Listeria Monocytogenes – What is it and how can it be controlled?

Listeria monocytogenes is a unique bacterium which is ubiquitous in the environment. It invades through epithelial cells of GI tract and targets the immune system. It is a very important pathogenic bacterium to be aware of as it can survive and grow at low temperatures i.e. it can grow at a range of -0.4-50 °C.

  1. monocytogenes will cause severe disease known as listeriosis if it got access to the food chain. Symptoms of listeriosis include septicaemia, meningitis and cervical infection in pregnant women leading to miscarriages.

Sources of the bacterium include soil, vegetation, silage, sewage, water and faeces of healthy animals and humans. It is frequently present in foods of animal and plant origin and can become endemic in food processing environments (research has shown that individual processing establishments often harbour their own unique population of L. monocytogenes and that these populations are capable of persisting in the environment over time (chemical resistant DNA). It may also be present in cooked foods as a result of post-process contamination or inadequate heat treatment.

Food borne outbreaks of listeriosis are small but because the mortality rate associated with this infection is so high it makes it of significant public health concern. An infamous case study involved

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