Let's replace "salad" with "burrito" and just look at Chipotle in isolation...
* In March and April 2008, 22 customers were infected with hepatitis A from a Chipotle restaurant in California.
* In April 2008, over 400 people were infected with norovirus from a Chipotle restaurant in Ohio.
* In February 2009, an outbreak of campylobacteriosis was traced to a Chipotle restaurant in Minnesota.
* In July 2015, five people were infected with E. coli traced back to a Chipotle restaurant in Seattle, Washington.
* In August 2015 nearly 100 people were infected with norovirus from a Chipotle restaurant in Califorina.
* In August 2015, 64 people were infected with Salmonella traced back to Chipotle restaurants in the Minneapolis area.
* In October 2015, 52 people were infected with E. coli traced back to Chipotle restaurants, with 20 requiring hospitalization.
* In November 2015, 5 people were infected with E. coli traced back to Chipotle restaurants in Oklahoma and Kansas.
* In December 2015, ultimately 141 people (80 directly) in Massachusetts were infected with norovirus traced back to a Boston, Massachusetts area Chipotle restaurant.
* In July 2017, more than 130 people were infected with norovirus traced back to a Chiptole restaurant in Virginia.