The following is from The Bug Bible – http://www.safefood.net.au/AudienceHierarchy/TheBugBible/Default.htm
Listeria monocytogenes has been known for at least 60 years, but it has only been linked with foodborne disease since the early 1980s. Since this time it has become recognised as an important food poisoning bacteria.
The organism is widespread in the environment and is carried by a number of domestic and wild animals. There are several species however, L. monocytogenes is the most common and is pathogenic for both animals and humans. Transmission can be by person to person by the faecal-oral route as well as from the environment and from aerosols. However, foodborne transfer is considered the most significant. The organism is very good at establishing itself on food contact surfaces and survives well in the refrigerator.
While normal healthy individuals can become infected by L. monocytogenes those most at risk are the elderly, the young and those who are immune-compromised or pregnant. The organism can cause serious illness in these groups of people.
The foods commonly implicated in foodborne outbreaks include cold deli meats, cold cooked chicken, soft cheeses, salads, smoked salmon and trout
The organism is not heat resistant however, it is very tolerant of cold and can grow at refrigeration temperatures lower than 1ºC although growth at these temperatures is slow.
Consumer education has concentrated primarily on the “at risk” groups and a number of health authorities have published guidelines for foods served in hospitals, aged care facilities and food consumed during pregnancy. These guidelines should also be adopted in the home for food prepared for at risk individuals
In the home good hygienic practices should be adopted and foods most at risk of containing Listeria should be stored for no more than the recommended shelf life.
Refrigerators should be kept in a clean and hygienic condition and the temperature kept as cold as possible. Foods should be placed in containers and covered. Cooked foods should always be stored above raw foods.
Cross-contamination from raw to cooked foods must be avoided.
Cleaning clothes must be disinfected and paper towel used where possible to wipe up residues from raw meats, fish and vegetables.
