Threads of copper found in some CalorieMate snack bars prompted Otsuka Pharmaceutical Co. on Friday to begin recalling around 14 million packets made at its factory in Tokushima Prefecture.

Chocolate- and fruit-flavored snack bars made between March 6 and June 5 at its Wajiki factory in the prefecture will be collected, a company spokesman said.

The products in question have the letters OPW on the sides or bottom of the boxes and have expiration dates between March 6 and June 4, 2001. Cheese-flavored snack bars made at other factories have not been affected, the spokesman said.

Since June 5, Otsuka Pharmaceutical has received four complaints from consumers who found tiny threads of copper in one out of four snack bars in a packet.

The 0.16-mm-diameter threads were between 1.5 cm and 4 cm long and are thought to have come from copper wiring in the production system, the spokesman said.

The products were shipped to Shikoku and to areas east of Kansai, but some may have been distributed to other regions, the spokesman said.

The company will accept inquiries from consumers at the toll-free number (0120) 30-1877.