The effect of a commercial UV disinfection system on the bacterial load of shell eggs

Aims: To study the effect of UV irradiation on the bacterial load of shell eggsand of a roller conveyor belt.Methods and Results: The natural bacterial load on the eggshell of clean eggswas significantly reduced by a standard UV treatment of 4?s; from 4? to3? log CFU per eggshell. For very dirty eggs no significant reduction wasobserved. Eggs inoculated with Escherichia coli and Staphylococcus aureus (4?and 4? log CFU per eggshell respectively) passed the conveyor belt and wereexposed to UV for 4?and 18?s. The reduction of both inoculated bacteriaon the eggshell was comparable and significant for both exposure times (3 and4 log CFU per eggshell). Escherichia coli was reduced but still detectable on theconveyor rollers. The internal bacterial contamination of eggs filled up withdiluent containing E. coli or S. aureus was not influenced by UV irradiation.Conclusions: There is a significant lethal effect of UV irradiation on the bacterialcontamination of clean eggshells and recent shell contamination, contaminationof rollers can be controlled and the internal contamination of eggs is notreduced.Significance and Impact of the Study: The penetration of UV into organicmaterial appears to be poor and UV disinfection can be used as an alternativefor egg washing.