The troops in Saudi Arabia are fed up with messy chocolate that melts in your hand and not in your mouth.

Now, the Army is on a mission to find a milk chocolate bar able to withstand temperatures of up to 140 degrees without melting or softening.

For companies interested in offering their sugary wares, there is one caveat: "These chocolate bars must contain real chocolate," the Army requirements declare.

The Army's Natick Research, Development and Engineering Center in Massachusetts is "conducting a market survey of potential supply sources" for the durable candy bars, according to a notice placed in a recent edition of Commerce Business Daily.

Researchers at the center have found that most commercial chocolate bars last no more than a few hours once temperatures reach 100 degrees. In fact, food experts at the center conducted special studies to determine what happens to a normal chunk of chocolate after 17 days storage at 100 degrees.

"Basically, after two days, the bars are completely melted and they don't resemble a bar any longer," Jerry Darsch, chief of the food technology division of the Army center, said yesterday in a telephone interview. "Once the wrapper is disturbed, the chocolate usually ends up in your lap."

The center has found one commercial candy bar that "might have some merit and tastes tremendous," Darsch said, adding that interested firms may submit their offers through Oct. 25. He declined to identify the company that makes the bar.

Several years ago the center developed a candy called a "tropical bar" that looked like chocolate, but after storage at high temperatures "had a waxy flavor and didn't taste as nice as a commercial off-the-shelf item," according to Darsch. The tropical bar subsequently was dropped from the military menu.

Candy isn't the only food on the center's research table, though.

Army researchers, with the assistance of a Texas bakery, recently developed a loaf of bread that won't mold, mildew or become stale for up to three years.

"It was quite a technical challenge in terms of bread," declared Darsch.

With the breakthrough, the Army accelerated the bread project to get the two-ounce loaves out to the troops on the Arabian Peninsula.

"The feedback we've gotten from the men and women has been outstanding," said Darsch.

Still, the Army isn't satisfied with three-year shelf life and is now trying to develop freeze-dried food packets -- ranging from chili to beef stew -- that will last up to 10 years.

The idea is to put such ration packs in war reserve stocks around the world. Now military foods last only about three years before becoming unpalatable and must be replaced, a costly logistical process.

"By the time the package comes out of the prepositioned cycle, it's already close to three years," said Darsch. "If we could get rations that could remain there for 10 years and still be serviceable at the end of 10 years, we could save the taxpayers a considerable amount of money."

Among the desserts that would be included in the 10-year packs are fig bars, "pan coated chocolate discs," chocolate bars and jelly candies.