International debate about the future (or lack of it) of antimicrobial food packaging is becoming more polarised, with larger suppliers still deterred by perceived risks in some markets, while in others rigid and flexible packs are already in use.
A joint venture by Spain's Zaragoza University and local converter Artibal first produced commercialised semi-rigid polyethylene terephthalate packaging with an integral antimicrobial agent two-and-a-half years ago. Of this application, professor of analytical chemistry Cristina Nerin will only say: "This is a non protein-based processed food, without additives. Shelf-life has been extended from one month to six and in 2007 distribution was extended to other parts of Europe."
The active antimicrobials used here and in polypropylene and low-density polyethylene flexible packs have included cinnamon extract and other "naturally-occurring" extracts. As Nerin explains, these types of essential oil and their constituents are classified as 'flavourings' under an EU Commission decision from 2002, and as Generally Recognised as Safe by the Food and Drug Administration in the US. Of the agents used in Artibal's packs, she says: "We've tested migration levels, and they fulfil all the legislative conditions."
Nerin, who knows of no other commercial production of antimicrobial plastics packaging, claims that the price premium on films incorporating these additives is minimal.
More recently, the Zaragoza team has worked with flexibles for baked goods. An almond cake for Spanish company Puyet has been wrapped in a film with integral cinnamon extract, extending the shelf-life from 15 to 45 days "with excellent results", says Nerin. With an even more complex bakery product, the original three-day shelf-life was stretched to 11 days.
Zaragoza University has also worked with natural antioxidants such as rosemary. And Artibal has commercialised films using this type of 'radical scavenger' technology.
Despite Zaragoza's confidence in the technology, others, such as multinational supplier of desiccants and iron-based antioxidants Multisorb, are far more cautious. Global manager for the specialty foods market John Solomon says: "We have looked at the different antimicrobial technologies. We feel that they would expose any supplier to potential legal claims for years to come." The perception, at least in the US, appears to be that the guarantees of food safety required for an antimicrobial would compromise suppliers far more than other technologies.
Consumer resistance could be another thorny issue. It is significant, for instance, that some of the Spanish brands using Artibal antimicrobial agents do not want the fact publicised - even though they are derived from edible plants.