Packaging for the good, the bad & the downright dangerous

10 March 2021

Moulds, yeast and bacteria exist everywhere on earth. They flourish in the soil of the farms that grow our grains and on fruit and vegetables, they also exist in water and in the air that we breath. Many of these organisms can be beneficial, for instance: lactic acid bacteria have been used by man for at least 4000 years for fermentation purposes or as cultures to preserve foods or enhance taste, appearance and texture. They are probably best known for the role they play in the fermentation of milk products such as yogurt, cheeses, butter and Kefir. Cultured milk products such as yogurt which contains lactic acid bacteria it is claimed can improve gastrointestinal function. Lactic acid cultures are now cultivated and exploited by food scientists which in turn is enabling many brand owners to bring many probiotic enhanced products to market.

Let’s turn our attention to yeast. Yeasts act as a raising or leavening agent and as most people know they are used in baking and brewing. Yeast is present naturally on red grape skin and for some wines this can be enough for the fermentation process. For a number of alcoholic beverages, a pure yeast culture: an example being Saccharomyces cerevisiae can be employed. This is used in breadmaking and in brewing of the ale type of beers. Saccharomyces is known as a top-fermenting yeast as it forms foam on the top of the beer. For beverages such as lager a bottom fermenting yeast: Saccharomyces pastorianus is an option.

Some moulds are positively encouraged to proliferate to provide many speciality cheeses with a distinctive taste. Moulds such a Penicillium camembert are used to ripen Brie and Camembert from the outside in. And of course, moulds, such as penicillium have enabled chemists and other scientists to develop antibiotics to treat many diseases that were once fatal.
While many of the microscopic flora such as moulds and fungi are beneficial in one way or another, there are those that create serious problem when encountered in our food and drinks and even in the water used to rinse fruit and vegetables.
The problems associated with these micro-organisms is that they may make food unpalatable. Food products such as meat, fish and numerous other items including beverages such as fruit juices and smoothies may develop undesirable flavours and odour when consumed by their use-by-date. Moreover, the appearance and texture of food and drink can change due to microbial growth. Another more dangerous problem is the spread of disease. Moulds, yeasts and bacteria are not the only micro-organisms that can jeopardise food and beverage items. Viruses such as hepatitis and parainfluenza may be transmitted via food products. Protozoan cysts of Giardia Lambia found in contaminated rinse waters can cause a human intestinal infection.

Washing of food is one of the most basic and oldest methods of microbial control. In food processing plants water is used for soaking, cleaning, blanching and chilling and often continues on with water being used for cooling, sanitising and then on to steam generation for sterilisation and even power and process heating. Sanitary conditions have always been of concern to anyone involved in the harvesting of fruit and vegetables and the manufacture of foodstuffs and beverages. Disinfection through chlorination has been widely used over the years but the generation of chlorination by-

products and associated toxicity as well as the odour and taste. Sterilisation and the use of UV-C germicidal radiative technology are some of the alternative options. While various technologies are used to safeguard the integrity of food during production or at post harvesting of fruit and vegetables it is equally important that the integrity and safety of a product is maintained at every point up to and including distribution, shipment thru to retail display and on up to the time the product is purchased by the consumer, taken home and then consumed by use-by-date. The safe and appropriate containment of food and beverages is dependent upon the suitable selection and use of packaging materials.

Selecting the most suitable packaging material for a product is often far from straight forward. Fruits and vegetables, fruit juices and many other food and beverages have different shelf lives. Vegetable items and most fruits have a high-water content. They are often easily bruised, easily crushed and split, which encourages the growth of fungi, bacteria and moulds. Not to mention providing an entry point for insects. The high-water content and the acidic nature of some items makes them susceptible to spoilage by yeasts. Fruit and vegetables are subject to an endogenous and degenerative process called senescence, in effect they breath and respire. Senescence cannot be stopped but various packaging technologies, materials structures and fast farm to plate pick, pack and distribution minimises wastage.

Retailers only have a short window of opportunity to shift products off the shelf. Once the product is out on display the product deterioration clock starts ticking. Shelf life even with modified atmosphere packaging and laminated, coated or multi-web barrier packaging materials can only be drawn out so far. Selecting the most appropriate packaging method is critical but so too is presentation. A pack that catches the eye of the consumer has more of a chance of being bought than one that has a wishy- washy colour design and is poorly printed.

Packaging material must be clearly labelled, must incorporate information on point of origin, harvesting date, shipper and size/weight of produce. With fruit and vegetable produce there is often a mix of packaging with both primary and secondary packaging of equal importance. Items may come in multi-pack corrugated or fibre case-board boxes that contain individually wrapped items. An example being clamshell packaging. This is a form of semi rigid plastic increasingly used for protecting a premium priced item such as avocado or slices of melon. Often the hinge of the clamshell is sealed by the label, which incorporates an aggressive adhesive.

Goods with a high-water content and a short shelf life may be ensconced in shrink wrap plastic. This helps reduce shrinkage and helps prevent the spread of microbial contamination. The surface of the shrink wrap is receptive to printed labels.

Let’s move on to another produce area, one that makes use of beneficial microbial organisms such as lactic acid but is also subject to spoilage by moulds, etc. Cheese is often packaged in LLDPE (low linear density polyethylene) or BOPP (bi-axially oriented polypropylene). These together with plastic/metallised Laminates enhance the strength of the pack, preserving the freshness and regulating moisture content. Water vapour, light and oxygen transmission rate affect cheese quality. Light and residual oxygen can result in the oxidation of fats that can impart an off taste, which is particularly noticeable in cheddar cheese. An insufficient vacuum in the pack or a compromised seal can result in oxygen not being excluded from the pack, which encourages the growth of moulds.

Brand owners of artisan cheeses in particular use packaging not just for protection but as an important differentiator. As such the packaging materials used are often innovative and on pack decoration must be of the highest quality. Innovative packaging materials used include wooden baskets, fabric and tinplate, colourised metallised papers and foils and paperboard boxes (for gifts). Some French cheese producers use a type of cheese paper or muslin cloth for ‘folk’ cheeses that are associated with different regions of the country.

Brand owners are keen to communicate brand history, the uniqueness and authenticity of the product and indeed, as with any other product category on pack decoration, judicious use of colour and illustrative content is of critical importance.
Colour communication or proofing devices enables users of many description to meet colour targets accurately, quickly and with minimal waste. At the same time, pilot coating, print and laminating systems such as RK Print Coat Instruments VCML-Lab/Pilot coater can be used for small scale production, the testing and trialling of materials so as to ensure material/ink compatibility, best method for coating adhesives or laminates and for determining what works and what doesn’t and to determine commercial and product viability.

The VCML Lab/Pilot Coater enables operators to print, coat and laminate on all types of flexible substrates and on a reel-to-reel basis. It has the ability to apply various inks, varnishes, adhesives and paint using environmentally acceptable formulations and where necessary – solvent-based materials as well.

The VCML Lab/Pilot Coater has a web width of up to 300mm, is touch-screen controlled and is equipped with a cantilevered unwind and rewind, head mounting station with tray lift and trough and a laminator station with pneumatic nip. Flexography, offset gravure and gravure, knife over roll, reverse roll coating, meter bar, slot die and many other processing options can be made available. The VCML can be configured for hot air drying, infrared and UV curing. The system can undertake corona treating; edge guide and heated laminator and ATEX coating zone can all be integrated in with the system.

Returning to the subject of colour communication. Colour quickly becomes associated in the mind of the consumer with specific brands and products. If the previous purchase has been positive, many consumers will go on to make repeat purchases of the brand or product using colour and on pack identifiers as retail signposting mechanisms. If colour is perceived as being ‘off’ for any reason the potential customer may avoid the item assuming that the product contained within the pack is also not quite right.

The FlexiProof, available in three variants, the original FlexiProof 100, the FlexiProof UV and FlexiProof LED UV can highlight potential issues associated with flexo inks and substrates before they become problematic on the production press. Apart from colour matching, the FlexiProof is useful for determining printability issues such as gloss, rub and chemical resistance, durability and so on.

Colour communication devices for print processes other than flexo are also available including the K Printing Proofer for producing proofs using gravure, gravure-offset and flexo inks. This device can also produce wet or dry laminating samples.

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