UV-C Irradiation of Rolled Fillets of Ham Inoculated with Yersinia enterocolitica and Brochothrix thermosphacta

Bacteria on ready-to-eat meat may cause diseases and lead to faster deterioration of the product. In this study, ready-to-eat sliced ham samples were inoculated with Yersinia enterocolitica or Brochothrix thermosphacta and treated with ultraviolet (UV) light. The initial effect of a UV-C irradiation was investigated with doses of 408, 2040, 4080, and 6120 mJ/cm(2) and the effect after 0, 7, and 14 days of refrigerated storage with doses of 408 and 4080 mJ/cm(2). Furthermore, inoculated ham samples were stored under light and dark conditions after the UV-C treatment to investigate the effect of photoreactivation. To assess the ham quality the parameters color and antioxidant capacity were analyzed during storage. UV-C light reduced Yersinia enterocolitica and Brochothrix thermosphacta counts by up to 1.11 log(10) and 0.79 log(10) colony forming units/g, respectively, during storage. No photoreactivation of the bacteria was observed. Furthermore, significantly lower a* and higher b* values after 7 and 14 days of storage and a significantly higher antioxidant capacity on day 0 after treatment with 4080 mJ/cm(2) were detected. However, there were no other significant differences between treated and untreated samples. Hence, a UV-C treatment can reduce microbial surface contamination of ready-to-eat sliced ham without causing considerable quality changes.