LABORATORY experiments have shown that iron contamination greatly increases both the rate and extent of the bacterial spoilage of experimentally inoculated shell eggs (Garibaldi and Bayne, 1960, 1962). The following experiments were conducted to determine whether or not iron also affects the microbial spoilage of eggs washed under farm conditions. Results of such experiments may explain some of the divergent results reported by various workers in the egg washing field.The washing experiments were conducted on two commercial egg farms in Sonoma County, California. Farm “A” had been washing all eggs for some time without any serious incidence of fluorescent “sours.” Farm “B,” which was of comparable size, had been dry cleaning their dirty eggs. Since dry cleaning was so laborious and time-consuming they decided t o change to the more rapid method of water washing. This change in cleaning procedure, however, was accompanied by a significant increase in the …