P3-150 Melon-associated Outbreaks of Foodborne Disease in the United States, 19732011

Wednesday, July 31, 2013
Exhibit Hall (Charlotte Convention Center)
Kelly Walsh, Centers for Disease Control & Prevention, Atlanta, GA
L. Hannah Gould, Centers for Disease Control and Prevention, Atlanta, GA
Sarah Bennett, Centers for Disease Control and Prevention, Atlanta, GA
Introduction: Fresh fruits and vegetables are an important part of a healthy diet.  Melons have been associated with outbreaks of enteric infections, investigations of which can inform efforts to reduce contamination of raw produce. 

Purpose: Describe the frequency and characteristics of melon-associated outbreaks in the United States.

Methods: We reviewed outbreaks reported to CDC’s Foodborne Disease Outbreak Surveillance System during 19732011 in which the implicated food was a single melon type, including cantaloupe, watermelon, and honeydew.  Published literature and records obtained from investigating agencies were also reviewed.

Results: From 19732011, 34 outbreaks caused by melons were reported, resulting in 3,601 reported illnesses, 321 hospitalizations, 45 deaths, and 3 fetal losses.  Cantaloupes accounted for 19 of these outbreaks, followed by watermelon (13) and honeydew (2).   On average, one melon-associated outbreak was reported each year; this increased from 0.5 outbreaks per year from 19731991 to 1.3 from 19922011. Half of outbreaks (17) occurred in JuneAugust.  Salmonella (19 outbreaks) was the most common etiology reported, followed by norovirus (5 outbreaks).  Among the 22 outbreaks with a known source of contamination, 15 were contaminated on-farm, 6 by an ill food worker, and one by cross-contamination.  Among outbreaks caused by melons contaminated on-farm, 8 were attributed to imported melons from Mexico and Central America and 7 to domestically-grown melons.  Seven outbreaks caused by imported melons were multistate; one occurred only in California.  Among the 13 multistate outbreaks, 10 were attributed to cantaloupe contaminated with Salmonella, one to watermelon with pesticide, one to honeydew with Salmonella, and one to cantaloupe with Listeria.   

Significance: Recognition and reporting of foodborne disease outbreaks due to melons has increased. Preventive measures focused on reducing on-farm contamination in cantaloupe by bacterial pathogens, including Salmonella and Listeria, would likely decrease the number and severity of melon-associated outbreaks.