Home > Packaging of Meat and Poultry Products

The packaging market in India seems set for the next level of growth. Strong favourable demographics aside, factors such as increasing income levels, rising consumer awareness and demand for processed food, and the multinational giants taking rapid strides in the food industry, are expected to be the key drivers of this growth story. These factors are forcing both packaging suppliers and end-user industry to shift from bulk packaging to retail, and unit-level and small-sized packaging. Although fresh meat is highly perishable, its packaging has, until recently, been a matter of only minor concern to meat traders, health officials, and consumers. Packaging is not just the materials immediately surrounding a product, it is equally essential to address specific functional and marketing requirements. These functions relate to all aspects of distribution, storage, and merchandizing along with containment, protection, preservation, portioning, convenience, and  communication. For meat and meat products, packaging should provide the customer with an appropriately portioned product in a safe and wholesome condition. The functional requirements of meat packaging systems are dictated by the required marketing performance. For example, the packaging requirements for international trade in chilled meat differ from those for domestic supply. The overriding performance requirement is, however, the same in both cases – adequate storage life ensuring product resilience to meet customer expectations.

Functions of the Package:

a. Protective Functions and Labels: A major function of the package is to serve as protection from external environment, which include temperature, moisture or humidity, oxygen, airborne
particles, and light. It must also protect against biological contamination from microorganisms, rodents, insects, and other pests. A package further serves as a marketing tool because it must
provide space for a label that carries information, such as product identification, ingredients, nutritional information, net weight, verification of inspection, cooking instructions, company
name and location, and instructions on how to contact the processor. Labels today frequently display the Universal Product QR Code, which is critical to laser scanning at the check-out
counter in virtually all stores and also plays an important role in inventory management.

The package must protect against loss or gain of moisture and regulate permeation of gases such as oxygen, carbon dioxide and nitrogen. This allows the package to function in managing meat color and appearance by minimizing oxidation, influencing color, odor, flavor, and safety, and also provide the environment to discourage microbial growth, which in turn delays the occurrence of spoilage and lessens the impact of food borne pathogens. The package cannot improve or completely stabilize the product quality, but it can only slow down quality deterioration. A major consideration is product’s shelf life, especially in the light of long distances for distribution of product to the ultimate consumers.

b. Barrier Properties and other package requirements: The barrier property of a packaging material is a measure of the resistance offered to a permeant, irrespective of it being gas like oxygen, carbon dioxide, nitrogen, or carbon monoxide; or moisture vapor; or a sensory trait such as aroma. This information is a very important part of a film or package specification.

Considerations in selecting and designing a package include strength factors, which include tensile, elongation and tear strength, and resistance to puncture, all of which should be considered at all temperature and humidity conditions expected. The shelf life of the film itself is important. Machinability factors include stiffness and slip (which affects the ability of people to open bags); and merchandising factors like clarity or transparency, gloss, absence of an undesired film color, and antifogging characteristics are important. The most widely considered factor, or the bottom-line trait, is the cost. It not only includes the film cost, equipment costs and labor involvement, losses due to the consequences for the product of package failure must also be strongly considered in determining cost.

Other important properties of films include flowability, machinability, printability, stability over a wide temperature range, shrinkability, thermoformability, and seal strength. Visual traits
such as clarity, sparkle, absence of color and antifog (minimizing of condensation on the inside of the package) are very desirable. Some marketing options include packages with zip openers
and resealable packages, such as luncheon meat packaging with resticking properties that allow it to be reopened and sealed multiple times.

Packaging materials and techniques:

a. Wrapping: The simplest form of flexible packaging – wrapping – does not require machinery at all. A meat product is simply placed on a sheet of material, often greaseproof paper or plastic cling film, which is wrapped around the product to protect it from the environment and vice versa.

b. Tray with Over-wrap: Retail cuts of fresh meat are generally placed in rigid trays of expanded polystyrene or clear plastic trays, over-wrapped with transparent plastic films. The advantages of using these trays are that they are non-absorbent and aesthetically appealing. Usually blotters are kept at the base of the tray to absorb meat juice. The over wrapping film should have excellent optical properties. Cellophane coated with nitrocellulose on one side has been in use for wrapping fresh meat for a long time. The un-coated side is kept in contact with the meat. Meat thus wrapped, can be kept for approximately 10 days at a temperature of 0°C before it becomes microbiologically unacceptable. However, it would be un-saleable in less than half this time because although still edible, it changes colour from red to an unattractive brown. If during storage, there are fluctuations in temperature up to 5°C (which is quite likely commercially) the actual shelf-life would be only 2 days. The storage life of meat is dependent on the initial level of bacterial contamination and the temperature during storage. Generally, therefore pre-packed fresh meat are refrigerated as near as possible to –1°C, which is the lowest temperature at which meat can be stored without freezing it.

c. Shrink packaging: Plastic Shrink films are used for wrapping large and uneven cuts of fresh meat. It is a technique in which heat shrinkable polymer film is shrunk around the meat product by application of heat to achieve a skin-tight and compact pack. The packaging film should have structural strength. It should be a good water vapour barrier and be capable of withstanding storage temperature of about – 45°C. The advantages include neat appearance, ease in handling and a contour fit. Hot tunnels are used to effect a tight wrap. Heat shrinkable polyvinyl chloride, polypropylene, irradiated polyethylene PVDC and rubber hydrochloride are used to shrink wrap fresh meat.

d. Vacuum Packaging: The basic principle of vacuum packaging is quite simple and has been successfully used commercially. The preservative effect in vacuum packs is achieved by removing air from within the pack and maintaining an oxygen deficient environment around the product by sealing the product in a flexible film of low oxygen permeability. This oxygen deficient in-pack environment extends the product’s storage life by selecting a slower growing anaerobic spoilage microflora and preventing the proliferation of the fast growing aerobic spoilage organisms. The plastic film used for vacuum packaging must have a high resistance to gases and water vapour with perfect seals and good mechanical strength. Since vacuum packaging provides a barrier to the product from oxygen and moisture, it is suitable for a period of 3 weeks. The most commonly used film for fresh meat vacuum packaging is PVDC (poly vinylidene chloride). It offers low oxygen permeability and shrink characteristics so that large cuts can be kept for up to 21 days with minimum loss of moisture. Typical packaging materials used are Polyethylene / co-polymer coated cellulose film laminates, Polyester / polyethylene film laminates, Polyamide / polyethylene laminates, laminates of plastic film with aluminium foil, PVDC co-polymer films, EVA / Saran / EVA laminates, Nylon / EVA / laminates, PVDC / Polyester / PVDC / PE laminates, LDPE / BA / nylon / BA /LDPE and etc.

Packaging of fresh meat:

Fresh meat is highly perishable and a biologically active item. The quality of fresh meat is affected by the growth of micro-organisms, enzyme activity and by oxidation. The microbiological activity continues even after refrigeration and packaging, though at a reduced rate. The factors that make fresh meat unsaleble are changes in colour, odour, taste and texture. The pigments present in fresh meat are proteins like hemoglobin and myoglobin. Hemoglobin does the function of transfer of oxygen from the blood and myoglobin acts as a storage mechanism of oxygen in cells. Myoglobin has a purple red colour, which is the characteristic colour of fresh meat when it is first cut. In presence of oxygen, there is formation of oxymyoglobin, which imparts a bright red colour to the meat. In the absence of oxygen, oxymyoglobin gets reconverted to myoglobin. An undesirable brown colour is formed due to metamyoglobin when meat gets exposed to air for a few days. Yet another form of discolouration on the surface of the meat, which is dark reddish-brown colour is due to loss of moisture. Dehydration of meat on the surface results in concentration of the pigments. Further concentration of pigments occurs, when the interior moisture containing dissolved pigments migrates to the surface and evaporates. Another factor, which accelerates desiccation and oxidation of meat, is ultraviolet light. Undesirable flavours, odours and textures can occur due to the action of enzymes, molds, bacteria and oxygen if they are not properly  controlled. During the storage of fresh meat, the flavour / odour may get affected due to the pick-up of foreign odours or as a result of oxidative rancidity. Hence, the principal role of fresh meat package is:

• To prevent moisture loss
• To offer the product to the consumers in most desirable colour-red bloom
• To prevent further bacterial contamination of meat
• To arrest pick up of foreign flavour and odour by meat
• To control oxygen transfer

To prevent dehydration, a relative humidity of 85% to 95% is required during storage. This can be achieved by use of a packaging material, which has a good water vapour barrier. Fresh meat should be stored at 0°C and 85 to 90% RH.

Packaging of frozen meat:

Major portion of exports of meat from India is in frozen form. Preservation of meat by freezing, offers the greatest advantages of increase in shelf-life, inhibition of bacterial growth and preservation of fresh texture and flavour. If frozen meat is not properly packed there is continuous dehydration from the surface resulting in freezer burn. This condition affects the surface texture and colour. Meat fat is also prone to the development of oxidative rancidity if a good oxygen barrier is not used. Hence, frozen meat needs protection against:

• Dehydration and loss of surface texture
• Moisture loss
• Temperature fluctuations
• Rancidification
• Pick up of odours / flavours
• Expansion and contractions which occur during freezing and thawing

Packaging requirements

A suitable packaging material must, therefore, have a very low moisture vapour and oxygen transmission rate. The material should also be durable at freezer temperature, have very high wet strength and be impermeable to odour and flavours. Packaging Materials Plastics are amongst the most commonly used materials for packaging of frozen meat Generally, low density polyethylene (150 – 200 gauge) is used for this purpose as it provides adequate clarity and is stable at low temperatures and is available at low cost. Polyester or Nylon / PE laminates and heat shrinkable low density polyethylene and PVC / PVDC co-polymer films also provide functional properties, besides giving neat appearance to the frozen meat cuts. Shrink packaging also allows convenient handling of the product. Frozen meat may be in the form of chunks, minced or various cuts. The unit packs consist of 1, 2, 4 or 8 lbs in LDPE bags of 250 – 350 gauge. After placing the meat in the bags, the bag is folded and then the packed product is blast frozen at – 40°C for a period of 4 to 12 hrs depending upon the size and shape of the package. After freezing, unit packages are packed and stored in corrugated boxes made of either paper or plastic, which are either waxed internally, or on both the surfaces. These boxes are stored at -20°C and the expected shelf-life for the product is around one year.

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• Handbook of Meat & Poultry Processing

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