An article published in the Sydney Morning Herald on 8 January 2016 claimed that supermarkets are the ‘missing link’ in egg-related Salmonella protection. Here is FSANZ’s response to the issues discussed in the article.
There is no food safety reason to require whole eggs to be refrigerated at retail, however retailers may choose to refrigerate eggs for their own reasons (for example, to maintain quality of the egg such as firmness of the yolk or reduce spoilage).
FSANZ undertook a thorough risk assessment of egg production and processing in Australia in 2011. This involved consultation with industry, scientists, government agencies and the public. The work was also undertaken with the assistance of international and domestic experts. We looked at the entire supply chain, including factors on-farm that increase the likelihood of Salmonella contamination, through grading, washing, packing, retail storage and consumer preparation.
An egg's shell, membrane and the egg white all form a barrier designed to stop food poisoning bacteria from contaminating the inside of an egg.
However, problems can arise when the bacteria on the eggshell come into contact with the inside of the egg, or the Salmonella is transferred from a person’s hands after handling eggs into a food that is not going to be cooked. This is why it is very important to follow safe food handling practices.
Whole un-cracked eggs aren’t required to be refrigerated at retail because:
- Unlike many other countries (e.g the US and UK), the types of Salmonella that can contaminate the inside of eggs as they are formed in the bird are not present in Australian laying flocks.
- Contamination of the surface of the egg with Salmonella can occur as it is laid, or via contamination from the farm environment. There are requirements in the Food Standards Code for egg producers to control this hazard, e.g. minimising the contamination of feed with Salmonella so it is not introduced to the laying flock.
- Salmonella must first cross the physical barriers of the shell and membranes, and tolerate the hostile conditions of the egg white before it can enter the yolk and grow.
- The temperature along the whole supply chain affects the rate at which the protective membranes within the egg degrade. The time eggs spend on the retail shelf is often short compared with the time between the being laid through to consumption (i.e. entire shelf life). Due to the nature of egg contamination in Australia, refrigeration of eggs at retail is considered to have a small impact on the overall risk of illness.
- Evidence shows that food poisoning outbreaks associated with eggs in Australia have been mostly due to uncooked or lightly-cooked foods containing contaminated raw egg such as sauces and desserts. Factors that may have contributed to outbreaks included cross-contamination during food preparation (i.e. transfer of Salmonella from the surface of the egg to other surfaces and/or foods) and storage of the food containing raw egg at temperatures that would permit growth of Salmonella.
Raw egg products like raw egg mayonnaise are considered high risk and they do require refrigeration. This is because pathogens may contaminate the egg pulp when the egg is cracked. Cracked and dirty eggs can’t be sold in Australia and are prohibited in the Food Standards Code.
Consumers can minimise the risk of food poisoning by following these tips:
- Dishes containing raw eggs as an ingredient, that aren’t going to be cooked before being eaten, should not be served to small children, pregnant women, the elderly and people with compromised immune systems (as they are at greater risk from food poisoning). Egg meals should be cooked for these vulnerable people until the yolk in a boiled egg has started to become firm or eggs have become set in omelettes or scrambled eggs.
- Check your eggs for visible cracks. If it is cracked, it is safest to discard them or cook thoroughly, for example in a baked cake.
- If you accidentally drop pieces of shell into your egg mixture, it too could be contaminated and the mixture will need thorough cooking. Remove the shell pieces with a clean spoon or fork.
- Wash your hands with soap and running water and dry thoroughly before handling any food including eggs and after handling eggs so you don’t contaminate other food
- If you are not going to cook the eggs further, don’t separate the yolk from the white using the shell as that could contaminate the raw egg. Invest in a plastic egg separator.
- Prepare raw egg foods (such as mayonnaise or mousse containing raw eggs) just before you are going to eat them and refrigerate immediately at 5°C or below, so the bacteria cannot grow.
To enhance the quality of eggs, consumers can keep eggs refrigerated in the cardboard box they are purchased in.