EU Regulation 853/2004 requires that knives used in meat processing be disinfected by submerging them in
hot water (+ 82 °C). Alternative procedures are permitted if the efficacy is proved to be equivalent. In the
present study, various time–temperature combinations together with pure water, water with lactic acid (2 %),
and the use of ultrasound with and without lactic acid (2%) were investigated. Steel plates were covered with
fat and protein and then inoculated with a standardized bacterial contamination assembled according to the
composition of bacterial contamination found in a previous field trial conducted with regard to the slaughter
of pigs. Several combinations with diverse temperatures and time intervals were tested until no microbial load
was detectable by using a wet–dry-swab technique that had previously been tested to ensure maximum bacterial
recovery. The following were effective in bringing the tested bacterial flora below the detection limit: