The Centers for Disease Control and Prevention announced an investigation Wednesday into an E. coli outbreak that's sickened 17 people in eight states.

The source of the outbreak has not been determined, but seven people in Maryland reported eating a pre-made chicken salad, called Ready Pac Bistro Bowl Chicken Caesar Salad, before getting sick. The salads were purchased at various Sam's Clubs, according to the Maryland Department of Health.

Investigators are looking into whether the E. coli found in the salad is genetically similar to the E. coli making people sick, which would indicate that the salad is a source. Patients in the seven other states affected by the outbreak — Arizona, California, Colorado, Idaho, Montana, Washington and Wisconsin — did not initially report eating this salad.

No deaths have been reported, but seven people have been hospitalized. Two developed a condition called hemolytic uremic syndrome, which is a type of kidney failure.

The CDC says that people should not eat or sell Ready Pac Bistro Bowl Chicken Caesar Salad with a "best by" date of Oct. 31, 2019. If you have this salad in your home, throw it away.