Researchers at Dublin City University have developed a new system of food packaging which can tell you whether the food inside is fresh, writes Dick Ahlstrom
A team of Irish scientists has come up with the ultimate in food packaging - it tells you whether the food is fresh. A simple hand-held scanner lets you know whether the packaging is intact and the food is safe.
The Dublin City University research group believes the test system, Intellipak, could be worth billions of euro to food processors worldwide. It allows on-the-spot testing - either on the production line or in the home - without having to open the pack or destroy the product.
The key to the DCU approach is a barcode-like test strip that provides the information which is built into the packaging itself, explains the head of the research group behind Intellipak, Prof Brian MacCraith.
Consumer demand for fresh convenience foods has led food producers to develop new kinds of packaging that can protect fresh food from bacterial contamination, says MacCraith. "Increasingly, a lot of consumer food is packed in packages with modified atmospheres," he says of packs where the oxygen has been removed and replaced with gases such as nitrogen and carbon dioxide. "The idea is to extend shelf life," he adds. "Carbon dioxide actually retards spoilage organisms."
However, this modified atmosphere packaging (MAP) must remain intact , right through production, shipping, storage on retail shelves and all the way home to the consumer. Even a tiny leak would let in oxygen, which aids the growth of the bacteria that cause spoilage.
The challenge, however, is how can you tell if the packaging is intact?
The current practice, he said, involves random destructive testing. A pack is taken off the production line and its oxygen/carbon dioxide gas mix is measured. If the sample is bad it may mean having to destroy the complete batch or repackaging the entire run, a wasteful loss that can run into hundreds of thousands of euro, says MacCraith.
There is also the risk that packaging failures will not be picked up in random testing, only to reach the marketplace with a now meaningless "sell by" date. If the MAP has failed, then its sell by date will not be correct and the food will spoil more quickly.
"Our solution was getting rid of the random test and the destructive test by using a sensor film inside the pack," states MacCraith.
The Intellipak was developed at DCU's National Centre for Sensor Research. MacCraith is the director of this multi-disciplinary centre, which involves 25 research academics, and 130 full-time researchers including about 100 post-graduate and post-doctoral researchers.
The €12 million centre was funded by a grant from the Government's Programme for Research in Third Level Institutions, a scheme administered by the Higher Education Authority.
DCU has, for many years, been involved in sensor research, including chemical and bio-sensors, says MacCraith. "Sensor research has been going on here for 15 or 20 years. These are systems and devices for making very precise measurements in a range of applications. Increasingly, the focus is on biomedical applications."
The NCSR is always developing other forms of Intelligent Food Packaging. In particular, it has developed packs for monitoring fish freshness based on the gas emitted when fish degrades. This work is carried out in the lab of Dr Gillian McMahon and Prof Dermot Diamond.
The team developed a special film that could be built into the packaging and that had special characteristics. It has tiny micropores that can hold luminescent dyes, which means it can be printed upon and is inexpensive.
Prof Han Vos, at DCU, developed dyes that have measurable levels of fluorescence, depending on either oxygen or carbon dioxide levels, and team members Dr Aisling McEvoy and Dr Colette McDonagh worked on developing the special film.
The dye is applied to the film in barcode-like stripes on the inside of the pack. An inexpensive opto-electronic scanner can read the fluorescence of the barcode stripes, thus showing whether the MAP gas mix has changed. It is accurate to within a fraction of one percent, says MacCraith.
The luminescent dyes don't react with the gases, only indicate their levels, so it is a reversible, non-consuming interaction, he adds. The approach allows flow-through scanning, so virtually every pack can be tested for integrity and only those that fail need be repacked or discarded, saving unnecessary loss.
It would be simple enough for a consumer to use a scanner at home to confirm product safety, he says. "This is going to add very little to the cost of the packaging but it gives huge added value," MacCraith believes.
"There are some similar systems around the world, but we have shown we can test for two gases with one scanner," he says. "We believe that there is massive potential business for this. It really is a multi-billion market and it is an Irish solution."
The team is in the process of patenting the system and has involved a venture capital company to work up a business plan.