In an opinion published yesterday, the Scientific Panel on Biological Hazards (BIOHAZ) of the European Food Safety Authority (EFSA) warned that listeria was on the rise, after a general decline in the 1990s. The number of human cases of the disease increased by 8.6 per cent in the EU from 1,427 cases in 2005 to 1,583 in 2006, even though the number of large listeriosis outbreaks has declined. It recommended that both industry and consumers need to focus on risk reduction practices during the handling and preparation of food. Listeriosis is a rare but potentially lethal food-borne infection which can kill vulnerable people such as the elderly and pregnant women as well as people suffering from immuno-compromising diseases such as cancer or HIV. Most cases of listeria are caused by the consumption of ready-to-eat foods which support growth of the bacteria and develop a high concentration of Listeria along the food chain, said the panel report. Surveys have revealed associations with food packaging type, preparation practices such as the use of slicing machines for meat products, storage temperatures, the stage of sampling with respect to shelf life, the lack of an effective HACCP system, and lack of education and training of food handlers. Officials in the US are currently investigating the deaths of three people from listeria contamination of dairy products produced by a Massachussetts dairy. The bacteria was discovered near a piece of equipment used on the production line after the milk is pasteurized, according to local media reports. The investigation is also trying to understand why the bacteria has been found flavoured milk products, with one theory suggesting that the higher sugar content favours growth of the bacteria. The EFSA panel recommended that to better assess the risk of the foods responsible for listeriosis it was necessary to investigate listeriosis cases more thoroughly and generate and analyse data on the consumption in the EU of ready-to-eat foods in which Listeria can be found. Storage temperature at retail and in domestic refrigerators can also vary significantly, raising the risk of growth of the bacteria, said the report. The panel also advised that consumers should take care to keep food at recommended storage temperatures at all times, and take note of the shelf-life of food in their refrigerators.