Immersion heat treatments for inactivation of Salmonella enteritidis with intact eggs

Abstract

ON , J . M. VA N DE PO P UL IE R E A ND H .R . B A LI JR . 1997. 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 3×10 8 cfu, inoculated near the centre of the yolk) were completely inactivated within 50-57·5 min at a bath temperature of 58°C and within 65-75 min at 57°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°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 immersionheated 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.

Effect of Radiofrequency Heating on the Dielectric and Physical Properties of Eggs

“…This can be achieved by conventional conduction heating methods, i.e., water-bath heating [19]. However, the egg white gets heated up more than the egg yolk in contrary to the prescribed temperatures, as the egg yolk is concentric within the egg white.…”

Hot air treatment for surface decontamination of table eggs

“…However this technique may induce shell microcracks (Himathongkham et al, 1999) thus increasing the risk of bacterial pathogen penetration. Water pasteurisation at temperatures ranging from 55 to 60°C needs longer treatment times: 25 min are required in order to obtain 3 log reductions of a S. Enteritidis population on eggshells experimentally infected , 50-57 min are required for the complete inactivation of S. Enteritidis at 58°C (Schuman, Sheldon, Vandepopuliere, & Ball, 1997). These treatment times are far too long in view of a possible industrial application and are sometimes associated with detrimental changes to quality traits of the albumen (Schuman et al, 1997).…”

Sous vide style cooking practices linked to Salmonella Enteritidis illnesses

“…An additional 20 minutes passed before the chef felt the eggs were overcooked. At lower temperatures, longer periods would be required to achieve pasteurization, between 50 and 57.5 minutes at 588C is required with a CUT of approximately 24 minutes (Schuman et al, 1997). One option for chefs to delay hardening of a sous vide egg is to transfer the shell eggs to a lower temperature immersion circulator once full pasteurization is achieved.…”