Pre-packaged caramel apples are linked to a listeria outbreak that has killed five and sickened 29.

ATLANTA — The Centers for Disease Control and Prevention continued on Dec. 22 to recommend consumers avoid consuming pre-packaged caramel apples. The product is considered the common denominator in a Listeria monocytogenes outbreak that has killed five and sickened 29 in 10 states.

“Investigators are working quickly to determine specific brands or types of commercially produced, prepackaged caramel apples that may be linked to illnesses and to identify the source of contamination,” the C.D.C. said in a statement on Dec. 22.

On Dec. 18, the agency took the unusual step of recommending consumers avoid eating prepackaged caramel apples “out of an abundance of caution.” As of that day, the agency said 28 people had been infected due to the outbreak, 26 had been hospitalized and 5 consumers had died.

The 10 states where illnesses have been identified include: Arizona (4 illnesses), California (1), Minnesota (4), Missouri (5), New Mexico (5), North Carolina (1), Texas (4), Utah (1), Washington (1) and Wisconsin (2).