E. coli are common germs (bacteria) normally found in the gut of warm-blooded animals and people. There are many types of E. coli, most of which are harmless and are an important part of a healthy human intestinal tract. However, some types can cause illness.
One type of disease-causing E. coli is known as Shiga-toxin producing E. coli or STEC. This may also be referred to as Verotoxin E. coli (VTEC). The types of E. coli that can cause illness can be transmitted through contaminated water or food, or through contact with infected animals or people. It usually takes between 2-10 days after the bacteria are ingested for the first symptoms to appear.
Giardia is a food- and water-borne disease that is caused by a parasite found in the gut of infected humans and animals (eg, cattle, sheep, cats, dogs, rats and possums).
Listeria is a foodborne bacteria which can make you sick. Infection with listeria bacteria is called listeriosis. In healthy adults and children listeria usually causes few or no symptoms, but some people are more at risk of severe disease.