Elevated Carbon Dioxide Atmospheres for Packaging Poultry: II. Effects of Chicken Quarters and Bulk Packages

Abstract

Chicken quarters (breast and leg) one day after slaughter were packaged in glass jars containing 0, 60, 70, and 80% carbon dioxide (CO2) (balance air) or in permeable film-wrapped trays, which were stored in large low permeability film bags and flushed with 80% CO2 (balance air). Storage temperature and times were 2 C and 7 to 35 days. Microbial analyses indicated a reduction in aerobic colony forming units in film packaged quarters of between 104 and 101 at 14 and 35 days of storage, respectively, when CO2 was added to the package. Other storage times and treatments generally fell within this range. Shifts in predominant types of bacteria from Gram-negative to Gram-positive occurred in all CO2 treatments while air-packaged samples remained predominantly Gram-negative. A residual CO2 effect was seen when quarters that had been stored in glass jars in 80% CO2 were removed and stored in air for 3 days prior to analysis. This effect was not apparent when storage was in 60% CO2; 70% demonstrated an effect in between these two. Microbial growth rates for quarters stored in film with 80% CO2 demonstrated growth rates similar to air packaged controls when removed from the CO2 atmosphere. Sensory analyses of raw quarters resulted in higher scores for CO2-stored samples with respect to odor, feel, and overall acceptability, and slightly lower scores for color. Sensory analyses of baked chicken showed that when CO2-stored chicken was compared with fresh chicken, the two samples were rated nearly equal in appearance, tenderness, flavor, and overall acceptability after 28 days of storage. At 35 days storage, CO2 treated samples were scored lower in tenderness, juiciness, flavor, and overall acceptability, but were still acceptable. We conclude that elevated CO2 atmospheres can increase shelf-life of fresh chicken carcasses to at least 35 days.