Throughout history mankind has struggled to preserve food by various means, including protective packaging. However, packaging that is not recyclable or sustainable has ravaged Planet Earth. The time has come for packaging to transform from being merely a barrier to becoming an active and intelligent participant in the fight against food spoilage. This demands the development of futuristic technology and a high level of social responsibility.
Avengers: Endgame is a recently released superhero film that has gone on to become the highest grossing film of 2019, with worldwide box office collections amounting to about US$ 2.5 billion. In the film a band of superheroes come together to save the world, which has been disintegrated by Thanos, an inter-galactic warlord. Each of those superhero characters is endowed with special powers that contribute in the fight against the destructive forces of Thanos. At the end of a bitter struggle, the Avengers emerge victorious and our world is preserved!
Something similar to the latest Avengers appears to be going on in the packaging world. An endless war for preservation of packaged food quality is being fought. The destructive forces of disintegration due to oxidation or microbial attacks need to be combatted. Freshness of packaged food has to be preserved without having to resort to the addition of alien preservatives, which may be harmful to health.
In the end, the Earth itself needs to be preserved from degradation caused by the pollution from discarded packaging material. Therefore, the traditionally understood role of packaging merely as a means of containment has begun to change. In order to maintain their relevance, packaging materials need to become active and intelligent agents to join the fight for food preservation as well as the safety of planet earth.
Enter the Scavengers
At this point we need to better understand the role that emerging new ‘active’ packaging films can play. Such packaging and films are the new heroes of packaging – The Scavengers!
Let us begin by understanding more closely the benefits of active packaging technology and what exactly the Scavengers can be expected to achieve.
As is commonly known, oxidative degradation is one of the most prevalent causes of food spoilage. Preservation of food against oxidative spoilage will help in increasing the product shelf life. As a consequence, it will also help to improve product acceptance by customers. The longer shelf life will even help to widen distribution of the product and provide better food security. Extension of shelf life also helps to reduce the extent of food thrown away due to expiry of ‘use by’ date. It reduces the amount of space needed for landfills. It allows food to be stored over longer periods and that can be of vital importance at the time of drought or natural calamities.
By improvement of preservation technology consumers can be offered a preservative free ‘fresh food’ range of products. As consumers become more aware of the harmful effects of chemical preservatives, there is a clamor of demand for such preservative-free products. The new methods of food preservation enabled by active packaging materials has also made possible the packaging of highly perishable products, which were previously considered impractical to package.
Active packaging materials primarily aim at removing (or scavenging) dissolved oxygen (or CO2, ethylene or moisture) from the product by interacting with the product instead of serving merely as a barrier or means of containment. Globally, oxygen absorbing – or scavenging – systems with high barrier packaging are considered reliable and are a preferred choice for the food industry. In this way the packaging plays an active role in preserving the color, texture and aroma of various food products and also inhibits the growth of food spoilage microbes.
Active anti-microbial packaging systems are designed to actively modify the environment inside the pack by continuous interaction with the product over the entire duration of its shelf life. This helps to alter the state of the environment and headspace, as well as the product, inside the pack. In this way the sensory qualities of the product inside the food package get enhanced, microbial safety is maintained and shelf life gets extended.
Scavenging systems that are reported to have now been developed and commercialized in the US and Japan are capable of absorbing deleterious compounds from the food surface (or from the headspace) or vice versa to emit certain compounds to act on the food surface and prevent growth of aerobic bacteria and molds. (www.frontiersin.org: Antimicrobial Food Packaging.)
Timed release agents
A sophisticated version of active packaging that is under development is the idea of Controlled Release Packaging. It focuses on creating a ‘delivery vehicle’ that releases the active substances at specifically controlled rates over prolonged periods to maintain the quality and safety of the food. By timed release of the antimicrobial agents at a targeted level over prolonged periods, the deterioration effect of microbial growth is controlled and keeps the food safe for consumption. It is notable that the idea of timed or slow release active agents is not new in prescription medication, vitamins or antioxidants and has been in commercial use for decades. However, the concept of Controlled Release food packaging materials is new and is undergoing research.
For example, bacteriocins are incorporated into food packaging films to control spoilage caused by food pathogenic microorganisms. The packaging needs to ensure that the antimicrobial film is in direct contact with the food surface such that the bacteriocins can diffuse across it. This method is reported to be more effective than dipping or spraying the food with bacteriocins. (Note: Bacteriocins is ‘a protein produced by bacteria of one strain that is active against those of closely related strains.’)
Similarly, HDPE and LDPE films loaded with Potassium Sorbate have been found to display antimicrobial and antimycotic (or antifungal) qualities for enhancing the shelf life of cheese. A natural antimicrobial known as Lysozyme has been effectively incorporated in PVOH films to be able to display effective antimicrobial action. Nisin (a food preservative) coated polymer films like PVC, Nylon and LLDPE have been observed to inhibit pathogen growth on packaged fresh meat. In fact, there appears to be a profusion of such research aimed at developing a range of diverse antimicrobial films capable of preserving meat, dairy, bakery, fresh agro or processed food. Research is also being carried out to determine the optimum methods of incorporating the antimicrobial agents into the films, from spraying to heat press to casting. More details about such developments may be found at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4375217/.
There is no denying that these days globally there is a challenge to the packaging world. In terms of its impact on the environment and on our lives it is expected to, as they say, shape-up or ship-out. In this context the role of emerging superhero materials – the scavengers, the anti-oxidants and the anti-microbials – is vital.
However, despite the many advantages such materials have the potential to offer, it is curious that the market has been slow to accept the technology. The initial assumption about this lack of market response appears to be that the technology has not yet been scaled up. The user industry is unwilling to accept the higher costs involved and unable to get the required health and safety clearance.
To check out the assumption I spoke to senior flexible packaging industry insiders and attempted to understand what is hindering the adoption of active packaging growth in India.
When asked how far active packaging technology has penetrated in India, the answer was, “next to nil.” When asked, why, the answer was, “two main reasons – unaffordable extra cost and lack of FFS machines being developed to handle active films.” Regarding the latter it was pointed out that in order to remain effective, scavenging films must be prevented from becoming saturated during the production and filling process. In addition, the scavenger must be made to function inside the pack only and not start scavenging from its external environment too.
Given the enormous potential of this technology and the benefits it can deliver across the value-chain, the reasons cited for its slow growth appear trivial and not insurmountable. The time has come now for the super packaging materials to appear boldly and stand up for the future and be counted as Preservers – not polluters.