Military Explores New Processes, Packaging for Combat Rations
By Donna Miles
American Forces Press Service
NATICK, Mass., Sep. 28, 2012 When a warfighter bites into a combat ration, Lauren Oleksyk wants it to taste as good as if it had been cooked up that morning at a local bistro -- even if it’s been stored for years, transported thousands of miles in sweltering or bone-chilling temperatures and airdropped by parachute from 100 feet overhead.
Lauren Oleksyk at the Natick Soldier Research, Development and Engineering Center's Combat Feeding Directorate, is working to revolutionize what warfighters eat on the battlefield. U.S. Army photo by Bob Reinert
(Click photo for screen-resolution image);high-resolution image available.
“Our mission is to provide warfighters with near-fresh, high-quality, shelf-stable rations,” said Oleksyk, team leader for food processing, engineering and technology at the Soldier Research, Development and Engineering Center here.
“What we are really going for is that, even if they get something that may be three years old, for them to feel like it was made yesterday, or even that same day,” she said.
In the quest to produce “fresh-like” combat rations and broaden the array of foods they can deliver, Oleksyk and her team are working with their industry and academic partners to push the envelope in food processing and packaging.
Meals, Ready to Eat, the individual combat ration that’s the centerpiece of the combat feeding program, are processed using retort thermosterilization, The process is similar to canning, Oleksyk explained, with items cooked at high temperatures and under pressure for as long as three hours to kill any bacteria.
“You get the sterilization that you need,” she said. “But because it involves cooking a product for a long period of time, it can be detrimental to the product itself.” Foods typically become stew-like, with mushy textures, bland colors and little flavor after extended cooking. The nutritional value drops, too.
That led Natick engineers to explore new processing methods that commercial food service companies are emulating.
One of the most promising technologies the Natick center pioneered is microwave-assisted thermal sterilization. The process uses giant commercial microwaves that kill bacteria within just eight minutes and heats packaged foods uniformly in a way that traditional microwaves don’t.
The result is higher-quality products, Oleksyk said, with firmer textures, more natural colors and fresher-tasting flavors. It’s also expanding the possibilities in terms of what foods can be included in combat rations.
Pasta, for example, tends to get mushy and lumpy using the retort method. The protein in fish and seafood breaks down, giving entrees a soft texture and an unpleasant “fishy” flavor and odor. Eggs take on a greenish cast. Fruits and vegetables become the consistency of baby food.
But a new developmental dish Oleksyk and her colleagues are advancing, Cajun chicken pasta, shows the difference microwave sterilization makes. When presented side-by-side with the same recipe processed using the retort method, the microwaved entree features al dente noodles, juicy chicken pieces and a just-cooked consistency and flavor.
“When you taste the microwave sterilized chicken, you really wouldn’t know that it was processed two years ago,” Oleksyk said. “You would think it was just prepared. And that is the goal.”
A salmon-in-alfredo-sauce MRE under development using microwave sterilization delivers a firm texture and fresh-caught taste. “It’s a very high-quality product, but also shelf-stable for three years,” said Jeremy Whitsitt, technology integration analyst for the center’s Department of Defense combat feeding directorate.
But the Natick team isn’t putting all its proverbial eggs in one basket. They’re working with industry and academia to advance a process using high pressure rather than intense heat to sterilize combat rations. “We’re not quite as far along with this as microwave sterilization, and we haven’t yet achieved the pressures necessary for full sterilization,” said Oleksyk. “But we are at the point where we are getting pasteurization using pressure, and pursing this [technology].”
A Natick research program still in its infancy is using supercritical carbon dioxide -- essentially, carbon dioxide that’s been heated and pressurized so it’s somewhere between a gas and a liquid -- to sterilize foods.
The commercial food industry uses this process to extract caffeine from coffee. But what Oleksyk found particularly interesting was learning that the medical field uses supercritical carbon dioxide to sterilize bone fragments, tendons and other tissue samples for transplant surgeries.
“When we found out it was being used for that, we said, ‘Why not look at it to see if it can sterilize foods?’” she said.
The Natick center partnered with a company that uses the process for medical sterilization to see if that’s feasible. “The program is still in the early stages of the research and development, but it is very promising,” Oleksyk said.
Osmotic drying is another new process being explored. This involves grinding up meat or vegetables, using a conveyor to roll them into a sheet, then running them through an osmotic tank that removes the moisture. The product remains in its raw form until the end, when it can be put into a smoker or otherwise cooked.
The result, unlike beef jerky in a combat ration that gets hard and brittle over time, is closer to the sliced deli meats one might find at the local supermarket.
“We are thinking of all kinds of applications for this product,” Oleksyk said. One is a “combat sandwich” of osmotic-dried meat, and shelf-stable cheese and -bread. Another is osmotic-dried pepperoni that could be used on a shelf-stable pizza.
Working with a large commercial meat producer in South Carolina, the team plans to prototype “all kinds of products” using this technology within the next fiscal year, Oleksyk reported.
While researching novel ways to process combat rations, the staff continues to investigate better packaging methods that will stand up to combat rigors and shelf-life requirements.
One program is looking into a variety of ways to keep combat rations sterile: controlling the amount of moisture in them, increasing their acidity and adding nisin, a proven antimicrobial compound. Another project involves injecting oxygen scavengers into food packages to reduce spoilage and extend shelf life. That process, Oleksyk said, could enable packaged bread to last in an MRE for as long as three years.
Oleksyk said she and her team are driven to provide warfighters the tastes of home, no matter where they may be deployed.
“We want them to have the kinds of foods they want, with the best quality possible,” Oleksyk said. “That’s the inspiration behind everything we do here.”