion proteins in animal by-products.