CHICAGO — Achieving a nine-month shelf life for tortillas or nutrition bars may sound difficult, but the task may fail to compare to the long-term goal facing Vickie Kloeris. Try reaching a five-year shelf life for food items designed for a mission to Mars. The items also need to have a certain amount of nutrients and low levels of sodium.

Ms. Kloeris spoke about her work with food destined for outer space at the American Society of Baking’s BakingTech 2014 on March 4 in Chicago. She holds a master’s degree in food science from Texas A&M University in College Station, Texas, and serves as manager for the international space station food system.

A trip to Mars might require 12,000 kilograms (26,455 lbs) of food for a total of six crew members. Ms. Kloeris said all the food would need to be shelf stable because no refrigerators or freezers would be allowed on the mission. They would use too much energy.

All beverages in the space program are in powdered form in packages. An adaptor, which has a straw sticking out of it at the top of the package, allows crew members to inject water into the package. Re-hydrated foods, too, require the addition of water before consumption. Tortillas with reduced water activity may have a shelf life of up to a year.

The space program has formulated thermo-stabilized food products. Some might last five years, but they would degrade over time and lose nutrients. Seven of the space program’s 65 thermo-stabilized food products are expected to still be palatable after five years, Ms. Kloeris said.

The space program for years has used meals-ready-to-eat (M.R.E.s) that are similar to those found in the military. The space program likes to formulate its own M.R.E.s because the M.R.E.s in the military have high levels of fat and sodium.

“The military is feeding a much younger crowd,” Ms. Kloeris said. “Their general customer is 18- to 21-year-olds.”

Astronauts, who tend to be in their 40s or even their 50s, do not need the extra fat and high sodium content, she said. The space program has achieved about a 40% reduction in daily sodium intake, bringing per-capita intake down to 3,000 mg.

“The advantage we have over the food industry is we’re producing in very small quantities,” Ms. Kloeris said. “We can reformulate our products and use more expensive ingredients like higher-priced herbs, spices and enzymes to offset the reduction in sodium.”

Further sodium reduction will be difficult, she said. The lack of refrigeration and freezing means crew members will eat almost no fresh fruit, which has little to no sodium.