US and Canadian food regulators are investigating a hepatitis A outbreak that could be linked to fresh organic strawberries.
The fruits were sold under the brand names FreshKampo and H-E-B.
The produce was available at various retailers across the US, including Aldi, Kroger, Safeway, Walmart and Trader Joe's, between 5 March and 25 April.
In the US, 17 people have become ill - 15 in California and one each in Minnesota and North Dakota, according to the US Food and Drug Administration (FDA).
Twelve of those who became ill were hospitalised.
In Canada, the strawberries were sold in Alberta and Saskatchewan between 5 March and 9 March.
Ten cases and four hospitalisations have been reported in both provinces, according to the Canadian Food Inspection Agency and the Public Health Agency of Canada.
FreshKampo, the Mexico-based company that grew the strawberries, said it is working with regulators to figure out the source of the problem.
How do strawberries get contaminated with hepatitis A?
Berries are a common conduit for viruses because they are so delicate that they can only be harvested by hand, according to the Live Science news outlet.
The virus is usually transmitted through the faecal-oral route, meaning that a person somehow ingests contaminated faces from an infected person.
If workers have not properly washed their hands after using the bathroom, they could transfer the virus to the fruit.
This is more of a risk in parts of the world where hepatitis A is more common.
Another way strawberries can be contaminated is if the water used to irrigate them has been contaminated with raw sewage, which can carry the virus.
The virus may not be washed off easily because there are nooks and crannies where particles can hide.
FreshKampo said the strawberries that were potentially affected had labels saying "Product of Mexico" or "Distributed by Meridien Foods".
H-E-B, a supermarket chain in Texas, said it has not received or sold organise strawberries from the supplier since 16 April.
The retailer said anyone who still has the strawberries should throw them out or return them to the store where they were bought.
Advice for consumers
Hepatitis A is a virus that can cause liver disease and, in rare cases, liver failure and death.
People can become ill 15 to 50 days after eating or drinking contaminated food or water.
Symptoms include fatigue, nausea, vomiting, abdominal pain and jaundice.
Consumers who have not been vaccinated against hepatitis A and ate potentially affected berries in the last two weeks should immediately talk to a doctor, the FDA said.
Although the strawberries have not been on sale for a long time people were advised to check any they may have frozen for later use.