Verification of Bacterial Killing Effects of Cage Wash Time and Temperature Combinations Using Standard Penicylinder Methods

We conducted the present study to evaluate various time and hot-water temperature combinations necessary to kill three common bacterial species in standardized cultures on stainless steel penicylinders, in accordance with methods approved by the Association of Official Analytical Chemists. Exposure for no more than 2 sec to water at 82.2 degrees C killed all three bacterial species, as did exposure for 3 sec to water at 80 degrees C, 4 sec at 77.8 degrees C, and 5 sec at 75.6 degrees C. We conclude that temperatures in the range of 75.6 degrees C to 82.2 degrees C will effectively kill vegetative bacteria in a matter of seconds and that failure to kill these bacteria in cagewash operations, with belt travel times in minutes rather than seconds, is due to other factors that prevent the effective application of sufficiently hot water to the bacterial load.