Listeria monocytogenes is a Gram-positive bacterium, found in at least 37 mammalian species, as well as 17 species of birds and possibly some fish and shellfish. The bacteria can be isolated from soil, and is resistant to heat, freezing and drying. Listeria has been associated with foods such as raw milk, soft-ripened cheeses, ice cream, raw vegetables, raw and cooked poultry, raw meat and raw and smoked fish. Unlike other pathogenic bacteria, such as salmonella, listeria can survive and grow at temperatures as low as 5¡C (41¡F). Acute infection with listeria may result in flu-like symptoms including persistent fever, followed by septicemia, meningitis, encephalitis, and intrauterine or cervical infections in pregnant women. Possible gastrointestinal symptoms include nausea, vomiting and diarrhea, alone or couple with other symptoms (mentioned above).