U.S. officials trying to contain the swine flu are now trying to contain the use of the phrase "swine flu" itself.

At a briefing with reporters Tuesday, Homeland Security Secretary Janet Napolitano and Agriculture Secretary Tom Vilsack pleaded with the media and others to start identifying the illness as "H1N1 flu."

"This really isn’t swine [flu], it’s H1N1 virus," said Vilsack, referring to the strain’s scientific classification. “And it is significant because there are a lot of hard-working families whose livelihood depends on us conveying this message.”

Specifically, federal authorities are trying to convey the message that – despite the name “swine flu” – pork products are safe to consume.

“You should know that you cannot get H1N1 from eating pork,” Napolitano said, emphasizing statements she has made repeatedly in recent days. “Pork products are perfectly safe.”

In fact, she said, authorities have not identified a single pig infected with the disease inside the United States.

Vilsack said it’s “very, very important” to get the message out. He noted that in the past two days alone the values of pork products, soy bean products and corn products have dropped.

“Virtually anybody who’s in the pork business, in the corn business or the soybean business has potentially [felt] an impact,” Vilsack said.

The economic impact of “H1N1 flu” touches close to home for Vilsack, who was governor of Iowa – "The Corn State" – until 2007.

But on Tuesday he and others insisted that the economic impact reaches far beyond U.S. borders, telling countries around the world that “there is no basis for restricting imports” of American pork products.

As of Tuesday, more than 10 countries placed restrictions on imported pork products from the United States. The U.S. pork industry exports nearly $5 billion worth of products each year.

“We want to make sure that a handful of our trading partners don’t take advantage of this legitimate concern over public health and engage in behavior that could also damage the world’s economy,” U.S. Trade Representative Ron Kirk said at Tuesday’s briefing with Napolitano and Vilsack.

“We are suffering through the strongest recession that we’ve seen in quite some time, and any actions … by any of our trading partners not based on sound science, and not based on our rules-based systems of governing, could do extraordinary damage not just to our economy but to those of other countries.”

Addressing countries around the world, Vilsack said: “We are open for business.”

Japan has stated publicly that “H1N1 flu” is not transmitted through pork products, and U.S. officials praised their Japanese counterparts for the “very clear message.”

Some countries have offered their own names for the virus. Israeli officials on Monday suggested renaming it Mexican flu, saying the reference to pigs is offensive to Muslim and Jewish sensitivities over pork. While the biggest outbreak and most serious illness so far is in Mexico, scientists don't yet have proof that's where the new virus originated.

Naming the flu, in fact, has a problematic history. The infamous 1918 pandemic was first called the Spanish flu, although scientists today all agree it didn't start there. It may have started in Kansas.

Meanwhile, the message from U.S. officials that it’s “not correct” to refer to “swine flu” may not be getting transmitted either.

As of Tuesday evening, the Centers for Disease Control still had a web page devoted to “Swine Influenza.” In an index of diseases and illnesses, no listing for “H1N1” could be found.

The Associated Press contributed to this report.