Survival of the smartest

Scientifically speaking, AIP spans a huge range, from oxygen scavengers to antimicrobials, and from time-temperature indicators (TTIs) to freshness indicators. Indicators harness a broad spectrum of technologies, from photoelectrics and polymerisation to microbiology. There is also a huge variety of natural antimicrobials.

The category of TTIs shows how opportunities and solutions are moving with the times.

Two and a half years ago, chemical firm BASF acquired Ciba. The Swiss company's portfolio of technologies included the OnVu TTI label, which BASF has since integrated into its Future Business division. OnVu operates on a temperature-sensitive ink system, where the pigment pales as temperatures rise above a preset threshold. Trigger temperatures and the speed of colour change can be customised to suit the application.

Senior manager for TTIs at BASF Martin Angehrn reports that one significant project in the UK has got past initial customer trials and is now at the chill chain testing stage. A final decision on a further "big name"​ application this time in continental Europe is expected early in 2012, he says.

These and existing applications with US seafood supplier Fresher than Fresh and Swiss poultry producer Kneuss (announced in the past couple of years) are examples of consumer-facing, item-level labelling. But other North American examples, says Angehrn, carry OnVu on the corrugated outer, aiming to provide the retail customer rather than the consumer with reassurance about the integrity of the chill chain.

For sound commercial reasons, technology suppliers such as BASF are keen to present item-level labelling as the real benefit for end-users. "There are some retailers in Europe using OnVu at a covert, logistics level, but even they see this as a stepwise approach to going item-level for the consumer," ​Angehrn states.

Those with long memories might remember similar debates about the item-level use of radio frequency identification tags. Champions of TTI technology will be eager to avoid falling into the lower-volume logistics-only trap, and would no doubt point out that the cost implications of item-level TTIs are very different.

But that leaves the question: What are TTIs for, anyway? Having sidestepped the traded-unit trap, suppliers risk getting stuck instead between a rock and a hard place, this time to do with the chill chain. After all, if a retailer has doubts about the security of its chill chain, it is likely to avoid arming consumers with TTIs. If, on the other hand, it knows the chain is secure, why bother going to the expense of endlessly proving it?

This is where marketing comes into its own. "We've just completed a major retail trial in Europe with over 1,000 products,"​ says Angehrn. "No deficiencies were highlighted in the chill chain for any item."​ In that case, why bother with a TTI? "Originally, the idea was that the label would be a tool with which the consumer could go back to the retailer."​ However, consumer surveys suggest otherwise.

"In fact, it's a tool to help the consumer keep the product fresh; a tool the retailer gives to the consumer." ​In other words, the real risk to chilled food is between the retail shelf and the consumer's fridge, and the TTI helps consumers to monitor that risk.

This summer, BASF introduced OnVu Ice for frozen food. Trials with the first small-scale customers are ongoing, but Angehrn says that the benefits of these applications are likely to be on a logistics rather than consumer level.

The survival of a given technology will not always depend upon it being the 'fittest'. But in terms of customer confidence, its chances will no doubt be helped by the support of a major industrial group. Only a few years ago, Timestrip was looking like one of the more promising TTI technologies, with applications including some among the larger brandowners. Last summer, the company behind it went into liquidation.

There is more than an element of 'natural' selection, too, in the development process. Angehrn admits that his job title leaves the door open to other TTI mechanisms. "We could add further technologies, but at this point, we're only looking at OnVu,"​ he says.

Nor is BASF scouting for other types of device such as 'freshness indicators', which are triggered by changes in the in-pack environment due to spoilage. This is not merely an oversight.

Freshness indicators​

The EU-funded online AIP Platform project recently held its concluding conference at which the work of partner institutes including ITENE, Spain, were showcased. ITENE researcher Inmaculada Lorente explains why freshness indicators are more challenging than TTIs. "Each product has a different spoilage kinetic, and the concentration of liberated metabolites in the headspace is never the same," ​she says. "So it is complicated developing a universal freshness indicator for all foodstuffs." ​

A meat product, for instance, could be affected by any one of several different types of bacteria. So which one do you monitor?

Part of the EU project's remit was to explore the potential for developing standards for the various AIP technologies. But in the case of TTIs and freshness indicators in particular, the range of mechanisms would present major difficulties.

One dynamic area of AIP that would merit exploration as a topic in its own right is antimicrobials. It could be argued that their action, like that of freshness indicators, is always going to be limited to certain foods and microorganisms. A universal antimicrobial is as unlikely as a universal freshness indicator. So why the far greater interest and research and development (R&D) effort?

For the researchers on the AIP Platform project, the distinction is clear. Food and drink firms will always be interested in technologies that extend shelf-life while relying on 'natural' additives in this case in the packaging.

Oxygen scavenging​

Another AIP strategy that is 'active', extending shelf-life rather than simply providing 'intelligent' information, is the oxygen scavenger. This absorbs oxygen from the headspace of a pack and so prevents or slows oxidative effects in sensitive product. This is an area where German supplier Albis Plastic is providing a strong R&D lead with its Shelfplus O2 system.

Coincidentally, both OnVu and Shelfplus were owned by Ciba before the BASF acquisition. The German chemicals giant chose to hang on to OnVu, but sold off the then underperforming oxygen scavenger business.

Since then, Albis has risen to the challenge. It too has, for now, focused on a single product its iron-based scavenger system. Its aim, it says, is to improve the system's efficiency by 500%.

It has started by reducing the size of the iron particles from 70 to 38 microns and improving dispersion through the polymer matrix to avoid agglomerations. "We are also using new additives to speed up performance and make more iron available,"​ product manager Torsten Clasen says.

In markets such as France and Germany, scavengers have for years been used in trays for long-life, ambient ready meals with oxygen-sensitive ingredients. They are also common in closures and even plastics bottles for vulnerable products such as beer.

Developing markets, says Clasen, include bag-in-box for wines, where a polyethylene valve can mean an "open door"​ for oxygen. "We've had good results from South Africa, where the quality of the wine is said to be much better after six months,"​ he says. Tests are continuing to monitor effects over the full product life of two years.

As well as polyethylene and polypropylene, Albis now offers a polyamide (nylon)-based variant. The idea is that by combining it with a strong passive barrier, the scavenger can in the longer term avoid the need for costlier layers such as aluminium and ethyl vinyl alcohol (EVOH) in structures such as pouches.

Meanwhile, with Germany's Fraunhofer IVV Institute, Albis has developed new applications in opaque trays for sliced meats. The products are in a modified atmosphere, but can discolour in the presence of oxygen.

Ciba carried out trials in the UK with Shelfplus for ready meal trays, but made little impact. Perhaps the fast turnaround in chilled meals makes shelf-life extension less of a priority here, but Clasen hopes that customers will look again at the higher-performing scavenger Albis offers.

Longer shelf-life is not always at the top of a manufacturer's wish list. In fact, Lorente at ITENE makes a strong case for the 'intelligent' rather than 'active' strand in AIP.

"The EU has made product traceability mandatory and, in fact, traceability in the supply chain has become a new factor of competitiveness in the food industry,"​ she says. "Intelligent packaging will directly support the successful implementation of this legislation." ​