BALTIMORE — Rep. Benjamin Cardin has fired a campaign staffer who posted racially charged comments against his opponent on the Internet, the congressman’s campaign said Saturday.

The staffer’s blog includes references to Oreo cookies. Mr. Cardin’s opponent, Republican Lieutenant Governor Michael Steele, who is black, has said people threw Oreos at him during a 2002 debate as a slight directed at his race and political views.

In a statement, Mr. Cardin, who is white, also condemned comments written by the female staffer on her blog that he considered derogatory to Jews.

“I am deeply offended and disgusted by the blog’s racial and anti-Semitic overtones,” the 10-term congressman said. “The staff person responsible was promptly dismissed and will have nothing to do with my campaign.”

A spokeswoman for Mr. Steele, Melissa Sellers, criticized the blog.

“It is deeply disturbing to learn that a staff member of 10-term Congressman Ben Cardin would keep a blog chronicling racial prejudices toward Lieutenant Governor Steele and others,” Ms. Sellers said. “This is the kind of attitude and gutter politics that Marylanders are sick of and why they are ready for change.”

The woman was “a junior staffer” who worked for the campaign for about a month, Mr. Cardin’s spokesman Oren Shur said. He declined to identify her or elaborate on her duties.

Mr. Shur said the woman was fired Friday “as soon as we learned of this.”

A blog posting August 25 refers to a stack of Oreo cookies “looming in the back of one of the campaign pantries” and how staffers have to “surreptitiously glance around” before eating them.

“The subterfuge would be unnecessary, and snack time would be far less amusing, had an angry citizen not thrown the aforementioned delicious snack food at one of our opponents to comment on his lack of racial loyalty,” the blog entry reads.

The blog also contains an entry describing Mr. Cardin’s friends as “large men with strong, loud voices and Jewish noses.”