The effect of the structure of frozen material upon the course of freeze-drying and upon some properties of the lyophilizate
Vávra, L.
Sbornik Vedeckych Praci Lekarske Fakulty Karlovy Univerzity V Hradci Kralove. Supplementum 22(1): 97-104
1979
ISSN/ISBN: 0049-5522 PMID: 42139 Document Number: 148876
Pre-sterilization contamination of skin grafts and the efficiency of substerilization doses of radiation were evaluated. The pre-sterilization contamination of disinfected and freeze-dried skin grafts is favorably low. An average number of 3.43 colonies/cm2 was found. A radiation dose of 15 kJ/kg did not reveal any surviving organisms in practical experiments. Isolated obligatory and facultative psychrophilic microorganisms did not represent a hazard with regard to radiation resistance. A radiation dose of 25 kJ/kg gives a high guarantee of sterility. The minimum sterilizing dose can be decreased to 20 kJ/kg provided the mean value of microorganisms on 1 cm2 of the disinfected and freeze-dried skin grafts of human cadavers in 100, with an upper limit of 130. The use of a lower dose would diminish the deterioration of physical qualities of dermoepidermal grafts.