Susceptibility of Campylobacter to high intensity near ultraviolet/visible 395 ± 5 nm light and its effectiveness for the decontamination of raw chicken and contact surfaces

Abstract

Campylobacter is an important cause of human gastroenteritis worldwide. Chicken meat is frequently contaminated with this organism and is considered to be a significant source of infection. It has been predicted that lowering the numbers of Campylobacter on chicken meat can reduce the risk to public health. The aims of the current study were to investigate the susceptibility of Campylobacter to high intensity near ultraviolet/visible (NUV–vis) 395±5nm light and to examine its potential for the microbiological decontamination of raw chicken and contact surfaces. Exposure of Campylobacter jejuni and Campylobacter coli to NUV–vis light of irradiances was assessed at three distances (3, 12 and 23cm) from the light source for up to 10min, corresponding to doses of 0.06 to 18J/cm2. Overall, levels of inactivation in liquid and on raw chicken improved with longer exposure times and shorter distances from the light source. Reductions of more than 7log10CFU/mL were achieved for Campylobacter isolates in liquid following 2min exposure at 3cm. Exposure of skinless chicken fillet to NUV–vis light for 1 or 5min at 3cm distance reduced C. jejuni by 2.21 and 2.62log10CFU/g, respectively. Increasing the treatment time to 10min did not significantly increase the level of inactivation. In general, NUV–vis light treatment did not affect the colour of raw chicken. Excluding treatments which resulted in excessive heating (>50°C) of chicken skin, a maximum reduction of 0.95log10CFU/g was achieved for C. jejuni following 10min exposure to NUV–vis light at 12cm (P<0.05). For Enterobacteriaceae and total viable counts, significant reductions were achieved only on chicken fillet samples. Light treatments were significantly effective for decontaminating contact surfaces as there were no C. jejuni recovered from stainless steel or cutting board surfaces after NUV–vis light treatments from an initial inoculum of 2–4log10CFU/cm2 (P<0.05). The current study demonstrates potential for the use of NUV–vis light for the inactivation of Campylobacter spp. in liquids, on raw chicken and contact surfaces. The incorporation of this technology could be implemented in a commercial processing plant at various stages, for example to decontaminate carcasses during air chilling. It could also be applied at critical stages within the plant to control microbial contamination on equipment surfaces.