A retort pouch is commonly defined as a flexible pouch for low-acid foods that are thermally processed in a pressure vessel, often called a "retort." The pouch is made of layered polyester, aluminum foil, and polypropylene. Commercial sterilization occurs at temperatures greater than 212 °F, typically 240 to 250 °F. The retort packaging is shelf stable at room temperature.

The history of retort pouches goes back to the 1960s when the military used them to replace C-Rations. They are lightweight and take up less space than canned goods. The development of the retort process had to overcome such problems as heat penetration, temperature distribution (some areas of the product cooking faster than others, resulting in hot or cold spots within the pouches), and residual air inside the package. Retort pouches are now available in clear or foil materials and are in several shapes. Special retort pouch features include hanger holes, pour spouts, handles, and tear notches.

The retort pouch has several advantages. It weighs less than a metal can. It is flexible, meaning that it can handle a lot of abuse when taken away from home or on military maneuvers. Because it is flat, it takes up little space, making it easier to carry in a backpack or pocket. The flat shape also gives the pouch an advantage during processing. In the plant, the pouch is filled with food, sealed, and then retorted at temperatures of 240 to 250 °F to commercially sterilize the contents. Because a pouch is flat, it takes much less time than a metal can does to heat the contents to the point of commercial sterilization. That can result in a better tasting product.

MRE stands for "Meal, Ready-to-Eat." MRE's were originally designed for the U.S. government and have been used since the 1970's in the U.S. space program, U.S. military, and USDA's Forest Service. The MRE package is officially known as a tri-laminate retort pouch. It contains normal food that is ready to heat and consume, such as chili or beef stew.

Yes. MRE's are shelf stable because they have been commercially sterilized by heat in a sealed container to destroy bacteria that can make it unsafe or spoil the food. Like food in metal cans, MRE's can be kept for a long time, but not indefinitely. The shelf life is highly related to the storage temperature. For example, if stored at 120 °F (a temperature that could be encountered on desert battlefields), the MRE should be used within a month. Stored at 60 °F, an MRE can last 7 years or more.

Nearly any type of food that comes in cans may be processed in retort packaging. Examples of food packaged in retort packages are chili, ham, chicken breasts, and tuna fish. These foods are available on grocery store shelves.

Aseptic packaging is the process by which microorganisms are prevented from entering a package during and after packaging. During aseptic processing, a sterilized package is filled with a commercially sterile food product and sealed within the confines of a hygienic environment.

Yes. There are no health concerns associated with aseptic packaging. The inside layer of an aseptic package, which touches the product, is polyethylene (plastic). There is no leaching of aluminum or aluminum components through the polyethylene layer. The polyethylene used in the aseptic package, low-density polyethylene (LDPE), is an FDA-approved food-contact surface material. It is the only material in the package that comes in contact with the food product. In addition, industry tests have shown that no polyethylene leaches into the food product.

Aseptic packaging is a beverage system first developed in Europe in cooperation with the World Health Organization to provide beverages such as milk and water to people involved in disasters. It was introduced to the United States in the early 1980's.

In retort packaging, food is filled into a pouch or metal can, sealed, and then heated to extremely high temperatures, rendering the product commercially sterile. In aseptic packaging, the food or beverage is sterilized by quick exposure to ultra-high heat, rapidly cooled to an ambient temperature, and filled into sterilized containers that are then sealed in a commercially sterile environment. However, the assembled aseptic package is not further processed like retort products.

An aseptic package, sometimes called a "drink box," is a laminate of three materials: high-quality paperboard, polyethylene, and aluminum. Paper (70%) provides stiffness, strength, and the efficient brick shape to the package. Polyethylene (24%) on the innermost layer forms the seals that make the package liquid-tight. A protective coating on the exterior keeps the package dry. Aluminum (6%) is the silver material on the inside of the aseptic package. This ultra-thin layer of foil forms a barrier against light and oxygen, eliminating the need for refrigeration and preventing spoilage without using preservatives.

Aseptically packaged products include milk, juices, tomatoes, soups, broths, tofu, soy beverages, wines, liquid eggs, whipping cream, and teas.

No. Because aseptic cartons contain a micro-thin layer of aluminum foil, the package cannot be used in a microwave. Check with the manufacturer of the product for specific information.

No, it requires refrigeration. Sous Vide is a French phrase meaning "under vacuum." Most Sous Vide food is used in foodservice establishments such as restaurants, but some is becoming available to consumers. With this method, fresh, raw ingredients or partially cooked ingredients are vacuum-sealed in a plastic pouch. The pouch is heat processed, quickly chilled, and transported under refrigeration. Sous vide products must be kept refrigerated, but can be stored for 3 to 4 weeks. To serve, you simply heat the bag in boiling water.

Absorbent packing: material within a package which absorbs liquids from product; pad in meat trays is made from paper and has a plastic liner.

Aseptic packaging: a technique for creating a shelf-stable container by placing a commercially sterile product into a commercially sterile container in a commercially sterile environment. The sealed container is designed to maintain product sterility until the seal is broken.

Bacon wrapper paper: a glassine, greaseproof, or vegetable parchment paper, or a laminated product made from these papers and other materials, used for wrapping bacon.

Blister packaging: the item is secured between a preformed (usually transparent plastic) dome or "bubble" and a paperboard surface or "carrier"; also referred to as a "bubble pack." (example: bologna package hanging on a peg in a supermarket's refrigerated case).

Boil-in-bag: a sealed container made of heat-resistant material designed to hold a food product and permit the ultimate user to bring the bag and product to boiling temperature in preparation for eating before the product is removed from the bag. (example: frozen entrees or vegetables).

Breathing package: packaging material made in such a manner that air may enter or leave under varying conditions, including temperature changes, with or without a drying agent to remove moisture from entering the package. Most wrap used for fresh red meat allows enough air to pass through to keep the proper color in the meat.

Can: a receptacle generally having less than 1 gallon capacity (consumer or institutional sizes); also means to pack a product in a can or a wide-mouth glass container for processing, shipping or storage.

Cardboard: term erroneously used for "paperboard." A stiff, moderately thick paperboard; heavier than paper. (example: used for frozen entrees).

CAP "controlled atmosphere packaging": a packaging method in which selected atmospheric concentrations of gases are maintained throughout storage in order to extend product shelf life. Gas may either be evacuated or introduced to achieve the desired atmosphere. Normally used for fruits and vegetables, not meat products.

CPET (crystallized polyethylene terephthalate): a heat-tolerant plastic that can be molded into multi-compartment and single frozen food containers; can be heated in the microwave or conventional oven.

Delicatessen paper: used as an inner wrap for meats and for soft foods to retain the moisture in the food and to prevent the outer wrapper from becoming water- or grease-soaked; made from bleached chemical wood pulp and may be given a dry paraffin wax treatment of about 10 to 20-percent of the weight of the paper.

Fiberboard can: a rigid container constructed almost completely of lightweight fiber stock; may be lined, treated or coated; ends of can may be made of paperboard or metal (composite can). (examples: packaging used for juice concentrates, potato sticks and onion rings)

Flexible container: bags, envelopes, pouches or wraps which can be changed in shape or bent manually; made of materials such as paper, plastic film, foils, etc., or combinations of them.

Foam trays and other foam shapes: made from expanded polystyrene (EPS); formed when foaming agents are added to polystyrene and passed through a die. (examples: trays for fresh meat; egg cartons) Styrofoam [trade mark] is an insulation used in building materials; it's not used in packaging.

Frozen foods paper: a type of high moisture and water vapor resistant paper used for inner liners in frozen food packaging; usually specially treated glassine or bleached chemical wood papers, waxed papers, or plain or coated vegetable parchment paper; pliable and strong to resist cracking at freezing temperatures and for high wet strength.

Glassine: smooth, dense, transparent or semi-transparent paper manufactured primarily from chemical wood pulps; is grease resistant and has a high resistance to the passage of air. May be waxed, lacquered or laminated to be impervious to the transmission of moisture vapor. White and colors.

Meat wrapping paper: a specially treated odorless and tasteless paper that resists meat juices, fat and grease, and is easy to remove from any kind of meat.

Metal can: a rigid metal container made of steel sheet or plate, 27 gauge or less in thickness, or a similar container made of aluminum, copper or other metal. (example: food cans).

Migration: transfer of a component of a packaging material into the product contained, or loss of a component of the product into the packaging material.

MAP ("modified atmosphere packaging"): a packaging method in which a combination of gases such as oxygen, carbon dioxide and nitrogen is introduced into the package at the time of closure. Purpose is to extend shelf life of the product packaged. (example: lunch meat in a blister package).

Netting (plastic): continuous extruded net of flexible plastic material, most commonly polyethylene, which can be made into bags, sleeves or wraps. (example: net over a frozen turkey package).

Nylon: nylon is a versatile family of thermoplastic resins that vary from relatively flexible products to tough, strong and stiff materials; resistant to oils and greases; widely used for meat and cheese packaging, for boil-in-bags and pouches.

Ovenable board: a paperboard that can be placed in an oven (microwave or conventional) to serve as the cooking utensil for food; typically a solid, bleached sulphate board coated with polyester terephthalate. (example: frozen entrees).

Packaging: the enclosure of products in a wrap, pouch, bag, box, cup, tray, can, tube, bottle or other container form to perform one or more of the following functions: 1. containment for handling, transportation and use; 2. preservation and protection of the contents for required shelf and use life; 3. identification of contents, quantity, quality and manufacturer; 4. facilitate dispensing and use.

Plasticizer: material added during the manufacturing process to increase flexibility; for example, the plasticizer ATBC (acetyl tributyl citrate), used in such DowBrands™ as Saran™ and Handiwrap™, is made from citric acid which is commonly present in citrus fruit.

Polyester, thermoset: filled plastic which is heated to harden into a shape and does not soften when heated during normal cooking temperatures; example: plastic dishes in frozen dinner entrees; can be heated in the microwave or conventional oven.

PET ("polyethylene terephthalate"): a thermoplastic polyester used in beverage bottles and food trays designed for microwave and conventional ovens.

Polyethylene film: the most-used transparent flexible packaging material; made from polyethylene, a synthetic clear compound formed by subjecting ethylene, a gas found in coal, to pressure. It is low cost, transparent, tough, heat sealable, moisture-proof and resistant to low temperatures. Examples: Glad® & Handiwrap™.

PVC ("polyvinyl chloride"): replaced cellophane as the preferred meat wrapping used in supermarkets; a member of the vinyl family made from a compound found in petroleum. Low cost, protects against moisture loss, but has some oxygen permeability so it allows meat to "bloom" (stay red and fresh looking).

Polypropylene: a synthetic resin plastic packaging material used for microwave-only heating of foods with low fat and sugar content; not heat stable for use in conventional ovens.

Polyvinylidene Chloride: ("polly-vanilla-deen") a thermoplastic polymer which can withstand higher temperatures than polyethylene; especially useful for covering utensils when microwaving foods; moisture-proof and transparent. (example: Saran Wrap™)

Retort packaging: a flexible container typically formed from aluminum foil and plastic laminants. Can withstand in-package sterilization of the product, and, like metal food cans, can provide a shelf-stable package for foods.

Shrink wrapping: plastic film that shrinks when heated, producing a tight, neat fit; the most popular form of grocery store meat packaging is PVC wrapping with foam trays.

Vacuum packaging: rigid or flexible containers from which substantially all air has been removed before sealing. Carbon dioxide or nitrogen may be introduced into the container. This process prolongs shelf life, preserves the flavors and retards bacterial growth.