Adaptation of Listeria in liquid egg containing sucrose resulting in survival and outgrowth

Survival of Listeria species was tested in liquid egg products such as albumen, yolk, whole egg and whole egg containing 25% sucrose. At an incubation temperature of 4 degrees C Listeria survived in all products, and even increased slightly in yolk, whole egg and whole egg containing 25% sucrose. However, at 20-22 degrees C, in whole egg containing sucrose, a rapid an dramatic decrease in numbers of Listeria was observed. Following this initial decrease, an increase in the numbers of Listeria was observed. The ability to grow in liquid egg containing sucrose was maintained upon reinoculation into a freshly prepared product. However, this property disappeared after subculturing in brain heart infusion broth. The significance of these findings is discussed.