Kvasny Prum. 1978; 24(11): 246-249 | DOI: 10.18832/kp1978041

Cultivation of Microorganisms Spoiling Beer.Peer-reviewed article

J. ŠAVEL, M. PROKOPOVÁ

The article deals with the cultivation in test tubes on semisolid beer medium (P₃) of microorganisms rapidly spoiling beer. Beer must be treated as follows: carbon dioxide should be expelled by shaking, the amount of dissolved oxygen reduced by introducing nitrogen stream under 1,5mg of O₂ in 1 litre, bottles filled, capped with crown corks and pasteurized. The storage period of beer so treated can be improved by applyingsome stabilizing adsorption preparation. Prior to inoculation 30ml of 0,7% hot water solution of agar must be mixed with 100ml of stored beer and this mixture poured in test tubes with 0,1 - 1,0ml samples or strips of membrane filter holding microorganisms. Microorganisms quickly spoiling beer can be identified after 4 days of cultivation at 28 °C. Slowly propagating microorganisms can be identified later. Tetracycline (50µg/ml) suppresses selectively propagation of bacteria, whereas actidion (30µg/ml) of yeast. Comparison of the numbers  of lactobacilli in cask beer, in highly nutritive medium and in P₃ indicates, that only a certain part of lactobacilli present in beer is responsible for its rapid spoilage. There is a corrrelation between the numbers of quick-spoiling microorganisms and storage quality of beer. Microorganisms multiplied in samples of benn in P₃ were morphologically identical with those multiplied in stored, bottled beer. The described method being simple and requiring little time is suitable for routine checking.
(In Czech, English summary only)

Keywords: cultivation, microorganisms spoiling beer

Published: November 1, 1978