STORAGE OF LYOPHILIZED CULTURES OF LACTOBACILLUS-BULGARICUS UNDER DIFFERENT RELATIVE HUMIDITIES AND ATMOSPHERES

The viability of lyophilized cultures of Lactobacillus bulgaricus in s kim milk, during storage at different temperatures, relative humiditie s, and atmospheres was investigated. Survival was greatest at 11% rela tive humidity and at 5 degrees C. Indirect and direct evidence is pres ented supporting the hypothesis that membrane damage occurs during sto rage. Experiments on the lipid composition of the cell membrane demons trate that changes occur with time that are probably the result of oxi dation. A study on the li!pid composition of the cell membrane by gas chromatography showed that the unsaturated/saturated fatty acid index changes with time during storage.