There isn't much commercial lettuce farming in the Midwest and Canada.

This company is based in Salinas, CA and has farms and plants in Mexico. They were able to identify that the outbreak came from Taco Bell locations. They also were able to determine that the common factor was lettuce served at Taco Bell locations in five states. There may be additional locations in other states that received the contaminated lettuce. There may also be stores other than Taco Bell but they haven't identified any yet. When they looked at records, they found that the contaminated lettuce all originated from a single processing facility located in Mexico. Taylor Farms has recalled all iceberg lettuce that originated in central Mexico.

Lots of produce is produced and processed in facilities far from where it is consumed. When shipping, they don't make stops along the way to drop off small amounts. They load large amounts of produce into trucks and trains, then send it to a distribution center. This lettuce was found to have been shipped from Mexico to five states including MI.