Maximizing carbon dioxide content of shell eggs by rapid cooling treatment and its effect on shell egg quality

• Published in: Poultry science 2012-06, Vol.91 (6), p.1444-1453
• Main Authors: Banerjee, P., Keener, K. M.
• Format: Article
• Language: English
• Subjects: Animals; Carbon Dioxide - metabolism; Cold Temperature; Eggs - analysis; Eggs - standards; Environment, Controlled; Food Preservation - methods; Ovum - chemistry; Ovum - physiology; Poultry - physiology; Time Factors
• ISSN: 0032-5791; 1525-3171
• DOI: 10.3382/ps.2011-01504

ABSTRACT Rapid cooling of shell eggs using liquid CO2 has been shown to cool eggs to 7°C within minutes, as opposed to days required by traditional cooling treatments. This quick-cooling technique is component in the maintenance of egg quality and extended shelf life beyond the current 30- to 45-d period. The hypothesis for the current study was that maximizing CO2 content of the eggs during cooling may increase Haugh units and thus extend shelf life (physical quality factors). The objective of this study was to maximize CO2 content of shell eggs during rapid cooling with liquid CO2 and determine its effect on egg quality during 12 wk of refrigerated storage. Three cooling conditions selected for the study were −45°C for 18 min (treatment A), −60°C for 15 min (treatment B), and −75°C for 12 min (treatment C). After rapid-cooling treatment, it took approximately 25 min for the internal temperature of eggs to equilibrate to 7°C. The Haugh units of the rapidly cooled eggs were significantly higher than the traditionally cooled (control) eggs. After 12 wk of refrigerated (5–7°C) storage, control eggs were only 37% AA-grade, 57% A-grade, and 6% B-grade. In comparison, all the rapidly cooled eggs averaged to 80% AA-grade and 20% A-grade. After 6 wk, the average quality of control eggs reduced to grade A, whereas rapid cooling treatment was able to maintain AA quality up to 12 wk. The CO2 content of the rapidly cooled eggs (1.8 mg of CO2/g of albumen) showed no difference between treatments A, B, and C, but it was significantly higher than the control (1.3 mg of CO2/g of albumen). In addition, the vitelline membrane strength of the control decreased 65% during storage and was between 30 and 50% of the vitelline membrane strength of CO2-cooled eggs at 12 wk. Rapid cooling with liquid CO2 extends shelf life of shell eggs.