Four people have been hospitalized with a life-threatening bacteria after consuming blueberries that were the subject of a recall earlier this month. 

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

So far, there have been 12 reports of illnesses and four hospitalizations in two states. No deaths have been reported.  

The fruits were sold in 10oz 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.

There are 11 E.coli cases in Florida and one in Georgia. 

The CDC states: 'CDC, public health and regulatory officials in several states, and the US Food and Drug Administration (FDA) are collecting different types of data to investigate a multistate outbreak of E. coli O145 infections.

'Epidemiologic data show that frozen GreenWise brand organic blueberries may be contaminated with E. coli O145 and may be making people sick.'

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. 

The CDC said the illnesses range from May 11 to June 5 and that the 'true number of sick people in this outbreak [is] likely much higher than the number reported, and this outbreak may not have been limited to the states with known illnesses.'

People with E.coli may recover without medical treatment or may not be tested for the bacteria. It also may take three to four weeks to determine if a sick person is part of a recall or outbreak.

Patients thus far in this outbreak range from two to 88 years old.

Of the nine people interviewed, seven reported eating the frozen blueberries.

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

The blueberries 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 SA said it started to investigate the blueberries after receiving reports of stomach illnesses from customers. 

'Food safety remains a top priority for Frutas y Hortalizas S.A,' the company said in its recall notice.

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 reactivated 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 complications and do not get tested for the bacteria.