Chemical apparatus and process disinfecting – deodorizing – preser – Analyzer – structured indicator – or manipulative laboratory... – Calorimeter
Reexamination Certificate
1999-05-06
2001-12-04
Alexander, Lyle A. (Department: 1743)
Chemical apparatus and process disinfecting, deodorizing, preser
Analyzer, structured indicator, or manipulative laboratory...
Calorimeter
C422S067000, C436S001000, C436S164000, C426S232000, C116S206000
Reexamination Certificate
active
06325974
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a package for decayable foodstuffs, which package consists of a package material and forms a mainly closed package space and a mainly closed indicator space for an oxidation indicator.
Specification EP 0627,363 presents a foodstuff package containing an indicator that changes its colour when the concentration of gas inside the package reaches a predetermined level. The indicator may consist of a label or printed material formed on the surface of the package. The indicator may be separated by a gas-permeable foil from the product contained in the package. The indicator may be a carbon dioxide or oxygen indicator. However, such an indicator only responds to gas penetrating into the package or gas formed inside the package. The indicator does not respond to ageing of the packge and/or to a rise in the temperature of the package.
Specification EP 0629497 presents a package material that comprises two foils joined together and forming between them a space for a colour indicator. When the package material is damaged, the colour indicator reacts with the gas entering into the package and changes its colour. However, such a leakage indicator only responds when the package material is damaged, it does not respond to decay of the foodstuff in itself.
Specifications U.S. Pat. No. 4,772,707, JP 55-41875, JP 61-152299, JP 62-259059 and FI 94802 present various absorbents for absorbing the oxygen remaining in the package, stabilisers, such as reducing agents, for stabilising a colorant before the foodstuff is packaged, and colorants for indication of gas penetrating into the package e.g. via a leakage or decay of the foodstuff. The indicators proposed in these specifications are placed in the package in conjunction with the packaging of the foodstuff; in other words, the indicators are separate from the package and they are manufactured separately. The manufacture and especially the storage of this kind of separate indicators before they are placed in a package is difficult as the indicators tend to react with oxygen as soon as they come into contact with ambient air. Further difficulties arise from the separate manufacture, storage and handling of the indicators.
Generally, the specifications referred to above relate to various leakage indicators designed for use in foodstuff packages and indicators that respond to damage of the package and decay in itself. However, the specifications referred to do not describe an indicator or package that would respond to ageing of the package and/or to an excessive rise in the temperature of the package and to the volatile compounds produced as a result of decay of the foodstuff.
SUMMARY OF THE INVENTION
The object of the present invention is to eliminate the drawbacks described above.
A specific object of the invention is to present a new type of active and intelligent package for decayable foodstuffs, which package contains an indicator, preferably an oxidation indicator, that makes it possible to detect a leakage in the package, incipient decay of the foodstuff or other chemical change and especially ageing and/or undesirable high temperature or thermal load.
A further object of the invention is to present a new type of package and indicator that reacts to volatile compounds produced as a result of decay of the foodstuff.
A further object of the invention is to present a new type of package for decayable foodstuffs that allows easier, simpler and more rationalised packaging of foodstuffs and especially placement of a freshness indicator in the package.
A specific object of the present invention is to produce a new type of package for foodstuffs that allows a separate indicator to be placed on the package before, during or after the packaging of the foodstuff.
A further object of the invention is to present a new type of package for foodstuffs that allows an indicator to be placed in the package independently of the time of packaging.
As for the features characteristic of the present invention, reference is made to the claims.
The invention is based on research work during which a new type of package was developed so that ageing and undesirable high temperature or thermal load of the package as well as decay can be recognised from an indicator comprised in the package.
In the package of the invention, an indicator space, e.g. an oxidation indicator space, forms an external wall adjoining the environment, which wall is made of a material controllably permeable to an atmospheric gas, preferably oxygen, permitting controlled entry of gas through the external wall into the indicator space as the package is ageing. The indicator indicates that gas has penetrated into the indicator space, thus showing the ageing of the package upon the lapse of a certain length of time after the package was exposed to the environment and especially to atmospheric oxygen.
Correspondingly, the interior wall between the indicator space and the package space can be made of a material with a controllable, preferably good gas permeability, so that oxygen or other gases leaking into the package space and/or generated in it, e.g. compounds produced via decay of the foodstuff, can penetrate from the package space into the indicator space, with the result that the indicator will indicate the penetration of oxygen or other gases into the indicator space. The interior wall of the indicator space can also be made of a material having a temperature-dependent gas permeability.
The exterior wall of the indicator space may be made of any known material permeable to gas, especially oxygen, such as polyethylene, polypropylene, other polyolefin, polyamide or in general any other plastic material commonly used as package material. The exterior wall may also be made of a cellulose based material, such as surface-treated paper, cardboard, dissolving-pulp based foil material or other cellulose or polyacetate based material. Further, the exterior wall of the indicator space may be made of a laminate of the above-mentioned or other known package materials or some other kind of material combination.
The gas permeability of the exterior wall of the indicator space may be based on the thickness of the wall material, its general structural permeability or porosity or its artificial micro-perforation. The overall gas permeability is also based on the area of the exterior wall of the indicator space. Generally, the permeability of the wall material is so adjusted that it corresponds to the length of time the indicator is intended to indicate. In packages designed for a shorter indication time, a thinner wall material, a more porous wall material structure, a larger area of micro-perforations and/or a larger gas permeable-external wall area and/or some other means for increasing permeability is used. Correspondingly, in packages designed for a longer ageing time, a thicker wall material, a less porous wall material structure or a structure with fewer perforations and/or a smaller exterior wall area or some other known means is used to reduce the permeability of the exterior wall.
The indicator can be adjusted to indicate the desired ageing of the package by selecting the wall material, or its permeability, i.e. its thickness, porosity, size of micro-perforation, external wall area and/or a combination of these, so that it corresponds to the desired package ageing time to be indicated. Further, the indication of ageing of the package, i.e. the response of the indicator, can be influenced by selecting the indicator according to the desired ageing time, in other words, it is possible to use an indicator with a faster or a slower response. Further, the indication of ageing of the package can be influenced by using a combination of an indicator and a gas absorbent and/or other stabiliser that absorbs a predetermined amount of gas, which consists of the residual gas remaining in the package or gas that otherwise penetrates into the indicator space.
In a preferred embodiment of the present invention, the indicator space wall adjoining the environment i
Ahvenainen Raija
Hurme Eero
Pullinen Timo
Siika-aho Matti
Smolander Maria
Alexander Lyle A.
Andrus Sceales Starke & Sawall LLP
Valtion teknillinen tutkimuskeskus
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