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Processing & Services: Extending shelf life

Processors turn to packaging to reduce shrink, add convenience to RTC seafood meals

By Lauren Kramer
December 01, 2007

Consumer demand for convenient meal solutions has increased the need for packaged foods that provide an easy-to-cook meal. Retailers and manufacturers are turning to eye-catching packaging to sell ready-to-cook seafood products as well as to extend 
the product's shelf life and reduce shrink.

A decade ago, modified atmosphere packaging (MAP) was touted as the packaging technique of the future for the seafood industry. The system involves replacing air in a package with a mixture of different gases in order to regulate microbial activity and reduce the product's deterioration. But today there still are only a handful of seafood processors using this packaging method.

That's because of the Food and Drug Administration's stringent regulations, says Barbara Blackistone, director of scientific affairs at the National Fisheries Institute. Should processors use MAP, controls such as breathable film and time temperature indicators (TTIs) must be used to avoid the potential outgrowth of Clostridium botulinum - botulism.

"The industry has not chosen to employ these controls to much extent, so MAP has not been a popular method for packaging seafood," she says. "Some say TTIs are unpopular with consumers because the color change is hard to interpret."

The cost of TTIs could be another reason for avoidance of MAP packaging in the sea-
food industry, says Brian Fortune, president of Atlantic Aqua Farms in Prince Edward Island, Canada.

Sealed Air's Cryovac Food Packaging is one company offering two MAP programs for seafood. The BDF 2060 film is a shrink film alternative that creates an oxygen barrier and is a resistant to punctures, tears and abrasions.

"The atmosphere of 70 percent nitrogen and 30 percent carbon dioxide will result in a quality life of the product for most species of 10 to 12 days," says Jim Belcher, director of case-ready marketing for the company. "But this is always contingent on the age and quality of the fish when packaged, and the temperature of the product during distribution and display."

The major advantage of BDF 2060 film is its ability to run multiple tray sizes with minimal change-over time on the processing line and still achieve a product that looks similar to an in-store overwrap, Belcher says.

Cryovac's lidstock and barrier tray package, together with gas flushing, is the second MAP option. The system creates a low-oxygen atmosphere with an oxygen-barrier layer to maintain the gas mixture, combined with two internal abuse layers for additional protection. The lidstock hermetically seals to the pre-formed barrier foam tray during the packaging process.

"This style is easy to run and the equipment costs can be less for the small processor, though changing tray sizes is a little more difficult," Belcher says. 
In addition, processors can choose from a large selection of barrier trays.

Both systems require TTI labels that inform retailers if the product has encountered fluctuations in temperature during transport or display. When activated, the TTI sensors change color from yellow to pink depending on the product's temperature exposure.

While the TTI labels meet Food and Drug Administration guidelines for MAP packaging of fresh seafood products, they can be an expensive addition to the packaging process. "We don't have a lot of customers using this, perhaps a dozen or so," admits Belcher.

Without the TTI labels, a machine that enables MAP can cost $35,000 for 10 packages per minute, and up to $250,000 for high-end equipment. "How long it extends the shelf life really depends, but if everything is done right and the temperature is controlled, you'd get between 10 and 12 days of life," he says.

Meanwhile, in a small corner of Canada, Atlantic Aqua Farms received a patent in August 
for a MAP system designed to keep shellfish fresh for between 14 and 21 days. The company has been working on the system for eight years, and while 
it is not the first MAP system 
for shellfish, "it is the best," insists Fortune.

"The other MAP system came out of Europe for European mussels, boosting its shelf life from five to nine days," he says. "By contrast, our mussels have a 10-to-14-day shelf life and I can get up to 21 days with our MAP."

The advantage of Fortune's system is its leak-proof container, allowing customers to throw a tray pack of mussels in a cart with dry food at a grocery store. In addition, the MAP mussels can be stored at a normal refrigerated temperature.

To date, Atlantic Aqua Farms' MAP system has been endorsed by the Canadian Food Inspection Agency and the Canadian government.

"Right now we're doing a study on microbiological challenge, to prove to the FDA that the packaging is safe for use in the United States," Fortune says. "The successful outcome of the challenge will allow us to ship the MAP products into the United States, which I can do right now, but only using a time-temperature indicator, which is expensive and unreliable for case-ready shellfish."

The FDA makes it difficult for processors to use MAP, concedes Todd Walters, packaging specialist for Koch Packaging Systems in Kansas City, Mo.

"It's a circus where you have to jump through hoops because there are so many restrictions," says Walters. "The FDA monitors the situation closely and as a result, you don't see many processors using this system 
for seafood."

Koch offers a variety of tray-sealing and vacuum chamber machines that aim to remove the ambient atmosphere from the package. The company's UltraVac 2100 Dual Chamber Machine is its most popular, a machine that works best when combined with Sealed Air's10K OTR bags, says Walters.

"Cryovac's product helps protect against cross contamination and this system as a whole helps protect the seafood product from freezer burn," he explains.

The bags have a guaranteed oxygen transmission rate (OTR) of greater than 10,000 cc per square millimeter per 24 hours. They don't need a TTI label, because they meet the FDA's OTR requirements for fresh seafood. Providing a skin-tight, oxygen-permeable barrier to preserve freshness, the 10K OTR bags allow the product to be quickly chilled after packaging with an ice brine solution, 
allowing processors to ship product at the lowest possible fresh temperature and with a reduced amount of ice. That, in turn, reduces the package weight and the overall cost of shipping.

The UltraVac 2100 starts at $11,795 and increases in price depending on the additional features added. For example, it can be equipped with sealing features, horsepower pump variations from five to 12 and a digital control panel.

In November 2006, as Wal-Mart was expanding its green packaging requirements, CPT Plastics in Edgerton, Wis., was unveiling its Go Green tray, a polypropylene tray produced with 30 percent less energy 
and waste.

"For fresh seafood, we use that in conjunction with a lidding film that has an oxygen transmission rate of 250,000 cc/m2/24 hours," says Jeff Madrzak, CPT's national accounts manager.

"It goes on the tray, allowing the package to breath and permitting the equal release and cycling of oxygen in the package, to create a fresh package with an extended shelf life of up to eight days," he explains. Essentially, the package brings fresh oxygen inside and releases the excess carbon dioxide that, if not monitored or released, will result in the product souring or in bacterial growth.

CPT has approximately 10 seafood customers using the system to date, and it works out to be a cost-effective alternative to MAP, says Madrzak.

"It takes a lot to put a MAP program together and is expensive with TTI stickers. By contrast, if you use a breathable film with the correct oxygen transmission rate and carbon dioxide balance, you don't need to use TTI stickers," says Madrzak.

For processors who already have lidding equipment, the film installation process is as easy as fitting the equipment to CPTs tray and film. Obtaining lidding equipment is an expense that varies according to how many trays per minute 
are required.

"You can get a machine that will do 10 trays per minute for about $12,000, and for 30 trays per minute it goes up to $70,000, depending on the machine," says Madrzak.

The cost of the film works out to between 30 and 35 cents per package, depending on volume, with the roll calculated to the individual package size. "Our packaging creates a true, extended shelf life," he insists.

"How long it lasts depends on the seafood inside, because some out-gas quicker than others. But we work with each customer to ensure they are maintaining the right packaging environment for their particular product."

Seafood processors know all too well that extending a product's shelf life has to be done safely. With the clock ticking the moment seafood is harvested, it is essential that the steps processors take along the way collaborate toward achieving a fresh, tasty, safe product for 
the consumer.


Contributing Editor Lauren Kramer lives in British Columbia


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