Back in March of this year, shortly after the Centers for Disease Control and Prevention (CDC) and other health departments around the country concluded their investigation into a multistate outbreak of Salmonella Panama that sickened at least 20 and was ultimately linked to the consumption of Del Monte cantaloupe, Food Safety News reporter Gretchen Goetz wrote an article about why it is that cantaloupe and other melons are often carriers of dangerous pathogens.

In light of the ongoing multistate Listeria outbreak that is currently affecting residents of Colorado, Nebraska, and Texas, and has been linked to one death, it seems worthwhile to revisit the key points of Goetz’s report published on March 25, 2011.

According to Goetz:

Cantaloupe is particularly susceptible to contamination because it grows on the ground, where it can come into contact with bacteria from animal feces harbored in soil or rainwater runoff. However, like any fruit or vegetable, it can also pick up pathogens during harvest, handling or preparation.

Foodborne illness outbreaks from cantaloupe have been traced back to wash water, shipping ice and even contact with contaminated meat, according to a 2005 study in the International Journal of Food Microbiology. 

Cantaloupe is also risky as a home for pathogens because of its unique skin. Bacteria sticks easily to the rough surface, and can even penetrate through the porous rind to the inside of the fruit.

“When it rains, [cantaloupe] could actually be sitting in water, and whatever’s in that water could actually enter inside the flesh,” says Doug Powell, professor and food safety expert at Kansas State University.

And there is one more aspect of this marbled melon that makes it more apt to cause an outbreak than other fruits: bacteria can grow on its surface after harvest. While bacteria normally cannot grow on fruits or vegetables after they are picked due to a lack of moisture and nutrients, E. coli has been shown to multiply on the surface of cantaloupe and watermelon, according to an FDA article on fresh produce safety.

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Even a small amount of bacteria can be dangerous if it reaches the inside of the cantaloupe, because once there it can increase. The FDA Food Code cites cut melon as a potentially hazardous food, since its low acidity and high water content make it capable of supporting bacteria growth.

Just how risky is it to eat cantaloupe? “Cantaloupe’s always in the top five of fresh fruits and vegetables for outbreaks,” says Powell. Indeed there have been at least five outbreaks linked to cantaloupe in the past five years alone, according to outbreakdatabase.com.

For more information about listeria and its symptoms and risks, visit www.about-listeria.com.