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participative support effort with the military researchers.

Among these ﬁrms were: Reynolds Metals, Flexible Packa-

ging Division of the Continental Can Company, Dow

Chemical, American Can Company, and Morton Chemical

Company. Reynolds Metals went so far as to establish a

pilot production line for vegetables. A tangible recognition

of this military–industry cooperation was the receipt of

the Institute of Food Technologists’ Industrial Achieve-

ment Award in 1978 jointly by Reynolds Metals, Conti-

nental Can Company, and the U.S. Army Natick Research,

Development, and Engineering Center.

There were foreign developments, more or less parallel-

ing those by the U.S. military. Although some of the

developments were proprietary, there was considerable

interchange of experiences through visits and joint tech-

nical sessions. Among those nations known to be probing

ﬂexible packaging for thermoprocessed foods were Japan,

United Kingdom, Italy, Sweden, Germany and Canada.

These foreign developments were oriented more toward

commercial markets than toward military. Japanese and

Italian representatives cited commercial successes.

The U.S. military’s program can be visualized in four

general development phases. During all phases the pro-

gram was supported by laboratory activities to develop

quality assurance tests and performance criteria. Overall,

as previously stated, from concept acceptance to ration

ﬁelding (i.e., the four phases) took 20 years. Early in the

program, ﬁeld tests revealed that if made properly, the

retort pouch performed well, but the tests also revealed

that the form–ﬁll–seal–process system and product

formulation required technical and engineering modiﬁca-

tions and improvements. This was to be truly an inte-

grated product-package development. This took time. The

development phases were as follows.

Feasibility Testing

This phase included selection of candidate ﬁlms; labora-

tory and small pilot plant size preparation of entrees

(Figure 2); informal ﬁeld evaluation via such activities

as carrying carton-enclosed pouched items in combat

clothing pockets over a clothing-wear obstacle course

(including prone position crawling over obstacles); initia-

tion of storage tests; vibration and drop test cycles

simulating transport abuse; and initial organoleptic ac-

ceptability evaluations. Extractives studies to meet Food

and Drug Administration regulatory standards were per-

formed, submitted, and accepted. The basic structural

requirements of the ﬁlm were established: a 0.004-in.

sealant and basic strength layer, a 0.0005-in. aluminum

foil oxygen/water vapor barrier, and an outer 0.0005-in.

protective layer. The pouch at this initial stage of devel-

opment enclosed and adhered to a kraft board envelope-

folder.

The initial sealant layers were polyvinyl chloride (PVC)

or a medium- to high-density polyethylene (HDPE) mod-

iﬁed with polyisobutylene, each ﬁlm bonded to the foil ply

by an isocyanate adhesive system. As the result of occa-

sional off-ﬂavor transfer and delamination, the PVC

material was replaced by the proprietary HDPE blend.

Figure 2. Thermally processed items. Early retort pouch items (for the MRE), opened to display typical items. Current ration of 24 menus

contains 40–42 thermoprocessed entre

e items in ﬂexible pouches.

778 MILITARY FOOD PACKAGING

Where feasible and comparatively valid, pouch perfor-

mance was compared to MCI canned entrees. The pouch

performed well.

Initial Field Tests

The limited feasibility tests were promising enough that

more extensive troop usage ﬁeld tests were carried out—in

Louisiana, Georgia, Arizona, and Alaska. These tests were

more formal; that is, they were carried out independently

by the Test and Evaluation Command (TECOM). The

Nlabs, the developer, could only act as observers. Based

on TECOM test personnel and user-documented assess-

ments, the retort pouch performed satisfactorily. The

material used featured the HDPE blend as the sealant

ply. Failures were few and mostly related to closure seal

defects; that is, irregularities and leaks caused by product

caught in the seal area.

Palatability was assessed by ratings on a 1–10 (inedible

to highly liked) hedonic scale by the users. The control for

all aspects of these tests was the can in the Meal, Combat,

Individual (MCI). Perhaps the most valid indication of

acceptability was the free choice of the pouch over the can

following tests in Alaska—that is, a choice with no hint of

a Hawthorne effect.

The overall conclusion was that the retort pouch was

acceptable for combat rations, but the failure rate (pri-

marily defects in the closure seal area) was too high for a

thermoprocessed food package.

Production Capability

Based on the ﬁeld test revelation that ﬁlling and sealing

ﬂexible pouches with original high water content ﬂuid,

semisolid, and one-piece solid foods remained a signiﬁcant

performance and reliability problem, a decision was made

to establish a pilot line of full-sized equipment, alter and/

or add functions to improve performance, and run diverse

representative food items in adequate amounts to provide

valid reliability data (in terms of low percent failures).

This approach would also provide future production moni-

tors an experience base for assisting contractors in start-

ups and in correcting production deﬁciencies. It would also

test quality assurance sampling and test protocols. Under

contract, a so-called Natick–Swift production Reliability

Program was established. This program was carried out

by a consortium headed by Swift and Company, with

membership by Continental Can Company, Pillsbury

Company, FMC Corporation, and Bartelt packaging ma-

chinery company. The package design was the four-side

seal and was formed online from a roll stock of 75-

mm-modiﬁed polyoleﬁn (blend of polyisobutylene with

medium- to high-density polyethylene) as the sealant

ply, a 9-mm aluminum foil barrier, and 12-mm polyethylene

terephthlate (Mylar) as the outer layer. Six diverse

products were run: covering those considered pumpable

into formed pouches (beef stew, pineapple); solids termed

placeable (beefsteak, four frankfurters in one pouch); and

viscous items termed extrudable (fruitcake, combination

ham and chicken loaf). Overall results were a 0.002% seal-

failure rate and a 0.016% closure-seal-contamination fail-

ure rate for 298,971 packages.

As reported by Lampi et al. (4), the Natick–Swift

Reliability program revealed an overall outgoing seal

defect rate of 0.017%. Tsutsumi (7) reported a ﬁnal pouch

defect rate of 0.02% in Japan. Nughes (8) reported similar

rates in Italy. If one accepts a failure rate of 0.1% as

published for the ordinary can, the pouch appeared to

meet commonly accepted reliability standards.

The description of the line and results of its usage to

pack six diverse products are described in the Proceed-

ings, Symposium on Flexible Packaging for Heat Pro-

cessed Foods (1973) sponsored by the National Academy

of Science, National Research Council. Each participant

detailed their task and its results. Overviews of results are

included.

As brieﬂy stated earlier, other pilot and manufacturing

lines had been established. Systems, circa 1977, are

summarily described by Lampi (9). Tsutsumi (10, 11)

covers a Japanese approach. Goldfarb (12, 13) describes

the Reynolds Metals system, the use of which is covered by

Mermelstein (14). Although these production systems

were not directly oriented to military use, their successful

functioning reinforced conﬁdence in the feasibility of the

pouch for U.S. military rations.

As mentioned previously, laboratory tests and other

supporting activities were ongoing during the general

development phases. These were conducted with two

ﬁlms: One of them was used in the comprehensive Relia-

bility Program; which was modiﬁed high-density poly-

ethylene (HDPE), the other had polypropylene (PP) as

the sealant layer. The latter had surfaced as an applicable

ﬁlm in usage paralleling the use of HDPE in separate but

similar activities. Details of the many tests and develop-

ments are covered by Lampi (9), and those associated with

seal performance are discussed by Lampi et al. (4). Among

the activities and ﬁndings are

Extractives Studies. Extractives studies were carried out

to establish that no meaningful contaminants were mi-

grating from the packaging materials into package con-

tents. Initial approvals were obtained; and in a later

general review (15) of the status of the program submitted

to regulatory agencies before ﬁelding, no extractives pro-

blems were identiﬁed. However, just before the military

was

to start procurement,

the FDA reported the presence

of 0.3 to 3.0 ppb of toluene diisocyanate migrating

into products. This caused a roughly ﬁve-year delay

(1975–1980) while coextrusion as a bonding technique

was ﬁnalized, assessed for migratory safety, and put into

use. Then, procurement of the MRE began.

Storage Stability. Storage studies were carried out on

representative products, such as ground beef in barbeque

sauce, pork sausage, and ham and chicken loaf (containing

ingredients apt to penetrate polymeric ﬁlms), and with

two ﬁlms (HDPE and PP) to assess product organoleptic

stability and to measure the effects of time and tempera-

ture on package seal tensile strengths and seal and body

area bonding. Storage temperatures were 71.61F and

100.41F. Criteria at that time (1969–1973) were four years

at 71.61F and six months at 100.41F (currently three years

at 80.61F).

MILITARY FOOD PACKAGING 779

The foods passed storage organoleptic stability criteria

on the basis of periodic hedonic ratings and in some

comparisons with like products in traditional cans.

Seal area tensile strengths and laminate bondings held

up very well over 27-month-long storage at 71.61F and

100.41F (16).

Resistance to Rough Handling. Retort pouches with

HDPE and PP sealant layers and containing ﬂuid and

semiﬂuid products were compared to like products in cans

when exposed to a rough handling cycle. The cycle was

vibration in case lots at 1 G for one hour followed by a

series of 10 drops from a height of 46 cm (18 in.) (ASTM D-

775-68, Objective B). The treatments were followed by

visual examination and microbiological testing via a bio-

tester (17). Neither ﬁlm nor type of product had failures

exceeding the can—a tentative performance standard for

this type of testing could be 2% or fewer leakers as

detected by microbiological testing.

In addition, free-fall airdrop of cases of rations in a ﬁeld

test demonstrated that the pouch met the recovery criter-

ion of 75% useable items.

Indication of Spoilage (Leaking or, More Likely, Under-

processing). With metal cans, swelling (i.e., a convex lid

shape) has been traditionally used as a proven indication

of microbiological spoilage. Cans and pouches were

equally inoculated with gas-producing bacteria through

silicone sealant septa and monitored visually for swelling.

Obvious swelling of the pouch was doubling of its thick-

ness, easily judged by any user. The pouch showed gaseous

swelling in 48 h, while it took the can 72–120 h.

Deﬁnition of a ‘‘Good’’ Seal. Based on production ex-

perience, early ﬁeld tests, storage tests, and controlled

laboratory tests, the criteria for deﬁning a high-perfor-

mance seal for retort pouches was established as follows:

1. Fusion must exist.

2. Internal pressure level

. 20 psig

. Hold time: 30 s

. Maximum seal yield: 1/16 in.

. Restrained pouch thickness: 1/2 in.

3. Tensile strength level

. 12 lb/in.

. Crosshead speed: 10 in./min

. Sample width: 1/2 in.

4. Visual—No visible aberrations.

Fusion exists when the opposing seal surfaces form a weld

where neither surface is visually distinguishable when

seal area is tensioned beyond the point of failure. The

presence of fusion cannot be understated. A polymeric ﬁlm

heat seal can pass all requirements, including tensile and

burst tests and general appearance, at the time of forma-

tion but based on experience that was not good, such a

nonfusion seal will fail on storage. To assist visual judg-

ment of seals, a table of photographs has been assembled

showing acceptable and nonacceptable seal surfaces and

characteristics (4, 16).

Seal Defect Scanner. In cognizance of the vagaries of

human leak defect assessment, an automatic seal defect

detection apparatus was devised, built, and tested. The

procedure used infrared radiometric scanning of heated

seal surfaces. One surface of a seal was heated, and any

heat impeded by defects in the seal area was detected on

the opposite side by the infrared scanner. Both the heat

source and scanner were stationary; the package seal was

aligned and passed between these two elements, and

packages with defective seals were diverted. Scanning

speed was 6 in./s. The apparatus cost was considered

high. Another deterrent to its use in the mid-1970s,

ironically, was that a criterion for acceptance/rejection

was a problem. It was too sensitive, rejecting pouches

with very minor seal deformations that did not negatively

affect seal integrity.

Leakers. The pouches are currently scanned by humans

visually for defects including leaks during and immedi-

ately following production. Subsequent leakers are de-

tected by transportation handlers and users visually

and discarded. Swollen pouches including those possibly

caused by product caking and plugging leak sites are

discarded. This procedure fortunately works as evidenced

by the 22 years of successful reasonably cost-effective

production and use of the MRE at the current rate of 46

million meals per year.

Since the initial consideration of using ﬂexible packa-

ging for thermoprocessed foods, there has been concern

over the presence, signiﬁcance, and reliable detection of

leaks. The deﬁciency of visual inspection (even multiple

ones, loss of acuity with time-related fatigue) has been

cited as justiﬁcation to develop online detection devices. A

prerequisite to exploring objective leak detection concepts

is establishment of criterion (i.e., the smallest leak that

needs to be detected).

Finding leaks, on the pouch body or through seals, is

governed by two speciﬁc characteristics. First, whereas a

rigid

can exhibits a

pressure difference between the out-

side atmosphere and its contents that could suck contam-

ination through any void into the can, a pouch, on the

removal of headspace air, collapses around the contents to

a point where no external to contents pressure drop exists.

A bio-tester (18) was constructed to create a momentary

pressure difference and has been used as the primary

bacteria penetration detection apparatus.

Secondly, ﬂuid contents can plug defects and greatly

reduce the sensitivity of such detection devices as the

Mead Test (pulling a vacuum on a container submerged in

water). With dry products, a 5-mm-diameter defect could be

detected, while with a pouch ﬁlled with distilled water, even

a68-mm hole was not detected. The accumulated knowledge

on pouch leaks starting with tests on ﬁlms per se and

ending with production, handling, and ﬁeld experience

through 1979 (the active development period) included:

1. Single plies of polymeric materials contain pinholes

that could permit passage of bacteria. A three-ply

780 MILITARY FOOD PACKAGING

construction does not; the statistical chances of

three holes coinciding to allow bacterial passage

are extremely rare. Candidate polymeric ﬁlms are

not degraded by direct exposure to bacterial

concentrations.

2. Manipulation of foil containing laminates results in

minute breaks in the thin foil; these breaks do not

result in ﬁlm failure or microbial hazards. The total

area exposed by such foil breaks is insigniﬁcant in

that their effect on water vapor and oxygen trans-

mission is nil.

3. Using a laser (crudely because of their technical

infancy) to ‘‘drill’’ minute holes in a three-ply

retortable laminate and exposing ﬁlled pouches

made with this material, each having a ‘‘laser

hole’’ to a bacterial ‘‘soup’’ in a tester, a tentative

minimum, laboratory-created defect was listed as a

11-mm diameter hole. In perspective, such a hole/

defect size is roughly 1/10th the thickness of the

packaging material. Because of the small number

of samples, no statistically valid conclusion was

possible.

4. In one series of tests, retortable materials were

subjected to multiple ﬂexing, punctured by a ﬁne

sharp needle, and abrasion on a raised peak. Flexing

resulted in a porous area that permitted gas ﬂow but

could not be deﬁned even microscopically. Puncture

by a ﬁre-hardened ﬁne-tip needle resulted in rela-

tively large defects (greater than 100-mm size) that

were visually detectable. Abrasion caused a variety

of hole sizes, the smallest of which was equal to a

24.4-mm diameter round hole.

5. Pouches that failed during a rough handling cycle,

as established by biotesting, were examined micro-

scopically to try to deﬁne the size of leak sites.

The smallest was 20 15 mm, the next largest was

20 40 mm, six were in the 100- to 999-mm range,

and 24 were 1000 mm or larger.

Nine defects were undeﬁned or destroyed during pouch

opening.

At the time the MRE was accepted as the standard

combat ration, the best estimate on leak occurrence was

that one package in 100,000 could have a leak smaller

than 100 mm.

Leak Detection Methodology. In this Production Cap-

ability development time frame, a concerted effort was

made to determine if any nondestructive online- or line-

associated leak test method could be made to apply to the

retort pouch. Spencer and Bodman (19) surveyed 24

conceivably applicable concepts. Criteria were a 30-mm

channel through the seal area and a 10-mm defect on the

pouch body. For ﬂuid foods, the best candidate was a

change in the conductivity of deionized water by product

forced out of the package by compression. For solid foods

(i.e., beefsteak), a helium tracer gas procedure detected

holes as small as 30 mm.

In each case, however, the design of an apparatus to

cover handling, preparation for analysis, performing the

analysis, and recharging or resetting for the next pouch

would have approached the size and complexity of the

basic production line.

Implementation and Field Improvements

The Meal, Ready-to-Eat, Individual (MRE) replaced the

Meal, Combat, Individual (MCI, commonly and belatedly

still referred to as the C ration) in 1975 with the caveat

that testing be continued with the U.S. department of

Agriculture to conﬁrm that insect penetration would not

become a problem. Reportedly, after further exposure to

gnawing and chewing insects, there is no problem. Also, at

roughly this same time, as cited previously, notice was

received from the Food and Drug Administration that 0.3

to 3.0 ppb of toluene di-isocyanate was determined to be

extracted by products from adhesives systems used in the

lamination of the desire ﬁlms. Rather than try to cope with

adhesives, ﬁlm suppliers developed coextrusion techni-

ques with approved polymers, and current ﬁlms are so

currently formed.

The

MRE, as it

is currently conﬁgured (Figure 3),

consists of entree/starch, crackers, spread (cheese, peanut

butter, jam, or jelly), desert/snack, accessory packet (bev-

erages, condiments, matches, gum, toiletries), and ﬂame-

less ration heater (FRH).

There are 24 menus/12 meals to a case. Each meal

provides 1300 kcal. Water requirement is approximately

23 oz to rehydrate beverages. The FRH has been in each

meal bag since 1993. Each meal weighs 1.5 lb and takes up

1/12th of a cubic foot in volume.

The ﬁrst four or ﬁve procurements surfaced the need

for technical assistance to suppliers, a need for coordi-

nated support by the procurement agency, and the

engineering support function of the developer. The pro-

duction of retort pouched items, although based on a blend

of frozen and canned food capabilities, required a higher

level of ﬂexible package performance, and new inspection

standards, and it was viewed by its proponents as essen-

tially a new technology.

From this rather tenuous start, with strong institu-

tional review, assessment, and support, the MRE has been

improved in both individual item quality and menu con-

ﬁguration. Through the year 2004 procurement, MRE

XXVI, the ration has been expanded to 24 menus includ-

ing four vegetarian meals. Since 1993, 150 new items have

been approved; 35 least acceptable items have been elimi-

nated. Over 75% of ration components are now non-

developmental items—that is, adapted directly from

commercially prevalent items. At this time, the ration

usage rate is such that storage stability is not a factor of

concern. Providing combatants that represent a country-

wide demography is paramount. Currently, the MRE

usage rate is 46 million meals per year.

Nutritional adequacy, related directly to combatant

performance, has been periodically measured. For exam-

ple, Lichton et al. (20) evaluated the nutritional value of

the MRE during a 34-day ﬁeld exercise (at an elevation of

1800 m). Compared with a control group, those fed only

MREs lost weight. Neither group appeared to be dehy-

drated. Both groups displayed normal values of serum

MILITARY FOOD PACKAGING 781

proteins, vitamins, and zinc, denoting acceptable nutri-

tional status.

The old C-ration cans were heated in water, in an

inverted combat helmet, in a canteen cup using heat

tablets, or in bulk in water in any large barrel or tank.

The advent of the Kevlar helmet removed one common

ﬁeld heating method. Subsequently, after some user skep-

ticism, an effective ﬂameless ration heater was developed

and has been in each MRE meal bag since 1993. This 22-g

ﬂat card-like heater can heat 200 g of retort-pouched food

in roughly 10 min. Any water can be used to activate

the heating action. An initial version discharged a small

amount of hydrogen, innocuous during use, but considered

a possible hazard when multiple cases were transported in

a closed container. A new hydrogen-free ration heater has

been developed.

After all the technical effort and testing, the MRE, plus

the engineering support it requires, has now supported

the military person for over 20 years (Figure 4). The

current packaging materials and the ensuing pouch used

to prepare thermoprocessed ration items are given in

Performance Speciﬁcation MIL-PRF-44073F (Figure 5),

Change 3, November 2006.

The skeleton requirements as abstracted from the

speciﬁcation are:

1. Pouch material (from the inside to the outside)

a. Preformed pouches: 0.003- to 0.004-in.-thick poly-

oleﬁn, 0.00035- to 0.0007-in.-thick aluminum foil,

0.0006-in.-thick biaxially oriented polyamide-

type 6, 0.0005-in.-thick polyester.

b. Drawn pouch; tray-shaped body of a horizontal

form-ﬁll-seal system, tray-shaped body: 0.003- to

0.004-in.-thick polyoleﬁn, 0.0006 inch thick

biaxially oriented type-6 polyamide, 0.0015- to

0.00175-in.-thick aluminum foil, 0.0010- to

0.0014-in.-thick oriented polypropylene Lid,

0.003- to 0.004-in.-thick polyoleﬁn, 0.00035 to

0.0007 inch thick aluminum foil, 0.0005- to

0.00075-in.-thick polyester.

2. Pouch conﬁgurations are shown in Figure 5, and

dimensions are shown in Table 2.

3. Performance requirements are:

a. Material must be capable of being formed into

pouches.

b. Oxygen transmission rate must not exceed

0.06 cc/m

/24 h/atm; Water vapor transmission

rate must not exceed 0.01 g/m

/24 h.

c. Residual gas volume shall not exceed 10 cc for

fruit or 20 cc for non-fruit items.

d. Filled pouches shall withstand a pressure of

20 psig for 30 s.

e. Postprocessed pouches must withstand abuse at

281F with a survival rate of 75% and a survival

rate of 100% at 1601F.

f. Pouches including seals must be free of visual

defects.

g. The carton enclosing each pouch needs to con-

form to Speciﬁcation PPP-B-566, Boxes, Folding,

and Paperboard.

The MRE is constantly being improved and updated—

menus and materials. As of 2006, the MRE is destined

to continue to be the combat ration for the foreseeable

future.

Figure 3. Meal, Ready-to-Eat, Individual. The large bag, labeled ‘‘Meal,’’ contains the rest of the items shown. The light-colored bag is the

ﬂameless ration heater.

782 MILITARY FOOD PACKAGING

UNITIZED GROUP RATION (UGR)

When ﬁeld conditions permit group feeding in small units

or even larger congregations, the unitized group ration

(UGR) has been designed, tested, and ﬁelded for such

situations. The basic objective was to simplify the logistics

for supporting small group feeding. The traditional proce-

dure had been to order a slew of food items via individual

requests and, similarly, to assemble preparation, serving,

and dining ware. That is, for each ﬁeld operation, a

multitude of individual issue requests were submitted

and, on receipt of items, rather haphazardly assembled.

The UGR is a pre-assembly of all the preparation, dining,

and consumable items into a single unit to support a

designated number of personnel.

The unitized group ration (UGR) is a program designed

to provide the highest-quality group meals to troops in the

ﬁeld by increasing variety, consumption, acceptability, and

nutritional intake. It is an efﬁcient method to provide

breakfast, lunch, and dinner by packing 50 meals to-

gether. There are about 7 breakfast menus and 14 lunch

and dinner menus, depending on options, for selection.

The pre-mixed selection of menus ensures variety and

maximizes consumption by avoiding repetition and ennui.

The unitized ration also includes disposable trays, cups,

ﬂatware, and trash bags. There are four different group

ration options, namely, unitized Group Ration Heat and

Serve (UGR-H&S), unitized group ration A (UGR-A),

unitized group ration B (UGR-B), and the recently ﬁelded

addition to the UGR concept, the UGR-E (‘‘E’’ for express)

featuring self-heating.

UGR-H&S. This option is available for military per-

sonnel who are in the worldwide operations and

Figure 4. Combatant in the ﬁeld preparing to eat the MRE.

3/ 8 R, TYP 2 PLACES

‘V’ or ‘C’ SHAPED TEAR

NOTCHES AT TOP HALF

OF POUCH

BOTTOM EDGE

CLOSURE SEAL

ALTERNATE

LOCATIONS OF

TEAR NOTCHES AT

BOTTOM HALF OF

POUCH

E E

SIDE

SEAL

BOTTOM SEAL

ROUNDED CORNERS

AT ALL 4 CORNERS

(RADIUS ~ 3/ 8 in

Figure 5. Pouch conﬁguration.

MILITARY FOOD PACKAGING 783

have organized food service facility. It includes a

complete 50-person meal except for milk, cereal,

bread, fruits, and vegetables. The breakfast includes

a combination of egg, pork, beef, juice, dessert, and

others. The lunch and dinner includes a combination

of vegetable, meat, rice, pasta, juice, dessert, and

fruits. Each menu, including other enhancements,

provides about 1450 kcal per serving. The UGR-

H&S Option has a pallet containing 4 tiers, and

each tier provides about 100 meals assembled at

government depots. They have a shelf life of 18

months at 801 F.

UGR-A. The UGR-A is similar to UGR-H&S except

that this includes perishable/frozen type entrees (A-

Rations) along with commercial-type components.

Currently, there are 7 breakfast and 14 lunch/dinner

menus available, and they provide around 1450 kcal

of energy per serving. Each pallet contains about 12

modules or 600 meals built-to-order with direct

vendor delivery. The average shelf life is around

3–6 months for frozen entrees.

UGR-B. The UGR-B ration includes dehydrated

food and also commercial type items. Currently, it

offers 7 breakfast and 14 lunch/dinner menus, with

each meal providing an average of 1300 kcal of

energy per serving. Each pallet contains around

8 modules or 400 meals assembled at govern-

ment depots. They have a shelf life of 18 months at

801F.

UGR-E. As cited in Natick PAM 30–25, 7th edition,

November 2006, ‘‘The UGR-E includes separate

group-serving polymeric trays and/or institutional-

sized pouches that contain a shelf stable entre

Table 2. Pouch Dimensions

Pouch Sizes Dimensions (inches)

ABCDEF

5-oz size 4

to 6

1(7

)

max.

min.

to 7

) 1 max

Primary 8-oz size 4

,—

) 1 max

min.

Alternate 8-oz size 5

, 

) 1 max

min.

Figure 6. Case containing components of the Unitized Group Ration—Express (UGR-E) ; section cut open to display arrangement of

contents.

784 MILITARY FOOD PACKAGING

vegetable, starch, and dessert (Figure 6). Additional

items include drink pouches, snacks/candies, com-

partmented dining trays, disposable eating and ser-

ving utensils, condiments, beverage bases, napkins,

wet-naps, and a trash bag (Figure 7). The UGR-E

will be available in up to three breakfast and six

lunch/dinner menus. Each UGR-E will provide 18

complete meals. The self-heated meal modules may

be pre-positioned or carried by operational units. The

UGR-E has a minimum 18-month shelf life at 801F.

Each pallet contains 18 UGR-Es or 324 meals. When

a remote unit requires hot food, a tab is pulled to

activate the heaters. In 30 to 45 minutes the module

is opened and hot food is ready to be served in trays/

pouches to Warﬁghters, like a cook prepared meal.

After opening, the heaters continue to provide heat,

keeping the foods hotter longer.’’

SUMMATION

Current developments and support to combat feeding

emphasize improvements in quality, responsiveness to

menu likes and dislikes, ration designs compatible with

high mobility ﬁeld tactics, and minimizing the time and

complexity of individual and small group food prepara-

tion. In many instances, as opposed to activities prior to

World War II, the military is pioneering food product and

packaging development. At the same time, they utilize

applicable commercial items when advantageous. The

criticality of adequate nutrition to combatant performance

seems to be ﬁnally recongnized and institutionalized.

Acknowledgments: The administrative and technical contribu-

tions of all who delved into the myriad of concepts and require-

ments to support the satisfactory feeding of combat troops merit

special acknowledgment. The historical reviews by F. A. Koehler

and S. M. Moody were keys to coverage to World War II. I also

wish to acknowledge the encouragement plus the editing and

organizational support of Professor Kit L. Yam of Rutgers, the

State University of New Jersey, without which this contribution

would not have been completed.

BIBLIOGRAPHY

1. F. A. Koehler, ‘‘Army Operational Rations—Historical Back-

ground,’’ Spacial Rations for the Armed Forces, 1946–53,

QMC Historical Studies, series II, No. 6, Historical Branch,

Ofﬁce of the Quartermaster General, Washington, DC, 1958,

Chapter 1.

2. Anonymous. Conference and Notes on Rations, QMS, January

1949.

3. S. M. Moody, ‘‘Chow Time: Military Feeding’’ in Bunker Hill to

Bosnia: The History of the Development and Utilization of

Military Rations in the United States Armed Forces, 2000,

p. 90.

Figure 7. Components of the UGR-E; food and utensils to prepare and feed 18 combatants.

MILITARY FOOD PACKAGING 785

4. R. A. Lampi, G. L. Schulz, T. Ciavarini, and P. T. Burke,

‘‘Performance and Integrity of Retort Pouch Seals,’’ Food

Technol. 30, 38–48 (1976).

5. K. E. Paquette, ‘‘Irradiation of Prepackaged Food: Evolution

of the Food and Drug Administrations Regulation of

Packaging Materials’’ in Irradiation of Food and Packaging:

Recent Developments, ACS Symposium Series 875,

American Chemical Society, Washington, D.C., 2004, pp.

182–202.

6. V. A. Loveridge, and L. E. Milch, ‘‘Physical Evaluation of High

Dose Irradiated Multilayer Pouches.’’ in Irradiation of Food

and Packaging. Recent Developments, ACS Symposium Series

875, American Chemical Society, Washington, D.C., 2004, pp.

305–313.

7. Y. Tsutsumi, The growth of food packed in retortable pouches

in Japan. Presented at Annual Packaging Institute Forum,

Chicago, 1974.

8. F. Nughes, ‘‘European Developments in Retortable Pouch

Packaging,’’ presented at Annual Packaging Institute Forum,

Chicago, 1974.

9. R. A. Lampi, ‘‘Flexible Packaging for Thermoprocessed

Foods.’’ in E. M. Mrak, G. F. Stewart, and C. O. Chichester,

Advances in Food Research, Vol. 23, Academic Press, New

York, 1977, p. 305–428.

10. Y. Tsutsumi, ‘‘Retort Pouch—Its Development and

Applications to Foodstuffs in Japan,’’ J. Plastics. 49, 24–30,

(1972).

11. Y. Tsutsumi, ‘‘The Growth of Food Packed in Retortable

Pouches in Japan,’’ Act. Rep. Res. Dev. Assoc. Military Food

Packaging. Syst. 27(1), 149–153 (1975).

12. P. L. Goldfarb, ‘‘Pouch for low acid foods I,’’ Mod. Packaging

43(12), 70–76 (1970).

13. P. L. Goldfarb, Pouch for low acid foods II. Mod. Packaging

44(1), 70–76 (1971).

14. N. H. Mermelstein, ‘‘An Overview of the Retort Pouch in the

U.S.,’’ Food Technol. 28–37 (1976).

15. J. W. Szczeblowski, ‘‘An Assessment of the Flexible

Packaging Systems for heat processed foods,’’ Technical re-

port 71-57- GP, U.S. Army Natick Laboratories, Natick, MA,

1971.

16. G. L. Schulz, ‘‘Test Procedures and Performance Values

Required to Assure Reliability’’ in Proceedings, Symposium

on Flexible Packaging for Heat-Processed Foods, National

Academy of Sciences, National Research Council, 1973, p.

71–82.

17. D. T. Maunder, J. F. Folinazzo, and J. J. Killoran, ‘‘Bio-test

Method for Determining Integrity of Flexible Packages of Self

Stable Foods,’’ Food Technol. 22(5), 81 (1968).

18. G. O., Payne, Jr., C. J. Spiegel, and F. E. Long, ‘‘Study of

Extractable Substance and Microbial Penetration of

Polymeric Packaging Materials to Develop Flexible Plastic

Containers for Irradiation Sterilized Foods,’’ Technical report

69- 57-FL, U.S. Army Natick Laboratories, Natick, MA,

1969.

19. W. T. Spencer, and H. A. Bodman, ‘‘Non-destructive Testing of

Packages of Thermoprocessed Foods,’’ Final report Phase II

(Draft) Contract DAAG17- 69-C-0013, U.S. Army Natick

Laboratories, Natick, MA, 1970.

20. I. J. Lichton, J. B. Miyamura, and S. W. McNutt, Nutritional

Evaluation of Soldiers Subsisting on Meal, Ready-to-Eat

Operational Rations for an Extended Period: Body Measure-

ments, Hydration, and Blood Nutrients,’’ Am. J. Clin. Nutr.

48, 30–37 (1988).

MILITARY PACKAGING

JEANNE M. LUCCIARINI

ROBERT L. T ROTTIER

US Army Natick Soldier

Center, US Army Natick

Soldier RD&E Center

BACKGROUND

Developing food packaging to withstand the military logis-

tics system poses both unique and difﬁcult challenges.

There are unusual supply constraints caused by the world-

wide presence and the complex requirements of the Mili-

tary Services. Current and future logistical complexities

resulting from widely dispersed joint service operations,

multinational deployments, and humanitarian missions

have signiﬁcantly changed the operational and organiza-

tional strategies in recent years. Even during peacetime—

such as for humanitarian relief or disaster assistance—the

military must satisfy its essential supply needs, anywhere

in the world, at any point in time, and in the face of

potentially severe and extreme environmental conditions.

Moreover, the products inside must arrive in a usable

condition, with very low levels of damage. Unless the

rations retain the properties that make them suitable and

desirable for consumption, they will be ineffective—or

worse, they could pose a health hazard. Consequently,

packaging technologists and engineers must design packa-

ging systems in anticipation of worst-case supply situations.

The current military policy necessitates readiness to

counter aggression or to provide disaster assistance wher-

ever it occurs, thus requiring the prepositioning of rations

for subsequent mobilization anywhere in the world. Con-

sequently, military rations must be shelf-stable across a

wide temperature and humidity range over prolonged

periods of time. The current shelf-life requirement of

many ﬁelded rations is a minimum of 3 years at 801F

and 6 months at 1001F. In addition, air drop delivery of

some rations is to be expected. During development of the

military’s primary individual combat ration—the Meal,

Ready-to-Eat (MRE)—cases of meals were dropped free-

fall from an aircraft ﬂying at 110 knots indicated air speed

and at an absolute altitude of 150 feet. Based on those

tests, the required recovery rate of the MRE components

was set at a minimum of 75% and remains the require-

ment even today.

CURRENT PACKAGING SYSTEMS

As in the commercial market, plastic materials are ideally

suited for military food packaging. Plastic materials offer

advantages such as material strength, light weight, corro-

sion resistance, and versatility. Through lamination tech-

nology and the use of plastic materials, the military has

signiﬁcantly improved the quality of operational rations.

786 MILITARY PACKAGING

These improvements have resulted from decreased ther-

mal process times, decreased overall weight, and reduced

volume. The development of multilayer structures allows

one to tailor a packaging structure for a speciﬁc product,

thus relying on the synergism of the various materials.

Such materials are currently being used to package the

MRE, which is used to sustain individuals during opera-

tions that preclude organized food service facilities, but

where resupply is established or planned. Each meal

contains an entre

e/starch, crackers or snack bread, a

spread (cheese, peanut butter, or jelly), a dessert/snack,

beverage powders, an accessory packet, a plastic spoon,

and a ﬂameless ration heater (FRH). The ﬂexibly pack-

aged entre

es are thermally sterilized, or retorted, at

temperatures up to 2501F to ensure shelf stability. The

entre

es are packaged in a retortable pouch, which is a

quad-laminate material constructed, from the inside out,

of 0.003- to 0.004-in.-thick polyoleﬁn, 0.0035- to 0.0007-

in.-thick aluminum foil, 0.0006 inch thick biaxially or-

iented polyamide-type 6, and 0.0005-in.-thick pigmented

polyester. The polyoleﬁn used for the sealant layer is

typically cast polypropylene (cPP) because it provides

good heat sealability, ﬂexibility, and low taste and odor

transfer properties. The aluminum foil provides sufﬁcient

barrier to moisture and oxygen to meet the shelf-life

requirements. The polyamide layer was incorporated

into the structure in order to address handling and cold

weather issues. The outside layer is typically biaxially

oriented polyethylene terephthalate (BOPET) because it

provides good strength and toughness. It also has excel-

lent dimensional stability and heat resistance, which is

ideal for the elevated sealing temperatures that it

encounters.

Tri-laminate, high-barrier structures are also used to

package various components in the MRE that are not

retorted. For example, for the crackers and snack bread,

the packaging materials may be constructed, from the

inside out, of 0.003-in.-thick ionomer, 0.00035-in.-thick

aluminum foil, and 0.0005-in.-thick oriented PP. These

items are typically vacuum-packaged to prolong shelf life

and to facilitate the use of horizontal form/ﬁll/seal (FFS)

equipment. However, this type of vacuum-packing often

introduces problems with pinholes and ﬂex cracks in the

aluminum foil. The ionomer resin is used to alleviate this

problem due to its outstanding puncture and impact

resistance. Ionomers have ionic interchain forces that

stiffen the polymer chain without hurting the melt pro-

cessability, and, because of melt strength, are ideal for

FFS applications such as the MRE crackers and snack

bread. The ionomer layer may be substituted with a blend

of linear low-density polyethylene (LLDPE) and low-den-

sity polyethylene (LDPE). A major difference between this

structure and the retort pouch is that the adhesives used

to bond the layers of the retort pouch are more heat-

resistant. Other commercially packaged components (e.g.,

commercial candies) are typically overwrapped in similar

tri-laminate pouches if their primary package does not

provide sufﬁcient O

and H

O protection or rough hand-

ling survivability.

In 1993, the FRH was incorporated into the MRE. The

FRH consists of a chemical heating matrix composed

mainly of magnesium and iron enclosed in a heat sealable

nonwoven polyester scrim material and sealed in a high-

density polyethylene (HDPE) heater bag. The HDPE is

pigmented olive drab to address battleﬁeld signature

concerns. The electrochemical heaters are activated by

the addition of less than 2 oz of water, and the exothermic

reaction raises the temperature of an 8-oz entre

e 1001F

in 12 min or less. It also keeps the entre

e warm for

approximately 1 h if the tactical situation prevents the

user from eating immediately. HDPE was selected as

the heater bag material due to its chemical resistance,

good moisture barrier properties, good thermal proper-

ties, and good mechanical properties. The ﬁlm is processed

by blown ﬁlm extrusion and, because of the orientation

of the polymer chains in the direction of ﬂow, it tears

evenly in one direction only. This is important to facilitate

opening of the bag, since tear notches are incorporated

into the design. Due to its excellent thermal properties, it

is able to withstand the temperatures encountered during

the heating reaction. Its moisture barrier properties ade-

quately prevent the permeation of water vapor into the

bag during storage, which further prevents accidental

activation of the heater pad. In some instances, when

FRHs are pre-positioned onboard ships, the FRHs are

further overwrapped in foil pouches to eliminate moisture

ingress.

Another addition to the MRE is the water-activity

controlled, shelf-stable pouched snack bread. In order to

retard potential oxidation of the bread, a ferrous-based

oxygen scavenger sachet was added to the package. The

scavenger itself is packaged in a pouch constructed from

spunbonded polyoleﬁn, which allows the passage of oxy-

gen molecules into the sachet, thus extending the shelf life

of the bread product.

MODIFIED ATMOSPHERE PACKAGING

JEFFREY BRANDENBURG

The JSB Group, LLC,

Greenﬁeld, Massachusetts

Modiﬁed atmosphere packaging (MAP) is a term applied

to a range of food packaging technologies that rely on

mixtures of the atmospheric gases oxygen (O

), carbon

dioxide (CO

), and nitrogen (N

), in concentrations differ-

ent than those in air, to retard deterioration processes in

foods. Such atmospheres, sometimes with the addition of

small amounts of other gases such as carbon monoxide

(CO), ethanol (EtOH), sulfur dioxide (SO

), or argon (Ar),

maintain foods in a ‘‘fresh’’ state for periods of time

necessary to move them through extended distribution

and marketing chains.

The majority of these technologies rely on a combina-

tion of MAP and rigorous refrigeration to forestall

microbial and chemical deterioration. The key to the

technologies lies in the different concentrations and

MODIFIED ATMOSPHERE PACKAGING 787