Plaintiffs Bianca Johnston of Big Bear and Anastasia Chernov of Escondido claim the Rotisserie Chicken is made with two added preservatives — sodium phosphate and carrageenan. Kirkland Rotisserie Chicken. "Because sodium phosphate and carrageenan perform preservative functions in the Rotisserie Chicken, the Rotisserie Chicken in fact contains added preservatives." Gary Hershorn/GettyIn a statement shared with PEOPLE on Thursday, Jan. 29, Costco said it had removed signage claiming the rotisserie chicken contains no preservatives. "We use carrageenan and sodium phosphate to support moisture retention, texture, and product consistency during cooking.