The company says the probability of serious health problems is remote.
Unilever's U.S. arm, based in Englewood Cliffs, N.J., says the ready-to-drink products were sold nationwide.
They came in cartons of four, six or 12 steel cans, 11 ounces in size, and they were also sold individually.
The recall, issued Thursday, covers all Slim-Fast products in cans, regardless of flavor, best-by date, lot code or UPC number.
Consumers who purchased any of the Slim-Fast ready-to-drink canned products are urged to discard them and contact the company for a refund at (800) 896-9479, Monday through Friday, 8:30 a.m. to 6 p.m. ET. A recorded message is available 24 hours a day.
Other Slim-Fast products, including powdered shakes, meal bars or snack bars are not affected by this recall.
The company said it is working to determine the production issue that caused the contamination. It has halted production.