Commercial food production laboratories are not equipped to test for hepatitis A in Australia, so Nanna's frozen berries have instead been sent to the United States and Italy to see if raspberries may be the cause of the virus outbreak.
Patties Foods, owners of the Nanna's and Creative Gourmet brands, added the Nanna's 1kg frozen raspberries on Tuesday to the three other lines recalled at the weekend. The Victorian Health Department advised Patties of the potential link to its Nanna's 1kg frozen mixed berries packs and the 300g and 500g packs of Creative Gourmet mixed berries on Friday afternoon.
As of Monday, nine cases of hepatitis A had been potentially linked to the mixed berry packets. The department is expected to make an announcement on further cases late on Tuesday afternoon. Microbiological tests have yet to prove a link between the virus and the berries but tests in the US and Italy should establish if raspberries, supplied in China, are the cause.
Patties managing director and chief executive officer Steven Chaur said Patties supplied about 50 per cent of the frozen berry market. He said the common link between the products in all four recalled lines was the raspberries which came from a supplier in China.
"That was a very clear marker for us that the consistency with the two products is the raspberries," he said.
"We don't believe at this time that our other products - sourced from other facilities and other countries and other regions - are at risk. The common denominator here is raspberries and we believe that could be an area to further investigate," he said.
Patties severed its links with the China supplier of those raspberries in November last year but Mr Chaur denied it was over health concerns and said it was to consolidate supply in China.
Mr Chaur said testing for hepatitis A virus was "difficult". No commercial food production testing facilities were equipped to test for viruses like hepatitis A in Australia, he said. He said the product samples were sent to laboratories owned by Patties' supply partners in Italy and the US. Results are expected in two weeks.
"We do test for markers (for hepatitis A) like e.coli which are generally associated with faecal matter. That is a pretty clear indicator if there is any concern," Mr Chaur said.
He said E.coli levels results showed its frozen berries were within safe tolerance levels.
"We had no reason to believe these products present a health risk," Mr Chaur said.
He said Patties tested more widely for contamination than it was required to by law, including annual supplier audits, testing before products were imported and again in Australia.
Patties has been criticised for importing berries but Mr Chaur said Australia did not have the facilities to quick freeze berries and supplies were too small to meet demand.
"Berries are a seasonal product and the Australian marketplace whilst producing very, very good quality berries doesn't have the freezing capabilities to deal with the type of product we sell in the marketplace. Most of the berries produced in Australia are sold fresh so hence we source globally from countries like China, Chile, Vietnam and, even countries like Turkey, where the manufacturing facilities are in place," he said.
He denied the berries were sourced overseas to save on costs.
Mr Chaur supported existing country of origin levels saying they were "very strict".
Asked about whether he was concerned about consumer legal action, he said it was too early to tell if this would occur.
"But the most important thing at this point in time is making sure that consumer safety is paramount and to get the product back on the market," he said.