One person is seriously ill in hospital, while a further six people are being monitored.
It is thought more cases of E-Coli will be confirmed over coming days because the bacteria has a 14-day incubation period.
Cardiff takeaway closed as a precaution
A take away called The Adonis Kebab House has been closed as a precautionary measure since the outbreak.
Cardiff City Council has confirmed that the kebab house was inspected by hygiene officers less than a month ago. It was given a hygiene rating at the time of one out of a possible five.
The law at present states that is is up to the individual business whether to display their hygiene ratings, but there are now calls to make it mandatory for all food hygiene scores to be displayed.
E-Coli strain is a serious bacterial infection
The confirmed E-Coli cases are all suffering strain 0157. E-Coli 0157 is particularly dangerous to elderly people, children and those with weak immune systems. It produces toxins which can be potentially fatal when ingested in small amounts.
E-Coli 0157 symptoms can range from mild diarrhoea, stomach cramps and fever to bloody diarrhoea. Most sufferers make a full recovery, but kidney failure can develop in more severe cases.
There are many ways people can contract E-Coli, though the most common is from raw fruit or vegetables. Cooking food will generally kill bacteria and prevent food poisoning.
