Egg washing using a small-scale bucket washer

Preliminary results on the microbiological implications of using a small-scale bucket-style washer are reported for chicken eggs. The bucket washer reduced the total bacterial numbers on the surface of cage-produced eggs under manufacturer-recommended conditions on average by 1.5 log CFU egg. When washing free range eggs which were visibly soiled, there was a tendency for the wash water to become dirty after only a few batches of eggs had been washed. Washing in dirty water could increase the levels of bacteria on the surfaces of the shells of visibly clean eggs. However, the additional bacteria did not manage to penetrate into the egg contents. A single batch of washed eggs (1 positive from 10 total) contained detectable numbers of bacteria in a pooled sample of contents after 2 weeks storage at 15oC. None (0 positive from 10 total) of the batches of unwashed eggs cultured bacteria from their contents. Eggs warmed to 37C, 30C, 25C or 20C were submerged in aqueous protein stain at 15C for up to 7 minutes and hard boiled to determine if visible volumes of stain were taken into the egg contents. We did not observe take up of the stain solution unless it was 15C cooler than the egg contents and eggs were immersed for at least 3 minutes.