Immersion heat treatments for inactivation of Salmonella enteritidis with intact eggs

The effects of water-bath immersion heat treatments on the inactivation of Salmonella enteritidis within intact shell eggs were evaluated. Six pooled strains of Salm. enteritidis (ca 3 x 10(8) cfu, inoculated near the centre of the yolk) were completely inactivated within 50-57.5 min at a bath temperature of 58 degrees C and within 65-75 min at 57 degrees C (an 8.4 to 8.5-D process per egg). Following the initial 24 to 35-min come-up period, semilogarithmic survivor curves obtained at 58 and 57 degrees C yielded apparent decimal reduction times (D-values) of 4.5 and 6.0 min, respectively. Haugh unit values increased during heating, while yolk index and albumen pH values were unaffected. Albumen clarity and functionality were affected by the thermal treatments; therefore, extended whip times would be required for meringue preparation using immersion-heated egg whites. Immersion-heated shell eggs could provide Salmonella-free ingredients for the preparation of a variety of minimally-cooked foods of interest to consumers and foodservice operators.