Listeria Alert

By Dietitian, Juliette Kellow BSc RD

An 80% increase in the number of people infected with Listeria has caused the Health Protection Agency to issue an alert in May 2007. Here's what Listeria is and where it comes from.

What is Listeria?

Listeria is bacteria picked up from infected food. Named in honour of Joseph Lister, a famous British surgeon, listeria is killed by pasteurisation and cooking, but if ingested causes listeriosis.

Who is At Risk?

Healthy adults sometimes become infected but do not have any symptoms, or experience only mild symptoms, which can be treated with antibiotics.

Listeriosis is most dangerous to unborn babies, young children, the elderly and those with a lowered immune system.

Where does It Come From?

Listeria can be found in the soil, decayed matter and in most animals. This means that unwashed fruit and vegetables (including pre-packed salads) can contain the bacteria.

Also raw or smoked meat and fish, pate and cooked meat that may have been infected after cooking such as deli counter products.

Unpasteurised dairy products are also a source, as are mould-ripened cheeses such as Brie, Camembert and Stilton.

Food preparation and storage are also important for those at risk as listeria is able to grow in temperatures ranging from refrigeration to body temperature (4C – 37C).

How Can You Reduce Your Risk?

• Ensure you have high standards of hygiene when storing, preparing and cooking food.
• Make sure you wash any fruit or vegetables (including pre-packed salads).
• Wash your hands before and after handling food.
• Cook food thoroughly (especially animal products).
• Keep uncooked meat separate from vegetables, cooked foods and ready to eat foods.
• Avoid unpasteurised milk or foods made from it.