Decontamination of knives used in a slaughterhouse by a commercial non-thermal UV-C treatment

Abstract

To assess the antimicrobial effect of a commercial UV-C system, knives inoculated with Escherichia coli and Staphylococcus aureus as well as naturally contaminated and collected from the wet and clean area of a slaughterhouse knives were examined. For inoculated knives, UVC treatment for 30 s reduced mean E. coli counts by 5.1 log CFU cm-2 and mean S. aureus counts by 4.5 log CFU cm-2. The presence of blood lowered mean reductions to 3.4 log CFU cm-2 for E. coli and to 2.5 log CFU cm-2 for S. aureus. The presence of fat had a greater negative impact on the efficacy of the UV-C treatment resulting in mean reductions <1.8 log CFU cm-2. For naturally contaminated knives from a slaughterhouse, total viable counts (TVC) before UV-C treatment varied considerably (wet area: 2.0-6.0 log CFU cm-2, clean area: 1.0–3.0 log CFU cm-2). UV-C treatment for 30s reduced mean TVC by 0.8 log CFU cm-2 (wet area) and 0.6 log CFU cm-2 (clean area), but the effect varied greatly between individual knives. Thus, under commercial conditions, the antibacterial effect of UV-C for the decontamination of knives is affected by the presence of additional contaminations like blood or fat. The adequate cleaning of the knives prior to UV-C decontamination is therefore of central importance.

Effect of non-thermal ultraviolet and ultrasound technologies on disinfection of meat preparation equipment in catering industry

“…It could be due to the fact that the distance of sharpener surface to the light source was less than the distance of other equipment and so UV dose received by sharpener surface was higher than other equipment. Raschle et al (2019) reported 0.6–0.8 log unit reductions in TAMB counts of knife samples used in commercial slaughterhouse after UV treatment for 30 s. In the present study, higher reduction value was obtained in TAMB counts of knife samples after UV treatment than Raschle et al (2019). Differences in log reductions may be due to using varying treatment times and UV source of varying efficiencies.…”

“…E. coli was detected only in swab samples taken from the cut-proof glove before the treatment, but E. coli was completely inhibited after UV treatment ( P < 0.05). Similarly, in a study in which UV treatment was applied to knife samples obtained from a commercial slaughterhouse, a significant decrease was found in the number of E. coli after the treatment ( P < 0.05) (Raschle et al, 2019). Haughton et al (2011) reported that E. coli was totally inactivated on contaminated stainless steel surfaces in poultry processing plant by application of UV treatment similar to the results found in the current study.…”

“…In recent years, non-thermal green sterilization technologies such as high pressure, ultraviolet (UV), ultrasound, pulsed electric field, irradiation, electrolyzed water, cold plasma, and dry ice have been developed to meet the needs of consumers (Kart et al, 2018). Studies have been conducted to show that these new non-thermal technologies are used for the disinfection of surfaces, tools, and equipment that come into contact with food, and effective results have been obtained (Brasil et al, 2017; Dasan et al, 2017; Gabriel et al, 2018; Lim and Harrison, 2016; Musavian et al, 2015; Raschle et al, 2019; Rajkovic et al, 2010; Sen and Mutlu, 2013; Uradziński et al, 2005; Uyarcan and Kayaardı, 2018; Zhao et al, 2017).…”

“…Among the non-thermal technologies, UV and ultrasound treatments have various advantages for the food industry. UV light is divided into different spectral ranges (UV-A: 315–400 nm; UV-B: 280–315 nm; UV-C: 200–280 nm), its effect varies according to these ranges and widely used in the food industry for decontamination of surfaces, water, or air (Raschle et al, 2019). UV-C spectral range shows germicidal effect on bacteria, fungi, protozoa, and viruses (Söbeli et al, 2021).…”

“…Most of the current research has focused on the effect of decontamination techniques on the cleaning of slaughterhouses and food contact surfaces in the meat industry (Brasil et al, 2017; Musavian et al, 2015; Raschle et al, 2019; Uyarcan and Kayaardı, 2018). As far as we know, there has been no research on the effect of new non-thermal technologies in reducing microbial load on the surfaces of processing equipment in catering sector.…”