(CNN) -- If you've bought California nectarines, peaches, plums or pluots lately, even the organic kind, check the label carefully.
The Wawona Packing Co. in Cutler, California, announced late last week it's expanding a voluntary recall of its products.
The fruit may be contaminated with Listeria monocytogenes, a bacterium that can cause listeriosis. This serious infection can give you temporary problems such as a high fever, abdominal pain and diarrhea, headaches, stiffness and nausea.
The initial recall covered specific lots of fruit packed from June 1 through July 12. The company expanded the recall "as a precautionary step" by five days, to fruit packaged through July 17, in large part because it has "yet to identify with scientific certainty the source" of the Listeria monocytogenes at the packaging facility.
It's a national voluntary recall because "we do not know the locations of the companies or stores that received the products from our direct customers," according to a company statement. The company's testing initiated the recall; scientists found the bacterium on a peach and on two nectarines.
Since the recall, no other products have been packed at the Cutler facility. The facility will stay closed until the source of the contamination has been determined. Wawona said it has brought in experts to help with the investigation, and the company is working closely with the U.S. Food and Drug Administration.
Websites for Trader Joe's, Kroger, Costco, Whole Foods Market, Ralphs, Food 4 Less and Walmart, which also operates Sam's Club, initially posted notices about the problem when the first recall went out around July 19.
If you do have the fruit in your fridge, look for a sticker that reads, "Sweet2Eat." The fruit may also be labeled Mrs. Smittcamp's or "Sweet2Eat Organic." Throw out the potentially contaminated fruit or take it back to the store for a refund.
Whole Foods also recalled some of their made-in-store products that may have been prepared with the fruit. The store recall involved salsas, tarts, prepared salad and cakes. A full list is on FDA.gov.
Products packaged after July 18 and fruit packaged outside of that one particular facility in Cutler is not affected by this recall and should be safe to eat.
For people with compromised immune systems, listeriosis could be a fatal infection. Children and the elderly are particularly vulnerable to severe reactions to the bacterium, according to the Centers for Disease Control and Prevention.
It can also cause miscarriages and stillbirths for women who are pregnant.
If you have eaten one of these products, see your doctor immediately.
So far, no one has reported getting sick from the fruit.
Generally the CDC estimates about 260 deaths and 1,600 people get sick after eating food contaminated with listeriosis.
The largest exposure to listeriosis happened in 2011 when people ate cantaloupes contaminated with the bacterium from a farm in Colorado. Nearly three dozen people died after eating the fruit, and an additional 147 people got sick. With that exception, outbreaks have been on the decline since 2001, according to the CDC.