Why are so many food illnesses tied to cantaloupe?

(Royalty-free image collection/Flickr)
(Royalty-free image collection/Flickr)

In the past couple years, cantaloupe has wound up in the headlines for the wrong reasons.

If you’ve passed up tossing a cantaloupe into your grocery cart, you’re not alone. Foodborne illness outbreaks related to the melon, including an outbreak that killed 33 and another that killed three and sickened 261, have made some consumers think twice about picking one up at the store.

Studies show cantaloupe is more likely to carry bacteria than most other produce, even more than its cousins in the melon family, like honeydew and watermelon. Cantaloupe regularly makes the top five in fresh fruit and vegetables likely to cause an outbreak, according to Doug Powell, professor and food safety expert at Kansas State University. Though, outside of the realm of fresh fruit, produce accounts for a small percentage of foodborne illnesses, at about 13 percent in 2005.

Researchers tried to explain why the fruit seems to be the vehicle that carries so many foodborne illnesses, at a recent cantaloupe symposium at Colorado State University. One reason, according to Larry Goodridge, a food microbiologist at Colorado State University, is the physical characteristics of the melon.

“The cantaloupe itself -- the flesh is very amenable to bacterial growth,” Goodridge said during a recent industry presentation he titled ‘The Curious Cases of the Contaminated Cantaloupes.’

Goodridge said from farm to table, there are many places where melons can be subjected to bacterial growth, whether on the rind or in the cantaloupe’s flesh. They’re also dense with water, which make them susceptible to the growth of listeria, salmonella, and E. coli.

“Bacteria love water to grow,” Goodridge said. “Inside the melon, there are a lot of nutrients. The pH of the flesh is neutral and bacteria love that.”

On the production and processing side of things, there are also increased chances of cantaloupe contamination. Unlike in many other fruits, bacteria can still grow inside cantaloupe after it has been picked.

Goodridge’s research also shows that many cantaloupe processing facilities are ill-equipped to process and pack the melon. Many facilities are using processing equipment made of foam, which cannot be easily cleaned. Goodridge said this problem is not unique to the cantaloupe processors, but still contributes to the high rate of foodborne bacteria.

Outbreaks have also been tied to melons sitting in contaminated irrigation water and rainfall runoff.

Cantaloupe growers are starting to understand they need make changes to repair their image, Goodridge said. Some farms have invested in new processing equipment and washing techniques, and one of Colorado’s largest melon processors even hired a full-time food safety manager.

Meanwhile, consumers can limit their risk. Food safety experts recommend storing the melon away from other foods in the refrigerator and thoroughly scrubbing with a brush and washing the cantaloupe before cutting it up.