Report of routine tests for psychophilic and mesophilic contaminants in banked blood.

Emphasis has recently been directed upon the clinical importance of "cold growing" (psychrophilic) as well as "gwarm growing" (mesophilic) bacteria as a source of contamination in banked blood (Stevens et al., 1953; Pittman, 1953; Wetterlow et al, 1954). These authors stressed that certain psychrophilic organisms are killed at an incubation temperature of 37 C and that it is therefore important in bacteriological studies on stored blood that a temperature range be selected to insure detection of such organisms. The present authors are not aware of any published results of the use of the newly recommended temperature conditions for routine sterility tests carried on in the course of a normal blood bank operation. This report is a brief summary of the results of bacteriological studies on 213 unselected outdated bloods; the techniques for culturing were designed to detect both mesophilic and psychrophilic organisms. Similar studies on the residual contents in 155 blood bottles returned from the hospital wards following transfusion are ineluded.