WASHINGTON — The prune burgers were great, but grapefruit juice won't be showing up on school menus if some of the government's official taste-testers have their say.

"The hamburger was good. It tastes like a grilled burger," said Mustafa Mattocks, one of 20 students at Washington's Van Ness Elementary School who tried several new products that the Agriculture Department may offer to schools.

Mustafa, 12, said the burgers, which are a blend of beef and prune puree, were better than the usual school fare. A raisin-tomato barbecue dip for chicken nuggets also was a hit with the students at Tuesday's taste test.

The Agriculture Department is under pressure from Congress to bolster produce prices by buying up surplus crops, including cranberries and prunes, and giving them to schools. Results from the taste test will be tabulated and sent to schools.

In a similar test last year in the Los Angeles area, the sweet potato pancakes were very popular, as were snack bars made with dates and almonds. Broccoli guacamole was a dud, and so was an asparagus version. The prune burgers and pizza topped with a prune-based sauce got better reviews.

USDA eventually intends to hold regular school taste tests in seven regions of the country.

"What we're really trying to do is find new uses for the products we've been purchasing," said Robert Keeney, deputy administrator of USDA's Agricultural Marketing Service.

There's such a glut of prunes that the department is paying growers to destroy 20,000 acres of plum trees. USDA also has been paying farmers to destroy potato and sugar crops, and last year sharply restricted the amount of cranberries that could be brought to market.

Schools, however, are leery of trying new products without evidence that kids will accept them.

"This is something we've been asking them to do for numerous years," said Marcia Smith, school food director in Polk County, Fla., and president of the American School Food Service Association.

The children at Van Ness tried 11 different items Tuesday and were asked to grade each on a scale from 1 (worst) to 5 (best) on taste, smell, color and overall appeal.

"Remember, all the kids around the country are going to hold you responsible for this," sixth-grade teacher Brenda Maxwell told one of her students who seemed reluctant to give bad grades.

Franklin Murphy, 10, gave all 5s to the sweet potato pancakes, but he frowned at all three versions of grapefruit juice he was offered.

Janee Henry, 12, gave the turkey-prune hot dogs a 3 on color but 5s on everything else, including taste. "It's light, and I'm used to dark colors," she said.

The kids weren't supposed to know what was in the food until they ate it, but some had seen a display of the products before the test started.

The presence of plums in the burgers turned off some of the kids. Both the government and the industry now refer to prunes as "dried plums."

The burgers, which contain about 4 percent prune puree and some soy, have about 40 percent less fat than an all-beef patty. The prune mixture adds moisture to replace the lost fat. The prune burgers served Tuesday were flame-broiled by the processor to give them the grilled flavor.

John Lund, a USDA official who oversaw the taste test, said there's no reason for schools to disclose that the burgers contain prunes, since there's too little of the fruit to have the laxative effect for which prunes are known.

On the Net: Agricultural Marketing Service: www.ams.usda.gov

American School Food Service Association: www.asfsa.org