Lauren R. Hartman

January 29, 2014

7 Min Read
Turkey pack 'gobbles' up oxygen scavenger technology

Foster Farms is a Livingston, CA-based poultry processor that prides itself on offering superior "down-home quality" and fresh, locally grown turkey and chicken. The processor says it's involved in everything from the hatching of its eggs to delivering the poultry to stores. Foster is also concerned about the care of its birds, disposal issues, the environment and the efficiency of its packaging operations. That's why it has selected OS Films invisible oxygen-scavenging technology from the Cryovac Div. of Sealed Air Corp. (www.sealedair.com) for the inner pouch packaging of its new, thin-sliced turkey. Packaged under modified atmosphere, the three new sliced-turkey products are contained in a formed film pouch holding 10 oz that's packed in a rectangular, rigid plastic tub with a snap-on plastic lid. The OS Films material of the inner pouch helps remove residual oxygen, achieving oxygen levels that maximize freshness and promote the products' amazing 55-day refrigerated shelf life.

The first processor of its kind to utilize the oxygen scavenger technology, Foster Farms adopted the patented film in the fall of 2005, when it launched the new line of premium turkey in Honey, Oven Roasted and Mesquite Smoked varieties. "We have used the scavenger to enhance food safety and to control the level of oxygen throughout the shelf life of the product," confirms Norm Ramos, business manager at Foster Farms.

The product must be packaged under modified atmosphere conditions, points out Cryovac, because the reduced-oxygen levels achievable by the OS Films material are dependent upon a low residual oxygen concentration inside the package.

The inner film pouch incorporates a top web of OS2330, a 3-mil lidding film that contains the OS Film oxygen-scavenging polymer layer incorporated in the core layer. The multilayer, coextruded, barrier sealant film is adhesively laminated to a reverse-printed, oriented polyethylene terephthalate (OPET) film.

Through a patented process, the scavenger is activated on-demand, by allowing an ultraviolet-wavelength light to penetrate through the sealant side of the film and into the internal, oxygen-scavenging layer. This is performed with Cryovac's Series SIS4104 UV light-triggering system.

The top web is heat-sealed to a bottom or forming web of Cryovac's T7050BZ film. The forming web is described as a 5-mil, multilayer, coextruded, barrier film that's thermoformed into a pocket. This web also provides an easy-peel mechanism. Both the forming web and the top web include ethylene vinyl alcohol (EVOH) as the barrier layer.

At its Simpsonville, SC, plant, Cryovac converts the two film webs as rollstock that is later sent to Foster Farms' facility in Turlock, CA. There, the turkey is packed on a modified-atmosphere horizontal thermoform/fill/sealing system from Multivac (www.multivac.com), equipped with one of Cryovac's UV-light-triggering units. Positionable at the infeed or outfeed of a packaging line, the UV-triggering system operates using a set of 80 germicidal UVC wavelength lamps (UVC radiation can be found in artificial sources such as mercury arc lamps and germicidal lamps such as these) to shine the UV light through the film and into the special, internal, OS film layer, activating the oxygen scavenger.

As the top web of film unwinds from a spindle on the tf/f/s machinery's normal web path, it's diverted to the SIS4104 light-triggering unit, which activates the scavenger layer to start the oxygen-scavenging process. After triggering, the web is diverted back into the normal web path to be fed into the rest of machine's packaging stations.

The sliced turkey is then loaded into the film, the headspace of the pouch is gas-flushed with nitrogen or carbon dioxide, evacuating most of the oxygen in the package, and the activated OS film is sealed to the bottom section of the package. A tab on the formed pouch allows consumers to peel open the seal to access the turkey slices. The pouch can then be loaded into the outer tub. To ensure that the oxygen in the package is actually being removed, Foster Farms also installed a three-cell, off-line scavenger-verification system from Cryovac called the SVS system.

Only the top web of the package contains the oxygen scavenger, points out Tom Kennedy, business development manager for Cryovac's OS Systems. "There are several reasons for this. There is enough scavenging capacity in the top web to provide the desired benefits, and it was much easier to develop the triggering equipment for the top web. If the bottom web were to be triggered, significant modifications to the packaging [equipment on the] line would be required between the unwind station and the forming station."

The third leg of the process, verifying that oxygen scavenging is actually taking place, is accomplished by the SVS scavenging-verification unit. According to Kennedy, the "go/no-go" quality-assurance inspection instrument and test procedure works with a proprietary, pressure-sensitive inspection label that's applied to the food-contact (scavenging) side of the OS Film after it has been "triggered" by the SIS4104 UV unit. The labeled film is then inserted into the modular SVS test instrument, which automatically queries the labels every five to 10 min. Test results are usually provided in less than 30 min.

According to Cryovac, the system works with the help of an oxygen-sensitive substance applied to the adhesive side of the label. When the label is applied to an activated oxygen-scavenging film, the oxygen concentration around the substance begins to decrease. Once the oxygen concentration reaches a certain "low level," the SVS equipment can expose the substance to light, causing it to fluoresce. The lower the oxygen concentration around the substance, the brighter the fluorescence appears. The SVS unit can be expanded to incorporate up to 12 cells, which allows a single verification unit to serve up to four packaging lines.

Says Kennedy, "The scavenging-verification system is set up as a QA sampling program, performed periodically among many thousands of packages, usually several hours apart." A positive result from the SVS system reveals that the film has received an adequate amount of UV light to activate the film and indicates that the film composition is scavenging oxygen acceptably.

Integral with the film and invisible to the naked eye, the "unseen" oxygen scavenger offers an alternative to oxygen-scavenging sachets, labels and coatings without altering transparency of the film, a feature Ramos says Foster Farms really wanted. The processor conducted multiple shelf-life tests before taking the package to market. Says Ramos, "We looked at scavengers incorporated within labels, but preferred not having anything a consumer could view as a foreign object placed within a package. We liked the fact that the OS Film delays the oxidative deterioration of flavor and color, so we use the OS material to maintain the integrity of the product throughout its shelf life."

While Foster Farms is the first commercial packager to adopt the award-winning, OS polymer-based, oxygen-absorbent film for easy-open, refrigerated deli-meat packages, Cryovac has had successful applications with several other customers' food and nonfood products already on the market (see PD, Sept. '04, p. 24 and March '02, p. 32).

Kennedy says the oxygen-scavenging OS Films technology can be delivered and produced in various formats, such as a fully coextruded film as well as a laminated format. Developed as a family of these films, they're not limited to one format or to food products. "We've been working for several years to continually improve the oxygen-scavenging performance and its triggerability," he says.

Ramos explains that the packaging is meeting Foster Farms' goals. "Customers continue to battle markdowns, so we strive to partner with them by investing in ways to extend shelf life and still provide great-tasting products."

Reusable and resealable, the outer tub is topped with an opaque lid that's almost completely covered with a colorful label. Provided by Presto Products (www.prestoproducts.com), both the clear container and the lid are made of a polypropylene blend. The tub allows the turkey to show through the clear pouch, which is a key advantage, he adds. "The film clarity is important [so that consumers can see the product]. The response to the new product line has been quite positive."


More information is available:

Cryovac Div., Sealed Air Corp., 800/845-3456. www.sealedair.com.

Multivac, 816/891-0555. www.multivac.com.

Presto Products, 800/558-3525. www.prestoproducts.com.

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