Abstract INTRODUCTION SPOILAGE of fresh refrigerated poultry is ordinarily caused by psychrotolerant bacteria growing on exposed surfaces (skin, muscle and gut-cavity lining), yet definite information on many of the physical and chemical factors that affect rates of growth is scarce. Results of published work are often conflicting and difficult to interpret because experiments were made with birds contaminated naturally during processing or handling and thus under conditions not controlled as to type and amount of inoculum. Comparative testing with controlled inoculation is required to determine the relative growth rates of the principal spoilage organisms and the extent to which these rates are affected by processing and storage conditions. Work has been undertaken, therefore, to study factors which affect the growth of pseudomonads and achromobacter (the two principal groups of bacteria responsible for low-temperature spoilage of poultry (Ayres et al., 1950; Thornley et al., 1960: Walker and Ayres, 1956)) on the surface . . .