Concerns about listeria contamination have led to the recall over the past week of numerous salad and lettuce products connected to two producers, Fresh Express and Revolution Farms.

The Revolution Farms recalls were initiated on Wednesday after the Michigan Department of Agriculture and Rural Development detected listeria in a random sample test of a Revolution Farms product with a “best by” date of April 2.

This recall was expanded to all Revolution Farms products Thursday after the initially recalled items were connected to a multi-state listeria outbreak, according to the Food and Drug Administration.

The Centers for Disease Control and Prevention have not listed a specific listeria outbreak connected to the two lettuce recalls as of Tuesday.

Listeriosis, caused by a listeria infection, can cause intestinal issues, as well as more serious symptoms such as seizures, loss of balance, stiff neck and fever.

In pregnant women, listeriosis has been known to cause miscarriages, stillbirth, premature delivery, and life-threatening infections to newborn babies.

The recalled lettuce products were sold in Michigan, Ohio, Indiana, Illinois, Kentucky, and Wisconsin. Retailers were urged to toss the salads, and customers were instructed to either throw them out or return them to the place of purchase for a full refund.

The Revolution Farms recall also led to recall announcements by retailer Meijer, which sold Revolution Farms lettuce as part of its own salad products, and by Russ’ Restaurant Commissary.

The Russ’ Commissary products recalled starting Friday are the 5.5-ounce Fruit Ridge Farms and Bell’s Bistro brand white chicken Caesar salad, and the 4.6-ounce Fruit Ridge Farms and Bell’s Bistro brand chef salad with ham with sell-by dates from March 10 to April 14.

The products contain either “EST. 17050” or “P-17050” within the U.S. Department of Agriculture mark of inspection.

These products were sold in the six states in the Revolution Farms recall, along with Tennessee. The recall of the Russ’ Commissary products was initiated when the company told the Food Safety and Inspection Service that the ready-to-eat salads used Revolution Farms lettuce.

There have not yet been any reports of illness or adverse reactions linked to the Russ’ Commissary products.

Salad kit maker Fresh Express launched its recall Friday after the Georgia Department of Agriculture detected listeria in a sample of one of their products with a use-by date of March 31.

The Fresh Express products being recalled are:

• A 9.4-ounce Caesar salad kit with a use-by date of April 2, sold in Florida, Georgia, North and South Carolina, with universal product code 00071279309194.
• An 11.3-ounce chipotle cheddar salad kit with a use-by date of April 2, sold in Florida, Georgia, Virginia, North and South Carolina, with universal product code 00071279306049.
• An 8.75-ounce Makoto honey ginger salad kit with a use-by date of March 31, sold in Florida, Georgia and North Carolina with universal product code 00071279309194.