​Toast served with half-boiled eggs is a popular breakfast in Singapore, but for elderly Singaporeans and those with weak immune systems, it may be prudent to avoid eating undercooked eggs which put them at risk of serious bacterial food poisoning caused by the Salmonella bacteria.

According to the Ministry of Health's Weekly Infectious Disease Bulletin, Salmonella is the leading cause of food poisoning in Singapore with 1,480 cases reported in 2010 and 1,383 cases in 2011. It can be particularly harmful for the elderly.

"Bacterial food poisoning caused by Salmonella or another bacteria known as Listeria can become very serious in the elderly because the bacteria may spread to other organs," says Dr Limin Wijaya, Senior Consultant at the Department of Infectious Diseases, Singapore General Hospital (SGH), a member of the SingHealth group.

"The weaker immune system of the elderly makes them more vulnerable to developing serious bacterial infections and complications," adds Dr Wijaya.

Causes of Salmonella food poisoning

Most food poisoning incidents are a result of mishandling of food. The Salmonella bacteria can spread through food contaminated by animal or human waste. Meat, milk, eggs and poultry are common breeding grounds for Salmonella bacteria. It gets to other food by cross-contamination from contact with raw food, utensils or equipments.

Fruits and vegetables contaminated with faeces in the soil or water can also cause Salmonella food poisoning.

Food handlers who do not wash their hands thoroughly after going to the toilet may cause food to be contaminated with Salmonella.

Causes of Listeria bacterial food poisoning

Listeriosis is another type of food poisoning caused by a bacterium known as Listeria monocytogenes. Listeria bacteria usually spread through raw foods such as soft cheeses, uncooked meats and vegetables, and unpasteurised milk. It may infect ready-to-eat deli meats, hot dogs and luncheon meats.

Learn to recognize the symptoms of food poisoning and prevention tips in the next page.

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