Inactivation of naturally occurring microorganisms in liquid whole egg using high pressure carbon dioxide processing as an alternative to heat pasteurization

The feasibility of high pressure carbon dioxide (HPCD) processing as a non-thermal pasteurization technique for liquid whole egg (LWE) was investigated. First, the influence of process parameters including temperature, pressure, agitation speed, working volume ratio (WVR) and holding time on the reduction of the natural microbial flora of LWE was studied. Temperature, WVR and stirring speed were the most important parameters in HPCD inactivation. HPCD processing at 13.0 MPa, 45 °C, 50% WVR and 400 min−1 stirring speed during 10 min proved promising for inactivating the native microorganisms in LWE. Secondly, the effect of HPCD treatment at these “optimal” conditions was evaluated on the microbial quality and pH of LWE under refrigerated storage (4 °C) and compared to stored heat pasteurized samples (69 °C, 3 min). HPCD processing extended the shelf life of LWE up to 5 weeks at 4 °C, which is the current shelf life of heat pasteurized LWE. No pH difference was detected between HPCD and heat treated LWE after 1 week of storage.