A nut butter sold exclusively by Walmart has been recalled over fears it could be contaminated with a potentially deadly bacteria.

Botticelli Foods issued the alert for its bettergoods-branded Pistachio Nut Butter after tests showed it may contain salmonella, a bacteria that can contaminate food through animal feces.

The recalled products were sold in 6.7oz glass jars and were available at stores in 19 states, mostly in the South and West of the country.

They have now been pulled from shelves, but health officials fear some may still be lurking in people's food cupboards. The nut butter has a best before date of January 27, next year.

No illnesses or injuries from the nut butter have been reported to date. Contaminated products, however, can look completely normal and still cause illness.

Customers who purchased the product have been urged not to consume it and to throw it out immediately or return it to the place of purchase for a full refund.

Health officials say anyone who believes they were sickened by the nut butter should contact their doctor. They can also contact their local health authority to report the infection.

Healthy people infected with salmonella often suffer from fever, diarrhea, nausea, vomiting and abdominal pain, which clears within a few days.

But, in serious cases, patients can suffer from potentially fatal complications including sepsis, which happens when the bacteria infects the bloodstream.

Health officials warn very young children, older adults and those with weakened immune systems are at higher risk of infection.

The recall was announced on the FDA's website on Monday, which said that one lot of the nut butter had been recalled. 

It is identified by the Lot number printed on the packaging of UPC 194346207961 or Lot Code LB028ACP04.

The nut butter had been sold in the following states: Alabama, Alaska, Arizona, Colorado, Florida, Georgia, Idaho, Kansas, Mississippi, Missouri, Montana, Nebraska, Nevada, New Mexico, Oregon, South Dakota, Tennessee, Washington and Wyoming.

The recall was not published until August 3, more than two weeks after Walmart was informed on July 17 that routine tests on three of its nut butter jars had detected the presence of salmonella.

It was not clear why there was a delay in testing.

It also was not clear how the products became contaminated, but in previous cases this has been linked to pistachio plants being irrigated with water that is contaminated with animal feces. 

The nut butter was manufactured by Italy-based Gustibus Alimentari Srl, and imported into the US by New York-based company Botticelli.  

In the recall notice, the FDA warned that salmonella can cause 'serious and sometimes fatal infections'.

The US is also currently battling an outbreak of salmonella linked to eggs that has sickened dozens and hospitalized 17 people. A recall of 1.5 million dozens of eggs was issued over the outbreak reported late last month. 

More than 1.3 million Americans are sickened by salmonella every year, while 26,000 are hospitalized and 400 die from the disease.

People can catch salmonella after eating contaminated food, drinking fluids laced with the bacteria or touching the droppings of infected animals.

Symptoms start within six days of infection, with patients told to call their doctor if diarrhea or vomiting lasts for more than two days, have blood in their urine or feces, develop a high fever or show signs of dehydration. 

Infections are treated using fluids to keep patients hydrated. In serious cases, individuals may also be prescribed antibiotics.