WHEN Soldiers open up pocket sandwiches in Afghanistan, they probably care a lot less about how they were developed than how they taste and whether they curb hunger.That's fine with the people at the Department of Defense Combat Feeding Directorate at Natick Soldier Systems Center in Massachusetts, which develops rations for all the services. They're much more interested in giving those Soldiers the fuel they need to accomplish the mission than in getting credit for the sandwiches. But they would tell them that other Soldiers were heavily involved in the process."We go out in the field on an annual basis with prototype food items and with existing ration items to make sure that what we're producing is what Soldiers are looking for," said Evan Bick of DOD CFD outreach and education. "We are constantly working on ways to incorporate that warfighter feedback and bring it into our product-development process."The pocket sandwiches, which can be eaten without preparation either individually or as part of a meal, are known for their ability to last and stay flavorful. These clearly aren't your father's combat rations. State-of-the-art science and packaging have made them more appealing and nutritious for today's Soldier."(Soldiers have) been asking for sandwiches for a long time," said Julie Smith, senior food technologist with the Combat Rations Team. "Trying to come up with that technology to be able to provide the sandwich to the warfighter is the difficult part."The CFD, which originated in the 1920s as the Quartermaster Subsistence School, has overseen major changes in individual rations since the days of beef, beans, rice and bread during the American Revolution. One of the biggest changes is increased input from warfighters.By the time a ration reaches a Soldier in the field, his or her peers have provided plenty of input about CFD products, including the "shelf-stable" pocket sandwiches. They were developed at Natick as part of the "First Strike Ration," a day's worth of food for highly mobile troops that weighs 50 percent less than three "Meals, Ready to Eat." Five different pocket sandwich varieties are already available."We're trying to move with the trends of the commercial industry," Smith said. "So we're always looking for new varieties. Nutrition is a key part. The sandwiches are planned into the menu, and we have to meet the nutrition standards for operational rations."That requires a lot of hard work behind the scenes. First, food scientists turn ration concepts into products. Next, a food item must be effectively packaged before becoming part of a ration. The sandwiches, like all food items, are then tested in the lab and field-tested by Soldiers."With every project that we do, we always try to get as much Soldier input as we can," said Bob Trottier, Combat Rations Team leader. "The feedback we have gotten is that those sandwiches, in particular, are good. Whenever we go out and do demonstrations and samplings of those sandwiches, it's always positive acceptance, because they're really good quality."After rations pass muster with Soldiers, they go back to the lab for further testing, nutritional analysis, approval and fielding. Obviously, the process is time consuming. "When we say warfighter recommended, warfighter tested, warfighter approved, we mean it," said Gerry Darsch, CFD director. "We're responsible for fueling the DOD's most important weapon, and we take that very seriously."When you invite several million people to breakfast, lunch and dinner, three times a day…it's going to be tough. Think about having just your immediate family over for dinner or for a holiday. Are you going to please everybody sitting around that table equally?"The pocket sandwich was based on a commercially available, microwavable pocket sandwich and became the centerpiece of the First Strike Ration, which must be able to withstand at least 80 degrees Fahrenheit for two years or 100 degrees for six months. Currently, there are three FSR menus centered around the various pocket sandwiches with six more expected this year."The FSR is approved for consumption up to 10 days," said Smith, "whereas the MREs…can be consumed for up to 21 days with no nutritional deficit."The early pocket sandwiches tended to be tomato-based. According to Smith, the acidity helped extend their shelf life. "Now, as time goes on, you're starting to see the change in what people prefer," Smith said. "Now we're moving to something that's not tomato based."By design, the sandwiches each provide only about 300 to 500 of the 2,900 calories in the FSR. "We try to plan it so they have a lot of components, rather than one item providing most of the energy," Smith said. "If they're walking around, they're not going to eat 800 calories during one patrol."The pocket sandwiches use what is called "hurdle technology," techniques or stress factors that inhibit the growth of microorganisms and promote stability. "It is this control of the microorganisms that preserves and stabilizes the rations," said Lauren Oleksyk of the CFD Food Processing, Engineering and Technology Team. "The hurdles we use may include a combination of ingredients that control a food's pH, water activity or moisture content; the addition of anti-microbial compounds; the addition of oxygen scavengers to control headspace gas in the package; or even the package itself."But as Oleksyk knows, flavor can't take a backseat to shelf stability. "If it doesn't pass our quality sensory test's flavor and texture acceptance, it will not be included in any ration platform," she said. "The addition of the hurdles also gives us more leeway to adjust the other ingredients in the sandwich to improve flavor and texture."That familiar, flexible packaging used for MREs aids that stability. Without it, the pocket sandwich wouldn't be edible for long. "We're protecting against oxygen, moisture and light," said Peter Sherman of the Packaging Integration Team. "It's a level of protection. If the food was sitting here on the table on a plate, it's only going to be good until the microbes start working."Joanna Graham, team leader for the Packaging Integration Team, said she thinks that the general public sometimes underestimates packaging. "The goal is to supply safe, nutritious food to the warfighter, but so much of what is now available in the field is made possible because of the flexible packaging," Graham said. "The historical transition from cans to flexible packaging changed the way our Soldiers eat and the food products that we are now able to supply, such as shelf-stable pocket sandwiches."Packaging is one of those things that is critical to getting the food from point A to point B."Trottier said CFD is always looking for new pocket sandwich flavors and types. "There's also some new breakfast ones potentially coming down the road, as well, which we will be looking at," he added.Dr. Scott Montain works for an organization at Natick that doesn't develop food--the U.S. Army Research Institute of Environmental Medicine--but he and his colleagues at USARIEM had critical input into the success of the pocket sandwich. They researched what should go into the sandwich and evaluated what Soldiers thought about the finished product."Our role was really…what would you put in a pocket sandwich…in terms of macro nutrients and micro nutrients?" said Montain, a research physiologist. "Do people like it? What flavors do they like? Is the size right? Is the weight right?"Then it was a matter of measuring how the ration affected performance. "We've played a role in seeing if the (FSR) itself produces the performance effects that one would have anticipated it would," Montain said. "There was a requirement to show that it performed better than the MRE. We led a set of studies for Combat Feeding, where we did those type of tests."They had wildland firefighters test the FSR. "They're not that different from infantry Soldiers in the sense that they do long days of physical activity," Montain said. "They would work about a half-hour more a day and rest about a half-hour less a day on a given work shift if they were consuming the First Strike Ration (rather) than the MRE. They self-selected to do more work."The portability of the rations made snacking convenient and kept energy levels high throughout a long workday. "If you feel like you need something to eat, you can get it pretty easily," Montain said. "All the components are ready to eat, making it easier to keep up with your caloric needs as you go."According to Montain, the ration's success revolved around the pocket sandwich. "The sandwich is the main component," Montain said. "The ability to start making sandwiches like this has probably led to the success, I would say, of the whole First Strike Ration concept. The pocket gives (Soldiers) the sense of, this is real food. It's not just snacking."Expect pocket sandwiches with Mexican, Asian and vegetarian ingredients in the near future. What else is on the horizon? Well, nothing says home quite like an old-fashioned peanut-butter-and-jelly sandwich. Smith wants to give Soldiers exactly that, but it's a lot tougher than you might think. Over time, the bread would absorb moisture from the jelly and fat from the peanut butter."It doesn't make a high-quality sandwich," Smith said. "We're still working on that. Who wants a soggy sandwich?" As Smith pointed out, Soldiers now can get peanut butter and jelly in separate pouches. "But then they have to make it," Smith said. "They like that eat-on-the-move capability."No matter what they produce next, the CFD professionals always have one goal in mind. "Basically, it all comes down to how we can support warfighters who are going to be operating in environments that are unpredictable," said Bick, "environments that are going to be very austere, and still provide them some little bit of comfort during that day."