“Nearly 1 out of every 25 restaurant-associated foodborne outbreaks with identified food sources between 1998 and 2008 can be traced back to contaminated salsa or guacamole, more than double the rate during the previous decade,” according to the U.S. Centers for Disease Control and Prevention (CDC). The report was issued July 12th of 2010 at the International Conference on Emerging Infectious Disease being held in Atlanta Georgia.
According to Magdalena Kendall a researcher from the Oak Ridge Institute for Science and Education (ORIS) who collaborated on the CDC study: “Fresh salsa and guacamole, especially those served in retail food establishments, may be important vehicles of foodborne infection.”
Raw Vegetables a Common Culprit
These products often contain diced raw produce including hot peppers, tomatoes and cilantro, explained Kendall, noting that each of these ingredients has been detected in past food-related illnesses. To assess the role of these foods in the outbreaks, Kendall and her colleagues analyzed all CDC confirmed or suspected reports of foodborne illness caused by salsa, guacamole, or pico de gallo. Notably, the CDC began monitoring food-related disease in 1973 but salsa- or guacamole-associated (SGA) outbreaks did not begin showing up until 1984.
The researchers determined that between 1984 and 1997, SGA illness accounted for only 1.5 percent of all food ‘poisoning’ associated with restaurants and delis; this figure more than doubled to 3.9 percent during between the years 1998 and 2008. According to the CDC, inappropriate storage times or temperatures were reported in 30 percent of the restaurants or delis involved in the SGA outbreaks. Food workers appeared to be the source of disease in another 20% of the outbreaks.
Proper Handling and Refrigeration of Foods Urged
“Possible 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 that even a small amount of contamination can affect many customers,” says Kendall who adds that “Awareness that salsa and guacamole can transmit foodborne illness, particularly in restaurants, is key to preventing future outbreaks.”
Anyone preparing fresh salsa and guacamole, even at home, stresses Kendall, should be aware that these and other foods made with raw ingredients risk microbial contamination and proliferation and she urges proper preparation and refrigeration to help prevent illness.
The International Conference on Emerging Infectious Diseases is organized by the CDC, the American Society for Microbiology (ASM), the Council of State and Territorial Epidemiologists, the Association of Public Health Laboratories and the World Health Organization. (See: www.iceid.org )
Information about foodborne illness can be found in:
Maki, Dennis G. "Coming to Grips with Foodborne Infection –Peanut Butter, Peppers, and Nationwide Salmonella Outbreaks." N Engl J Med; 360 (10), March 5, 2009: pp.949-953.
Full Picture Caption: Color-enhanced scanning electron micrograph showing Salmonella typhimurium (red) invading cultured human cells. Credit: Rocky Mountain Laboratories, NIAID, NIH
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