THE RELATION OF THE HYDROGEN ION CONCENTRATION OF EGG WHITE TO ITS GERMICIDAL ACTION

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Abstract
The germicidal action of raw egg white is markedly influenced by the OH-ion concentration, which increases rapidly from p H 7.6 to 9.5 during the 1st days of storage of untreated eggs in a ventilated room. This increase in p H is due to loss of CO2. It was found that the OH-ion concentration in the white corresponding to that at the time the egg was laid would permit growth, while white with OH-ion concentration corresponding to that of eggs aged in air a few days was germicidal to 8 of the 9 test organisms used. The remaining organism, Bacillus subtilis, was killed very rapidly by raw egg white at all pH values, the toxic substance being capable of diffusing through collodion membranes and rendering the diffusate germicidal. Heat and alcohol coagulation rendered the white less germicidal even at high p H. Raw egg yolk showed germicidal properties similar to the white when alkali was added to increase the OH-ion concentration to the same level as that found in the aged white. Attention is called to the possible practical importance of variations in OH-ion concentration of the white in resisting bacterial invasion of eggs in storage.