Me. Berrang et al., MICROBIOLOGY OF SANITIZED BROILER HATCHING EGGS THROUGH THE EGG-PRODUCTION PERIOD, Journal of applied poultry research, 6(3), 1997, pp. 298-305
Nest-clean and dirty eggs were sampled monthly across the productive p
eriod of a commercial broiler breeder flock. Eggshells and membranes w
ere examined for total aerobic bacterial and Enterobacteriaceae counts
per egg. Paired nest-clean and dirty eggs were spray sanitized in a t
wo-stage commercial egg sanitizing machine (a chlorine detergent wash
followed by a quarternary ammonia sanitizing spray) and tested for bac
terial contamination. As the flock aged, numbers of bacteria per nest-
clean egg fluctuated without a noticeable trend (from log(10) 0.8 to 3
.2 cells total aerobic bacteria and 2 to 5 cells Enterobacteriaceae pe
r egg) regardless of hen age. Those eggs classified as dirty had visib
le fecal contamination and higher bacterial numbers than nest-clean eg
gs (log(10) 5.9 to 7.6 cells total aerobic bacteria per egg). After sa
nitization, previously dirty eggs had bacterial populations comparable
to those of sanitized dirty eggs were still microbiologically indisti
nguishable from sanitized nest-clean eggs, though both groups had high
er bacterial contamination levels than had been observed in samples ta
ken immediately following sanitization.