Over the last ten years, tainted salsa or guacamole have caused roughly 1 out of 25 restaurant-related food illnesses. This is double the number of similar outbreaks in the previous decade, according to the Centers for Disease Control which compiled the data.
The study found that 30% of the outbreaks were due to the foods being stored at incorrect temperatures or being stored for too long. Another 20% of the outbreaks were linked to food handlers as the cause for contamination.
“Fresh salsa and guacamole, especially those served in retail food establishments, may be important vehicles of foodborne infection," says study author Magdalena Kendall in the CDC news release. Kendall and her team combed CDC data for all instances of salsa/pica de gallo or guacamole being a confirmed or likely culprit for infection. They compared these instances to all instances of food-related illnesses over the same period, and found that 3.9% were likely the result of contamination of the condiments.
What is it about these foods that so often leads to outbreaks? "Salsa and guacamole often contain diced raw produce including hot peppers, tomatoes and cilantro, each of which has been implicated in past outbreaks.” Kendall adds that the "[p]ossible reasons salsa and guacamole can pose a risk for foodborne illness is that they may not be refrigerated appropriately and are often made in large batches so even a small amount of contamination can affect many customers."
Interestingly, no salsa- or guacamole-related illnesses were reported between 1973, the year the CDC started monitoring foodborne illnesses, and 1984. The reason for the rise over the next couple of decades is unclear, but it may be due in part to the rise in popularity of the foods themselves and the cuisines that offer them.
Kendall concludes by saying that awareness is key: "[w]e want restaurants and anyone preparing fresh salsa and guacamole at home to be aware that these foods containing raw ingredients should be carefully prepared and refrigerated to help prevent illness.”
The research was presented July 12, 2010 at the International Conference on Emerging Infectious Diseases, in Atlanta. Magdalena Kendall is affiliated with the Oak Ridge Institute for Science and Education in Oak Ridge, Tenn.