Food Safety Focus (171st Issue, October 2020) – Food Safety Platform
Preparation of Eggs and Egg Products – Safety First
Reported by Ms. Melva CHEN and Mr. Kenneth YIP, Scientific Officers,
Risk Communication Section, Centre for Food Safety
Consuming raw or undercooked eggs potentially causes Salmonella infection, which can pose severe, sometimes life-threatening, health risks, especially to susceptible populations. During August 2017 to August 2020, there were 328 food poisoning outbreaks related to food premises involving 995 victims caused by Salmonella species referred by the Centre for Health Protection. With a view to assist the food trade in preventing food poisoning due to Salmonella in eggs and egg products, the Centre for Food Safety is going to publish a guideline, giving out practical food safety advice about using eggs in food preparation. This article serves as a sneak peek at the guideline.
Figure 1: Common high-risk egg preparation practices in food premises.
Choosing of Eggs
Keeping food safe starts with choosing safe raw materials. Food businesses should purchase eggs from reliable sources and only accept eggs that are clean without cracks or leakage. For dishes that often use lightly cooked or uncooked eggs, e.g. soft-scrambled eggs or tiramisu, choose pasteurised eggs, egg products or dried egg powder. Pasteurisation is the process of applying low heat to kill pathogens and inactivate spoilage enzymes.
In some countries, certain shell eggs are produced under certification systems with measures at farm level that aim to reduce the risk of Salmonella contamination. While claimed to be safe for raw consumption, these eggs have been reported to be tested positive with Salmonella, occasionally causing foodborne disease outbreaks overseas. Therefore, pasteurised eggs or egg products are still the much safer choice if undercooked eggs are required.
Storing and Handling of Raw Eggs
Shell eggs should be stored in a cool, dry place, ideally in the refrigerator, and used on a first-in-first-out basis. Improper handling of raw eggs may result in cross-contamination and thus food poisoning. Food handlers should wash their hands thoroughly before and after using eggs. All utensils and other food contact surfaces such as whisks, bowls and benches should be cleaned and sanitised every time before handling eggs and egg products. Washing shell eggs is unnecessary because this facilitates the entry of bacteria from the outside of the shell to inside the egg through the pores in the shell. When separating the yolk from the white, it is better to use a clean egg separator instead of the egg shell which may contain traces of Salmonella on the surface.
Pooling Eggs is a High-risk Practice When Preparing Egg Dishes
Pooling refers to the practice of breaking a number of eggs into containers and using the combined eggs to make multiple servings of egg dishes or for use in multiple recipes. Pooling is a common practice in some restaurants to save time and control portion size. However, pooling eggs can allow one or more infected eggs to contaminate the whole pool of eggs. If people consume egg dishes prepared from the pool without thorough cooking, they may get food poisoning. The batch of contaminated pooled eggs can also serve as a reservoir for Salmonella in the restaurants which may contaminate utensils or other foods.
Restaurants should only break enough eggs for immediate service in response to a consumer's order. If you are breaking eggs for later use, keep the pooled eggs in covered containers in the refrigerator and only take out the amount as needed. Use all pooled eggs on the same day and do not top up with new eggs. As pooled eggs have a higher chance of harbouring bacteria, they should be cooked thoroughly and not be used for making raw or lightly cooked dishes.
Cook Eggs Thoroughly and Keep Them at a Safe Temperature
The best way of eliminating harmful bacteria is to cook the eggs thoroughly until the core temperature reaches 75°C or the yolks are firm. Also, improper holding temperature of egg dishes is a common cause of local food poisoning outbreaks. If not consumed immediately after preparation, hot dishes such as soft-scrambled eggs should always be served or kept at above 60°C, and cold dishes such as sandwiches and desserts should be kept at 4°C or below.
The above advice is applicable not only in food businesses but also in domestic settings to reduce risks of food poisoning.