Whole shell eggs were coated with the following materials: Zein (com prolamine), Polidene 930-H (polyvinylidene chloride), Epolene Wax E-45 (epolene wax emulsion), and 974-1 (hydrolyzed sugar derivative plus shellac). Surfaces of coated and uncoated eggs were inoculated with Salmonella typhimurium and Pseudomonas fluorescens. Contents of each egg were then replaced aseptically with a sterile agar medium containing triphenyl tetrazolium chloride. Eggs were sealed, incubated, and examined for shell penetration and growth of P. fluorescens and S typhimurium. The ability of the two microorganisms to decompose films of the dry coatings was also tested. All coatings greatly retarded penetration by both microorganisms, although P. fluorescens was retarded more than S. typhimurium. When incubated for 7 days, heavy suspensions of P. fluorescens and S. typhimurium did not decompose films of dried coatings. After 48 hr incubation, growth of either organism was not obtained in media containing only dried coating films as added substrates. The dry coatings did not inhibit growth of either organism.
1Scientific Paper No. 3993, Washington Agricultural Experiment Station, Pullman, Project No. 2006.
2Present address: Lydia Tryhnew Goatcher, Department of Dairy Science, University of Maryland, College Park, Md. 20740.