One shopper talked about how his daughter one day lugged home a dozen one-kilogram (2.2 pound) bags of oatmeal because she passed a shop that had just received a shipment. A professor said that he had bought a second refrigerator, even though he really could not afford it, to store more meat. No Shortage of Suspects

Muscovites are too conspiracy-minded to believe that hoarding alone explains the shortages. Some people suggest that old-line Communists are scheming to keep food off the shelves to make Mr. Gorbachev look bad. Others blame it on an economic "mafia," a group of speculators or middlemen who putatively get their hands on food that was destined for state shops, then sell it at much higher prices in the Western-style farmers markets, where there are no price controls and where food supplies are abundant.

"A lot of this food is taken by the mafia," said Tamara Artemyeva, who worked at a cashier at a delicatessan that had only one thing for sale: cabbage. "I don't know whether they destroy it or sell it on the black market. But I'm sure they do something that's profitable for them."

Many Muscovites are convinced that clerks at state shops are selling their goods out the back door more than ever before. Such corruption, a longstanding practice here, pays off better than ever now because the difference between the fixed prices at the state shops and the unrestricted prices at the food markets is larger than ever. A kilogram of meat sells for 2 rubles at the state shops, and 25 rubles in Moscow's markets. The average Soviet citizen earns 280 rubles a month.

At Food Store No. 19 one afternoon not long ago, shoppers nearly began a scuffle when they discovered that employees had stashed away some milk that was supposed to be sold to the public. 3 or 4 Hours in Line

Although shortages seem ubiquitous, shoppers say they somehow scrape by. Pensioners, who receive about 130 rubles a month, say they sometimes wait on line three or four hours a day in state stores to purchase what they and their children need.

To avoid lines, consumers can shop at the well-stocked farmers markets, but not everyone has the money. "The prices at the market are just too high," Svetlana Palgina said as she waited in a 45-minute line at a fish store.