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The Influence of Preparation Technique, Humidity and Irradiation Conditions on Radiation Inactivation of Streptococcos Faecium , Strain A 2 1
Author(s) -
Emborg Claus
Publication year - 1972
Publication title -
acta pathologica microbiologica scandinavica section b microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0365-5563
DOI - 10.1111/j.1699-0463.1972.tb00048.x
Subject(s) - irradiation , sterilization (economics) , relative humidity , humidity , radiation effect , cobalt 60 , chemistry , bacteria , strain (injury) , radiation resistance , radiation , significant difference , radiochemistry , biology , optics , medicine , meteorology , physics , anatomy , nuclear physics , monetary economics , economics , foreign exchange market , genetics , foreign exchange
Cobalt‐60 gamma radiation has a greater inactivating effect on dried preparations of Str. faecium , strain A 2 1, than electron radiation from a 10–MeV linear accelerator. The difference in effect varies with relative humidity and preparation technique. The difference is 10–20 per cent when the bacteria are dried with serum broth at 10–50 per cent r. h. The radiation resistance under these conditions corresponds to the resistance of standard preparations of this strain for control of microbiological efficiency of radiation sterilization plants. Increase of the relative humidity to 55 per cent leads to a significant drop in radiation resistance, and a doubling of the difference in effect between gamma irradiation and electron irradiation. The response of cleaned preparations is less dependent on relative humidity and very similar to the response observed at high humidity in preparations with serum broth. No difference in the effect of the two irradiation sources is observed when the bacteria are irradiated in aqueous suspension or suspended in serum broth.