"In the new case, the person ate the berries in late October and reported symptoms at the beginning of this month. The person was briefly hospitalised for observation, but released the same day," he said.
Mr Thomson said the next step was to have the virus tested to "see if it is the same strain as that in the four other Hepatitis A cases". The Ministry of Health was working on this now results were expected at the latest by early next week, he said.
Mr Thomson said MPI has an extensive investigation and work programme underway in relation to frozen berries.
"A key focus of this is our continuing forensic examination of the supply chain. Last week we established an increased surveillance programme, including testing imported frozen berries at the border.
"Given the incubation period can be between 15-50 days, it is not unexpected that a new case of Hepatitis A potentially linked to these berries has been notified," he said.
He advised anyone eating other imported frozen berries to wash their hands before eating and preparing food.
Anyone concerned should briefly boil any imported frozen berries before eating them, or ensure cooking exceeds 85 degrees Celsius for one minute.
"Elderly persons and those with chronic liver damage should avoid imported frozen berries that have not been heat treated."
FSL foods owner Mike Glover confirmed the company had recalled of the mixed berries products.
"We've recalled all the products on Friday and over the weekend.
"It should be all off the shelves now," he said.
He said it was not unexpected that they would be more cases of contamination.
Supermarket giant Foodstuffs New Zealand, which operates New World and Pak 'n Save supermarkets across the country, were continuing to liaise with the Ministry of Primary Industries on the recall of the Fruzio mixed berry product.
Foodstuffs New Zealand corporate PR director Antoinette Laird confirmed all affected product was removed from shelves last week.
"We continue to encourage customers to follow MPI's medical advice and if they have any health concerns to contact their GP or local healthcare provider.
"Customers should return any Fruzio frozen berries to the store they purchased it from to receive a full refund," she said.
Progressive, which operates Countdown supermarkets, didn't stock any Fruzio mixed berry products, a spokeswoman said.
Recall "came too late"
The Labour Party says the recall for the frozen mixed berries came too late after a fifth New Zealander could be infected with the Hepatitis A virus.
The Ministry of Primary Industries was trying to protect the incomes of importers rather than the heath of New Zealanders, Labour food safety spokesman Damien O'Connor said.
After days of pressure the Ministry of Primary Industries finally issued a recall, he said.
"That's not good enough from the government agency charged with ensuring our food is safe."
Mr O'Connor said New Zealand needed to have a Country of Origin Labelling and also needed to revert to a stand-alone food safety agency.
He urged Minister of Primary Industries Nathan Guy to issue a directive to his ministry to put the "health of Kiwi consumers at the heart of all its decisions".
People concerned about a potential risk to your health, or the health of others, should seek advice from their medical practitioner, or call Healthline on 0800 61 11 16.
People concerned about the safety of food products should contact the MPI consumer helpline on 0800 00 83 33.
Products under recall:
• Fruzio Mixed Berries 1kg and 500g products, which contains strawberries and blackberries
• Fruzio IQF Strawberry 1kg
• Fruzio IQF Blackberry 1kg
• Fruzio IQF 3 Mixed Berry 1kg (blackberries, strawberries and blueberries).
Investigation timeline:
• Late October - early November, 2015: Four people reported getting sick with Hepatitis A.
• Friday 20 November, 2015: Ministry of Health informs MPI of a potential link between the 4 cases of Hepatitis A to consumption of food.
• Monday 30 November, 2015: MPI's investigation progresses to the point where it identifies a risk of Hepatitis A associated with imported frozen berries. MPI issues a statement advising consumers of the risk, and plans to increase its surveillance and testing of imported frozen berries.
• Wednesday 2 December, 2015: MPI institutes testing of imported frozen berries at the border as part of a wider surveillance programme. It continues investigations into the genetic makeup of the virus and an examination of the supply chain.
• Thursday 3 December, 2015: MPI receives new genetic evidence about the virus and a continued examination of the supply chain allows MPI to direct FSL Foods to recall its Fruzio Mixed Berries product.
• Friday 4 December, 2015: FSL Foods chooses to voluntarily recall further products to provide extra assurance to its customers.
• Wednesday 9 December 2015: A newly notified case of Hepatitis A is likely to be linked to the consumption of the Fruzio Mixed Berries product.
