Look closely next time you stroll down the grocery store aisle. Changes are afoot on the shelves: Wishbone salad dressing in plastic bottles, beef teriyaki dinners in lunar-looking foil pouches, milk sitting in small unrefrigerated boxes on the food rack.
All are part of sweeping changes taking place in the staid packaging industry.
New technologies are spurring a thrust toward packages that are cheaper to make, more energy efficient to transport and store, and easier to use for an increasingly leisure-oriented society.
''Much of the packaging in the 1990s will be lighter weight, easily disposable, and suitable for use in microwave ovens,'' says Arthur Stupay, an analyst with Prescott, Ball & Turben Inc., a Cleveland brokerage firm.
Glass and steel remain the stewards of the store shelves. But new packaging materials are chipping away at their dominance in special food areas:
* Retort pouches. The idea of putting food in sealable pouches has been around since the time of Napoleon. But only now are they beginning to show up on US store shelves. In retort packaging, food is vacuum sealed in a three-layered container, then heated to kill bacteria.
On the plus side: the easy-to-use pouches can sit unrefrigerated for several months. Minuses: pre-heating saps some of the flavor. The packages also are costly.
But better versions being devised should make retort pouches more common for such foods as pie fillings, seafoods, and ''ethnic dinners.'' Even so, anaylsts consider the flexible pouch more a package of the 1990s, since today's consumers aren't familiar with it. By 1990 some 1.9 billion pouches are expected to be in use by stores and food-service organizations - up from 20 million this year, predicts FIND/SVP, a New York market-research firm.
* Plastic films. High energy costs have already given lightweight plastics a boost over more conventional steel and glass containers, used largely for beverages. Now new technologies are slowly pushing composite plastics into other food areas. These co-extruded materials form a plastic sandwich, with one layer of sheets blocking moisture, another sealing in flavor.
H.J. Heinz Company is test marketing a squeezable plastic ketchup bottle. At least one brand of barbecue sauce is being put in the semirigid plastic containers, as are some salad dressings and lunch meats. Still, Philip Silver, president of the Continental Packaging Company, an arm of the Continental Group, sees the new plastics largely confined to easy-to-use foods that aren't subject to high temperatures - ketchups, oils, and mayonnaise.
* Aseptic packaging. These laminations of paperboard, plastic, and aluminum are considered to have the biggest near-term potential of the new packaging ideas. Since their debut in the US in mid-1981 - they have long been used in Europe and Canada - they have been booming in the small juice market.
Their biggest impact, however, will be felt in the dairy industry, where the brick-shaped packs are slowly coming into wider use as milk containers. The food is heated, then put in the aseptic package (which has been separately sterilized), and quickly sealed. The packages require no refrigeration or freezing (milk, for instance, will last about three months on the shelf). The advantages: cost savings in the manufacture of the containers and energy savings in the store and at home because the packaged products require no refrigeration. ''What all these are leading to in the 1990s is a whole new series of foods that make the refrigerator obsolete,'' says Mr. Stupay of Prescott, Ball, & Turben.
Use of aluminum is also on the rise. The traditional steel can is considered stronger and less permeable than the lighter metal, but aluminum containers hold several trump cards: light weight, resistance to rust, and ease in the recycling process. Already holding a formidable presence in the beverage market, aluminum is slowly making inroads in such areas as canned meats, juices, deserts, vegetables, and soups.
The ultimate question, of course, is whether consumers will be willing to stuff shopping carts with the new packages. People are notoriously cautious when it comes to unfamiliar wrappings. With some of the plastics and new aluminum alloys, the changes will be barely noticeable. But the pouches and aseptic boxes will require some changes in the way consumers think about food.
''People just don't like to buy things that are different,'' said Leonard Barol of Leonard, Lincoln, Barol, a Philadelphia-based packaging consultant. ''You have to educate the consumer.''
If there is one force working in favor of the new designs, however, it may be people's growing familiarity with technology in general. The high-tech era has made consumers less jittery about the science that goes into packaging.
''There is an awareness of technological change and what it can do,'' said Lorna Opatow, president of a New York market-research firm. This is leading to a ''willingness to accept innovations'' in packaging, too.