Eggs: washed or unwashed?

By Ahmed ElAmin

- Last updated on GMT

Related tags European food safety authority Food administration Food

A report by the EU's food regulator not only indicates that it is
moving to recommend that table eggs be washed in the bloc, but also
provides insight to the different methods and equipment food plants
use to handle procedure.

The report by an European Food Safety Authority (EFSA) panel could also end up providing a push toward better technology within plants for egg washing, cleaning, and drying equipment.

Eggs are a primary source of human salmonellosis in Europe. Egg-associated infections are mainly caused by Salmonella Enteritidis. The EFSA panel found that the evidence from other countries thatrequire egg washing indicates that the procedure might help to prevent food contamination and illnesses in human. However in weighing the advantages and disadvantages of the requirement, the safetyregulator says it needs more scientific evidence on whether to recommend that the bloc makes a shift in requirements.

In particular the panel will now look into how to make the washing process and the hygienic design of the equipment better. It recommends that EFSA should look into developing a code of practicefor egg-washing systems based on food safety requirements.

It calls for the testing of post washing practices, including the effect of oiling and storage conditions on washed eggs.

"Developing new technologies to decontaminate the external surface of the eggshell, without damaging the shell integrity, should be encouraged,"​ the panel stated.

EU regulations require that eggs sold directly to the public, defined as "Grade A", must not be washed or cleaned before or after grading. Producers also cannot chill or treat eggsfor preservation. Grade B eggs, the second classification in the EU, may only be used by the food or non-food industries and can be washed or unwashed.

Other countries like the US and Sweden require that all eggs be washed prior to being sold, claiming the procedure's food safety benefits outweigh the disadvantages.

The practice of washing of eggs has been mainly developed to clean dirty eggs in the Grade B classification. Another reason for washing eggs is to improve the hygienic quality of eggs by decreasingthe bacterial load on the surface and thereby preventing the infection of the inside.

Modern in-line egg washing procedures involves three stages. The pre-washing or wetting stage is usually done using a gentle spray of warm water. The washing processtypically involves rubbing the eggs with brushes or spraying them with jets of potable water containing chemicals.

Rinsing completes the process and aims to remove any loose debris that the egg has picked up during the main wash and to remove the residues of any chemicals or otherdissolved matter. Post-washing treatments involve processes such as drying and possibly oiling and cooling .

Normally the unwashed egg shell serves as a good barrier to bacterial contamination and provides an array of antimicrobial properties for the egg. Washing may harm the delicate shell, encourage thepropagation of crack sites and eventually bacterial contamination.

Scientific data regarding current egg washing practices indicates bacteria are reduced on the surface. However, sanitising eggs will not prevent egg related diseasescaused by microorganisms, such as Salmonella that are already present inside the egg.

"Table eggs sanitised by these means will contribute to a general hygienic improvement and a decrease in the potential for cross-contamination during foodpreparation,"​ the panel concludes.

The major disadvantage of egg washing is the potential damage to the physical barriers, such as the cuticle, which can occur during or after washing, for instance fromincorrect operations, in particular washing eggs in cold water.

"Such damage may favour trans-shell contamination with bacteria and moisture loss and thereby increase the risk to consumers particularly if subsequent dryingand storage conditions are sub-optimal,"​ the panel stated. "Whilst any shell damage should be seen as a disadvantage of washing, it should be balanced against the fact that washedeggs normally have considerably lower microbiological populations on the shell."

After evaluating Sweden's egg washing requirements and industry practices, the panel concludes that the risk associated with current commercial practices in the countryis low.

On the other hand, taking into account the very low prevalence of Salmonella​ in layers in Sweden, the overallrisk associated with egg washing is assumed to be low.

In Sweden eggs are required to be washed in a fine water spray at high pressure, and gently brushed for 45 seconds at a temperature of 41°C. Under this procedurecontact with the shell surface is minimised.

The standards adopted in Sweden for egg washing, as set out in the National Food Administration's Inspection Manual for Egg Packing Centres, are broadly similar to those in place in the US.However, Sweden's regulations do not include a specification for iron content in the water.

In addition, in Sweden the temperature of the water must exceed the temperature of the egg by at least 15°C, whilst in the US the comparable figure is 11°C. Swedish legislation states thatrinsing water must not be recycled other than as wash water, but there does not seem to be any equivalent requirement in the US, the panel stated.

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