Knife Decontamination by Cold Water Treatment Supplemented with InspexxTM 210—A Validation Study in an Abattoir

Abstract

To evaluate the decontamination effect of Inspexx 210, a cold-water disinfectant containing peracetic acid and peroctanoic acid (0.16%), knives contaminated with E. coli ATCC 25922 and S. aureus ATCC 29213 as well as naturally contaminated knives collected from different slaughtering steps of an abattoir were examined. Treatment with Inspexx 210 for 15 s reduced mean E. coli counts by 5.95 log CFU/cm2 and mean S. aureus counts by 6.24 log CFU/cm2. Contamination of the knives first with fat and thereafter with the bacteria led to lower mean reductions of 5.52 log CFU/cm2 for E. coli and 3.58 log CFU/cm2 for S. aureus. Contamination first with blood and thereafter with the bacteria had the greatest negative impact on the inactivation effect, with mean reductions of 3.70 log CFU/cm2 for E. coli and 1.55 log CFU/cm2 for S. aureus. Rinsing the blood with tap water before contamination with S. aureus led to the reduction of 5.50 log CFU/cm2. Treatment with Inspexx 210 was also assessed for naturally contaminated knives from an abattoir. After treatment under routine conditions, colony counts were 0.09 log CFU/cm2 (pigs) and 0.35 log CFU/cm2 (sheep) in the wet area and below detection limit (pigs) and 0.91 (sheep) in the clean area. This study shows that Inspexx 210 can be an adequate alternative to knife decontamination with 82 °C hot water, but pre-rinsing is recommended especially in dirty process steps with a high contamination of blood and fat.