Systematic Veterinary Bacteriology and Mycology

HABITAT

• Listeria species are widely distributed in the environment and can be isolated from soil, faeces, plants, decaying vegetation and silage (pH 5.5) in which the bacteria can multiply.
• Silage is commonly implicated in outbreaks of listeriosis in cattle and sheep.
• In poor quality sailage the listerial numbers may reach 107 cfu/kg of silage.
• Asymptomatic faecal carriers occur in man and many animal species.
• L.monocytogenes can be excreted in bovine milk.
• Human foods associated with listeriosis in man include soft cheeses, milk and poultry meat.