Plastic fragments found in California Pizza Kitchen frozen pizzas have led to a nationwide recall of pizzas sold by Nestle USA.

The Wisconsin-based company announced Thursday that a "small number of consumers reported that they had found small fragments of plastic on the CPK Crispy Thin Crust White pizza."

The fragments reported by consumers were "clear, brittle plastic, in irregular triangles, and may have sharp edges," according to the U.S. Department of Agriculture.

The plastic fragments came from a lot of spinach the company received from a supplier, Nestle reported.

Nestle has ordered a voluntary recall of the following four of its frozen pizzas sold in the United States:

• California Pizza Kitchen (CPK) Crispy Thin Crust White®, UPC 71921 98745; production codes are 3062525951, 3062525952 and 3063525951.
• California Pizza Kitchen® Limited Edition Grilled Chicken with Cabernet Sauce, UPC 71921 00781; production code is 3059525952.
• DiGiorno® Crispy Flatbread Pizza Tuscan Style Chicken, UPC 71921 02663; production codes are 3057525922 and 3058525921.
• DiGiorno® pizzeria!™ Bianca/White Pizza, UPC 71921 91484; production code is 3068525951.

The pizzas affected by the recall were produced during February and March, according to Nestle, and are in the process of being removed from the shelves of retail stores where they are sold.

Consumers are being asked to contact Nestlé USA Consumer Services at 800-456-4394 or nestlepizza@casupport.com.

The company says it will provide customers who report a recalled pizza with a replacement coupon.