Cold water, ultra-high pressure cleaning of abattoirs.

Cold water (10 degrees C) at ultra-high pressure (38-5--49 kg/cm2) was compared with (a) hot water 65-6--82.2 degrees C) at low pressure (4-2--5-6 kg/cm2) and (b) hot water containing a detergent (2% (w/v) sodium silicate). Seven sites were examined in a beef abattoir and six in a bacon factor. Three surfaces in the beef abattoir had lower residual colony counts (higher reductions) after hot water/low pressure than after cold water/high pressure. However, the differences were not significant (P greater than 0-05). The range of the mean log10 count/cm2 before cleaning was 4-02-5.15, and after cleaning 1-73-2.32 (hot water) and 1-9--2-85 (cold water). On three of the remaining sites, the three methods were compared. The total differences between treatments were not significant (P greater than 0-05), although there was an effect of surface and an interaction between surface and treatment. The cold water produced lower residual counts on three sites in the bacon factory than the hot water (45--54 degrees C). However, the differences were not significant on the remaining surfaces.