Survival of bacteria in lyophilized plasma.

Although lyophilization reduces the bacterial population in plasma, some species survive for several months. Sensitivity or resistance to lyophilization in plasma is a characteristic of each morphological type, with gram-negative species being more sensitive to destruction than cocci or sporulating gram-positive species. Reconstituted preparations of lyophilized plasma must be incubated for 24 hr to prevent false-negative sterility tests. The killing process in lyophilized plasma continues with time if the preparations are stored at room temperature. Strict asepsis must be realized during processing of plasma because lyophilization alone does not destroy the microorganisms present.