Egg age and the growth of Salmonella enteritidis PT4 in egg contents.

The growth of Salmonella enteritidis PT4 in albumen around an intact yolk was governed by the age of the egg on inoculation. In the majority of eggs, held at 20 degrees C, the bacterium was unable to grow rapidly until eggs had been stored for approximately 3 weeks. The multiplication of S. enteritidis in stored eggs appeared to be associated with alterations to the yolk membrane which allowed the bacterium to either invade the yolk or obtain nutrients from it. The rate at which egg contents change to permit the growth of S. enteritidis would appear to be temperature related and took place more rapidly when eggs were stored under conditions where temperatures fluctuated and, on occasions, reached 30 degrees C.