- Food was the major mode of transportation for outbreaks of E. coli O157 in the U.S. from 2003 to 2012, according to a summary of these outbreaks from the Centers for Disease Control and Prevention.
- Out of 390 outbreaks of E. coli O157 from all sources, which include food, person-to-person contact, contact with animals, and water, 65% of these outbreaks were attributed to food.
- Beef was the highest contributor to the outbreaks at 20%, followed by leafy vegetables at 7%, and dairy at 4%.
The reasons for these outbreaks may not come as a surprise to some in the food industry. In the beef category, outbreaks came from ground beef and steak that had been mechanically tenderized. Thirteen of the 16 outbreaks tied to dairy came from unpasteurized milk and the other three from cheese made from unpasteurized milk.
What may be less known are factors like time of year for foodborne illnesses, such as that close to half of the outbreaks occurred between July and September. Also, more foodborne outbreaks related to leafy vegetables occurred in the fall. This could be attributed to "summertime application of irrigation water to seedlings, soil amendments, or fertilizers that might contain more E. coli O157 organisms than other seasons," Food Safety News reported. Also potentially surprising is that more foodborne outbreaks occurred in the Northern states, though the reason why is unclear.