- Listeriosis is caused by a type of bacteria called Listeria monocytogenes (listeria) and is mainly spread through contaminated food.
- Listeria is widespread throughout the environment and can be found in soil, wood, decaying vegetation and water.
- Unlike most other types of bacteria, listeria can survive and often multiply in temperatures below 5ºC (41ºF). Therefore, listeria can still grow to potentially harmful levels in food stored in a fridge.
- Listeria cannot multiply in temperatures below 0ºC (32ºF), but freezing food doesn't necessarily kill all listeria bacteria.
- Listeria can be removed by cooking food thoroughly or, in the case of dairy products, pasteurising it (a heat treatment designed to kill bacteria).
More top news
A five-year-old boy whose surprise meeting with "Spiderman" became an online hit has died.
It's going to feel very cold in parts today, with temperatures between 3C and 6C before falling to as low as -6C in some areas overnight.
A son paid off his parents' mortgage for Christmas - reducing them to tears.