Once cantaloupes have been cut, they must be refrigerated to help prevent listeria infection, according to a new study.

Fresh-cut cantaloupe must be stored at 41 degrees or colder immediately after preparation to maintain food safety, according to a study in the November issue of the Journal of Food Protection.

In the study, scientists injected Listeria monocytogenes into whole cantaloupes and fresh-cut cantaloupes, then compared the growth of the bacteria depending on whether fruit was refrigerated, for how long and at what temperature and whether or not it was treated.

Fresh-cut cantaloupe pieces were left at 41 degrees, 50 degrees and 68 degrees (room temperature) for two hours and four hours. Fruit was then refrigerated at 41 degrees.

Fruit was then left untreated or treated with water or a 2.5% hydrogen peroxide solutions.

Microbial populations of fresh-cut pieces were determined by the plate count method or enrichment method immediately after preparation.

The higher the temperature, the more listeria thrived, researchers found.

“Increased storage temperatures enhanced the lag phases and growth of L. monocytogenes. The results of this study confirmed the need to store fresh-cut cantaloupes at 5°C (41 Fahrenheit) immediately after preparation to enhance the microbial safety of the fruit.”

The study comes on the heels of deadly listeria outbreaks linked to listeria this year and in 2011.

In an outbreak linked to Owensville, Ind.-based Chamberlain Farms Produce Inc. that lasted from July 6 to Sept. 16, three people in Kentucky died and 261 people in 24 states were sickened.

Last year, an outbreak traced to Holly, Colo.-based Jensen Farms claimed 33 lives and sickened at least 146 people in 28 states.