Determination of Cooling Rates and Carbon Dioxide Uptake in Eggs - By P. A. Curtis, Auburn University and K. M. Keener, K. E. Anderson, and J. B. Foegeding, North Carolina State University - The ability to rapidly cool shell eggs to 7°C is important in the prevention of Salmonella Enteritidis (SE) growth. In addition, quality may also be maintained longer from rapid cooling of shell eggs.

Abstract

A commercial cryogenic CO₂ egg cooling unit was designed and installed in a commercial egg processing facility. This unit was installed on a packer head to rapidly cool eggs individually prior to packaging. The objective of this study was to determine cooling rates and CO₂ gas changes that result from rapidly cooling eggs using this commercial cryogenic egg cooling system and subsequent storage for 15 wk.

Results indicated that cryogenic CO₂ cooling quickly cooled shell eggs in approximately 45 min, whereas traditional cooling required from 19 to 116 h. CO₂ uptake into the albumen was greater in cryogenically cooled eggs (2.11 mg/g) than in traditionally cooled eggs (1.81 mg/g) immediately after processing.

No differences were observed in albumen CO₂ content after 2 wk of storage; at 10 wk statistically greater CO₂ content remained in the cryogenically cooled eggs (1.75 mg/g) compared with the traditionally cooled eggs (1.60 mg/g). These results suggest that a large amount of CO₂ enters the egg during the cryogenic cooling process but is quickly lost during storage.

Beyond 10 wk of storage, the albumen CO₂ content in cryogenically cooled eggs was higher than in the traditionally cooled eggs suggesting chemical changes may have occurred in the albumen.

The study is published in Poultry Science 83:5-14, January 2004 edition

Source: Poultry Science - January 2004