Shell egg pasteurization using radio frequency in combination with hot air or hot water

This study investigated the effectiveness of three thermal treatments; hot air (HA), hot water immersion (HWI), and hot water spraying (HWS); alone and in combination with radio frequency (RF) on the inactivation of Salmonella Typhimurium in shell eggs. In addition, the physical quality of the treated eggs and their functional capability to produce angel food cakes were determined. The results showed that HWI and HWS were significantly (P < 0.05) more effective at pasteurizing shell eggs than HA, and the pasteurization time was significantly reduced when eggs were first processed with RF. The times needed for RF/HWI and RF/HWS to achieve 5-log reductions of S. Typhimurium were 19.5 and 24.5 min, respectively. Yolk index was unaffected by heating, but Haugh unit and albumen turbidity were increased dependent on the length of treatment. Eggs after HWI, combined RF/HWI, and RF/HWS treatments were able to make good angel food cakes if whipping times were extended. The results of this study demonstrated that combined RF/HWS treatment was comparable to RF/HWI treatment in terms of shell egg pasteurization without damaging egg quality. Therefore, both HWS and HWI may be used as the second step of radio frequency pasteurization.