Egg contamination occurs whilst forming eggs are bun the productive tract, but the presence of S. enteriditis in ovaries and oviducts does not mean necessarily mean that egg contents will become Salmonella –positive.
Approximately 0.9% of eggs were eaten without cooking. Salmonella outbreaks can contribute risk factors for human infection.
These risk factors included poor refrigeration practices, improper storage of pooled eggs, use of raw eggs, substantial time and temperature abuse of eggs, and exposure of highly susceptible individuals.
The principle site of contamination in egg contents appears to be either the yolk membrane of the albumen immediately surrounding it.
Salmonella are unable to traverse the yolk membrane of fresh eggs but can do so when the membrane permeability has been altered as a consequence of storage.
According to Food Safety News (Sept 24, 2015), between 25 May and 18 June 1024, five patients died at Heartlands Hospital in the Bordesley Green area of Birmingham, England and the bacteria were traced back to eggs from the Bayern Ei (Bavarian Egg) factory in Germany.
Salmonella contamination in eggs