THE EFFECT OF WIPING AND SPRAY-WASH TEMPERATURE ON BACTERIAL RETENTION ON ABRADED DOMESTIC SINK SURFACES

The relative cleanability of artificially abraded stainless steel, ena melled steel, mineral resin and polycarbonate domestic sinks was asses sed by examining bacterial retention after cleaning. Two cleaning regi mes were used: the mechanical action of wiping combined with a spray-r inse, and spray-washing at a range of temperatures. After wiping, stai nless steel retained 0.5-1 log order fewer bacteria than the enamel si nks which in turn were 0-5 log order cleaner than the mineral resin an d polycarbonate sinks. After spray-washing, stainless steel retained 0 .5 log order fewer bacteria than enamel which in turn was 0.5 log orde r cleaner than the polycarbonate and mineral resin. Extending the numb er of wipes or increasing spray-wash temperature enhanced bacterial re moval but, in general, did not change the relative cleanability of the sink materials. As a cleaning technique, wiping was shown to be more effective than spray-washing in reducing bacterial numbers. SEM studie s showed that bacteria were typically retained in surface imperfection s, particularly pits and crevices such that surfaces which sustained t he most extensive damage due to abrasion retained higher numbers of ba cteria.