RETAINING freshness and taste is a key objective with packaged foodstuffs but, in some cases, packing in air tight bags can create problems.
The contents, after the bag is sealed, can emit gasses, causing the bag to inflate, or even burst on some occasions.
An economically priced, locally produced solution is now available.
Initially developed for fresh coffee beans and freshly ground coffee - both of which give off gas after sealing in bags - the solution is a system incorporating a simple one-way valve into the material of the bag, at time of bag manufacture.
"Although such bags have been made in Europe and the United States it has not been the case in Australia, at least as far as I know," Jeremy West of West's Packaging Services said.
"Companies requiring such bags have been faced with the added costs and delays associated with importing from Europe or the U.S.
"We have recently installed new machinery that enables us to seal into laminated film (e.g. foils and Nylon Co-ex) a low cost polyethylene one-way valve.
"The valve has approvals for food in the United Kingdom, the European Union and the US," he said.
In the case of valves for coffee bags, there are two versions. One valve suited to beans and the other for ground coffee.
The ground coffee version has an additional membrane to prevent the coffee granules blocking the valve. By squeezing the bag the customer can smell the fresh aroma of the contents.
According to West's Packaging the pressure required for gas to pass through the valve is in the range of 3-4.5 millibar.
The valve is suited to incorporation in laminated film for stand up pouches (with or without a zipper), side gusseted bags or flat bags and does not interfere with print design.
"Until now, people requiring such packaging have had to import the bags which requires the purchasing of large quantities - for example, 100,000 - and having to wait up to ten to twelve weeks,” Mr West said.
“Now, quantities as small as 15,000 can be offered, lead times are only two to three weeks and at advantageous prices.”
According to the company, correct performance of the valve is guaranteed for a minimum of 12 months in storage in a wide temperature range and a relative humidity range of 30-75%.