Trends in meat packaging

The primary function of packaging is to contain the product, protect it and maintain its quality, as well as facilitate handling and provide information to the consumer. Packaging is an integral part of the strategies to maintain the quality and safety of meat and meat products.

In general, for fresh meat, plastic films obtained by lamination or coextrusion are used as primary packaging, as part of most packaging systems in combination with refrigeration or freezing.  Oxygen permeable packaging systems are very popular, although the shelf life is relatively short in comparison with other systems such as vacuum packing or modified atmosphere packaging (MAP).

The vacuum system aims to extract  the air and oxygen, at levels below 500 ppm of residual oxygen, preventing the proliferation of spoilage aerobic bacteria and reducing oxidation reactions, thus prolonging the shelf life of the meat for several weeks. In this system, the use of shrink films that contract around the product is preferred, avoiding the formation of folds of the packaging material where the residual air could be housed. During storage, tissue respiration and the development of anaerobic bacteria that have a slow growth takes place. However, exposure to conditions of abuse in the storage temperature can accelerate the development of psychrophilic microorganisms that will cause a rapid alteration and production of gas accompanied by the loss of vacuum.

The modified atmosphere packaging (MAP) comprises the exchange of air by a mixture of gases (oxygen, carbon monoxide, carbon dioxide and nitrogen) modifying the gaseous environment. Generally,  the mixture of gases consisting of different proportions of oxygen (O2), carbon monoxide (CO), carbon dioxide (CO2) and nitrogen (N2), which are classified into mixtures with a high oxygen content (70-80%) or mixtures of ultra-low oxygen concentration. It should be noted that there will always be a residual oxygen fraction within the muscle tissue;  besides,  the composition of the gaseous environment within the packaging may vary due to deficiencies in sealing, as well as by tissue respiration and microbial development.

In recent years, the use of smart packaging has become popular, as well as the active packaging. The former allows registration and provides information throughout the distribution chain, since may include time-temperature indicators generally related with quality and shelf-life.  On the other hand, active packaging potentiates the protective function of the packaging, ensuring the quality and safety of the product, derived from the incorporation of active agents such as organic acids, proteins or vegetable extracts with antimicrobial o antioxidant action within the matrix of the film.

In addition, composite and nanocomposite materials constitute a new generation of packaging materials formed by a plastic matrix with nanoparticles of carbon fibers, graphene, glass, or silicates, that improve  the barrier and mechanical properties. Plus, the use of bioplastics with mechanical properties like the synthetic films is growing fast. Examples of these bioplastics include polylactic acid (PLA), polyhydroxyalkanoate (PHA) and polyhydroxybutyrate (PHB), as well as mistures of protein, native and modified starches, chitin, chitosan, alginate, dextrins, pectins, cellulose fibers (bamboo, sugarcane, corn residues, among others). An additional advantage of composite and bioplastic packaging materials is that they can include in their structure a wide variety of functional agents, thus facilitating the creation of active packaging, as well as the possible reduction of preservatives in clean label products.

Regardless of the type of material, some properties that determine the selection of the packaging materials include the mechanical strength, the barrier properties associated with low permeability to gases, aromas, water vapor, oxygen; also, the sealing efficiency, as well as the ease of printing and cost, along with the environmental impact that is becoming increasingly relevant.

This topic was authored by  the AMEXITEC (Mexican Association of Meat Science and Technology) was founded in 2008, with the aim to generate and promote scientific knowledge on issues related to the meat science and technology. AMEXITEC is integrated by a network of researchers, academics, students, industrialists, and professionals related to the meat industry.

Be part of AMEXITEC by visiting our website and attend our 4^th Virtual Forum on October 26-27 https://amexitec.org/index.php/4to-foro-amexitec