Foodborne outbreaks from leafy greens increasing
NEW YORK (Reuters Health) - Over the past three and a half decades, the United States has seen a substantial increase in the number of foodborne outbreaks linked to consumption of lettuce and other leafy green vegetables, research suggests, and the increase can not be entirely attributed to Americans eating more salads.
The research was presented today at the International Conference on Emerging Infectious Diseases in Atlanta.
Prompted by the rash of E. coli outbreaks associated with spinach 2 years ago, investigators from the Centers for Disease Control and Prevention, Atlanta analyzed data from the CDC foodborne disease outbreak surveillance system reported between 1973 and 2006.
Of the 10,421 foodborne disease outbreaks reported during the 13-year period, 502 (4.8 percent) were associated to leafy greens, Dr. Michael Lynch and colleagues found. Most of these outbreaks (58.3 percent) involved Norovirus, followed by Salmonella (10.4 percent) and E. coli (8.9 percent).
"During 1986-1995, US leafy green consumption increased 17.2 percent from the previous decade. During the same period, the proportion of all foodborne disease outbreaks due to leafy greens increased 59.6 percent," Lynch and colleagues report in a meeting abstract.
"Likewise, during 1996-2005 leafy green consumption increased 9.0 percent and leafy-green associated outbreaks increased 38.6 percent."
These data, Lynch said in a statement, indicate that the "proportion of outbreaks due to leafy greens has increased beyond what can be explained by increased consumption."
Because contamination can occur anywhere along the chain from the farm to the table, "efforts by local, state and federal agencies to control leafy green outbreaks should span from the point of harvest to the point of preparation," Lynch said.