Efficacy of Ultra Violet Light for Elimination of Salmonella on Broiler Hatching Eggs

Abstract

Germicidal UV light at a wavelength of 254 nm was tested as a means to eliminate inoculated Salmonella from eggshells. Eggs inoculated with 105 cells Salmonella were treated with UV light (600 μW/cm2) for 1 to 10 min. When inoculation was made by a drop of suspension on the eggshell surface, UV light treatment significantly lowered the incidence of positive eggs (P≤.05). However, UV light treatment was less effective against Salmonella when the inoculum was applied to the egg as a submersion dip. Salmonella inoculation placed on the eggshell by a drop of suspension and covered with a fecal smear was not eradicated by the UV light treatment. As few as ten cells of Salmonella in feces was sufficient to result in positive eggs following exposure to UV light (600 μW/cm2). Following a fecal smear inoculation with 100 cells, even UV light intensity as high as 1600 μW/cm2 lead to less than 25% reduction in the percentage of eggs positive for Salmonella. Continuous exposure of eggs to UV light in the incubator did not affect hatchability.