A planeload of food arrived in Moscow Thursday in the first shipment by German charities aimed at easing the chaotic food situation in the Soviet Union.

The planeload of 25,000 pre-packaged meals was being sent to children's hospitals and orphanages, said Valeria Kuprina, deputy chairman of the Moscow branch of the Soviet Children's Fund.She said food deliveries to the children's institutions are becoming irregular, so officials decided the first shipment of Western food should go to them rather than the barren shops.

On Thursday, President Mikhail S. Gorbachev pronounced himself and other Communists "guilty before the working class" and promised immediate steps to improve food supplies.

Gorbachev said he had concluded agreements for the republics of Estonia, Kazakhstan and the Ukraine to send dairy products to Moscow and Leningrad, where milk is hard to find in stores. Food shortages have caused a public outcry.

The Soviet leader also said powdered milk would be taken out of storage and distributed to the people.

In a wide-ranging hourlong speech before a conference of the Moscow City Communist Party organization, Gorbachev also reiterated his determination to hold the Soviet Union together.

Gorbachev later canceled a planned trip Friday to the troubled southwestern Soviet republic of Moldavia, where he was hoping to ease ethnic tension and dissuade separatists, the official Tass news agency said.

The one-day trip to Kishinev, announced Thursday, would have been Gorbachev's first visit to a Soviet republic outside the Russian Federation where the capital is located since a politically uncomfortable stop in Lithuania in January.

In the face of widespread worries that the foreign food shipments might be stolen or simply stalled and left to rot, the Children's Fund made highly unusual arrangements for supplies to be delivered to the institutions within hours of landing at the airport.

Trucks quickly met the Aeroflot cargo flight and delivered the food packages immediately, Kuprina said.

A vanload of food arrived after 11 p.m. at a children's home in western Moscow, but there was no joyous welcome. The kids were all asleep.

The food was to be distributed Friday to the 150 children, ages 4 to 18, at Children's Boarding Home No. 24. Director Tatiana Vyedyokhina said the home has been receiving supplies from its regular domestic sources but that she worried about the future.

"The situation in Moscow is getting worse and worse," she said in a late-night interview. "I think it will affect the children's home eventually."

Despite the start of aid from West Europe that is just beginning to arrive in Moscow, the supply situation is unlikely to change rapidly for most Soviet shoppers.