Listeria-tainted cantaloupe has taken 13 lives and left 72 sick in the United States — the deadliest outbreak involving the bacteria in a decade.

But what makes cantaloupe susceptible to listeria — and even salmonella — in some cases?

The fruit, like its melon and gourd relatives, grows on the surface of the ground rather than beneath it, exposing it to fertilizers, possible animal waste or even unsanitary human handling.

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Unlike other microorganisms that threaten the food supply, listeria can survive in both cold and hot conditions, meaning it's not something a fridge or cooking can fix. Typically, this strain of bacteria isn't found in cantaloupe but rather in meats and dairy products.

When officials got to the bottom of the listeria outbreak, they discovered the strain of bacteria wasn't embedded in the orangish flesh of the fruit. Rather, it hitched a ride in the tough outer rind, where microorganisms have plenty of crevices and nooks to cling to.

While examining the recent outbreak, experts think it's likely that when people prepared unwashed cantaloupe, they inadvertently transferred listeria from the outside rind to the inside of the fruit by cutting into it with a knife, according to a NPR post on the topic.

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To help steer clear of food-borne illnesses, follow these tips when preparing cantaloupe and other produce.

  • Wash your hands

  • Thoroughly wash the outer rind of cantaloupe, using a clean produce brush to scrub its surface. You can also make a simple cleaning solution, diluting small amounts of vinegar into water, to rinse the fruit with. This will reduce the chances of the bacteria traveling from skin to fruit via knife blade.

  • Much like with buying other fruits and vegetables, avoid purchasing cantaloupe with bruises or cuts. If you notice small areas that are bruised, cut them out before eating the rest.

  • Keep your fridge at 40 degrees Fahrenheit or lower. Don't eat cut fruit that has been exposed to room temperature for more than two hours. Also, it's not a good idea to eat cantaloupe seven days after it's been prepared, even if it's refrigerated.

  • Keep separate cutting boards and knives for preparing raw meats, vegetables and fruits.


If you think you've been exposed to tainted cantaloupe — or any other contaminated food, contact your state health department.

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So far, cases in 18 states link people's illnesses to the bacteria, according to the Centers for Disease Control and Prevention. Despite cases surfacing in late July, officials were only recently able to find the source of the contaminated fruit: Rocky Ford cantaloupes, shipped by Jensen Farms in Granada, Colo.

Although the farm recalled the cantaloupe, the CDC warns consumers to throw out any Rocky Ford cantaloupes in their kitchens. If you're unsure whether you ate this brand of cantaloupe or have it in your home, contact your grocery store to see if it's sold there.

When in doubt, dump it.

But you shouldn't be discouraged from eating other brands of cantaloupe not associated with the outbreak.

It's also worth mentioning that the majority of people with listeriosis — the life-threatening condition caused by listeria bacteria — are more than 60 years old or have pre-existing health issues that leave them vulnerable to infection.

Pregnant women and their newborns are also at an increased risk of becoming ill if exposed to the bacteria. People with listeriosis usually experience fever, muscle aches and digestive problems for a prolonged period. Most people see a delay in illness, usually a few weeks to two months.

Photo: iStockPhoto