Closures help protect the contents inside food and beverage packages. But consumers favor them most for their easy open, dispensing and reclosing features.

Here’s a rundown of handy closures across multiple package types and product categories.

-Easy-open metal cans. Consumer preferences for easy-open ends on aluminum cans have sparked easy-open steel food cans.

Precision offset steel end scoring technology took hold during the late 1990s. Campbell Soup is among the latest companies to use this technology on easy-open soup cans.

Another easy-open food can is Dot Top from Silgan Containers. The skirted steel end or closure sits on the flange of the can body. A vacuum within the can draws the end tightly and hermetically seals it.

A barrier plastic “dimple” seals a die-cut opening at the center of the end. The can opens by peeling back the plastic to release the internal vacuum.

This action allows the user to lift off the lid easily. Snapping the lid onto the can reseals the container.

-Snap-on overcaps. Snap-on overcaps help keep foods fresh inside containers after opening. These caps appear on coffee cans, paperboard composite canisters and plastic cups, tubs, bowls and trays.

Perforated overcaps appear on food packages destined for the microwave oven. The small holes allow some of the steam produced during microwaving to vent.

-Zippers. Although developed more than 40 years ago, zipper-style closures did not become prominent commercially until about 10 years ago. They first appeared on shredded cheese pouches, and now top hundreds of flexible packages.

Zippers involve two interlocking devices—a “male” ridge on one interior face of a flexible pouch that fits snugly into a “female” slot in the other face of the flexible material.

The zipper complements the basic heat-seal closure of a flexible pouch or formed tray. The consumer opens the primary closure in the usual fashion.

After removing part of the contents, the user presses the two faces of the zipper together to reclose the package.

Heat-resistant zippers are beginning to appear on hot-filled and retorted pouches.

Slider-type zippers provide a more positive means of reclosing the pouch after opening.

-Bottle closures and dispensers. Dispenser-style closures have revolutionized the delivery of many viscous and liquid foods such as catsup, mustard and single-serve drinks.

Flip-top and push-pull devices sit atop many personal care products to offer single-handed use in the bathroom and shower.

These closures have sparked the movement toward “inverted” bottles for condiments. Inverted plastic bottles ensure that the contents are present at the opening for immediate dispensing.

As the user squeezes the bottle, the pressure expands a silicone valve in the closure and forces product through the opening.

Upon releasing the pressure on the package wall, the silicone device reverts to its original closed position.

No discussion on package closures is complete without reference to bottled water. Who, a decade ago, could have imagined the multi-billion dollar market for personal-size bottled water? It appears almost universally in classrooms, offices, car cup-holders, bicycle holders and other away-from-home places.

Single-handed dispensing while jogging on a treadmill or driving a vehicle appears to be a universal attribute. Convenience of opening, dispensing and instant closure is fundamental to the popularity of bottled water. BP