Listeria a bacterium which can occur in food and cause listeriosis, a serious illness. Its full name is Listeria monocytogenes, and it was named after the famous 19th-century surgeon and pioneer of hygiene, Lord Lister. Listeriosis was first found in a rabbit in 1926, and a few years later in a human adult. It was not until the 1980s that investigations and experiments led to the conclusion that most outbreaks of listeriosis have been due to contaminated food. These bacteria occur widely in the environment, for example in the soil of pastures. Much work was done in Scandinavia to improve methods of close-cutting grass for silage to reduce the level of uptake of the bacteria from the soil (Rance, 1989). They are destroyed by high heat and do not survive pasteurization, although normal reheating of foods will not kill them. But they have the unusual property of multiplying at low temperatures, even as low as 0 °C (32 °F), and for this reason pose a special problem.
