A custom-built hospital blood bank.

Table I shows that a marked reduction in contamination was effected by using UV radiation in the Gallenkamp oven. After subtracting the number of colonies estimated to be due to the pouring process (ie, filter paper control or F.P.C. level) a 67 5% reduction at 35'C, and a 100% reduction at 45'C and 55'C were found. Plates dried in the incubator at 35'C showed a level of contamination intermediate between the ultraviolet radiation-dried plates and those dried in the oven without ultraviolet radiation. At 55'C, incubator contamination was similar to that in the oven without ultraviolet radiation. The temperature range chosen for testing the special Laboratory and Thermal Equipment cabinet (38-48'C) proved to be satisfactory both for speed of drying and for prevention of contamination, so other temperatures were not employed. Table II gives the results with this cabinet. After subtracting the filter paper control colonies, 96 colonies on the 359 plates dried without ultraviolet radiation were reduced to nine colonies on the 360 ultraviolet radiation plates, a reduction of 90-7% in drying contamination.