CANBERRA, Jan. 3 (Xinhua) -- Nine people have been admitted to hospital, including two children, after contracting salmonella from the same South Australian bakery.

South Australia (SA) Health confirmed on Tuesday night that the number of salmonella cases linked to Gawler South Bakery in Adelaide's northern suburbs had risen to 35, up from 17 on Friday.

Authorities expect the figure to rise further with products containing chicken at the bakery identified as the source of the outbreak.

Among those hospitalized were two children, one of who is just two years old.

"We've now seen cases in people aged two years old up to 70 years old and we are anticipating more cases as further test results come through," SA Health public health director Kevin Buckett said.

"This is a significant outbreak, it's quite a large number of people.

"We don't know yet that this outbreak is actually over. We know that the laboratories still have some stool samples waiting to be tested."

Food safety authorities returned to the bakery on Wednesday morning as the investigation into the source of the outbreak continued.

"We don't think it's the product that's coming into the bakery that's contaminated," Buckett said.

"Somehow there's been cross-contamination associated with probably less than adequate sanitation and cleaning, and also the potential to mix raw food with cooked ready-to-eat food."

Salmonella infection is a type of gastroenteritis which causes fever, diarrhoea, vomiting, cramps, loss of appetite and headaches.

The same bakery was the source of a similar outbreak in October 2016 which only affected eight people.