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Plastics’ designs on dairy

October 1, 2006

5 Min Read
Plastics’ designs on dairy

A greater emphasis on children’s nutrition and the relative affinity and comfort younger populations have toward plastic containers are helping the transition of milk from glass and paper cartons gain momentum. This hasn’t been lost on machinery and material manufacturers serving the market, with interested players making a renewed push into the U.S. and other dairy markets.

According to a year-long test conducted by the U.S.’s National Dairy Council involving 100,000 students and 146 schools, milk consumption increased 19% on average when the dairy was packaged in plastic versus paper, with elementary schools seeing a 15% jump and secondary school posting a 22% increase.

Global fast-food giant McDonald’s took notice, offering regular and chocolate milk as an option on its children-oriented Happy Meals beginning in 2004. The single-serve plastic Milk Jug containers were chosen in part because the Dairy Council survey determined that children consume more milk when it’s in grab-and-go containers. Rival fast-food restaurant Burger King followed suit, starting to offer Hershey’s low-fat white and chocolate milk in resealable 8-oz plastic bottles on the menu as an option for kid’s meals.

Extrusion blowmolding machine manufacturer Bekum America (Williamston, MI), the North American branch of the Berlin, Germany firm, is looking to tap this potential market, which it says the Dairy Management Institute pegs at more than six billion containers/yr.

Bekum is promoting its BM 406D double-station fully-automated shuttle-blowmolding machine to produce milk bottles for such lunch programs, with the typical container having an 8-oz (236-ml) volume, weighing 10-12g, and featuring a 38-mm spin-trimmed neck. With a cycle time of 7.5 seconds for such a container, Bekum says its machines could produce 11,520 bottles/hr using a 24-cavity mold, for an annual production of more than 90 million bottles. Market studies indicate children prefer round containers, but square bottles could more seamlessly transition into the milk-crate shipping infrastructure already established for paper cartons now prevalent in school.

PET’s pitch

Stretch blowmolding machine manufacturer SIG Corpoplast (Berlin) is promoting its two-stage machinery for PET packaging of milk and flavored-milk products, with some commercial applications, including Nöm’s (Lower Austrian Regional Dairy Cooperative) Fasten wellness dairy product, whose PET bottles are made on a Blomax 10 and two Blomax 12 Series III machines. Nestlé’s Nescafé Xpress chilled coffee drink, which is available in five flavors and now sold in 250-ml PET bottles instead of the aluminum cans it was launched in, uses SIG’s aseptic Asbofill technology, with a filler installed at Nestlé Germany in Biessenhofen. Milchwerke Mittelege (Stendal, Germany) also uses an ABF 710 SIG Asbofill line for milk drinks that are ultrahigh-temperature (UHT) treated for a seven-month shelf life without refrigeration.

Transparent PET can be used for milk in the so-called cold chain, which usually only has a shelf life of 10 days and doesn’t require UV light protection. UHT, which involves the partial sterilization of food by heating it for 1-2 seconds at temperatures above 135°C (275°F), gives milk a shelf life of six to nine months and has seen wide acceptance in Europe. UHT has had less penetration in the U.S., where refrigerated shipping and storage obviate the need for ambient storage and the wider populace is generally uneasy about consuming perishable goods that are sold without refrigeration.

Strong light barriers are needed for UHT, since after only 12 hours in the fluorescent light of a supermarket, milk can lose half of its riboflavin and its proteins can experience a chemical reaction that leaves a metallic aftertaste.

For a PET container, sleeves would have to cover the bottle or white titanium-dioxide-based masterbatches would be added directly to the virgin PET. SIG applies Asbofill aseptic-filling technology for the UHT process, which can be equipped with a capper or aluminum-foil sealing unit with a 12,000 bottles/hr capacity. Hydrogen dioxide vapor is used for sterilization, with only the bottle’s neck entering the sterilization chamber.

Dairy friendly

Uniloy Milacron (Tecumseh, MI) displayed a reciprocating-screw extrusion-blowmolding line at NPE, making three-layer HDPE milk containers that featured an integrated UV barrier layer for extended shelf-life milk: a market that could be bigger outside the U.S., where refrigeration isn’t as prevalent. Currently 20% of its machinery sales go into the food and beverage market, and traditionally dairy has been a good market for Uniloy. But according to Uniloy’s VP and general manager, Dave Skala, the narrow consumption window for milk, especially compared to water and juices that have become nearly ubiquitous thanks to PET bottles, has limited its growth. Skala points out that the vast majority of milk is consumed within feet of a home refrigerator, and only seconds after it’s been removed. It is not consumed in cars, on the go, or elsewhere. “Do you order milk at a restaurant?” Skala asks rhetorically.

But now, milk drinks, or other dairy products like drinkable yogurts, are making headway in the U.S., especially through aforementioned school-lunch programs. Uniloy, which began selling reciprocating-screw machines in the 1950s and has 3800 in the field, believes the relatively simple operation of the units could make them friendlier to the emerging market compared to shuttle or rotary-style lines. Since most of the new machinery is being bought by dairies that only dealt with tetrapak cartons and have no plastics background, simplicity will be key.

Polyolefin’s push

For its part, polyolefin supplier Sabic is understandably betting on an extrusion-blowmolded HDPE solution for the milk market. The company says the European market, for one, is still dominated by cartons, but even in 2001, HDPE bottles held an 18% market share that was growing for a sector that consumed 30 million liters of milk. In the UK, which is Europe’s biggest market for pasteurized milk, HDPE bottles have an 80% share, with glass still used for doorstep delivery.

On the continent, cartons, and UHT-processed milk, versus sterilized products, which must be refrigerated, dominate. Although HDPE tailored for UHT is making inroads, according to Sabic, most private-label milk still uses cartons, while HDPE is gaining traction among most branded milks.

Tony Deligio | [email protected]

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