Patties Foods has said its lab tests on its recalled frozen berries – pulled in February after a possible link to an outbreak of hepatitis A – has shown the products do not contain the bacteria.

The Australian group said tests in four labs of 1kg packs of mixed berries sold under the Nanna's brand "had not detected hepatitis A contamination in any batch of … product".

Patties said it had adopted a "positive release protocol" on all non-recalled batches of frozen berries held in Australia and restarted supplying the products.

"Accordingly, all batches of frozen berry products, not just those supplied from China, are being tested in Australia for hepatitis A and e.coli. To date, no detection of either hepatitis A or e.coli has been found in any batch."

Tests by the Australian government showed one of two packs recovered from consumers tested positive for hepatitis A but it was unclear how the contamination occurred.

Tests on eight random samples from supermarkets showed one pack had a "trace amount" was detected. However, the amount was "at such low levels" that it "was not precise", Patties added.

The Nanna's frozen mixed berries comprise of four berries – strawberries, raspberries and blackberries from China, as well as blueberries from Chile. The product is packed in China and distributed by Patties in Australia.

In the wake of the recall, Patties had warned it could have a "material" impact on its results.

Speaking today (15 April), Patties MD and CEO Steven Chaur said: "It is still too early to assess the significance of any financial implications … of the product recalls and this latest development, although it is possible that ultimately the impact could prove to be material. This aspect of the recall is still being monitored."