The Effect of Different Rations on the Number of Free Ruminal Bacteria in Sheep

The predominant type(s) of microbial flora and the changes in types resulting in the particular ascendency pattern on spoiled chicken meat has been a subject of study by various investigators. Ayres et al. (1950) identified the microorganisms contributing to spoilage of chicken meat which had received no treatment other than chilling. Walker and Ayres (1956) concluded that the increase in numbers of organisms on the surface of birds during processing could be attributed to the distribution (by washing and handling) of organisms occurring on the feet and feathers and in the feces and intestinal tract. Yeast were found to be present initially at levels of about 1000 per cm2 and after 2 weeks' storage to increase 100-fold. The types found were reported to belong to the genera Rhodotorula, Cryptococcus, and Torulopsis. Ziegler and Stadelman (1955), in reporting the results of work involving treatment of poultry meat with chlortetracycline, state that yeasts having the shape and budding characteristics of Saccharomycetaceae and gram-negative rods formed the predominant flora of the meat treated in this manner. Ayres et al. (1956) found that yeast numbers were higher on chlortetracycline-treated birds than on controls and they indicated that the marked reduction in bacterial numbers may provide a more readily available substrate for yeast development. Njoku-Obi et al. (1957) reported studies on the isolation and identification of the fungal flora of spoiled, chlortetracycline-treated chicken meat. They found representatives of five genera of yeasts to be present on these spoiled carcasses whereas only three genera were found on the spoiled untreated controls. They also commented on the potential pathogenicity of Candida parapsilosis which they isolated from the antibiotictreated meat. This report covers a study which was undertaken to gather more information on the yeast types developing on both chlortetracyclineand oxytetracycline-treated poultry meat as well as the increases of spoilage from yeast development after treatment with antibiotics.