Kerala Agricultural University
POST HARVEST TECHNOLOGY AND AGRICULTURAL PROCESSING
KELAPPAJI COLLEGE OF AGRICULTURAL ENGINEERING AND
A Seminar report on
SPACE FOOD TECHNOLOGY
COURSE TEACHER: Mrs: SREEJA.R
PRESENTED BY: AJNA ALAVUDEEN
First of all I bow my head before “THE ALMIGHTY” for the blessings showered
on me to successfully complete the endeavour. It is with great respect and devotion I place on
record my deep sense of gratitude and indebtedness to my seminar.
I place a deep sense of obligation to Mrs.Sreeja R., Asst.Prof. Department of
PHT&AP, for the help and cooperation received from him during the entire seminar.
I also express my sincere gratitude to Dr.Prince M.V., Asst.Prof. Department of
PHT&AP for providing relevant data on the topic.
Finally, I must acknowledge the great moral support I received from my friends in
getting the references and materials required for my seminar.
Space food history................................................................................................6
On ward to mars (present)....................................................................................9
Functional foods for space..................................................................................11
Types of food......................................................................................................13
Application of food technology in space............................................................18
Packaging evolution and resource utilization.....................................................22
Space food system laboratory.............................................................................25
Space food safety................................................................................................26
Space food for future..........................................................................................27
Case study: 1.......................................................................................................28
Case study: 2.......................................................................................................42
Many people may wonder about what and how the astronauts eat aboard
the space shuttle and the space station. The foods they eat are not provided in tubes and they
are neither bland nor unsavoury. Food systems and menu items evolved tremendously since
the days of the mercury programme. Food technology spin offs benefit dining rooms
throughout the world. It is estimated that a food system for a long duration mission must
maintain organoleptic acceptability, nutritional efficacy, and safety for a 3 to 5 year period to
be viable. In addition, the current mass and subsequent waste of the food system must
decrease significantly to accord with the allowable volume and payload limits of the
proposed future space vehicles. Advancements in food packaging, preservation, preparation
and nutrient to meet the challenges of space resulted in many commercial products. Here’s a
look at the era of food systems, nutrition foods used, menu items selection, packaging, safety,
how, what, limitations and advancements in the field of space food technology.
Space food is a variety of food products, specially created and processed for
consumption by astronauts in outer space. The food has specific requirements of providing
balanced nutrition for individuals working in space, while being easy and safe to store,
prepare and consume in the machinery-filled low gravity environments of manned spacecraft.
In recent years, space food has been used by various nations engaging on space programs as a
way to share and show off their cultural identity and facilitate intercultural communication.
While starting a mission, there are many factors being considered, one such very important
thing is about their FOOD. Dining in space takes culinary art to new heights in orbit and on
Earth. With the zest of space technology, astronauts today are able to take in a variety of
tastes and textures that please their palates and satisfy their stomachs while orbiting hundreds
of miles from home.
Food needs to be edible throughout the voyage, and it also needs to provide
all the nutrients required to avoid vitamin deficiency diseases. But many of the current space
menu items do not maintain acceptability and nutritive value beyond 3 years. Longer space
missions require that the food system can sustain the crew for 3 to 5 years without
replenishment. However, space travel requires that new methods be devised for keeping
foods edible. For that, a number of technologies are adopted both for processing as well as
packaging, while these forms of food products are fine for travel for the mission. Moreover,
foods taken into space must be light-weight, compact, tasty and nutritious. They must also
keep for long periods without refrigeration. A variety of menus consisting of foods similar to
those displayed here provided each astronaut with 2500 or more calories per day. There are
many limitations to weight and volume when travelling and the microgravity conditions
experienced in space also affect the food packaging. Currently, there is limited storage space
and no refrigeration. To meet these challenges, special procedures for the preparation,
packaging, storing of food for space flight were developed. Moreover for each space
programmes like mercury, Gemini, Apollo, Skylab, space shuttle and international space
station (ISS) respectively have used different fooding system .So a lot of improvements had
experienced from processing as well as packaging from mercury to ISS .
SPACE FOOD HISTORY
The food that NASA’s early astronauts had to eat in space is a testament to
their fortitude. John Glenn, America’s first man to eat anything in the near-weightless
environment of Earth orbit, found the task of eating fairly easy, but the menu limited.
1. Mercury :-( 1962-1964)
Mercury was the United States’ first space program that sent humans to space.
Astronauts in later Mercury missions disliked the food that was provided. They ate bite-sized
cubes, freeze-dried powders, and tubes of semi liquids. The astronauts found it unappetizing,
experienced difficulties in rehydrating the freeze-dried foods, and did not like having to
squeeze tubes or collect crumbs.here the flavour was unchanged,but the texture was
significantly different from the original product.
2. GEMINI :-( 1965-1967)
Project Gemini, was created to bring NASA one step closer to going to the moon.
Gemini missions eating improved somewhat. Bite-sized cubes were coated with gelatine to
reduce crumbling, and the freeze-dried foods were encased in a special plastic container to
make reconstituting easier. With improved packaging came improved food quality and
menus. Gemini astronauts had such food choices as shrimp cocktail, chicken and vegetables,
butterscotch pudding, and apple sauce, and were able to select meal combinations
3. APOLLO :-( 1968-1975)
For the Apollo program -- the first to land men on the moon -- NASA provided its
astronauts with hot water, which made rehydrating foods easier. The Apollo astronauts were
also the first to have utensils and no longer had to squeeze food into their mouths. The
mission introduced the spoon, a plastic container with dehydrated food inside. After the
astronauts injected water into the bowl to rehydrate the food, they opened a zipper and ate the
food with a spoon. The wetness of the food made it cling to the spoon instead of floating
away. The Apollo mission also introduced thermo stabilized pouches called wet packs. These
flexible plastic or aluminium foil pouches kept food moist enough so that it didn't have to be
rehydrated. The Apollo crew was able to dine on bacon squares, cornflakes, beef sandwiches,
chocolate pudding and tuna salad.
4. SKYLAB :- (1973-197)
The goals of the Skylab program were to prove that humans could live in space
for long periods of time, and to perform scientific experiments. Skylab had one of the best
space food systems. Larger living areas on the Skylab space station allowed for an on-board
refrigerator and freezer, which allowed perishable and frozen items to be stored. Food
containers for the Skylab astronauts consisted of aluminium cans with full panel pull-out lids.
Cans containing thermo stabilized food had a build-in membrane to prevent spillage when
removing the lid in can and had a water valve for rehydration. Canned, ready-to-eat foods
were held in the can with a slit plastic cover. Instead of plastic drinking bags, Skylab drinking
containers were collapsible bottles that expanded accordian style when filled with hot or cold
water. Because of its relatively large storage space, Skylab was able to feature an extensive
menu of 72 different food items. Unique to Skylab were a freezer for foods such as filet
mignon and vanilla ice cream and a refrigerator for chilling fruits and beverages. To prepare
meals, the Skylab crew placed desired food packages into the food warmer tray. This was the
first device capable of heating foods (by means of conduction) during space flight. Foods
consisted of products such as ham, chilli, mashed potatoes, ice cream, steak and asparagus
5. Apollo-Soyuz docking mission
The Apollo spacecraft did not have the freezer that Skylab featured but many of the
food advances from Skylab and the earlier Apollo missions were incorporated. Because of the
short duration of the flight (nine days), many short shelf-life items were added to the foods
carried. Fresh breads and cheese were included as a part of 80 different varieties of food
dined upon by the Apollo while others were placed in spoon-bowl packages or plastic
drinking bags. To make eating easier, a food tray was carried on the mission. The tray did not
warm the food as the Skylab tray did, but it held the food in place with springs and Velcro
fasteners. The tray was secured to the crewmember's leg during meal time.
6. SPACE SHUTTLE :-( 1982)
Here, meals looked almost identical to what astronauts ate on Earth. Astronauts
designed their own seven day menus selected from 74 different foods and 20 drinks. They
prepared their meals in a galley with a water dispenser and an oven. Irradiated foods joined
the major categories of consumables, primarily to make meats safer, as they had to be stored
at lower-than-refrigerated temperatures.
7. INTERNATIONAL SPACE STATION (ISS) :-( 1998)
The International Space Station (ISS) is a giant environment for living. Most
consumables on the international space are canned, frozen or wrapped in sealed packs. The
fuel cells, which provide electrical power for the Space Shuttle, produce water as a by-
product, which is then used for food preparation and drinking. However, on the ISS, the
electrical power will be produced by solar arrays. This power system does not produce water,
water will be recycled from a variety of sources, but that will not be enough for use in the
food system. Therefore, most of the food planned for the ISS will be frozen, refrigerated, or
thermostabilized (heat processed, canned, and stored at room temperature) and will not
require the addition of water before consumption An adapter located on the packagewill
connect with the galley, or kitchen area, so that water may be dispensed into the package.
This water will mix with the drink powder already in the package. The adapter used to add
water also holds the drinking straw for the astronauts. The food package is made from a
microwaveable material. The top of the package is cut off with a pair of scissors, and the
contents are eaten with a fork or spoon. Spicy food turns to be favourite. Thus, richly
flavourful items like shrimp with tangy sauce, or jambalaya with garlic beans are preferred
the longer astronauts are in orbit.
ONWARDS TO MARS - PRESENT
Menus are designed to fulfil the nutritional requirements of crews in terms of
days, weeks or months at a time on the ISS. Of course, the Space Station is quite close to
Earth, and re-supply vehicles are comparatively easier to come by than they would be on a
mission to Mars, which might last 2-3 years. The new goal will be to create foodstuffs that
last far longer than the 12-24 month shelf-life they have now, but can they still make them
light, edible, transportable, safe and nutritious? We all know that science improved a lot, and
we can definitely say that science has its influence in almost all fields of human activities.
Here the question arrives, can’t plants grow on the surface of mars? It is impossible, why
because the average surface temperature of mars is -60˚F.But their application of science
technology arrives, i.e.; the crop will be either grown hydroponically or airoponically.
a) HYDROPONICS SYSTEM
HYDROPONICS is a subset of hydro culture and is a method of growing plants
using mineral nutrient solutions, in water, without soil. Scientists are trying to find a way to
adequately feed them. As we haven’t yet found soil that can support life in space, and the
logistics of transporting soil are impractical, hydroponics could hold the key to the future of
space exploration. The benefits of hydroponics in space are two-fold: It offers the potential
for a larger variety of food, and it provides a biological aspect, called a bio regenerative life
support system. This simply means that as the plants grow, they will absorb carbon dioxide
and stale air and provide renewed oxygen through the plant's natural growing process. This is
important for long-range habitation of both the space stations and other planets.
b) AEROPONIC SYSTEM
AEROPONICS systems, which utilize a high-pressure pump to spray
nutrients and water onto the roots of a plant, may be an essential part of space missions in the
future. Aeroponic growing systems provide clean, efficient, and rapid food production. Crops
can be planted and harvested year round without interruption, and without contamination
from soil or pesticide use. Plants grown in aeroponic systems have also been shown to take in
more vitamins and minerals, making the plants healthier and potentially more nutritious.
These ‘space gardens’ could provide up to half of the required calories for the astronauts
though tomatoes, potatoes, and other fruits and vegetables. It can also help to recycle
nutrients, provide drinking water and create oxygen in space.
Food provides the nutrients that human beings need to maintain their
health. Getting enough calories, vitamins and minerals is as important for astronauts as it is
for people living on Earth. The space food systems supply a more limited variety of items
than one would find in the grocery store here on Earth, so menu planning is very important to
make sure the astronauts can get the nutrients they need from their food. The nutrients
astronauts need in space are the same ones all people need, but the amounts of some differ.
Astronauts need the same number of calories of energy during spaceflight as they need on the
ground. Most of the vitamins and minerals they need are the same as on the ground. The
amount of iron in an astronaut’s diet should be less than10 milligrams per day for both men
and women. Most of the ion absorbed from food goes into new red blood cells. If astronauts
were to eat foods high in iron, the iron would be stored in their bodies and could cause health
problems. Sodium and vitamin D affect bone. The amount of sodium in the astronauts’ diet is
limited because too much can lead to boneless as well as other health problems. The body
usually makes vitamin D when the skin is exposed to sunlight, but spacecraft are shielded to
protect the astronauts from harmful radiation.. As the body adapts to weightlessness, many
physiological changes occur. Many of these can affect nutrition or be affected badly it. The
changes include loss of bone and muscle, changes in heart and blood vessel function, and
changes in blood and the amount of fluid in different areas of the body. Astronauts usually
lose weight during spaceflight. Being sure they eat enough calories is important, because if
they eat enough calories, they will also eat enough of most other nutrients, including vitamins
and minerals. For ISS crewmembers, it is important that they begin their mission in excellent
health, maintain that state of health as much as possible, and then get back to it as quickly as
possible after the mission. ISS crewmembers have their nutritional status checked before,
during and after flight to help reach this goal. Before and after flight, blood and urine samples
from crewmembers are analyzed for chemicals that indicate nutritional status .During the
mission, crewmembers fallout a computerized Food Frequency Questionnaire to report what
foods they have eaten during the previous week. The computer results are sent electronically
to the ground, and nutrition specialists analyze the data right way so they can recommend
ways to improve the astronauts’ dietary intake. As mission lengths increase from weeks on
the shuttle to several months on the ISS and perhaps two years on a mission to another planet,
nutrition become many more important.
FUNCTIONAL FOOD FOR SPACE
It is well documented that, during space missions, the human body is
subjected to extreme stress, both physiological and psychological, that may negatively impact
health. Multiple risks are associated with space flight including exposure to microgravity,
increased ionizing radiation levels as well as living in a small, confined environment. These
stresses imposed by space travel on the human body make it particularly difficult to ensure
the health of the crew members especially in longer missions. It is therefore imperative to use
whatever means available to protect the crewmembers, and in this context food becomes a
tool of paramount importance. Food provides not only the nutrients necessary to fulfil the
physiological needs of the astronauts but also the following: a familiar element in an
unfamiliar and hostile environment, a reminder of home, a break from work, and an
important social activity for the crew.
Unfortunately up to the present, the food intake of astronauts has been
below the minimum recommended level (e.g. 50 % lover energy intake in Shuttle; 13). This
lack of adequate consumption has been associated with the very busy schedule of the
astronauts during missions and, consequently, their tendency to skip meals; 13). In addition,
in microgravity astronauts are subject to a significant decrease in taste and odour sensitivity
(possible consequence of the body-fluids shift towards the head induced by the lack of
gravity) that could affect appetite and eating habits. The challenge for the space-food
scientists is to produce appetizing food items that tempt the astronaut increasing the
anticipation towards meal time and increasing their food intake.
In recent years there has been an increasing awareness of the role of
food as a tool to improve well-being and as means to prevent and counteract specific
pathologies. Specific components of food products have been isolated and proven to have
some beneficial effect on the body. This new vision of food has become popular with
consumers and has led the food industry towards development of foods with positive health
properties. A food so formulated is called “functional food”.
The addition of functional foods targeted to astronauts for consumption
during space missions is advisable to help mitigate the deleterious effects of space flight on
the human body. Such foods would not only provide the appropriate nutrients to the
astronauts but they could also be specifically designed to be rich in ingredients with
Development of functional foods for space travel should focus on the following properties:
High antioxidant activity: antioxidants act in concert as the body’s defence against
free radical damage. A number of studies have shown that adding an antioxidant to
the diet can modify the radio sensitivity of human cells in ground-based models.
High in water: It is essential for crew members to consume adequate amounts of
fluids. The current recommendation is for a minimum of 2 litres/day. Fulfilment of
this requirement can be quite difficult because reduced thirst (consequence of body-
fluids shift) is common in space flights and causes a low fluid intake (16, 14).
Slow energy release: Slow energy release would provide energy support to the body
for extended periods of time (e.g. extravehicular activity) and would help maintaining
high levels of attention
High in fibre content: dietary fibre, and in particular prebiotic fibres, reduce
constipation and prevent intestinal dismicrobisms.
Rich in bio available calcium: dietary calcium should be provided in adequate
quantities for preserving bone quality and quantity. The risk of kidney stones is low
enough and does not indicate that calcium intake should be lowered.
Low in sodium: excessive sodium intake during space flight may be problematic
because sodium exacerbates bone loss and dietary sodium recommendation for the
space flight. The reduction of sodium in the food supply is difficult since sodium
chloride is not only the responsible for salty taste but it is often used to increase shelf
life of a product.
Our research group has, therefore, been working on a research project
aiming at the creation of three highly acceptable, nutritionally dense, stable functional space
food products. Functional ingredients have been used to enhance the nutritional value of food
beyond basic calories and nutrient content by incorporating and maximizing the use of food
ingredients of high nutritional interest. The functional food products that have been
developed are a blueberry gel-like snack, nutritionally enhanced tortillas and nutritionally
enhanced pasta sheets and lasagne.
TYPES OF FOOD
There are eight categories of space food;
1. Rehydratable Food:
Rehydratable items include both foods and beverages. One way weight can be conserved
during launch is to remove water in the food system. During the flight, water is added back to
the food just before it is eaten. The shuttle obiter fuel cells, which produce electricity by
combining hydrogen and oxygen, provide ample water for rehydrating foods as well as
drinking and a host of other uses. Foods packaged in rehydratable containers include soups
like chicken consomme and cream of mushroom; casseroles like macaroni and cheese and
rice and chicken; appetizers like shrimp cocktail; and breakfast foods like scrambled eggs and
cereals. Breakfast cereals are prepared by packaging the cereal in a rehydratable package with
non-fat dry milk and sugar, if needed. Water is added to the package just before the cereal is
2. Thermostabilized Food:
Thermostabilized foods are heat processed to destroy harmful
microorganisms and enzymes. Individual servings of thermostabilized foods are
commercially available in aluminium or bimetallic cans, plastic cups, or in flexible retort
pouches. Most of the fruits, and fish such as tuna and salmon, are thermostabilized in cans.
The cans have easy-open, full-panel, and pull-out lids. Puddings are packaged in plastic cups.
Most of the entrees are packaged in flexible retort packages. This includes products such as
beef tips with mushrooms, tomatoes and eggplant, grilled chicken and ham. After the pouches
are heated, they are cut open with scissors. The food is eaten directly from the containers with
conventional eating utensils.
3. Intermediate Moisture Food:
Intermediate moisture foods are preserved by restricting the amount of water
available for microbial growth, while retaining sufficient water to give the food a soft texture
and let it be eaten without further preparation. Water is removed or its activity restricted with
water binding substance such as sugar or salt. Intermediate moisture foods usually range from
15to 30 percent moisture, but the water present is chemically bound with the sugar or salt and
is not available to support microbial growth. Dried peaches, pears, and apricots, and dried
beef are examples of this type of shuttle food.
4. Natural Form Food:
Foods such as nuts, granola bars, and cookies are classified as natural form
foods. They are ready to eat, packaged in flexible pouches, and require no further processing
for consumption in flight. Both natural form and intermediate moisture foods are packaged in
clear, flexible Packages that are cut open with scissors.
5. Irradiated Food:
Beef steak and smoked turkey are the only irradiated products currently used
on the shuttle. The food is cooked, packaged inflexible, foil-laminated pouches, and sterilized
by exposure to ionizing radiation so they are stable at ambient temperature.
6. Frozen Food:
These foods are quick frozen to prevent build-up of large ice crystals. This
maintains the original texture of the food and helps it taste fresh. Examples include quiches,
casseroles, and chicken pot pie.
7. Fresh Food:
These foods are neither processed nor artificially preserved. Examples include
apples and bananas.
8. Refrigerated Food:
These foods require cold or cool temperatures to prevent spoilage. Examples
include Cream cheese and sour cream so they can be kept.
2. Different types of food system
Early space voyagers were allowed to select their own personal menu from
limited number of flight-qualified foods. During the design phase of the Shuttle food system,
it was determined that a universal menu would be more appropriate, due to the larger crew
sizes and increased flight rate. A universal menu was selected after a series of sensory
evaluations by representative astronauts. Each meal was overwrapped in a plastic bag to keep
everything together. Experience with more flights resulted in more complaints about the
universal menu and the bagged meal, Each astronaut wanted to select his or her own menu
prior to the mission and did not want to be restricted to a sacked meal. Even though a few
commanders have dictated use of the universal menu for the convenience of food preparation,
the majority of flight crews prefer the personal preference menu. The system was changed
early in 1984 to allow crews the option of choosing the universal menu or their own. There is
no universal menu and crews must have options for menu selection with some real-time
Food and how it is eaten and packaged have been greatly affected by the
unique microgravity environment of space. A microgravity environment is one in which
gravity s effects are greatly reduced. Microgravity occurs when a spacecraft orbits Earth. The
spacecraft and all its contents are in a state of free-fall. This is why a handful of candy seems
to the Space Shuttle when it is released. The candy does not drop to the floor of the Shuttle
because the floor is falling, too. Because of this phenomenon, foods are packaged and served
to prevent food from moving about the Space Shuttle or ISS.Crumbs and liquids could
damage equipment or be inhaled. Many of the foods are packaged with liquids. Liquids hold
foods together and, freed from containers, cling to themselves in large drops because of
cohesion. It is similar to a drop of water on piece of wax paper. The only difference is that
this drop of water is moving about the microgravity environment of the Space Shuttle.
Special straws are used for drinking the liquids. They have clamps that can be closed to
prevent the liquids from creeping out by the processes of capillary action and surface tension
when not being consumed. Microgravity also causes the utensils used for dining to float away
magnets on the food tray when they are not being used. The effects of microgravity have had
an enormous impact on the development of space food packaging, food selection etc.
APPLICATION OF FOOD TECHNOLOGY IN SPACE
1. Provide an adequate food system
Develop a safe food system.
Develop a nutritious food system.
Develop an acceptable food system.
2. Provide a food system that efficiently balances vehicle resources
Minimize trace gas emission.
Minimize crew time.
Development of space food in the United States has evolved over a
series of manned missions into space in various types of vehicles with a wide variety of
objectives and goals. Man’s first ventures into space were in small space craft with a crew of
one or two. Food development for space flight has always been from a systems approach,
since the food has so many intricate interfaces in the closed environment of a spacecraft. The
design goals, from the consumer Point of view, have always been basically the same and are
not any different from those of the general public. These goals are:
The initial approach to developing food to meet the constraints of the small
spacecraft was to produce highly engineered foods. Tube foods were the first to be consumed
in space by U.S. astronauts. Astronaut John Glenn was the first to eat in space when he had
applesauce in a tube. Tubes were later supplemented with cubes. Both types of foods were
highly engineered and met all the constraints imposed by the vehicle, such as pressure
changes, high oxygen content, etc. There were virtually no crumbs associated with
consumption, no possibility of water escaping into the cabin, and the food provided a
balanced diet. But there was a problem, In order for food to be nutritious and provide
psychological well being, it must be eaten. Food in tubes could not be seen or smelled and the
texture was not normal in most cases. Cubes were made from crackers and cookies. The
flavour was unchanged, but the texture was significantly different from the original product.
Even though astronauts on taste panels in the test kitchen thought they tasted great, a majority
of the cubes were returned after each mission. Concentrated food or the meal-in-a-pill
concept was not acceptable for space food systems.
As food systems evolved from cubes and tubes to dehydrated foods, the need
for hot water or a method of heating food in space became apparent. Hot water was available
on the early space craft and methods were devised to add hot water to food for rehydration.
However, the water was seldom hot enough to provide a “hot” meal, especially after it was
transferred to a package with ambient temperature food and then allowed to sit for up to ten
minutes while the food rehydrated. A food warmer was first introduced on the Skylab
programming 1973. With mission length lasting up to84 days, the ability to heat food became
an important factor in the acceptability of the food. The Skylab food warmer was built into
the serving tray with three food cavities having the ability to warm. A food heater was not
used again until the Shuttle program, which began in 1981. The first food warmer used on the
Shuttle was portable carry-on suitcase heater. Hot water was not available from the tap, so in
order to get hot water, the astronauts had to fill a beverage package with ambient temperature
water and place it in the food warmer for 15 to 20 minutes. The galley was introduced on
STS-9in 1983. In addition to having the capability to heat foods in the forced-air convection
oven, the galley also provided measured quantities of hot and cold water, and a food
preparation area Plans for the Space Station galley include forced-air convection oven with
the capability to reach 350˚F. The ability to heat food significantly improves the
Refrigerators and Freezers
A passive freezer, which used liquid nitrogen as the coolant, was
developed for the Apollo program, but was never used due to weight and volume restrictions.
Freezers and refrigerators were first used by the U.S. on the Skylab program, which began in
1973. Frozen and refrigerated foods enhanced the Skylab food system, which tended to be
bland and lacked variety due to the metabolic studies which controlled food intake. Only a
limited quantity of frozen and refrigerated food could be included, so the astronauts were
involved in the decision as to which foods would be frozen. The refrigerator was used as a
chillers for food preparation. The two most popular frozen foods were steaks and ice cream.
Food freezers and refrigerators were not included in the design of the Shuttle food system due
to limited weight and volume allocations. Three servings of vanilla ice cream and done steak
were sent up in a laboratory experimental freezer on STS-4. No other frozen food has been
used on U.S. missions since the Skylab program. Frozen and refrigerated foods have been
included in the plan for Space Station food. Current plans call for around 50 percent frozen
food for the 90-day missions. So Food freezers and refrigerators are essential for long
Thermo-stabilized Retort Pouches
The first retort pouches were used by NASA in 1968 on the Apollo Missions,
long before they were approved for the general public. Even though the pouches added more
weight and volume to the food system, the variety and minimum preparation efforts made the
retort pouches a favourite. Retort pouches have continued to be used in space food systems
from Apollo through the current Mars program.
Some irradiated foods offer a distinct advantage for use in space food systems.
They require no freezer or refrigerator space and allow the processor to control the amount
offered liquids and doneness in meat products, Shelf life of bakery goods is significantly
improved with irradiation. Irradiated ham was first used on Apollo17 in 1972. Irradiated flour
was used to make shelf stable bread for Skylab, and irradiated steak, ham, and corned beef
were used on the Apollo-Soyuz Test Project in 1975. Irradiated bread and breakfast rolls
were used on the early Shuttle missions, but were discontinued when permission was granted
to load perishable food son the Shuttle at 16 hours before launch. Irradiated steak, corned
beef and smoked turkey have been used on Shuttle missions. Irradiated ham was first used
on Apollo17 in 1972. Irradiated flour was used to make shelf stable bread for Skylab, and
irradiated steak, ham, and corned beef were used on the Apollo-Soyuz Test Project in 1975.
Irradiated bread and breakfast rolls were used on the early Shuttle missions, but were
discontinued when permission was granted to load perishable foods on the Shuttle at 16 hours
before launch. Irradiated steak, corned beef and smoked turkey have been used on Shuttle
PACKAGING EVOLUTION AND RESOURCE UTILIZATION
During the development of a space flight food system, many resources must be
considered. These include:
waste disposal capacity
Ineffective use of vehicle resources will decrease the possibility of mission
success. Due to the lengthening of mission duration and lack of refrigeration, foods are
required to be shelf-stable. The production of by-product water from fuel cells on the Shuttle
brought about the development of freeze dried foods. Apollo era hard plastic spoon bowls
were reduced and replaced with a clear flexible plastic laminate. Rigid cans were replaced
with a flexible laminate with an aluminium foil layer for thermo stabilized foods. These new
flexible packages reduced mass and volume requirements during storage.
Food packaging is a major contributor to mass, volume and waste
allocations for NASA missions. Packaging is integral to maintaining the safety, nutritional
adequacy and acceptability of food, protecting it from foreign material, microorganisms,
oxygen, light, moisture and other modes of degradation. Higher packaging barrier properties
equate to greater food protection from oxygen and water ingress. Oxygen ingress can result in
oxidation of the food and loss of quality or nutrition. Water ingress can result in quality
changes such as difficulty in rehydrating freeze-dried foods and increased enzymatic and
microbiological activity. Clear, flexible, plastic laminate is currently used for freeze-dried
and natural form foods. This packaging enables a visual product inspection. This clear plastic
laminate is also able to be thermoformed and thermo sealed without flex cracks that are
common with foil laminates. That being said, the clear packaging does not have adequate
oxygen and moisture barrier properties to allow for an 18 month shelf-life for ISS missions.
Foods are overwrapped with a second, opaque foil containing package that has higher barrier
properties. The packaging materials used for the thermo stabilized, irradiated and beverage
items contain a foil layer that protects the food from oxygen and moisture beyond the
required 18-month shelf-life.
The oxygen and water vapour permeability of current NASA food packaging materials are
listed in tables
Oxygen Permeability of Packaging Materials (CC/100IN_2/DAY)
73.4°F @ 100% Relativity Humidity
Thermo stabilized and Irradiated pouch <0.0003
Rehydratable Lid and Natural Form 5.405
Rehydratable bottom (heat formed) 0.053
Vapour Permeability of Packaging Materials (G/100IN_2/DAY)
100°F @ 100% Relativity Humidity
Thermo stabilized and Irradiated pouch 0.0004
Rehydratable Lid and Natural Form 0.352
Rehydratable bottom (heat formed) 0.1784
A significant resource concern lies with the mass of the system. Mass of
the food is dependent on the type of food taken and the quantity required per crew member.
The Apollo food system provided 0.82 kg of food per crew member per day. Thermo
stabilized foods were included starting in 1968. These were preferred to freeze-dried options,
which justified the weight increase. By Apollo 14, food averaged 1.1 kg per crew member per
day. The Apollo food system still contained a significant number of freeze dried foods since
water from the fuel cells was available for rehydration (Evidence Category III). Current ISS
crew members receive approximately 1.8 kg of food per person per day (this number includes
packaging). Due to crew preference, a higher percentage of the food is thermo stabilized
(compared to Apollo era missions). This contributes to the weight increase. Since the ISS
used solar power instead of fuel cells that produce water, there is little mass advantage to
using freeze-dried foods.
The average caloric requirement for each crew member is now 3,000 kcal,
as opposed to 2,500 kcal provided for the Apollo crews. The actual, number of calories
allocated for each crew member is now based on the actual caloric needs of each crew
member, according to weight and height. This has caused a food weight increase.
Space Food Systems Laboratory (SFSL)
The Space Food Systems Laboratory is a multipurpose laboratory responsible for
space food and package research and development. This facility designs, develops, evaluates
and produces flight food, menus, packaging, and food-related ancillary hardware for Shuttle,
Space Station, and Advanced Food Systems. Capabilities of this facility include: food product
development, food preservation technology, sensory evaluation, menu planning, freeze
dehydration, blast freezing, package development, fabrication and design of packaging
equipment, physical testing of packages and materials, and modified and controlled
Space Mission / Purpose
Evidence strongly supports the role of nutrition in maintaining the health and
optimal performance of astronauts during space flights and return to Earth. The key to
providing good nutrition in support of human space flight is to provide high-quality food
products that are appetizing, nutritious, and safe and easy to prepare and eat. The mission of
the Space Food Systems Laboratory is to provide high-quality flight food systems that are
convenient, compatible with each crew member's physiological and psychological
requirements, meet spacecraft stowage and galley interface requirements, and are easy to
prepare and eat in the weightlessness of space.
Technical Specifications of Facility
The Space Food Systems Laboratory is located in Building 17 at Johnson Space
Centre and is comprised of four laboratories: a Test Kitchen, fully equipped with sensory
testing capabilities; a Food Processing Laboratory (Pilot Plant); a Food Packaging
Laboratory; and an Analytical Laboratory. The Space Food Systems Laboratory has the
capability to fabricate custom-moulded flight food containers; process foods using a variety
of stabilization techniques, including freezing and freeze-drying; package foods in a nitrogen
environment for long-term storage; provide long-term controlled environment storage for
processed foods; conduct physical and sensory analyses of food; evaluate prototype and flight
food preparation hardware; and, develop food preparation and serving techniques for space
Faced with the problem of how and what to feed an astronaut in a sealed
capsule under weightless conditions while planning for human space flight, NASA enlisted
the aid of The Pillsbury Company to address two principal concerns: eliminating crumbs of
food that might contaminate the spacecraft’s atmosphere and sensitive instruments, and
assuring absolute absence of disease-producing bacteria and toxins. Pillsbury developed the
Hazard Analysis and Critical Control Point (HACCP) concept to address NASA’s second
concern. HACCP is designed to prevent food safety problems rather than to catch them after
they have occurred. The U.S. Food and Drug Administration have applied HACCP guidelines
for the handling of seafood, juice, and dairy products.
SPACE FOOD FOR FUTURE
In the future, NASA is looking to send astronauts to outposts on the moon
and Mars. Although the target for liftoff for the moon mission is not until 2020, efforts are
already under way at the Space Food Systems Lab. Scientists in the Advanced Food
Technology group, led by NASA food scientist Michele Perchonok, are developing foods that
are nutritious, good tasting, and provide variety for a 3-year mission. “The biggest challenge
for these future missions is a food’s shelf life˝. For an initial trip to Mars, you will need
products that have a 5-year shelf life,” Kloeris says. The only foods that have currently
shown such a long shelf life are a few thermo stabilized foods, which is not enough to
provide a balanced diet, Kloeris says Perchonok and her team are looking always to improve
packaging materials that will provide a better barrier to water and oxygen—which can cause
food to spoil. This way, the shelf life for many current food items can be extended. Another
area of research is to develop ways to transport some foods—such as wheat berries and
soybeans—in bulk to reduce the amount of packaging materials used and to minimize waste.
“A 1,000-day mission to Mars for a crew of six will need about 10,000 kilograms if we went
with our packaged food system,” Perchonok says. “If we can save on that by growing some
items, by bringing some items up in bulk, it will be a lot easier.”
Assessment of the Long-Term Stability of Retort Pouch Foods to
Support Extended Duration Spaceflight
Beom-seok song et al
The Advanced Food Technology (AFT) Project of the National Aeronautics and
Space Administration (NASA) Human Research Program (HRP) is currently working to
design a stable, palatable, and nutritious food supply to support long-duration spaceflight. A
large part of this food supply is expected to be positioned, unrefrigerated, at relevant
destination sites prior to crew arrival .Therefore, AFT anticipates that the food products used
on the emissions must maintain acceptable quality for a minimum of 3 to 5 y at ambient
conditions. The current spaceflight food system, designed to support short duration
spaceflight, consists of an assortment of retorted foods, intermediate moisture foods, freeze-
dried foods, and irradiated foods (Perchonok 2002). Of these, retort-processed pouch
products have the highest acceptability, and the greatest potential to maintain this
acceptability, in addition to safety and nutritive value, for 3 to 5 y. To this point, however,
there has been no quantitative shelf life testing completed on the entirety of NASA’s retorted
products. Such data are desired by NASA, to aid in assessing the compatibility of the current
short-duration menu with future plans for extended-duration spaceflight. While the
technology still relies on aggressive application and penetration of heat throughout foods,
recent advancements in process engineering coupled with evolution of packaging
technologies have allowed for an overall improvement of the technology (Lopez1987;
Goddard 1994; Brody 2002; Jun and others 2006). The current state of the art in retort pouch
processing has increased commercial value, and can offer to consumers a level of quality,
safety, and convenience not realized by other means (Brody 2002).Recent work has also
suggested that the unique properties of retort pouches allow for maximum heat penetration,
and reduction of nutrient losses associated with standard processing of cans (Chiaand others
1983; Lopez 1987). Additionally, as acknowledged by NASA, retort pouch products are
efficient in their distribution and have a limited impact on mission-critical resources, such as
launch mass and stowage volume (Perchonok 2002; Perchonokand Bourland
2002).Deterioration of foods throughout storage is considered a function of 4 general
phenomena: enzymatic, microbial, chemical, and physical processes (Kuntz 1994). Standards
of Identity, consumer expectations, and, often, nutrient content claims. NASA risk
assessment has also identified the importance of food system acceptability and nutrient
stability as integral to maintaining successful performance in missions (Perchonok and
Bourland 2002). Therefore, the objectives of this study were to furnish data on the chemical
and physical stability of NASA’s 65 retort processed foods, and to assess the feasibility of
using them to support long-duration missions. The study proceeded first by establishing
principle modes of deterioration, corresponding Q10 values, and ambient shelf life values for
13 representative retort pouch products. After consideration of the data obtained in this,
estimates were generated to establish shelf life values for the entirety of NASA’s retort
processed product stock. Finally, an overall assessment was made as to the suitability of these
products for use in extended duration missions.
Materials and Methods
Accelerated shelf life testing of representative products
Thirteen retort processed pouched products were evaluated by accelerated shelf life
testing (ASLT).carefully chosen for evaluation, in order to be representative of a standard
spaceflight menu. A combination of menu items and proposed new products, were carefully
chosen for evaluation, depicted on table 1; all samples were processed with appropriate time
and temperature parameters to achieve commercial sterility.
Storage and sampling parameters.
Shelf life extrapolation was conducted via the standard ASLT procedure, which
included analytical quantification of quality, application of Arrhenius kinetics, and
mathematical prediction of shelf life for each food product (Labuza 1982; Perchonok 2002
Table 1–Food products evaluated by ASLT and their corresponding, designated categories.
An asterisk (∗) next to product name indicates that the products were developed for stability
assessment and were not standard menu items. Category Food Products
Instrumental quality analysis.
Instrumental evaluation of products proceeded at 4-mo intervals for the first 2 y of
evaluation, and at 6-mo intervals during the 3rd year. Specific analytical methods were
chosen in light of anticipated modes of deterioration for each product, in order to characterize
effectively quality loss through storage. Texture analyses were performed on aTAx-T2i
texture analyzer. Colour data were gathered on a Hunter Lab Scan XE colorimeter, Water
activity was measured with a Decagon CX-2benchtop water activity meter. pH was measured
on a standard bench top pH meter. ◦Brix was measured with a standard handheld
refractometer. All of these instrumental analyses were conducted in the Space Food Systems
Assessment of product nutritional quality.
Tests included a broad assessment of macronutrients, essential vitamins, and
minerals in products were submitted for baseline nutritional analysis within 3 wk of
production. Final evaluation was performed at shelf life endpoint, or after 36 mo of storage, if
shelf life exceeded 36 mo.
Analysis of product sensory quality.
Sensory evaluation of products proceeded at 4-mo intervals for the first 2 y of
evaluation, and at 6-mo intervals during the 3rd year. Panellists were maintained in isolation
for the duration of each test. Approximately 24 h prior to testing, samples were pulled from
each storage condition and allowed to equilibrate to room temperature (70 ± 2 ◦F). If
necessary, samples were heated in a 150 ◦F convection oven for 30 min prior to serving; all
other samples were served to panellists at ambient temperature (70 ± 2 ◦F).Within 2 wk of
receipt into the lab, food products were evaluated by quantitative affective testing for baseline
acceptability. These affective tests utilized a 9-point Hedonic scale .Attributes considered in
both acceptability and difference testing were product specific but generally included
assessments of appearance, texture, aroma, flavour, and aftertaste. Between 22 and 38
Panellists evaluated products at each baseline test point. Separate paired t-tests were
conducted to compare acceptability of the 2treatment samples and control samples (α = 0.10).
After baseline acceptability was determined, Difference-from control testing, based on
procedures outlined by Meilgaard and others (1999), was used to quantify differences
imparted to products over storage time. The specific Difference-from-control test employed
involved the presentation of 3 successive sample pairs to panellists, consisting of a control
(40 ◦F) sample paired with one of the treatment samples (72 ◦F, 95 ◦F) or blind control (40
◦F), and prompted them to assess the magnitude of the difference between several attributes
of the two. Panellists indicated their responses on a9-point verbal category scale that ranged
from “Extremely Different “to “Definitely the same. The mean Difference-from control score
was calculated for each sample and blind control. These data were evaluated by paired t-tests
to determine significance of the effects of storage temperature on each attribute (α
=0.10).After a significant difference from control was determined for any treatment, products
were evaluated at remaining test intervals by quantitative affective testing. The remaining
affective testing of products utilized the same questions as those used to determine baseline
acceptability. Affective testing continued until the average acceptability had declined to a 6.0,
or decreased by at least 20%,if original rating was initially less than 7.5. Separate paired t-
tests were conducted to compare acceptability of treatment samples and control samples (α =
Shelf life extrapolation.
Shelf life endpoints (ts) at ambient temperature, which were not observed in the
36-mo testing period, were calculated by the following equation:
ts = t0e−aT, where ts = shelf life at 72 ◦F/22.2 ◦C, t0 = shelf at 95 ◦F/35 ◦C,
a = lnQ10/10, T = 12.8 ◦C.
Where analytical measurements did not reflect sensory assessments of quality, Q10 values
were obtained from the literature and used to predict shelf life value at ambient temperature
from observed sensory endpoints at 95 ◦F. This was the case for products whose main
mechanism of quality loss was defined in terms of flavour deterioration.
Estimation of shelf life for all retort processed pouch Products.
Estimates of shelf life values were made for all NASA standard menu retorted
products. This product information was reviewed to identify a maximum of 3representative
products (of the 13 evaluated by ASLT) that were comparable or similar to each menu item.
The average of the ASLT estimates for all comparable products identified was computed.
This average was accepted as the preliminary estimate of the shelf life for the menu item .To
compute a final estimate of the menu item’s shelf life, a list of differences expected to affect
longevity were noted between the menu item and the representative product(s). The
preliminary estimate of the shelf life for each menu item was then adjusted based on these
identified differences. These differences and their corresponding shelf life adjustments were
kept consistent and are summarized in Table 3.
Results and Discussion
Shelf life endpoints of representative products
Shelf life endpoints determined for the 13 representative products are summarized in
Table 4. Of these, 4 endpoint (SugarSnapPeas, Broccoli Soufflé, Vegetable Omelette, and
Rhubarb Applesauce) were observed during the 36 mo analysis; the shelf life values of the
remaining 9 items were determined by extrapolation.
Table 4: shelf life of food products evaluated by ASLT and principle mechanisms of quality
loss. Ranges have been given for those products whose shelf life end point was defined in
terms of a 20% quality loss, rather than by a minimum 6.0 quality rating
Baseline acceptability of representative products.
Baseline acceptability of sugar snaps peas
Bitterness and an unacceptable after taste as the reasons for the low acceptability
of Sugar Snap Peas after production. These off flavours were attributed to the increase in
organic acid content typically present in canned green vegetables (Lin and others 1970,
Clydesdale and others 1972). Incorporation of a preliminary blanching step and inclusion of a
brine packing solution are conventional means to avoid this off-flavour development.
Baseline acceptability of egg products.
Although retort processed egg products are not currently offered in the NASA
food system, 2 Candidate egg products were developed for consideration in this study. The
Broccoli Soufflé and Vegetable Omelette products were proposed .Texture was anticipated to
be an issue for these products, as the high heat applied the retort process would allow
extensive aggregation of egg proteins. In addition to texture, unacceptable appearance and
odour of egg products were cited by panellists as reasons for failure at 0 mo. The
unacceptable odour was likely due to formation of sulphurous gases produced during cooking
of eggs, and subsequent containment of that gas within the retort pouch. The observed,
greenish gray colour is likely due to the formation of ferrous sulphide that is often observed
with extended heating of liquid eggs at high temperatures (Gossett and Baker 1981). Odour
could be curbed by decreasing the egg product fraction of the formulation, and appearance
maybe improved either by acidifying the formulations with salts or through the addition of
various chelating agents. The phenomenon has been attributed to the denaturation of egg
albumin proteins with the continued application of heat, and reassembly into an extensive
fibre-like network. Although increased cohesiveness was not indicated by panellist comments
on the representative egg products studied, unacceptable hardness, springiness, and rubbery
quality were observed. Instrumental texture analysis of these products was carried out for the
duration of the storage analysis and showed that hardness of Broccoli Soufflé decreased
gradually over time (P <0.05).No such decline was observed for Vegetable Omelette,
presumably because of its higher protein content. Even with reformulation and in spite of
texture softening over time, retorted egg products are not likely to be acceptable for extended
duration missions. Emerging processing technologies (microwave/radio frequency and
pressure-assisted sterilization) should be considered for this purpose, as they appear to
provide acceptability and storage stability that are more appropriate to NASA’s needs
Quality loss to representative products throughout storage.
Overall, changes to the colour and flavour of representative products over time were
found to have the greatest impact on product quality. For the most part, these changes were
slowed significantly with product storage at low temperatures. Changes to product texture
and nutritive value during storage were also observed for several of the representative
Colour loss in representative products.
Significant colour loss was generally limited to fruits, vegetables, and products
containing high proportions of dairy ingredients..Colour changes previously reported in long-
term storage of canned goods have been defined in terms of colour fading in green vegetable
products, high carotenoid products, and uncured meats; and colour darkening in bakery
products, starch products, fruits, and cured meats (Feaster 1949; Cecil and Woodruff 1963;
Goddard 1994). Although both fading and darkening were observed in the present study, the
latter was the most significant colour change influencing product quality. The most
substantial declines in colour were observed for fruit and vegetable products. On average, the
critical colour limits of fruit and vegetable products represented a decline of 20% in the value
of initial colour parameters .The most substantial fading of colour was observed in green
colour of Sugar Snap Peas, where the Hunter a-value had increased from 1.75to 2.92 after 20
mo of storage at 72 ◦F. However, decreases in the Hunter L-value during this time, indicating
darkening of the product, were found to have a greater effect on overall product quality.
Additionally, some colour fading was measured in the Grilled Pork Chop product, but was
not found to have a significant effect on the overall panellist acceptability over time. Colour
fading in Grilled Pork Chop was characterized in terms of a hue shift from orange to yellow-
green. This shift appeared to coincide with decreased reporting by panellists that the product
appeared red or pink over storage. The shift was not significant for the product stored at the
low temperature (40 ◦F) conditions. Although instrumental assessment showed gradual
change of all colour parameters over time for ambient and high temperature storage of these
products, panellist perception of colour change was limited to discernment of relative product
darkness. The lack of significance of colour fading in these products is likely due to their
formulations: Carrot Coins contains butter at 1.61% w/w; Apricot Cobbler contains pie crust
and sugar at 8.37% and 21.22%, respectively. Both of these products contain reasonable
levels of reactive browning precursors, which would therefore account for their darkening
over time. Cecil and Woodruff (1963) assessed storage stability of retorted Apricot Jam at 70
and 100 ◦F, and have noted similar product observations to those of the present study. Colour
changes in the Bread Pudding and Tuna Noodle Casserole products were characterized only
by product darkening. The critical limits of colour decline in these products were more
moderate than in fruits and vegetables However, although the colour changes were minor,
they were still reflected in panellist ratings of appearance for this product. This was likely due
to simultaneous progression of other quality changes that affect appearance, such as moisture
migration between sauce and noodle components. Rodriguez and others (2003) have reported
Similar findings in their analysis of retorted burrito combat rations. Specifically, their work
has suggested that extended storage of multi component pouched foods with high starch
contents has detrimental effects to the appearance, texture, and flavour of the food. The most
significant effects to these quality parameters in their retorted burrito products were found to
result from storage of the products at high temperatures. Similar characteristics were
observed for the darkening of Roasted Vegetables, but the colour aspects were overcome by
off-flavour development, presumably because of the relative mildness of the initial product
Flavour changes in representative products.
Flavour loss was observed in terms of loss of characteristic product flavours and
formation of unacceptable flavour, with the latter contributing most significantly to overall
acceptability. For most products, flavour change was accompanied by a change in colour. For
those products found acceptable at baseline, flavour did not appear to drive overall sensory
acceptability until after a minimum of 16 mo of storage at ambient conditions .Panellist
acceptability of the flavour of all representative vegetable products (Carrot Coins, Three
Bean Salad, Roasted Vegetables, Sugar Snap Peas) was found to decline over time, especially
at ambient and high temperatures. Similarly, a decreased acceptability of aroma and
aftertastes were observed in vegetable products stored at high temperatures over time (P
<0.05). As these changes tended to coincide with product darkening, and because of the
nature of the products, flavour changes in these vegetable products were assumed to be
resultant from Millard browning reactions. Maillard reactions were also implicated in the
flavour and colour change observed in the Bread Pudding representative dessert product.
Association of colour and flavour changes has previously been observed in a canned fruit
cake product by Cecil and Woodruff (1963). Their research noted increasing perception of
“bitter” and “burned flavour” with darkening of colour. As these changes were accompanied
by hydrolysis of 50% of the product disaccharides, the study attributed them to non
enzymatic or Millard browning reactions. NASA dessert products are formulated with
adequate dairy, egg, and sugar ingredients to allow formation of characteristic flavours and
colours in dessert products by Millard reactions during processing. As most dessert products
are formulated similarly and are potentially subject to these reactions, they should
conceivably benefit from a moderate amount (<16 mo) of high temperature storage. The
extensive heat applied in retort processing typically results in an over processing of meat
products, to ensure sterility throughout the entire product (Potter and Hotchkiss 1998).
Perhaps with the implementation of non-thermal processing methods, off-flavour
development in these types of meat products could be avoided, and initial panellist
acceptance of the products might be improved. This could ultimately serve to increase the
shelf life of the meat entree products.
Texture changes in representative products.
Texture changes affecting quality of representative products in storage were limited
to moisture migration, starch gelatinization, and syneresis. These changes were most
considerable for those products with discrete components, and in products with high starch or
protein contents. Despite this perception of soft texture, panel list acceptance of initial
flavour, aroma, and other quality factors was satisfactory and allowed maintenance of product
quality throughout shelf life. Declines in flavour and aroma attributes, therefore, were
determined to be the primary mechanisms of quality loss for Home-style Potatoes. Schmidt
and Ahmed (1971) also reported decreased hardness of thermally processed potatoes relative
to unprocessed control samples after retorting. They attributed this difference to solubilisation
of intracellular pectic substances, absorption of water, and gelatinization of starch granules.
Prolonged storage of their processed potato samples indicated some hardness decrease due to
a reduction of starch granule water holding capacity over time. Another high starch product
considered in the present study was the Three Bean Salad vegetable product. Texture of this
product was found to be quite stable over time, but was greatly degraded by storage at low
temperatures. Storage at 40 ◦F was found to result in gelatinization of filling aid starches,
which shortened the shelf life of the product considerably to 12 m. With extended storage of
the retorted product, and especially with exposure to freeze thawcycling, cooked starches
within retort product filling solutions can be prone to retro gradation (Goddard 1994).
Replacement of the starch used in this formulation and avoidance of low temperature storage
of this product are proposed as countermeasures to realize the greatest shelf life for this
product. Changes to the textural quality of representative fruit products were reflected in
sensory ratings of each product’s texture, and were also presumed to have affected panellist
ratings of appearance. Both fruit products were noted by panellists to have lost firmness and
become thinner over time, with such effects being most pronounced at higher temperatures.
This was assumed to be the result of moisture release from fruit tissues and a subsequent
increase in free water in the products over time. However, no conclusive analytical data were
available to assess the rate of this deterioration. Texture data and free liquid measurements
were very inconsistent. This is likely due to the addition of varying levels of sauce to the
products, as sauce addition occurs as required to maintain acceptable pouch fill weights.
Shelf Life Estimations for All NASA Retort Pouched
Shelf life estimations of NASA’s current stock of retorted products are
summarized in Figure 1. Fruit and dessert products were estimated to have a minimum shelf
life between 1.5 and 5 y; vegetable side dishes were estimated to have a minimum shelf life
between 1 and 4 y; soups and starch side dishes were estimated to have a shelf life between
1.75 and 4 y; and dairy products and vegetarian entrees are estimated to have a shelf life
between 2.5 and3.25 y. Meat products were found to be the most durable products, as they
were all estimated to maintain quality for a minimum of2 y, with an expected shelf life
maximum of 8 y. Of the 65 products, only 27 are estimated to have a shelf life of greater than
3 y, and would therefore fall within the minimum range required by AFT to support extended
duration spaceflight. Additionally, there are likely to be mission scenarios requiring up to a 5
y shelf life for food. Supporting such a scenario with the current food system would allow
only the provision of a limited number of entree products with shelf life estimates that extend
beyond 5 y.The bubble chart plots in Figure 2 are provided to represent the caloric and
nutrient provisions that would be possible in various mission scenarios, based on the shelf life
estimates of this study. Figure 2A represents a full landscape of foods in NASA’s thermo
stabilized product stock, with respect to each food’s caloric content and calculated nutrient
density parameter. The size of the bubbles in these charts is defined with respect to the
number of foods that exist in a given category. Calories are considered per100 g of the food
product. The nutrient density parameter for each food was defined internally, using NASA
requirements for food system nutrition (Smith 2005). The following 18 nutrients were
considered in the definition of this parameter: vitamins A, C, D, E, K, B1, B2, B3, B6, B12,
folate, biotin, pantothenic acid, calcium, magnesium, potassium, iron, and zinc. The level of
each nutrient that was present per 100 g of food was compared against the corresponding
NASA requirement, and points were awarded as follows: the presence of 10% to 49% of the
NASA RDI of a given nutrient contributed 1 unit to the nutrient density, the presence of 49%
to 99% of the NASA RDI of a given nutrient contributed 2 units to the nutrient density of the
food, and a nutrient present in excess of 100% of the NASA RDI contributed 4units to the
nutrient density. The sum of the nutrient density units awarded to each product per its
nutritional profile is represented in the nutrient density parameters plotted in menu landscapes
of Figure 2. While Figure 2A represents the menu landscape of the full product stock of
thermo stabilized foods, Figure 2B represents a menu landscape comprised of only the food
provisions that would-be possible with a 3-y shelf life requirement for NASA missions.
Furthermore, Figure 2C depicts the even more limited landscape of options that would be
available to support a 5-y shelf life requirement. As is apparent from the progression of the
charts in this figure, the menu landscape available to support a NASA mission becomes quite
limited with increasing requirements for the shelf life of the food system. In fact, supporting a
5-y scenario with the current food system would allow the provision of a very limited number
of meat entree products. Therefore, modification to the current food system will be required
to ensure provision of an adequate food system in extended duration mission scenarios.
Modification maybe accomplished in terms of individual product reformulations, application
of emerging non-thermal processing technologies, and development of low temperature
options for food stowage volumes. Reformulation of retorted pouch products should include
changes that will improve the initial acceptability of products, as well as those that may
improve product stability over time. Several means of reformulation have been proposed for
representative products herein. These should be considered on a product-specific basis as
appropriate for the entire stock of NASA’s retorted item. Additionally, Branagan and Pruskin
(1993) have reported that fortification of thermally stabilized cheese spread products can
allow the maintenance of adequate levels of several nutrients, even after exposure to adverse
storage conditions. Fortification of NASA’s retorted foods is likely to have a similar benefit
and should be considered to improve the nutrient value of the products after storage
.Incorporation of emerging and non-thermal preservation technologies are currently being
investigated by NASA through collaboration with the U.S. DoD. These are being considered
for their potential to improve the initial quality and as a means to extend the longevity of the
food system for use in extended duration spaceflight. Finally, as the present study dictates,
the most significant changes to the quality of NASA’s retorted products occurred at ambient
and high temperature storage conditions. Consequently, NASA should consider incorporating
low temperature storage volumes for support of extended duration missions, to further
prolong food system shelf life. These efforts would likely require significant integration
between the AFT program and relevant vehicle design teams. Provision of low temperature
storage volumes would allow shelf life for a majority of products to extend into the minimum
range defined by AFT.
Shelf life endpoints were established for all of NASA’s retorted pouch products. At
ambient storage conditions, shelf life endpoints of the products range from 0 to 96 mo,
depending on the product formulation. Therefore, use of these products to support extended
duration missions will not be feasible without modification. Modification may be
accomplished in terms of individual product reformulations, application of emerging non-
thermal processing technologies, and development of low temperature options for food
Development of freeze-dried miyeokguk, Korean seaweed soup, as
space food sterilized by irradiation
Beom-seok song. et al
Seaweed has a long history as a food resource and popular food ingredient in Korea.
In particular, miyeok is often served in soup, salad, and side dishes. The Korea Atomic
Energy Research Institute has used irradiation technology to develop Korean traditional
foods, such as kimchi, as space foods.Irradiation technology has been considered as an
effective sterilization method to extend the shelf- life of space foods, without compromising
their nutritional proper- ties. Safety and taste of space food are important considerations for
astronauts; therefore, space food should meet rigid microbial specifications (Bourland, 1993).
The microbiological requirements for space foods used by the Russian Institute of Bio-
medical Problems (IBMP), which is a unique institute that certifies space foods for use on the
International Space Station, are shown in Table1. The sensory quality of space food is also
important to prevent malnutrition, because astronauts tend to avoid consuming unappetizing
food .The purpose of this study was to identify microorganisms in freeze-dried miyeokguk
and to sterilize freeze-dried miyeokguk using gamma irradiation in order to meet the IBMP
regulations pertaining to space food.
Dried miyeok and sea tangle were purchased from Chung-hoCo. (Busan,ROK).Other
ingredients were purchased from local markets.
The preparation of freeze-dried miyeokguk is showing Fig. 1. Briefly, meat stock was
prepared by boiling 400g of beef, 20g of sea tangle, and 5gofgarlic in 3 L of water for 30
min. The meat stock was then stored for 24 h at 4 1C to remove the separated lipid layer from
the surface. After adding 2 g of dried miyeok and 1 g of salt to 25 mL of the meat stock, the
mixture was boiled for 10 min. The miyeok and aqueous soup were separated and freeze-
dried individually using a freeze drier. Finally, 2 g of freeze-dried miyeok and 2 g of soup
powder were mixed and packaged in an aluminium-laminated LDPE-polymer bag.
Samples were irradiated in a cobalt-60 gamma irradiator at the Korea Atomic Energy
Research Institute. The source strength was approximately 320 kBq with a dose rate of 10
kGy/hr, and the actual doses were within 2% of the target dose. The absorbed doses were
measured using the alanine-EPR dosi- metry system
Microbiological evaluation and identification
A portion (10g) of the sample was aseptically placed into a sterilized bag with90mL of
sterile peptone water (0.1%) and homogenized in a stomacher blender for 2 minute. The
following medium were used for culturing :plate count agar for total aerobic bacteria ,SS agar
or Escherichia coli, Staphylococcus spp., and coli form bacteria ,potato dextrin agar for fungi.
A 1Ml aliquot was spread on to plates containing one of the above-mentioned media and
incubated for bacterial growth at 351°C for 48h and for fungal growthat25 1C for
5days,under aerobic conditions. Microbial populations from the sample cultured in triplicate
on each medium were evaluated by manually counting the colonies on each plate.
Colour measurement and sensory evaluation
Colour change in gamma-irradiated and rehydrated miyeokguk was measured
using a colour difference meter with the following standard colours: lightness (90.5), redness
(0.4), and yellowness (11.0).The sensory testing panel was composed of 10 trained panelists.
Each member evaluated the samples independently for its colour, flavour, taste, texture, and
over all acceptance using a7-point scale rangingfrom1(very bad)to7(very good).
Results and discussion
. Microbial evaluation and identification The evaluation of total aerobic bacteria ,
coli form bacteria, Staphylococcus, Salmonella, E. coli, B. cereus, and fungi in miyeokguk
and freeze-dried miyeokguk is performed. Colonies were not detected within the detection
limit of l.00 log CFU/g for any microbial species. To validate sterilization of the freeze-dried
miyeokguk, miyeokguk was rehydratedwith200mLofhotwaterat70˚C and was incubated at
35˚C for 48hr.Results are shown in Table 2. Total aerobic bacteria counts were 3.2 log
CFU/gat24h and 7.01 log CFU/g at 48h.These results suggest that heat treatment in the
preparation process was not sufficient to in activate all microorganisms in miyeokguk.
Species were tentatively identified as Bacillus cereus, B. subtilis, Enterobacter hormaechei,
and Acineto -bacter genom ,.B.cereus is widely distributed in several environments and is
known to cause food poisoning symptoms such as emesis and diarrhoea. Even if
microbiological regulations on space food permitted the presence of B. cereus below
10CFU/gin dried food products, the presence of B. cereus could be harmful to astronauts in
aerospace who have a lowered immune function .Therefore, sterilization of space food is
recommended in order to prevent food poisoning, because spore-forming bacteria such as B.
cereus can grow after rehydration and produce toxins. Sterilization by irradiation is an
effective method to inactivate microorganisms in dried food, because heat treatment of dried
food products can cause browning .Gamma irradiation of freeze-dried miyeokguk was
conducted to investigate the optimal dose for sterilization. Aerobic bacteria were not detected
in any sample just after gamma irradiation, and were also not detected in the incubated
samples irradiated at doses above 10 kGy.These results indicates that gamma irradiation of 10
kGy is enough to inactivate all microorganisms in the freeze- dried miyeokguk.
The result of this study indicate that gamma irradiation at 10 kGy could sterilize
freeze-dried miyeokguk without deterioration of the sensory quality of the food. In addition,
gamma irradiation at 10kGy was sufficient to fulfil microbiological requirements as space
food. Following this study, the microbiological and sensory qualities of freeze-dried and
irradiated miyeok- guk was further tested during a 51-day space environment simulation by
IBMP .Freeze-dried miyeokguk was certified by IBMP as space food usable in the Russian
segment of the International SpaceStationin2010.
There are many more lessons to be learned for the application of food technology to
space food without an adequate food system, it is impossible that space crew member’s
health and performance would be compromised. It is clear that in developing adequate NASA
food systems for future missions, a balance must be maintained between use of resources and
the safety, nutrition and acceptability of the food system. In short, the food must provide the
nutrients to sustain crew health and performance, must be safe even after cooking and
processing, must be formulated and packaged in such a way that the mass and volume are not
restrictive to mission viability. It is this delicate balance that frames the food system needs for
our next mission and charts the work for NASA ADVACED FOOD TECHNOLOGY.
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