Making the Cut

Sept. 1, 2009
Packaging solution allows food processor to enter the growing fresh-cut market.

The use of fresh-cut vegetables for foodservice has seen significant growth in the past few years, driven by hygiene regulations, customer preference for fresher meals and convenience factors, such as quicker cooking times and reduced preparation time. According to the Fresh Cut Produce Association, fresh-cut fruits and vegetables make up one of the fastest-growing food categories in U.S. supermarkets with sales increasing from $3.3 billion in 1994 to $15 billion in 2005 and expansion set to continue.

However, innovative new packaging and processing developments are essential to the industry's further growth. Food producers, having traditionally focused on more heavily processed products — such as raw ingredients, bulk or frozen items — are now seeking avenues to deliver their products to the market in refrigerated fresh-cut formats. To take advantage of this opportunity, food manufacturers are turning to a new array of packaging and processing technologies.

Keystone Potato Products, a Hegins, Pa.-based producer of dehydrated potato flakes and potato flour, exemplifies this trend. As demand for refrigerated fresh-cut potatoes has grown since Keystone was founded in 2003, the company saw an opportunity to expand into a new market sector, add value to its product and drive profitability. The organizational structure of Keystone — essentially a cooperative of dozens of potato growers — gives the company an almost unlimited supply of raw potato product, including white potatoes, russet potatoes, red potatoes and yellow potatoes. Thus, it was simply a matter of building the processing and packaging capacity to break into the market.

With the objective of producing a shelf-stable refrigerated product of fresh-cut potatoes in four formats (French fry cut, dice, slice and quarter potato wedges) and two package sizes (five- and 10-pound bags), Keystone made the decision to expand its capacity with a new production line at its Hegins location. In specifying the processing-line components, a key requirement was a packaging solution that could handle a range of product formats and package sizes, ultimately opting for a vertical form-fill-and-seal machine from Bosch Packaging Technology.

Within each of the four potato formats, there is a diversity of sizes. For example, dices come in sizes from 3/8-inch square to 1 ½-inch square. The form-fill-seal machine is specifically designed to package free flowing, loose products and can handle a variety of product sizes and formats. Incoming product flow is continuous and enters the machine from the top, fed by a weigher integrated into the packaging machine's control system. Simple adjustments to the weigher allow for a quick changeover between product formats and sizes, dependent on the target weight for the bag.

Keystone is using the packaging machine for two bag sizes: five and ten pounds. The machine uses one forming tube to create both bags, so it is only a matter of changing the bag length and adjusting the fill weight, an almost immediate operation. The machine currently runs 30 bags per minute for the five-pound bags but is capable of up to 120 packages per minute, depending on upstream product flow and bag size. If necessary, the machine can package bag widths ranging from two inches to 15 inches and lengths of three inches to 24 inches.

Extending Shelf Life

Because Keystone is moving into the refrigerated fresh-cut market, shelf life concerns are paramount. The difference in shelf life between frozen and refrigerated is months versus days. Thus, any extension of shelf life means more time available for distribution and storage, thus facilitating deeper market penetration and broader regional access. The two methods of addressing this challenge, barrier films and gas flush, are both facilitated by the form-fill-and-seal machine.

Currently, Keystone is using a range of barrier films and experimenting with different gauges with different oxygen transfer rates. The packaging machine is designed to process a variety of packaging films and varying gauges, including heat sealable and polyethylene materials. Likewise, it is equipped with the capacity to implement gas flush for modified atmospheric packaging. With nitrogen flush to displace the oxygen within the package, Keystone is able to inhibit the growth of aerobic pathogens and other agents that lead to product spoilage and thus lengthen the shelf life of its potato products.

The machine's servo motion control technology adds to the efficacy of Keystone's operations. The film-sealing system features servo motion control for both film handling and independent jaw movement. Designed around a Rockwell/Allen-Bradley integrated control system for total system awareness, the machine's online machine documentation allows real-time diagnostic capabilities.

The packaging material is fed continuously and precisely by a vacuum-supported servo belt system, without any friction between the belts and forming tubes. Simultaneously, a strong longitudinal seam with minimal overlap is formed. The cross-seal jaws are synchronized with the packaging film advance to ensure precise top and bottom seals and enable smooth separation and finish.

Servo drives also electronically control the vertical and horizontal motions of the cross-seal jaws. One servomotor is dedicated to the vertical movement of the cross-jaw assembly. The second servomotor drives the opening and closing of the cross-seal jaws. These features facilitate many different movement profiles, enabling Keystone to use an array of sealing parameters.

With the line up and running since August 2008, Keystone is currently producing packaged fresh-cut potatoes for the foodservice market and is soon to break into the consumer space. As growth continues, the company plans to expand its workforce and capacity to accommodate more volume. The form-fill-and-seal machine is equipped to handle the increased volume with its high-speed capacity. And, the flexibility of the machine — allowing for a variety of bag sizes, sealing configurations and packaging films — will enable Keystone to adapt to the notoriously fickle demands of the restaurant and retail consumer markets.

This article is based on material developed by Bosch Packaging Technology, a provider of packaging equipment and process technologies.

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