The Prevention of Microbial Spoilage in Whole Shell Eggs by Heat Treatment Methods

Abstract

SUMMARY: The prevention of microbial spoilage in whole shell eggs by heat treatment methods has been investigated. After shell eggs had been immersed for 3 min in water at 144·5 ± 0·5°F the incidence of microbial rotting was reduced by over 90%. Consistent reductions in spoilage losses were obtained with farm steeped eggs, eggs produced under commercial conditions, and eggs held in cold storage for 6 months. Heat treatment efficiently controlled green, sour and black rots in stored eggs, but although reductions were noted in the number of mould rots, it cannot be guaranteed that this type of spoilage can be controlled with similar certainty. Internal quality in heat treated eggs was satisfactory. During protracted holding in cold storage, heat treatment appeared to result in a better internal egg quality and a more stable keeping quality, than when untreated eggs were held under similar conditions.

The Course of Microbial Infection of the Hen's Egg

“…This was possibly the main reason why producers preferred to wash eggs. The influence of this practice on the storage behaviour of eggs has been the subject of much controversy and of many investigations, as witnessed by the reviews of Jenkins & Pennington (1919), Haines (1939) and Knowles (1956). Although these authors are of the opinion that the incidence of rotting is generally increased by washing, they cite many investigations in which no detrimental effects attended this practice.…”

“…With such machines it would be possible to hold eggs at temperatures of 135.6-168"F. According to Gorseline, Moser & Hayes (1950) it was common practice in Europe and North America in the mid-19th century for farmers to preserve eggs by dipping them momentarily in boiling water. The heat treatment of shell eggs has been the subject of many investigations (Funk, 1943;Romanoff & Romanoff, 1944;Murphy & Sutton, 1947;Funk, 1948 Knowles, 1956) and it has been established that 'shell pasteurization' effectively reduces the incidence of rotting in washed eggs and retards the breakdown of the albuminous sac. The latter effect led Funk (1950) to coin the term 'thermostabilization'.…”