Key Considerations for Frozen Food Packaging
Stefano Rizzato | Food Manufacturing
Global interest in frozen foods has soared in recent years, resulting in numerous growth opportunities for manufacturers. Expected to reach close to $9 billion (USD) by 2019, the global frozen food packaging market will grow at a compound annual growth rate of approximately 5 percent during the period 2016-2020.
Worldwide economic growth and rising incomes, as well as consumers’ increasingly busy lifestyles, mean that more and more people are looking for convenient meal options that fit within their busy lives. Technological advancements have also played a central role, with new film types and improved packaging designs coming to the forefront. Vertical form, fill and seal (VFFS) systems are widely used to package frozen produce due to their flexibility, high sealing performance, hygienic design and reliability in harsh environments. However, there are several considerations for manufacturers when specifying a frozen food packaging system.
The frozen food industry has some of the highest safety standards, particularly concerning sanitation and cleaning procedures. Food packaging machinery in this industry needs to withstand some of the most demanding sanitation requirements and cleaning procedures. Ingress Protection (IP) ratings are commonly used across the food industry to measure the protection level of equipment against solid objects, liquids and mechanical parts. Frozen food packaging technology should typically be IP65 protected. Such machinery offers total protection from dust ingress and harsh washdown procedures, including low-pressure water jets (from any direction).
Individual components of the packaging system are also required to meet regulatory requirements. The National Electrical Manufacturers Association’s NEMA 4x rating, for instance, stipulates that control systems must be protected against the ingress of solid foreign objects, such as windblown dust, as well as harmful effects on the equipment caused by water or ice. Typically more corrosive-resistant than standard NEMA 4 units, NEMA 4x enclosures are regularly used in food processing facilities to offer protection for controls systems, where total washdowns with disinfectants occur frequently.
A hygienically designed packaging system is one of the best ways to optimize food safety and quality. VFFS systems are a popular choice, as they are designed to leverage the benefits of gravity to transport products and their sloping surfaces make it is easier to prevent food residues from accumulating on the equipment. Easier access to machine parts further simplifies cleaning procedures. Ideally, cleaning should be possible without removing components; but if components need to be removed, it should have a tool-less design, with no loose parts. In addition, crevices, corners and other areas where food can build up are open invitations to cross-contamination. The packaging system design should therefore be free of features that create recesses, gaps and areas that are typically hard to clean.
Product application and the type of cleaning procedure often determine the best construction materials for the packaging system. When using harsh cleaning agents or frequent high-pressure washdowns, stainless steel is a must. It offers a smooth, defect-free surface to prevent product residue build-up, as well as easier cleaning. Alternatively, if dry cleaning is applied, food producers can consider other alternatives, such as aluminum.
Film choice is a key consideration for frozen food manufacturers. It not only increases visual appeal and informs consumers what’s inside, but it also plays a key role in protecting the contents, and can even improve the convenience of the product. Frozen food products have very specific characteristics, which will affect packaging material choice. Besides a frozen product’s possible sharp edges, the packaging must be able to withstand the pressures of sealing, freezing, storage, transportation, thawing and, in some cases, even cooking.
As with all foods that are stored for significant periods of time, packages should be protective against light and air to prevent product degradation. Failure to do so may result in loss of nutrients from the product, as well as “freshness” or perceived quality. When it comes to thawing, packaging materials should be liquid-tight to prevent leakages. The choice of packaging material and the thickness of the packaging film are therefore important attributes when packaging these types of goods.
Although single-layer films are available, packaging films in the frozen foods industry are typically based on multiple layers of different polymers. By combining different laminates, it’s possible to achieve specific film functionalities, depending on what is required in terms of barrier properties, sealability, printability and overall appearance and feel of the bag. For example, some manufacturers may want to present their product in opaque or colored bags, to protect the contents from the fluorescent lighting in some freezers or hide the ice crystals typically surrounding frozen foods.
The film’s compatibility with the chosen packaging system is equally important. For example, on VFFS systems, the coefficient of friction (COF) is a significant consideration, as it will directly affect the performance of the machine. Too much friction on the sealant side of the film can cause poor film feeding or inconsistent package sizes and slow down the packages’ progress through delivery chutes. On the other hand, too little friction on the outside can cause packages to slip or fall off inclined conveyor belts. Controlling the COF therefore means maximizing performance and avoiding issues in forming, transporting and storing frozen food products.
The type of sealing technology employed by manufacturers is crucial when trying to achieve an efficient packaging process. A high-quality seal ensures that the contents are fully protected against the intrusions of unwanted external materials or gases, and is also important for the overall visual appeal of the bag. Which type of sealing technology is the most suitable depends on the film material used.
Constant or direct heat sealing is particularly suitable for thicker films with a high melting point, such as coated Polypropylene, as constant heat sealers are able to reach higher controlled temperatures than other forms of sealing technology. VFFS systems with high thermal conductivity jaws provide additional benefits, as these can be up to 10 times more heat conductive than regular jaws, delivering optimal seal performance even on thick laminate films. They’re also better at maintaining a set temperature profile, mitigating potential temperature fluctuations that could affect the seal integrity when the cold film hits the hot sealing jaws.
Contrary to constant sealing technology, an impulse heat sealing system only applies an electrical current "on impulse." For this, a small piece of wire is heated instantly and then immediately cooled once the sealing process is complete, lowering operating costs as the sealing jaws are not required to be heated constantly. Additional benefits of impulse heat sealing technology include faster heat-up times and improved sealing accuracy on films with low melting points, like PE, for example -- making this technology a widely used choice within the frozen sector.
With the boom in the frozen food market, it’s vital that manufacturers can react quickly to meet the growing levels of consumer demand while also providing a safe product that is attractive and stands out among competitor products. VFFS systems are the ideal solution for frozen foods, as they can quickly and effectively bag a wide variety of products and operate well in the harsh environments of the frozen food industry. By optimizing their VFFS packaging process, manufacturers can further boost productivity and food safety while also increasing product shelf life and enhancing visual appeal to create a product that stands out.
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