It was 2003 and there was a pizza sauce problem at Hirzel Canning Co. and Farms, a Toledo food manufacturer. Across the canning industry, sales of the tomato concoction, designed to be slathered across a homemade pie, had become lackluster. Bigger rivals had begun experimenting in order to jump-start sales, but Hirzel was still casting about for a fix.

One competitor, Contadina, had already introduced a convenient plastic squeeze bottle for its pizza sauce. A second, Boboli, had put its sauce into a flashy plastic pouch. Hirzel's pizza sauce, however, remained stuck inside a plain old metal can. "We needed more pizazz," said Steve Hirzel, retail sales manager at the company.

If ever there was a time to kick the can, this was it. But Hirzel not only stuck with the well-worn container, it made an even bigger investment in it, commissioning an innovative resealable can. Lift the small plastic tab on Hirzel's Dei Fratelli pizza sauce now and the vacuum seal breaks, allowing consumers to easily pop off the top. There are no sharp edges, and snapping the lid back on is a cinch.

Hirzel's successful experiment is part of a wave of innovation sweeping through the canning industry. Manufacturers are rolling out new easy-to-open lids, eye-catching body shapes, and even a self-heating can that creates piping hot coffee with no microwave oven in sight.

Can manufacturers say they have little choice but to upgrade their product. In the past decade, the number of cans bought in the United States dropped by more than 600 million units, according to the Can Manufacturers Institute, a Washington-based trade group.

The reason: Americans are fixated on nutrition, freshness and convenience -- and in the minds of consumers, industry analysts say, old-fashioned cans do not stack up.

In a poll conducted last year, the Can Manufacturers Institute found that only 39 percent of consumers believed that canned food is as nutritious as fresh food. And only 54 percent said canned food was as good as frozen. The belief that canned food is less healthy "is a misperception," said Robert Budway, the trade group's executive director, but the poll shows it is widely held.

What's more, the can's competitors are quickly gaining ground. Brands long synonymous with the can have begun flirting with plastic containers, arguing they are easier to open and harder to damage and that consumers perceive their contents as fresher than those inside a can.

Bumble Bee, Starkist and Chicken of the Sea tuna brands are now available in a plastic pouch. Campbell Soup Co. has introduced two lines of its soups in a microwavable plastic bottle. And Folgers, which has packed coffee in a metal can for 150 years, just launched what it calls a "revolutionary plastic container."

"We woke up and realized there are alternative kinds of packaging," said Tom Hale, vice president of sales and marketing at Broomfield, Colo.-based Ball Corp., one of the country's biggest can manufacturers, which is developing a self-heating can.

They also woke up to benefits of publicity. The Canned Food Alliance, a partnership between can manufacturers and food processors, has struck agreements with celebrity chef Jacques Pepin and Oprah Winfrey's personal trainer, Bob Greene, to promote the can's convenience and nutritional appeal.

Some of the canning industry's innovations, such as the easy-to-open lids, are widespread. Campbell's Soup and Progresso brand soup, for example, now use ring-pull lids, which do not require a can opener. Industry executives estimate that such pull-tabs, originally introduced for pet food in part so pet owners didn't have to use their can opener on Kitty's liver dinner and then on their own canned corn, are used in more than 40 percent of all new food cans.

Other designs, such as the resealable can lid and shaped cans, are just trickling into the U.S. market. Hirzel is using the lids on only two product lines, its dips and pizza sauces, though the company may eventually apply them to more foods. So far, sales are healthy, Hirzel said: "We are pleased."

Can manufacturers describe the new features as a long-overdue makeover for the tired old can, which has dutifully preserved everything from peach slices to baked beans over the past two centuries.

French chef Nicolas Appert is credited with inventing the sealed tin can in the early 1800s, but the technology enabling mass production was not in place until the 1940s, said Len Jenkins, an industry veteran and vice president of technology and development at Crown Holdings Inc., a Philadelphia can manufacturer.

The can soon became the country's most popular packaging device, extolled for its durability, sterility and low price. But even though manufacturers were improving cans over the past 30 years -- for instance, getting rid of the of telltale "tinny" taste with ever-improving interior coatings -- sales were dropping dramatically as foodmakers, grocers and consumers rushed toward competing products and packages.

In 1971, can manufacturers shipped 31 billion cans to retailers, a figure that fell to 24.5 billion a decade later and has remained essentially flat through 2003, when they shipped 24 billion, the Can Manufacturers Institute found.

Why did it take the makers so long to shake up the can? Industry executives blame an over-emphasis on cost cutting and a series of mergers throughout the past two decades, which kept the industry's focus on integrating companies, not tweaking their products.

"The business model for cans has been, for some years, 'increase production and reduce cost,' " said Ben Miyares, vice president of industry relations at the Packaging Machinery Manufacturers Institute, a trade group. "If you were thinking of innovating, the response, almost universally, was 'only if it does not cost more.' " But that is beginning to change.

Take Hirzel's new can, which its manufacturer, Silgan Containers Corp. of Woodland Hills, Calif., calls the dot-top lid. The resealable system is not only convenient, it extends the length of time a can -- and therefore, a brand name -- remains inside a consumer's home. Today, most shoppers dump a can's contents into a pan and, whether they have used it all or not, quickly toss the container into the trash.

The resealable cans are designed to stick around -- replacing, say, Tupperware, which does not remind consumers that they are eating Bush's baked beans, Dei Fratelli pizza sauce or Campbell's Soup. "It extends the brand message," said Jeff DeLiberty, Silgan's marketing manager.

DeLiberty predicts the dot-top lid will reach much of the domestic market in the next year. Because it is resealable, the can is best suited for large servings of products such as spaghetti sauce or macaroni and cheese.

Then there is the shaped can. Already popular in Europe, the concept is slowly making its way into the United States. Trader Joe's markets six of its soups in a can whose sides bulge out to resemble a kettle. The gourmet grocery introduced the concept in 1997, and it has become the chain's top-selling ready-to-serve soup, said Trader Joe's spokeswoman Pat St. John.

"The shape is very distinctive and it grabs attention," she said.

But innovation does not come cheaply. Funky-shaped cans and ring-top lids add costly steps to the manufacturing process, which are typically passed on to consumers, industry executives say. In Campbell's case, the company is eating the cost of the more-expensive soup cans. Today Campbell produces only ring-top cans, but the price on the supermarket shelf is no higher than for traditional containers, said spokesman John Faulkner.

Several companies are developing a can that heats itself, allowing consumers to drink hot tea, hot chocolate and soup when there is no time for, or access to, a microwave oven or stove. The concept is not new, but the product has yet to be sold widely by a major U.S. food company.

The self-heating can looks just like its standard counterpart, but inside there is a chamber containing lime and water. When a button on the can is pressed, the water and lime mix, producing a reaction with enough energy to heat the liquid in the can, said Daniel A. Abramowicz, executive vice president of technology at Crown Holdings.

In 2002, Swiss beverage maker Nestle SA tested a self-heating can holding its Nescafe Hot When You Want coffee in England. But the company ended the trial run after several months, finding the can did not heat the liquid to a consistent temperature, said Nestle spokesman Francois-Xavier Perroud.

"It didn't pan out," he said. Nestle is still interested in the idea, which it believes will be popular with consumers, but it is "not aware of a self-heating can that lives up to our expectations," Perroud said.

Crown Holdings says it is engaged in discussions with what it describes as "major food companies," who may use the technology, but it would not disclose their names.

Crown and Ball are working separately on a microwavable can, which they hope to have on the market in the next year or so. The radio waves a microwave oven generates to heat food are absorbed by plastic, glass and ceramics, but bounce off metal. So to create a microwavable can that adequately heats food, engineers must change the shape of the can, creating less surface for the waves to hit.

"There is a misunderstanding that metal cannot be used in microwaves," Abramowicz said. "It just has to be properly designed."

Not everyone is convinced these new can designs will reach consumers anytime soon. One doubter is Miyares, of the Packaging Machinery Manufacturers Institute. He believes the lime and water chamber inside the self-heating can, for example, reduces the amount of space for liquid while sharply increasing the cost -- two compromises shoppers may not rush to embrace.

"I don't think it's likely to be standard American fare for some time," he said.

But as companies that sell canned products look for ways to compete with plastic packaging and fresh foods, can makers predict they will seek out such innovations. The era of the humdrum can, said Ball Corp.'s Hale, is over.

"The obituaries for the metal container have been written at least 15 times in my career," he said. "The reality is that the metal container is alive and well."