Moscow's first fast-food operation comes in a red, white and blue package: a mobile pizzeria - all the way from Trenton, N.J.

This is almost too good to be true, said one Soviet shop manager as he aimed a slice of Astro-Pizza into his mouth.Everything on the pizza - mushrooms, cheese, pepperoni and tomatoes, even the dough - comes from the United States.

U.S. Commerce Secretary William C. Verity seemed surprised when told last week that U.S. pizza was available just yards from where he stood.

Oh, it's here now? he asked, visibly disappointed that he would have to forgo a slice because of pressing engagements.

Mr. Verity was in Moscow as head of a team of U.S. officials meeting with their Soviet counterparts on trade matters.

At the time, the spic-and-span mobile pizzeria was parked outside the International Trade Center in Moscow where the recent Soviet-U.S. trade meetings were held.

Since then, the pizza truck has dispensed pies at Gorky Park, at the Exhibition for Soviet Economic Achievements (another sprawling park area), and on Gorky Street close to the Kremlin.

Shelley Zeiger, one of the two brains behind the pizza venture, said he invested about $350,000 in the venture with the Soviets, adding he expects reasonable profits from the enterprise that, for him, already is a success.

The other brain behind Astro-Pizza is Lou Piancone, chairman of Roma Foods Enterprises, of Piscataway, N.J. Earlier this year the pair signed a contract to bring their mobile pizzeria to the Soviet Union as part of a joint venture.

Mr. Zeiger and Mr. Piancone were also part of a 500-member delegation of U.S. businessmen who met with Soviet officials recently and were Kremlin dinner guests of Soviet leader Mikhail S. Gorbachev.

Mr. Zeiger, who describes himself as a firm believer in U.S. expertise and competitiveness, says he plans to open a restaurant in Moscow perhaps in time for the July 4th Independence Day. it will have a choice location across

from the Pushkin Museum about five minutes from Red Square, he said.

At the moment, however, all his thoughts are on the mobile pizzeria, a major attraction for this city of almost 9 million people.

The computer-controlled pizzeria was designed by Mr. Piancone over a five-year period and was unveiled two years ago at a pizza convention in Orlando, Fla. It has a giant freezer-refrigerator, a device that presses the dough in seconds and other up-to-date equipment. It also dispenses U.S. soft drinks.

It takes seven minutes to cook a 16-inch pizza. With six pizzas baking all at once, Mr. Piancone says, one pizza pie is ready every 20 seconds, making 70 pies an hour or 7,500 slices a day.

Mr. Zeiger, 50, considers himself a contemporary U.S. success story. Born in the Ukraine before World War II, he came to the United States in 1949.

Today he is a hotel owner and real estate developer. He is chairman of the Trenton Chamber of Commerce and is a member of the mayor's Economic Development Committee. He also is engaged in promoting Soviet-U.S. cultural exchanges.

Mr. Zeiger is optimistic about his pizza joint venture with the Soviets.

Our experience is short, but there is a general desire on our part and on the Soviet side to make this work, he says.

Mr. Zeiger has done business with the Soviets for almost 15 years through his company, Shellmar Imports Ltd.

Nothing comes easy, he says. But we worked hard, never quit and did things the right way. Now, maybe our experience can help other American companies do business in Moscow.