Frozen blueberries sold at a major grocery store have been recalled after 12 people who consumed them suffered from a potentially life-threatening bacterial infection.

Frutas y Hortalizas del Sur S.A., a Chile-based grower, issued a recall for its GreenWise Organic frozen blueberries after tests returned a presumptive positive result for E.coli.

The fruits were sold in 10-ounce beige bags depicting blueberries in a bowl surrounded by leaves on the front.

They were available at Publix stores in eight states: Alabama, Florida, Georgia, Kentucky, North Carolina, South Carolina, Tennessee and Virginia.

Announcing the recall, Publix said the berries were available in stores between May 11 and June 5 this year. The recalled blueberries have a best before date of February 9, 2028. 

Consumers who have the affected blueberries at home have been urged not to consume them and throw them out immediately or return them to stores for a full refund. 

In previous cases, customers have also been urged to throw out other foods that came into contact with contaminated products and clean areas of the freezer where they were placed.

No deaths or hospitalizations have been reported to date in relation to this outbreak.

The blueberries have tested presumptively positive for E.coli O145:H28, a highly virulent strain of the bacteria that is more likely to cause bloody diarrhea and more severe symptoms. 

Those infected with the strain also have a higher risk of suffering from hemolytic uremic syndrome (HUS), a lifelong kidney complication.

Children under five years old and people with weakened immune systems are most at risk from the infection.

Recalled blueberries have the lot code 60401, which is normally printed on the barcode of the packaging.

No further details have been released on the sick individuals, including their ages and in which states they consumed the blueberries.

In its press release announcing the recall, grower Frutas y Hortalizas del Sur said it started to investigate the blueberries after receiving reports of stomach illnesses from customers. 

The company said it is now working with health agencies. The FDA and CDC have not yet made a public announcement about the recall.

It was not clear how the fruits became contaminated, but this can happen if they are treated with water that contains animal feces.  

E.coli bacteria stop growing at temperatures below 45.5F (7.5C), but can survive being frozen and are able to withstand temperatures below -112F (-80C).

Once back in a warm environment, the bacteria are re-activated and start to grow - potentially causing an infection.

E.coli is a Shiga toxin-producing bacteria that typically sickens people between two and eight days after exposure.

Most patients develop bloody diarrhea and vomiting, as well as stomach cramps, but recover within a week. In more severe cases, some develop a fatal kidney disease called HUS.

HUS is a type of kidney failure that can occur in anyone but is most common in children under five, the elderly and people with compromised immune systems.

Symptoms include easy bruising, decreased urine and a pale appearance. A kidney transplant may be necessary in severe or life-threatening instances.

About 90,000 Americans and at least 1,500 Britons are sickened with E.coli every year, while around 100 people die from the infection in the US and UK annually. 

However, cases are vastly undercounted because most people recover without complication and do not get tested for the bacteria.