Control of Salmonella Contamination of Shell Eggs - Pre-harvest and Post-harvest Methods: a Review

A new and thorough review from researchers based in Romania and Belgium examines how Salmonella contamination of shell eggs can be minimised by preventative methods on the farm and further along the food chain.
calendar icon 16 March 2013
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Salmonella Enteritidis is one of the most prevalent foodborne pathogen, its main reservoir being considered the shell egg, according to a recently published review in Comprehensive Reviews in Food Science and Food Safety.

Anca M. Galis of the University of Agronomical Sciences and Veterinary Medicine of Bucharest in Romania and co-authors there and at the University of Liege in Belgium report that, as the concern grows over the increase in human salmonellosis cases, the need for an application of preventive methods either at the farm level or during the processing steps is crucial for a better control of the foodborne outbreaks due to the consumption of this specific food product.

Their review focuses on the application of preventive methods at the farm level, on pre-harvest step, in order to reduce the risk of shell eggs contamination with Salmonella, especially S. Enteritidis, through a better control of the laying hens' infection with this pathogen.

Among post-harvest methods, a first approach is the egg storage conditions and the prevention of Salmonella spp. growth and multiplication. In addition, shell eggs may be subjected to eggshell decontamination to reduce the risk of foodborne outbreaks.

Several of these latter methods are already authorised in different countries, as it is the case in the US and Canada. Their efficacy has been proven and their use is regarded by some as mandatory for ensuring shell eggs safety for the consumers.

In their conclusion, Galis and co-authors state that the use of different preventive methods has the effect of reducing the likelihood that eggs become contaminated with Salmonella spp., especially with S. Enteritidis.

On the farm level, the different pre-harvest methods may reduce the risk of egg contamination by interfering in the infection process and reducing the likelihood of this foodborne pathogen penetration in the forming egg.

Further on, post-harvest methods may reduce the risk of human salmonellosis, by respecting the refrigeration step and by different procedures, either chemical or physical. These latter reduce the existing bacterial counts, especially on the eggshell and ensure the microbiological quality of the shell eggs marketed in different parts of the world.

However, the researchers add that post-harvest chemical or physical procedures are not worldwide accepted and implemented, as research is still needed on this topic, to ensure that the nutritional quality and properties of shell eggs are maintained, no matter which processing methods are applied.


Galis A.M., C. Marcq, D. Marlier, D. Portetelle, I. Van, Y. Beckers and A. Théwis. 2013. Control of Salmonella contamination of shell eggs - preharvest and postharvest methods: a review. Comprehensive Reviews in Food Science and Food Safety, 12:155–182. doi: 10.1111/1541-4337.12007

Further Reading

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March 2013

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