Edwin Traisman, a food scientist who created the process for freezing McDonald's french fries and helped develop Cheez Whiz, has died at age 91.

Traisman died Tuesday following a heart attack, said his granddaughter Jenna Greene.

Born in Chicago on Nov. 25, 1915, to Latvian immigrants, Traisman worked for Kraft Foods on the teams that created Cheez Whiz and individually packaged cheese slices in the 1950s. He became a division director of food research with responsibility for cheese and related projects.

Then Traisman wandered into a McDonald's restaurant near Chicago to ask about opening a franchise, said his wife of 44 years, Dorothy. He approached a man who was sweeping and asked for the manager. The man said the manager was not in, but he might be able to help.

"It turned out it was Mr. Ray Kroc himself," Dorothy Traisman said.

The McDonald's founder and Traisman became friends, and within 14 years, Traisman owned five restaurants.

One problem McDonald's Corp. had was producing french fries when Idaho potatoes were not in season, Greene said. Freezing uncooked potatoes ruined their texture. Traisman eventually developed and patented a process for partially cooking the fries and then freezing them.

Traisman also broke ground by hiring women, violating the fast-food company's rules, his wife said.

Desiring a return to research, Traisman went as a program manager at the University of Wisconsin-Madison's Food Research Institute in 1970. He officially retired from the institute in 1988.

Traisman had five children.