A new, highly sensitive testing method whereby leaking packages can be detected right on the packaging line has been developed for food packages. This package leak tester developed in Finland measures minute leakages in less than a second. The first testers will be introduced on packaging lines during spring 1999.

The patented leakage detection method (Espoon Paineilma Oy, Finland) is based on the introduction of a small amount of hydrogen trace gas into the package, which enables even the smallest of leakages to be rapidly detected without damaging the package. This method, which won an award given by the International Association of Packaging Research Institutes in 1998, is based on the use of a highly sensitive trace gas detector. The package is conveyed along the packaging line to a test chamber where trace gas flow from a package with a defective seam is rapidly detected by the sensor system. The trace gas employed by the method is safe and suitable for use with foodstuffs.
"The advantageous physical properties of the trace gas, such as low molecular weight and extremely low background concentration in air as well as the sensitive sensor enable reliable leak detection. Moreover, the method is relatively
inexpensive," says Eero Hurme of VTT Biotechnology and Food Research.
The leak tester is suitable for use in detecting leaks from most packages with a headspace, such as flowpacks, deep draw packages and carton containers. The leak tester is also suitable for detecting leaks in vacuum packages. In such cases the trace gas is added to the package either before packaging or by means of overpressurisation after packaging.
"The suitability of various testing equipment for detecting leakages in packaging for ready-to-eat foods and sterilised products has already been studied for many years. The leak testing equipment now being introduced for use on packaging lines is the first apparatus suitable for on-line measurement of gable-top cartons," says Tapani Penttinen, Development Manager for Stora Enso Paperboards. In trial runs the leak tester has been used with Walkican and gable-top cartons in Stora Enso Paperboards' Enso Performa and Ensobarr grades.
Espoon Paineilma Oy, VTT Biotechnology and Food Research, VTT Manufacturing Technology, Stora Enso Paperboards, UPM-Kymmene, the Technology Development Center and the Foundation for Finnish Inventions were involved in developing the leak tester.

Caption:
A leak tester, developed for food packages is said to be the first system suitable for on-line measurement of gable-top cartons. In trial runs the leak tester has been used with Walkican and gable-top cartons in Stora Enso Paperboards, Enso Performa and Ensobarr grades.

For further information please contact:
VTT Biotechnology and Food Research
Eero Hurme, Senior Research Scientist
P.O. Box 1500
FIN-02044 VTT, Finland
Tel. +358-94566191, Fax +358-94552103
FinlandE-mail: eero.hurme@vtt.fi

Stora Enso Paperboards
Tapani Penttinen,
Development Manager
P.O. Box 25
FIN-48601 Karhula,
Tel. +358-204626755,
Fax +358-204626774

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