MINNEAPOLIS (CNN) -- Pillsbury Co. is recalling 8,800 cases of refrigerated chocolate chip cookie dough because walnuts may have been mistakenly placed inside.

The dough presents a danger only to those who are allergic to walnuts. Pillsbury spokesman Terry Thompson said five people have had mild allergic reactions after eating the cookies.

Pillsbury is recalling 18-ounce packages of chocolate chip cookie dough that bear the code "NOV 18 K" and "NOV 18 J," printed on the side seam after the phrase, "For Best Results Use Before." The product was available for sale between September 16 and October 2 and was believed to have been shipped to stores in Indiana, Illinois, Wisconsin and Iowa.

The company had detected the problem and ordered a nationwide recall of the dough on September 8, but a small amount was later inadvertently shipped to stores from a Chicago warehouse. All of the dough was produced at a Pillsbury plant in Chicago.

Reuters contributed to this report.