Königsweg 69
14163 Berlin
+49 30 838 62551 / 52790
lebensmittelhygiene@vetmed.fu-berlin.de / fleischhygiene@vetmed.fu-berlin.de
The bacterial contamination of eggshells with food-borne zoonotic agents in the commercial egg production is an important One Health issue. The traditional Ultraviolet-C (UV-C) mercury vapor lamp technology is already used for bacterial decontamination on eggshells in individual packaging lines in Germany. A novel system of UV-C light-emitting diodes (LEDs) poses an alternative providing many ecological and economic advantages. The aim of the study was to develop and establish a UV-C LED light method for the commercial application in egg packaging lines. Therefore, the production parameters from an egg packaging line were determined. Thereafter, the bacterial decontamination efficiency of the UV-C LED light on ESBL-producing Escherichia(E.)coli, Enterococcus(E.)faecium, Campylobacterjejuni, Methicillin-resistant Staphylococcusaureus, and Salmonellaon the eggshell surface with and without organic load, was evaluated and compared to the traditional UV-C light method. For this purpose, the surfaces were inoculated with a defined bacterial concentration and the bacterial count was estimated before and after UV-C treatment. Finally, a reproducible method for detecting the decontamination efficiency via UV-C on eggshells was developed and established. A high organic load of 10g bovine serum albumin (BSA) and 10g yeast extract resulted in a protective effect of Gram-negative bacteria against UV-C treatment of up to 2log CFU/cm2in contrast to no organic load. Gram-positive bacteria are less vulnerable to UV-C and stable in their detection rate with and without BSA. A high contamination dose of 107CFU/cm2with E.colishowed only 1logCFU/cm2reduction after UV-C treatment. In contrast, under a contamination dose ≤ 105CFU/cm2E.coliwas no longer detectable. High contamination dose of E.faeciumof 107CFU/cm2 showed only 0,5log reduction and 1log reduction using contamination doses ≤105CFU/cm2after UV-C treatment. In general, field isolates from egg-producing poultry farms showed an increased UV-C tolerance. The comparability of the mercury vapor lamps and the LED panels is possible if the wavelength and the radiation intensity [W/m2] are similar.