According to a new report many restaurants across the U.S. are cooking up food violations.

The Center for Science in the Public Interest evaluated more than 500 inspection reports from 20 cities nationwide.

More than half of the inspected restaurants had at least one high-risk food safety violation, like contaminated food prep areas, and not enough hand washing.

The CPSI wants the country to take a hint from Los Angeles County. It requires all restaurants to post an inspection letter grade in the window.

"Before the only thing a restaurant cared about was not getting closed, if they were open, people didn't know how it had scored, now people see the grade and the inspections are all unannounced," said Jonathan Fielding, director of the Los Angeles County Department of Health.

Kansas City and Saint Louis were two of the 20 cities featured in the report.

Kansas City was one of 5 cities with the most violations.

Saint Louis was in the top 5 with the fewest violations.