Testing Time for the Packaging of Fresh, Frozen, and Processed Meat Products
By Tom Kerchiss, RK Print Coat Instruments
Food technologists, health and safety legislators, food quality inspectors, chemists, packaging technocrats; the converters and consumable providers and others, including brand owners and marketing professionals take the packaging of fresh and processed meats very seriously. The material that surrounds or wraps meat must securely contain the product and protect the meat and meat by products from a wide range of contaminants that may compromise the appearance, taste, texture and aroma of the produce or affect the health and well-being of consumers. Bacteria, yeasts and moulds are of high concern but so too is contamination from parasites and from chemicals and from the effects of light, oxygen and loss or uptake of too much moisture: water absorption and evaporation.
Meat products may be sold fresh from the butchery counter, sold from the freezer in the supermarket for ready transfer to the freezer at home and sold from chiller cabinets and even purchased non refrigerated in retort pouches and in various other forms of packaging configurations. Produce may be packed with an inner pack which is in direct contact with the product such as a foil container or laminate and then enclosed with a decorative outer pack or sleeve often of paper or paperboard to provide for marketing and information.
Semi-rigid, rigid and flexible plastic materials are available. With regard to flexible filmic structures they are generally engineered to provide good mechanical strength yet they are light in weight, offer good sealing capabilities and barrier resistance.
For both practical and aesthetic reasons good barrier resistance against oxygen and evaporation is high on the packaging technologist agenda. Air needs to be excluded from meat packs because oxygen affects meat that is not effectively sealed, turning the colour of meat from an acceptable colour to an unpalatable grey, brown or green. Not only is this unattractive it also means that oxidation and rancidity of fats is or has taken place. This gives an off taste when consumed. This problem is particularly noticeable when meat is sold as deli items which are prominently displayed for the consumer to view and select. In an attempt to counter the effect of oxygen as a spoiler meat and meat products such as pate and spreads are often packed using oxygen resistant films. These filmic materials may be utilised in vacuum packaging, ensuring that virtually no oxygen remains in the pack or can penetrate into the pack.
But its not just oxygen that can cause colour changes in meat along with rancidity, etc., light can be equally problematic. For really light sensitive products, meat can be packed in either coloured or opaque substrates. A decorative printed PS overlay or a printed card when the meat is packed in a thermoformed tray and covered with plastic film can minimise exposure to light, at the same time enhancing the perception of the brand with the inclusion of logo, bright colours and cooking instructions, etc.
Transparent packaging film is favoured where the potential for high product turnaround is required or t least envisaged. Marketers, brand owners and retailers are united in preferring to use transparent materials, where and when its possible because it allows for attractive presentation and encourages sales.
Products may be processed and packed using a variety of techniques and technology. One method that is suitable for small cuts of meat such as a chicken portion, steak or sausages is form shrink technology whereby the produce is placed between two sheets of shrinkable films which are then moulded together to completely and almost seamlessly encompass the product. A PS label is affixed with relevant information and a marketing message. Form shrink, sometimes termed skin packaging is generally economically only for long runs and is carried out on packaging machines equipped with sealing station.
Vacuum packaging, shrinkable films, modified atmosphere packaging (MAP), retort and laminated pouches or rigid films moulded and shaped are also available. The choice of packaging material, the processing and decorative/informational to be employed is not always clear cut and often the decision on which material or materials to use comes about as the result of extensive substrate and consumable trialling. Different processes and applications often have specific performance requirements that have to be met. For instance, with frozen food packaging puncture resilience especially pin hole resistance is as important as barrier performance and light resistance.
With frozen food packaging low temperature resistance over long periods is an obvious requirement but abrasion resistance and resilience against impact as the rough surfaces of a product or products rub against the surface of a flexible packaging bag are essential. Packaging, which includes the inks, adhesives for the seal; laminates and coatings must be able to survive temperature extremes including the rapid thaw process when the product is shortly to be consumed.
New ink and coating formulations as well as substrates make it easier to print cleaner graphic images that improve freezer and chiller presence. Blends of low-density polyethylene with low density polyethylene remain popular but filmic materials tailored to provide specific mechanical and optical properties abound.
Packaging for many of the speciality or expensive cuts of meat must support premium pricing and mark the product out as being something special. For an elegant appearance but without compromising on quality and functionality, vacuum packs overlaid with paperboard provides optimum billboarding opportunities. With modern print decorative processes such as flexography, UV flexo and gravure and combination the artistic possibilities are almost limitless.
Form, functional properties and product appearance needs to be monitored in order that process variables such as colour accuracy, printability, ink, coating and other elements are bought under control and that nothing mars brand Image. Equally its important that processes and materials are compatible, that the right print process and coating technology is suitable and any potential problems are dealt with prior to commercial production.
RK Print Coat Instruments VCML-Lab/Pilot Coater permits many types of companies serving many different product sectors to trial materials, processes and formulae and to determine the suitability of coating technologies, laminate and print processes for an application taking into account factors such as product and commercial viability.
The VCML-Lab/Pilot Coater can print, coat and laminate on all types of flexible substrates and on a reel to reel basis. The operator can apply various inks, varnishes, adhesives and even paint using environmentally acceptable formulations and where necessary solvent-based materials as well.
The system also offers short production run capability which makes it ideal for product monitoring, the undertaking of many ‘real time, real world’ tests and procedures and for speedily bringing new products to market.
The VCML-Lab/Pilot Coater has a web width of 300mm, is touch screen controlled and is equipped with a cantilevered unwind and rewind as well as a head mounting station with tray lift and trough and a laminator with pneumatic nip. Flexography, offset-gravure and gravure; knife over roll; reverse coating; meter bar; slot die and numerous other processing options can be made available. It can be configured for hot air drying, infrared and UV curing. Corona treatment, edge guide and heated laminator and ATEX coating zone can be integrated in with the system.
Finally, with so much riding on appearance RK offer a wide range of colour communication or proofing devices that help printers and converters to meet colour targets and make the product look as inviting as possible. The FlexiProof family consisting of the original FlexiProof 100 and variants, FlexiProof UV and FlexiProof LED UV enables users that are involved with the flexo process, including ink and substrate producers to determine elements associated with printability such as gloss, durability, chemical resistance and rub resistance. As the FlexiProof is essentially a scaled down but component critically exact version of a flexographic press it can be used for pilot runs, the processing of unfamiliar product materials, product monitoring and many R & D projects.
RK Print Coat Instruments Ltd
Litlington, Royston, Hertfordshire SG8 0QZ
www.rkprint.com sales@rkprint.com
Source: RK Print Coat Instruments Ltd
