Avoid processed meat‚ or cook it well‚ if you don't want listeria

With 172 people dead in the world’s largest documented outbreak of listeriosis‚ the government is urging people at high risk of the disease to avoid processed meat - or to cook it well before eating.

Listeriosis is caused by a bacteria that contaminates food. About one in three babies who have contracted the disease in this outbreak have died.

The bacteria‚ named listeria monocytogenes‚ will be killed if the food is cooked at temperatures above 70 degrees celsius.

The National Institute for Communicable Diseases (NICD) is leading the hunt for the cause of the outbreak‚ and said on Thursday that people who are at high risk of infection should avoid processed ready-to-eat meat products‚ soft cheeses‚ and unpasteurised milk and dairy products.

The NICD explained: "Processed‚ ready-to-eat meat products include viennas‚ polonies‚ russians‚ ham‚ other ‘cold’ meats‚ sausages‚ various corned meats‚ salami‚ pepperoni and similar products typically found in the processed meat sections of food retailers and butcheries.”

People at high risk of listeriosis are pregnant women‚ adults aged over 65‚ and people with weakened immune systems including those living with HIV/AIDS‚ cancer‚ kidney or liver disease‚ diabetes. People on medication that weakens the immune system are also at risk.

The NICD said that if you want to eat processed meat such as sausages‚ viennas‚ corned beef or polony‚ the food must be thoroughly cooked at temperatures of 70°C or higher before eating.

The institute is testing many foods to try and find the cause of the outbreak.

Telling people at risk of disease to avoid processed meat‚ unpasteurised milk and dairy products is the clearest indication yet of what the NICD is looking at as a possible culprit.

The difficulty of tracing what is causing the listeria outbreak is that the bacteria is very common and is found in soil‚ water‚ vegetables and in the faeces of some animals. It can contaminate a wide variety of food types‚ meaning a huge number of tests need to be done.

Patients are interviewed by NICD staff about what food they have eaten‚ but given that it can take 70 days after infection before getting sick‚ it is then too hard to remember what was eaten.

The NICD has urged people to follow the World Health Organization’s five steps to safer food to prevent infection.

These are:

• Wash hands and surfaces before‚ and regularly during food preparation.
• Separate raw and cooked food‚ and don’t mix utensils and surfaces when preparing food.
• Cook food thoroughly – all bacteria are killed above 70oC.
• Keep food at safe temperatures – either simmering hot‚ or in the fridge.
• Use safe water and safe ingredients to prepare food.

“The NICD is optimistic that the source of this outbreak will be found‚ and urges members of the public not to panic unnecessarily. Members of the public are urged to be vigilant all the time by observing the above guidelines‚ and to assist health authorities by spreading the message as widely as possible‚” the institute said.