The big guns in the Italian leathergoods industry may not be forced out of business nor do Hong Kong tailors need to run out and re-train for other work, but I think I see a sharp shift in U.S. citizens' souvenir shopping coming on.

Going through the Customs line I noticed four other returning Americans who'd been on my plane from London almost defiantly declaring the same sort of loot I was. I had an advance inkling that this would happen when I boarded and the flight attendant laughed out loud.

"What?" she said. "You too?"

It turned out that the plane's refrigerator was stuffed beyond capacity due to the fact that my felow travelers and I were all slipping home with the newest yet oldest thing in status/security symbols - food.

Actually, your everyday normal neuroses may play only a small part. Take a long look at prices and it becomes instantly apparent that you'd be hard-pressed to find souvenirs that are more pleasurable or more practical. You can even read that "cheap" if you wish.

In fact, the temptations are such that before leaving London I, for one, beat it over to the vast food section in Harrod's department store and barely got out in time for the flight. Only by exercising outstanding self-control was I able to keep my buys doen to a mere five pounds of cheese, four packages of crackers for the cheese, two pounds of chocolate-covered mints, and two tins of specially blended teas.

On reflection, if someone were to suggest I need to have my head examined, I'd have to agree. I must have been out of my mind not to get an entire wheel of Stilton. And surely if I hadn't been temporarily insane I would also have realized that one should run, not walk, towards potted shrimp, Devonshire cream, smoked salmon, marmalades and certain luscious-looking cookies. I mean, not only are some of the goodies on sale in London unobtainable on this side of the ocean, but in England many of them are far better buys. The crackers alone sold for about 75 cents a package less, and most of my cheeses were $1 to $2 a pound under the U.S. price.

The good news is also the bad news. To pass some of these things without buying is more painful than sitting smack on a buzzing bee, yet circumstances and the U.S. government may be against you.

The government is hardest to beat. Uncle does have a long list of prohibited items, and you can easily and innocently come a copper and have your finest purchase confiscated.

How the list is made is beyond my comprehension. It also seems to change. Not being able to keep up, I've taken to going with my own rule of thumb (forget meats, sausages, fresh fruits and fresh vegetables) and holding my breath that everything else is okay. It's possible there are U.S. consulate officers who can reveal which are the verboten items, but I've sometimes gotten green lights from them when they should have flashed red.

Meanwhile, you may notice that the whole world is full of succulent surprises that you'd like to take home for yourself or friends. Every time I've been in the Hong Kong department stores operated by the People's Republic of China, I've felt myself go totally soft on communism. I think it's because hardly anyone else in the world wants to sell me such good tea at such dirt-cheap prices. It's difficult to leave room for preserved fruits and ginger but you're foolish if you don't try.

In the French parts of the Caribbean, there are equivalent tests. The motherland subsidizes some food prices for its overseas "departments," and you can find a gratifying number of French foodstuffs (particularly canned goods) for considerably less than they're tagged in Paris, and monumentally less than in the United States. I've also found many spices to be a particularly good buy as well.

Ireland tends to rest in my mind as one big "carryout." That's partly because the Irish get along with our Customs and their bacon, their sausage and even their hams are okay to bring back. (While about it, stop at the Country Shop on St. Stephen's Green North in Dublin and load up on bread.)

Of course, if you were flying back from Mexico, you would skip bread in order to concentrate on rolls, the chewy, good ones called bolillos. They're light to carry, they freeze, and as presents they will win you friends. Similarly, for any Francophile, the perfect present from France is the croissant - preferably as many as you can carry. (Hot tip: They make just as good ones in Montreal and Quebec, and sell them for way under U.S. Prices.)

I also happen to know for certain that a Sacher torte, a chocolate layer cake that by all rights should have kept Hitler at home and happy in Austria, can last as long as a year if you (a) don't go into the freezer after it too often and (b) serve thin slices.

Actually, sensuous souvenirs are available all over this country, too. East Coasters have been bringing crabs and salmon back from northern California (as well as the old favorites, sourdough bread and Italian-style salami), and my mother in the Midwest is waiting (a little impatiently) for a pepper-coated smoked country ham that I'm supposed to send her from Virginia.