Effect of an Elevated Level of Carbon Dioxide Containing Atmosphere on the Growth of Spoilage and Pathogenic Bacteria at 2, 7, and 13 C

The effect of 80% CO2 (balance air) on the survival and growth of microorganisms most often associated with spoilage and foodborne disease in poultry carcasses was compared to air at 2, 7, and 13 C. The CO2 atmosphere substantially retarded the growth of the total bacterial load in uninoculated ground chicken meat and parts at all temperatures when compared to air; however, temperature had a larger overall effect than atmosphere. Ground chicken meat and synthetic broth were inoculated (greater than 10(4) cells/ml or g) with Pseudomonas fragi, Salmonella typhimurium, Staphylococcus aureus, or Clostridium sporogenes and the influence of 80% CO2 and incubation temperature studied. With the exception of Cl. sporogenes, 80% CO2 was inhibitory when compared to air at any given temperature. In most cases, CO2 was more inhibitory at 2 C than at 7 or 13 C. The Cl. sporogenes inoculum failed to grow above initial inoculum levels in any combination of temperature and atmosphere, but samples packed in 80% CO2 had higher numbers of colony forming units than air-packaged samples. This study does not indicate that modified atmosphere packaging of refrigerated poultry in elevated CO2 atmospheres increases the microbial hazards when compared to air at the same temperature.