Linings containing BPA are drawing unwelcome attention, but metal containers continue to make strides in both design and function.

Metal packaging is seeing some interesting innovations, but it’s also fighting to defend itself over a widely used coating additive that has suddenly become increasingly controversial.

The additive in question is bisphenol A (BPA), which helps the plastic lining in steel food cans retain its integrity under severe thermal or chemical conditions. It has come under criticism because some laboratory studies with rats have linked it to birth defects, low birth weights, cancer, early puberty and other health problems. Congressman Edward Markey (D-Mass.) has introduced legislation to ban BPA in all food and drink packaging.

 As with many health-related food issues, the science is frustratingly inconclusive. And so has been the response of government agencies. Last April, the National Toxicology Program, an agency of the U.S. Department of Health and Human Services, issued a report stating that BPA presented “some concern for neural and behavioral effects in fetuses, infants, and children at current human exposures” (emphasis in the original). On the other hand, an advisory committee appointed by the Food and Drug Administration reported in June that the evidence against BPA was not conclusive enough to support a ban.

Polycarbonate baby bottles containing BPA have been the major focus of this controversy. But BPA also is a component in the interior epoxy coating for more than 90% of the food cans in the United States, according to the North American Metal Packaging Alliance (NAMPA), a trade association of metal can manufacturers and users devoted to food-contact safety questions.

The use of BPA in food cans has drawn concern from consumers and regulators, although not to the extent of baby bottles. For instance, Canadian health minister Tony Clement announced in April a ban on the import and sale of baby bottles containing BPA. However, Clement’s department, Health Canada, stated the next month that BPA migration into canned food was too low to cause harm.

Bean cans from Eden Foods tout their BPA-free status.

Rare alternatives

Alternatives exist, but their use today is rare. Eden Foods, a manufacturer of organic canned foods based in Clinton, Mich., has put out a full line of beans in BPA-free cans since 1999-a fact touted on some of its back labels. Eden produces and markets about a dozen bean products in 15-ounce cans, along with a half-dozen more in 108-ounce foodservice cans.

The cans, supplied by Ball Corp., are lined with oleoresinous enamel, made with resin from pine or balsam fir. These cans used to be the industry norm before coatings containing BPA came along. But now, Eden is Ball’s only customer for these cans, says Sue Becker, Eden’s vice president for marketing. The cans cost 2.2 cents apiece more than standard BPA cans.

“I hope that this awareness causes other people to start purchasing it too,” Becker says.

However, there are limits to what even a committed canner like Eden can do. Eden produces tomato products for Canada; when the company inquired about non-BPA cans for those products, it was told that they would have a shelf life of only six months.

For high-acid products like tomatoes, BPA cans are the only game in town. A consumer-relations executive for a tomato canner, who asked not to be identified, says she has received inquiries from concerned consumers about BPA, but that its use is pretty much mandatory.

“There’s nothing we can do about it. That’s why it’s such a touchy issue,” she says. “All the cans have it in there. If you want to have a lining in your cans, [BPA] is going to be in there. And if you don’t have a lining, then something like a tomato is going to eat through the can.”

NAMPA notes that several studies, from different parts of the world, have shown that BPA migrates from packaging in levels far below the threshold believed to pose health dangers-up to 300 times less, in one study.

NAMPA chairman John Rost notes that the only BPA that can migrate into a product is the trace amount that remains unreacted with the can’s internal epoxy coating.

“There’s some concern when a story comes out that there is a significant health issue,” Rost says. “There are some concerns among consumers and brand owners about products that go into metal packaging. Our main objective is to educate people about the real science about BPA.”

The Easylift is an improvement on Crown's Eole easy-open can end.


Worries about BPA may be a strong negative for food cans, but metal packaging is undergoing some positive developments, too. Several leading metal packaging suppliers have recently placed innovative products on the market.

One of the biggest knocks against metal packaging is its uniformity. While this can be an advantage in handling, storage, transport and interchangeability, it doesn’t help distinguish products on the store shelf.

Shaped metal cans have the potential to break through this clutter. The latest product to enter this market is the Sculptured Metal Technology line of cans from Silgan Containers Corp. The Silgan cans are available in a variety of both stock and custom shapes, in both steel and aluminum, with regular and pop-top can ends.

One of the most unusual innovations in metal packaging comes from Ball Corp. Its Widget Can releases a load of nitrogen upon opening to charge up foaming beverages like beer or coffee drinks. Similar technology has existed for years for certain beers, but it’s just starting to move into soft drinks.

The key is the “widget,” a capsule affixed to the bottom of the can during manufacturing. After the can is filled, it’s dosed with liquid nitrogen, which starts to boil off. The can is immediately sealed and inverted for at least 15 seconds. The nitrogen continues to boil off, entering the now-exposed widget while it pressurizes the can. Once the can is turned right-side-up, the nitrogen is trapped inside the widget, where it remains until the can is opened. Upon opening, the transition to atmospheric pressure releases the nitrogen, which rushes upward and creates foam.

“It definitely makes a different sound,” says Ball spokesperson Jennifer Hoover. “When you open the can, you can hear that release, kind of like a whoosh, which is a neat cue for consumers. If you pour that beverage out, it foams up, like a drink you might get at a coffee bar.” The Widget Can had originally been used for beer; it now also is being used in Kenco Ice Cappio, a coffee-flavored soft drink marketed in Europe by Kraft Foods.

Straw can

Ball Corp. also has a product on the way that represents a metal-can alternative to aseptic drink boxes with straws. The Straw Can is a standard 8.4-ounce beverage can with a pop-top can end. The small, round aperture on the can end exactly fits the diameter of a straw supplied with the can-so exactly that, once the straw is inside, the product won’t leak from around the straw even if the can is inverted. The Straw Can is not yet commercially available.

Ball also is contributing to the trend of aluminum beverage bottles with its Alumi-Tek bottle, currently being used for Caribou’s line of retail iced coffee (produced and distributed in a joint venture with Coca-Cola). Aluminum beverage bottles are still rare enough to contribute cachet to a product; they also combine the quick-chilling properties of aluminum with the reclosability of screw-top glass or plastic.

Another Ball advance is its Eyeris direct-print technique. Eyeris is a proprietary improvement on plate technology that can give noticeably higher resolution than conventional direct can printing. The first to use Eyeris was Jones Soda, when it came out in autumn of 2007 with a promotion based on the NFL’s Seattle Seahawks.

Ball also is marketing another decoration innovation: pull tabs customized with laser etching. The tabs, introduced in 2006, were first used by Go Fast Sports & Beverage Co. to carry its logo on its eponymous energy drink.

“We wanted to connect the Go Fast taste with the Go Fast Brand as strongly and quickly as possible, with the consumer, and using the etched pull tabs was the best way to accomplish this,” company president Troy Widgery says in an e-mail. “Go Fast was the first customer of Ball to use the pull-tabs.” The tabs add about one half-cent apiece to the cost of the cans, Widgery says.

For more technologies from Ball, see “Ball’s innovative pitches truly catching on” on p.38.

Crown Food Packaging North America recently brought over from Europe an improved version of its Eole pull-ring food can end. The new end, trade-named Easylift, features more space underneath the beveled pull ring for even easier opening.F&BP


The following companies contributed to the research for this article:

Ball Corp.

Crown Food Packaging North America

Silgan Containers Corp.