The strain of Salmonella thought to have killed two nursing home residents and caused dozens of others to fall ill has been found in a Wollongong bakery, tests have confirmed.
Two patients have died as a result of the outbreak.
The nursing homes involved are either run by Illawarra Retirement Trust or supplied catering by IRT.
Last month testing conducted by the New South Wales Food Authority at Bettamaid wholesale bakery in Unanderra came back positive for Salmonella.
The Food Authority then carried out further testing on environmental swabs and food samples taken from the bakery.
A test on an environmental swab has returned positive to the strain of Salmonella detected in sick residents, Salmonella bovismorbificans.
A spokeswoman said food samples supplied by the bakery to affected facilities also tested positive for Salmonella, but the strain was still being typed.
There were no reports of illness in the broader community related to consumption of food from the bakery, which supplies a number of shops and school canteens.