Those Soviet food shortages . . . 'No main course, but would jello help?'

''Dear customers,'' began the tinny, amplified voice in the Moscow grocery, ''there is a limit of two packs of butter per person.'' With that, people waiting in other lines for other delicacies moved, like iron filings to a magnet, toward the butter counter.

Rationing, still unevenly applied in the crowded and ill-lit state food stores of the Soviet capital, is not particularly bad news for the average shopper.

Two packages of butter - about one pound - can go a long way. And two packages is, after all, better than none. More than a few shops have none - even , in some recent instances, the showcase of all shops, the hard-currency grocery reserved for foreigners.

The butter shortage is new to Moscow (although not to the rest of this enormous nation, traditionally less well-supplied.)

But other products, particularly meat, have been scarce here for many months. The situation shows no signs of improving.

Not too long ago, a group of Western visitors arranged for a sumptuous banquet at Moscow's newest and poshest hotel - the International. All went smoothly until the main course, which was to have been meat. But the main course never happened. The chef, as a concession, added an extra dessert: jello.

The Soviet authorities, aware that the country's third poor grain harvest in a row could further complicate food supplies, have been engaged in some high-profile groping for a counterstrategy.

Ultimately, the hope is to piece together a ''food program'' to deal with the inefficiency, corruption, and waste endemic not only in Soviet agriculture, but in the civilian economy as a whole.

This, for the time being, seems to have run into problems. Soviet President Leonid Brezhnev originally suggested the scheme late in 1980. In February 1981, at the five-yearly Soviet Communist Party Congress, he said the program was still being worked out. Senior officials said privately it would be unveiled at a plenum of the party's Central Committee in November.

But those sessions have passed. It has been announced that the food program is still being worked out.

Officials hasten to point out that measures can be - and are being - implemented without the announcement of a full food program.

But the measures so far taken seem to focus more on the symptoms than on the structural causes of the Soviet Union's worsening food situation.

For instance, the Soviets have contracted for large purchases of grain from abroad, to compensate for domestic shortfalls and to avoid the need for crisis slaughter of livestock herds.

Deals have also been sealed, on a smaller scale, for meat purchases for foreign suppliers.

An official decree earlier in the year envisaged increased backing for a small ''private plots'' outside the country's network of state and collective farms. Accounting for only a tiny percentage of Soviet farmland, such holdings nonetheless provide about one-third of the nation's meat, milk, and eggs.

But the small plots' output has been falling off in recent years as farm youngsters continue to opt for city life. Moreover, private farmers seem barely more efficient at times than the huge state farm network. They tend to ''borrow'' resources from the state or collective farms. That having been done, small-scale farming is simply easier than large-scale farming. Window boxes would be even easier. Soviet officials tend to see private farming more as a short-term counter to the food problem than as a long-term panacea. And in at least one area - grain - the small plots seem to have little role to play.

Meanwhile, as Brezhnev told the Central Committee plenum, the food shortages remain both an economic and a political problem for the Soviet leadership.

Some Western headlines notwithstanding, the political problem shows no sign as yet of getting out of hand. Soviet police power is one ever-present deterrent. Soviet propaganda helps, too. One Moscow radio report on a snowstorm in the Midwestern US last winter, for instance, evenly recounted a tale of ''interrupted'' food supplies.

To the American listener, this meant no Sara Lee poundcake on aisle seven. To the Soviet, it meant no meat, no butter, and, in effect, no less a ''food problem'' in the decadent West than at home.

Soviets, in any case, don't generally compare their shopping woes with the West's. Older Soviets, too, have lived through much worse, during and after World War II. They will make do, particularly by eating more bread, a commodity that remains in generally good supply. Or, for more rubles, they will turn to private farmers' stalls or to the black market.

The potential political problem for Brezhnev and company presumably centers on younger citizens, who grew up at a time when just about every aspect of Soviet life was visibly getting better.