What could cause a change in the pH of the egg yolk or egg white?
The two possibilities I thought of straight off are, age, or infection by a strain of bacteria. As an egg ages, water and CO2 diffuse out through pores in the shell, which raises the pH (it becomes more alkaline). The pH of the white of a freshly-laid egg is between 7.6 and 7.9, but that is largely due to the presence of CO2, which is slightly acidic. As the CO2 is lost, the more alkaline compounds predominate and pH rises. The yolk is different, though — it’s more acidic to begin with because of its composition, around 6.2, and age alone does not affect that pH much. Some bacteria, however, are just as happy feasting on eggs as we are, however, and they do three things: — they use available gases in the egg to power their metabolisms — they degrade the proteins which compose the egg — they produce nitrogenous and sulfurous waste products Depending on the bacteria and the level of bacterial activity, this can make both yolk and white either more acidic, or more alkaline. Not all ba
