SHANGHAI, China — In an effort to reassure American consumers about the safety of food and medicine made in China, U.S. and Chinese officials signed agreements Tuesday giving U.S. officials a stronger hand in screening Chinese exports.

But consumer groups and lawmakers in Washington pointed out that the two agreements covered only a small number of products. And the success of the new regulatory effort depends on whether Chinese officials can get producers to meet U.S. safety standards and whether thinly stretched U.S. government agencies can ensure that China keeps its promises.

“Today’s agreement applies only to a tiny fraction of the food we import from China,” said Sen. Richard Durbin, D-Ill. “And while it can be expanded, it doesn’t cover nearly enough products to restore our confidence in Chinese goods.”

Some American consumers have grown wary of the “Made in China” label after a series of safety problems, including tainted pet food ingredients, lead paint in toys, defective automobile tires and toothpaste laced with an antifreeze ingredient.

The pacts signed in Beijing by U.S. Health Secretary Mike Leavitt require companies that export certain foods and medicines to the U.S. to register with China’s food and drug watchdog agencies and agree to annual inspections. The U.S. government will maintain an online list of registered exporters. China also will implement new certification and testing systems to ensure shipments meet American standards.

Foods covered are canned vegetables and other preserved fare, pet foods and treats, raw materials such as wheat and rice protein used in a variety of products, and farm-raised fish and shellfish.

Covered medicine includes some antibiotics, a cholesterol-lowering drug, generic Viagra, human growth hormone and an antiviral drug.