EFFECT OF ETHANOL GAS ON THE GROWTH OF MICROORGANISMS

The effect of ethanol gas on the growth of microorganisms was tested i n a small glass vessel. With ethanol gas alone growth inhibition of th e microorganisms could not be observed, but with ethanol gas and glyce rol growth of the microorganisms was inhibited. After the ethanol gas test, about 80% of the ethanol was absorbed in the agar medium and the ethanol in the vessel air was about 1/200 approximately 1/1000 of tha t in the medium. From inhibition tests with different volumes of agar medium, we concluded that growth inhibition of microorganisms with eth anol gas was mainly due to the ethanol absorbed in the medium and not to that in the vessel air. Ethanol absorption into the agar medium was found to be a fairly lengthy process, and the ethanol content in the medium came to equilibrium only after 2 approximately 3 days. The low ethanol content in the agar medium during the initial 2 days allowed c ells to grow when ethanol gas alone was added. Glycerol added with eth anol gas seemed to contribute to the inhibition of microbial growth du ring the initial period. The addition of glucose, polypepton and starc h to the agar medium accelerated the transfer of ethanol into the medi um at high ethanol concentrations. These results indicate that studies on the relationship between food components and ethanol absorption in to the food are important in terms of food preservation with ethanol g as.