(CNN) -- In the wake of a multi-state outbreak of listeriosis linked to bacteria-tainted cantaloupe, authorities assured the public that cantaloupe grown in places other than Colorado's Jensen Farms is safe.
But if in doubt about a fruit's origin, they said, it's best to throw it out.
The outbreak -- blamed on the bacteria Listeria monocytogenes -- was first reported September 12. As of Wednesday, it had grown to 72 cases in 18 states and had killed 13 people, officials with the Centers for Disease Control said. The number of cases is expected to rise, as it can take one to three weeks for a person who ingests the bacteria to show symptoms.
All of the tainted cantaloupes were grown at Jensen Farms in Granada, Colorado, although they were shipped to 17 states -- Illinois, Wyoming, Tennessee, Utah, Texas, Colorado, Minnesota, Kansas, New Mexico, North Carolina, Missouri, Nebraska, Oklahoma, Arizona, New Jersey, New York and Pennsylvania.
"It's important to know that if you know the cantaloupe that you have is not Jensen Farms, then it's OK to eat," CDC Director Tom Frieden told reporters during a conference call Wednesday. "But if you're in doubt, then throw it out."
The recalled cantaloupes may bear a green-and-white sticker that says, "Product of USA-Frontera Produce-Colorado Fresh-Rocky Ford-Cantaloupe," or a gray, yellow and green sticker that says, "Jensen Farms-Sweet Rocky Fords."
But not all cantaloupes may have a sticker, Frieden said. Consumers are urged to ask the supermarket or supplier if they know where the cantaloupes came from. If the cantaloupe's origins remain unconfirmed, it should be disposed of, he said.
However, the likelihood of tainted cantaloupes in the nation's food supply is decreasing, thanks to the fruit's short shelf life -- about two weeks, officials said. The recalled cantaloupes were shipped from July 29 through September 10, "so we really are nearing the end of the shelf life of the product in addition to its recalled product," Sherri McGarry, a senior adviser with the Food and Drug Administration (FDA), told reporters.
The recall itself should be removing the cantaloupes from shelves, she said, but the shelf life means the tainted cantaloupes will not be edible much longer. "But consumers do have their own practices so we need to be cognizant some folks may hold that a little bit longer than we might expect," she said.
If consumers do have a cantaloupe from Jensen Farms, authorities recommend they don't try to wash off the bacteria. "We want you to throw that product away," McGarry said.
The fruits should be disposed of in a closed plastic bag and placed in a sealed trash can, to prevent people or animals from eating them, the CDC said.
Refrigeration will not kill the Listeria bacteria, which can grow even at low temperatures, officials said. And the longer a contaminated food is stored in the refrigerator, the more opportunity the bacteria has to grow.
"It is very important that consumers clean their refrigerators and other food preparation surfaces" in order to minimize risk, the FDA says on its website. After washing refrigerators, cutting boards and countertops, the agency recommends sanitizing them with a solution of one tablespoon chlorine bleach per gallon of hot water and drying them with a paper towel or cloth that has not been previously used.
Jensen Farms has now ended its cantaloupe harvest for the season, so no new contaminated fruit will be entering the market, FDA Commissioner Margaret Hamburg said Wednesday.
Although Jensen Farms does produce other products, there is no concern for any other product from the company, McGarry said.
Listeriosis causes fever, muscle aches, diarrhea and other gastrointestinal symptoms. It rarely is a serious concern for healthy children and adults, the CDC said, but can be dangerous for older adults or those with weakened immune systems. It can be treated with antibiotics.
The source of the outbreak -- the deadliest U.S. outbreak of a food-borne illness since 1998 -- remained under investigation. Officials could not give a figure Wednesday for the number of cantaloupes recalled.