Surface pasteurisation of shell eggs

Abstract

Microbial and visual contamination of eggs during production and processing is of concern to the consumer and to the egg industry for both health and economic reasons. While egg washing has the potential to reduce significantly the amount of visual and microbial contamination of eggs, there are substantial concerns as to the effectiveness of current egg washing technology. It is also unclear whether the use of egg washing results in salmonella moving from the exterior of the egg shell through the shell into the contents of the egg where they may grow to high levels. A short investigation was carried out on the applicability of four different heat treatments (hot air, hot water, infra-red radiation, and atmospheric steam) for the surface pasteurisation of shell eggs. The aim of this work was to assess temperatures on the outside and interior of the shell to identify the highest surface temperatures that could be achieved without damaging the contents of the egg. Initial results show that temperatures sufficient to achieve significant reductions in salmonella numbers can be attained on the outside of an egg without raising interior temperatures to those that would cause coagulation of the egg contents.