What is Listeria Monocytogenes?

Organism Description
L. monocytogenes is a Gram-positive, non-spore forming rod-shaped bacterium. It belongs to the genus Listeria along with L. ivanovii, L. innocua, L. welshimeri, L. selligeri and L. Grayi. Of these species, only L. monocytogenes causes illness humans.

Listeria monocytogenes is a bacterium that causes listeriosis, a disease that can have severe consequences for particular groups of the population. In healthy people, listeriosis generally only causes a mild form of illness. It can cause miscarriages in pregnant women and be fatal in immuno-compromised individuals and the elderly. L. monocytogenes can be found throughout the environment. It has been isolated from domestic and wild animals, birds, soil, vegetation, fodder, water and from floors, drains and wet areas of food processing factories.

Disease Symptoms
Symptoms of non-invasive listeriosis can include fever, diarrhoea, muscle aches, nausea, vomiting, drowsiness and fatigue. The incubation period is usually 1 day (range 6 hours to 10 days). While invasive listeriosis is the severe form of disease and can be fatal.
The most common transmission route of L. monocytogenes to humans is via the consumption of contaminated food. However, L. monocytogenes can be transmitted directly from mother to child (vertical transmission), from contact with animals and through hospital acquired infections.

Associated foods
L. monocytogenes has been isolated from various ready-to-eat products. The presence of L. monocytogenes in ready-to-eat products is probably due to contamination occurring after the product has been processed. This contamination may occur during additional handling steps such as peeling, slicing and repackaging. Also, in the retail and food service environment, contamination may be transferred between ready-to-eat products.

Regulatory requirements
Most meat processing facilities in Victoria require mandatory Listeria management program in place. Business producing RTE packaged meats must demonstrate compliance to mandatory Listeria management program. Requirements of mandatory program are published on PrimeSafe website and in Australian standards. Regulatory Guidelines for the Control of Listeria.

Nav Labs (Aus) has in-house expertise for interpretation of these standards. Our consultants have many years experience in manufacturing and auditing of meat processing facilities. For more information, call our consulting team on 03 93693313 or email info@navlabs.com.au