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Psshhhht - the familiar sound of opening a bottle of fizzy drink. Marketers know the power that noise can have in awakening our thirst, but it also provides an indication that the seal to the bottle has remained intact until the moment the consumer chooses to open it.

In sensitive sectors such as food, drink and pharmaceuticals, proof that a product has not been opened or tampered with is vital to reassure consumers of a product’s hygiene and authenticity. High-value products are particularly at risk of empty packaging being refilled with substandard ingredients and sold on as the real thing. To protect their brands and consumers, manufacturers are employing a growing range of tamper-evidence devices. These can take a number of forms, from plastic tear strips around the base of a cap, to film seals under a lid and labels that self-destruct when removed.

Tetra Pak’s research and development team concentrates on three senses when designing new tamper-evidence features – feeling, seeing and hearing – and every device should use at least two senses. A plastic cap with a detachable, drop-down band beneath it is potentially apparent to all three senses; the consumer can see and feel the gap between cap and band and may be able to hear the bridges between the two breaking.

Two become one
Retail manager for the UK and Ireland Ian Williamson says that it is particularly important to meet at least two senses in order to cater for customers with disabilities, as people who are deaf or blind will not be able to detect a purely audible or visual indicator. However, two sensory indicators in a tamper device can be reassuring for everyone.

When Tetra Pak first put caps and closures on to its cartons it used a removable membrane under the cap to show if a carton had been opened. However, Williamson says there is a move towards one-step opening to increase convenience – removing the need to unscrew the cap and then peel off a film.

Early last year, the firm started trials of the Tetra Top Eifel 038, which opens in one movement with no membrane required beneath the cap. A ‘slip skirt’ is used, which is a plastic base that clamps on to the underside of the carton top. When the cap is twisted off, the seal is broken between the cap and the slip skirt which remains in place. The carton can still be given a hermetic seal because the cap is applied before the cartons are filled and are integral to the pack. The cartons are filled upside down, then the base is sealed and the cartons are rotated, explains Williamson. The Tetra Top one-step opening is now in use in Europe and the company hopes it will extend to the UK.

Bapco Closures has also been working to make the lid and tamper device integral to a pack, but in a very different way. The Guildford-based closure manufacturer first removes the original neck from the container. Then a laminated foil is induction welded on to the jar before the neck is applied. The foil has a built-in ring-pull device. This is then overcapped with a simple screw or flip cap. The foil traps the vacuum, rather than the overcap, which is therefore easier to twist off. Sales and marketing director Neil Fowell says that any attempt to open the container would destroy the foil, which is impossible to replace without removing the neck.

The closure could be used for a range of products, but we have had a lot of interest from companies that produce car oil. They have huge issues, particularly in parts of Asia. If you use a normal seal, then when the oil canisters are thrown away they can be washed out, refilled and sold on, says Fowell.

The Bapco closure also means that the main body of the pack can be lightweighted. Because the neck is separate to the body, the body does not need to be thick enough to support the threading required for a screw cap. Fowell says the Bapco closure is roughly on a par price-wise with similar products.

Last year, a Bapco closure was launched on Tropicana’s easy-pour pitcher in the US. The company is also working with some  high-profile food brands in the UK.

Bapco works extensively with RPC in the UK. However, RPC also has dedicated closure facilities of its own at RPC Halstead. Phil Goodwins, sales and marketing manager at RPC Halstead, argues that for closures and tamper evidence it is often a case of simplicity sells. He explains that tooling costs for manufacturing caps are very high and unless a major manufacturer has a really large brand that they would like to launch with a bespoke cap, people are generally looking for off-the-shelf solutions.

Tooling for a closure is around three to four times the cost of tooling for a bottle because a cap has to perform so many more functions, he says. The closure, he points out, can sometimes get left to the last minute. It does happen occasionally that a company is about to launch a product and has considered the bottle and then suddenly realises they need a cap and they haven’t thought about what size orifice they want or how far the flip top has to go back.

Lasting ideas
Goodwins says the vast majority of work at Halstead uses an induction heat sealed foil under the cap to provide tamper evidence – this also has the advantage of making the container leak proof, even without the cap. Halstead also manufactures detachable drop-down tamper bands and break tabs. What’s out there in the market works well – that’s why it’s been out there for so long, he adds.

Silgan White Cap, part of the American company Silgan Holdings, has combined two long-standing tamper-evidence devices into one closure. The composite closure combines a drop-down tamper band with a pop-up button commonly found in the centre of metal lids on glass jars. Silgan White Cap, which is based in Germany, has developed two composite press-on twist-off caps – the 40mm Band-Guard and the 51mm PT-Band, which is patent pending. When the cap is opened for the first time, the seal is broken and the central button pops up with an audible click – the plastic band is permanently detached so customers can hear, see and feel the change.

While there is innovation in the development of tamper-evidence devices, it centres on modifying existing methods – as in the case of Bapco Closures, which has taken a standard induction sealed foil and made it more secure. Or, as in the case of Silgan, in combining existing methods. And the message for all forms of tamper evidence closures appears to be that seeing, feeling and hearing is believing.

INTO THE VOID
Payne Security head of marketing Simon Wildash says that while tear tapes were initially introduced to film overwraps to make packaging easier to open, they also provide important tamper evidence as their use destroys the integrity of the pack.

Tear tapes are commonly used for products ranging from biscuits and chewing gum to cigarettes and are usually a thin red ribbon applied to the underside of the film. As the film is formed into a pack, the tear tape is already in place.

Payne Security also manufactures ‘void’ labels and frangible labels, both of which can be applied over a pack’s opening to show if it has been tampered with. Void labels leave a layer of adhesive behind when they are removed. The adhesive contains ink, which will commonly say ‘void’ or something similar. A frangible label contains microcuts and slits so that it self-destructs when removed.

Tamper evidence is normally part of a larger brand protection strategy, incorporating counterfeiting and authentication as well as anti-tamper devices, says Wildash. Anti-tamper devices can work well when combined with anti-counterfeiting devices such as holograms and colour shift inks – which appear one colour when viewed from one angle and a different colour from another angle. 

Wildash explains that it would be possible to build a hologram into a label so that when the label is removed the hologram is destroyed. Devices such as holograms, colour-shift inks and microtext are difficult and expensive for counterfeiters to reproduce.

Microtext is text too small to be visible to the naked eye; it will often have the appearance of a line and can be incorporated into a design or full size text on the pack. Under a magnifying glass, text sized between 80 and 150 microns is revealed. Wildash explains that an average printing press would not be capable of this level of detail. You need the machinery and the know-how. We can print microtext on all our gravure presses using special cylinders, he adds.

When anti-tamper and anti-counterfeit devices are combined, something as simple as a tear tape or label can protect not just an individual pack but a brand’s reputation.