"Our investigation is ongoing and, at this stage, our advice concerning all imported frozen berries stays the same," Mr Thomson added.
FSL owner Mike Glover said he was "devastated" and was in touch with his Chinese berry supplier.
"We're obviously devastated that a product that we have sold to our loyal customers has been found to have traces of Hepatitis A."
Mr Glover told NZME his Nelson-based firm had been importing from the Shandong-based suppliers for seven years.
Kiwis concerned over scare
Some Kiwis who bought the berries quickly contacted the Herald this evening to share their concerns.
Chloe Rarity from Blenheim said her family was "really shocked" about the berries and found out she'd been eating the Fruzio berries over the past week.
She'd made "a huge batch" of berry sorbet for her new neighbours and four families ate it at a barbecue.
Justin Robbins said as a father, he was worried for his family after hearing of the Hepatitis A cases.
"When you realise that you are totally and utterly in control of someone else's life, the feeling that you could've given them something that would make them sick - that's not a nice place to be.
"To say it's unnerving is probably a massive understatement," he said yesterday.
Mr Robbins said it was imperative the identified brand was named.
"If they knew who the brand was and didn't name it, I think it would be a complete and utter breach of trust."
Mr Robbins said the family would probably hold off buying frozen berries for a while.
He said he called Healthline earlier, and was very impressed with the service. Mr Robbins said his family would probably visit the doctor soon, for more peace of mind.
Wendy Adams said she had been eating the Fruzio mixed berries for months now.
"Will be seeing my doctor tomorrow can be sure I will get myself tested," she wrote.
"I purchased these exact same berries in a 1kg bag last week and I've been on a smoothie diet so have been through most of the bag. Today I had lost my appetite and had stomach pains. Best I get checked," Brad said in an email.
But Ben Tuitama emailed to tell the Herald he ate the Fruzio berries "all the time" and hadn't had any problems.
GH De Jong was one of several people who bought the frozen berries regularly, and had them in smoothies.
Expert speaks about symptoms
A microbiologist said the most likely source of the problem was contamination with faeces or faecal-contaminated water during handling.
Dr John Brooks, Microtech Services consultant microbiologist and director, said Hepatitis A caused liver disease, which was rarely fatal, but could cause debilitating symptoms.
These symptoms included nausea, vomiting, fever, and jaundice.
"It is shed in the faeces of the infected individual," Dr Brooks said.
"Hepatitis A does not colonise plants and fruits and cannot multiply on them, so if frozen berries have indeed caused the four recent cases seen in New Zealand, it is because the berries have been contaminated with faeces during handling.
"The contamination has most likely come from an infected food handler, but might have come from human waste used for field irrigation or from faecally contaminated water used in processing."
Dr Brooks said the virus could take up to 50 days to cause symptoms in consumers.
"...It is very difficult to trace the cause of the infection," he added.
Elderly people and those with chronic liver damage were advised to avoid imported frozen berries that had not been heat-treated.
"People should wash their hands before eating and preparing food. Anyone who is concerned should briefly boil any frozen berries before eating them, or ensure cooking exceeds 85 degrees Celsius for one minute," Mr Thomson said.
MPI not ruling out further reccalls
The ministry said it was thankful to FSL Foods "for its full co-operation" in the recall.
MPI said it could not rule out further recalls.
"This is an evolving and complex situation and we were able to reach this conclusion today because of new genetic evidence about the virus and a continuing examination of the supply chain," Mr Thomson said.
The Hepatitis A scare sparked calls this week for compulsory "country of origin" labelling on New Zealand foods.
Food Safety Minister Jo Goodhew yesterday ruled this out, but in Australia, country of origin labelling was mandatory on all foods. MPI said the main reason for not adopting mandatory country of origin labelling was the cost involved, the Herald reported yesterday.
"The Government should back consumers and local food producers and introduce mandatory country of origin labelling on all food," Green Party food safety spokesman Steffan Browning said yesterday.
Yesterday, MPI was refusing to release the name of the brand or the berries' country of origin, despite identifying the source of three of the four cases.
Labour food safety spokesman, Damien O'Connor urged MPI yesterday to name the affected product.
He said the absence of specific information was not helpful for consumers, food producers or importers of safe products.
Mr O'Connor said until more information was released, people would keep "throwing away products that might be safe."
MPI said earlier this year a Hepatitis A in Australia was linked to pre-packaged berries.
The ministry said there were concerns in New Zealand last year when a Hawkes Bay fruit packhouse worker was diagnosed with the disease.
MPI said people concerned about potential health risks should talk to their doctor or phone the Ministry of Health Healthline on 0800 61 11 16.
The ministry said people worried about the safety of food products could phone the MPI consumer helpline, on 0800 00 83 33.
Hepatitis A virus is a waterborne and foodborne liver infection for which a vaccine is available.
The disease is spread through contact with faeces of an infected person, such as through failure of an infected food handler to wash hands properly after using the toilet. After consuming the virus, it takes 15 to 50 days for symptoms to appear.
Hepatitis A symptoms include:
• Vomiting
• Fever
• Nausea
• Loss of appetite
• Jaundice (yellow skin)
• Dark urine
• Fatigue
• Abdominal pain
