MINNEAPOLIS, November 20—The Minnesota Department of Agriculture is expanding its warning about cookies containing the industrial chemical melamine.

Melamine, which has been the subject of numerous food product recalls in China, can cause kidney and urinary tract problems. Minnesota has received no reports to date of illnesses caused by the cookies.

The department says three brands of Wonderfarm brand cookies sold in Minnesota — "Royal Flavour Biscuits," "Lovely Melody Biscuits" and "Daily Life Biscuits" — have tested positive for melamine. Earlier this month, the department said Wonderfarm "Successful" cookies had tested positive for melamine.