WO1998038112A1

WO1998038112A1 - Package and method of making the same

Info

Publication number: WO1998038112A1
Application number: PCT/SE1998/000231
Authority: WO
Inventors: Henning Laursen; Stig Jönsson; Christer Ahlberg; Arne Troedsson
Original assignee: Visual Indicator Tag Systems - Vitsab Ab
Priority date: 1997-02-27
Filing date: 1998-02-11
Publication date: 1998-09-03
Also published as: SE9700699D0; SE9700699L; AU6640498A; EP1036017A1

Abstract

A package and a method of making the same are described. The package includes a temperature-sensitive or time-temperature-sensitive product, which is enclosed in a surrounding casing. Besides the package includes a temperature-sensitive or time-temperature-sensitive indicator, wherein: a) the casing (2, 7) is provided with printed information about the indicator, b) the indicator (5) is arranged inside the casing (2, 7), but separated from the product (1), c) the casing (2, 7) containing the product (1) and the indicator (5) is sealed (12), d) the indicator (5) and the printed information can be observed from the exterior of the package. When making the package, the product and the indicator are enclosed separated in the casing, which is sealed, the casing being provided with printed information about the indicator and is at least partially transparent such that the indicator and the printed information can be observed from the exterior of the package.

Description

PACKAGE AND METHOD OF MAKING THE SAME

Field of the Invention

The present invention relates to a package including a temperature-sensitive product, which is enclosed in a surrounding casing, and a method of making such a package. More specifically, the invention concerns a package including an indicator for monitoring the handling conditions in the handling, such as storage, transport and similar treatment, of the temperature-sensitive product. In this context, handling conditions relate to the temperature or the temperature as a function of time during the handling of the product. Background Art

There are a great many objects and products, such as foodstuffs, medicines, vaccines, blood products, pho- tographical film etc, that are temperature-sensitive and should be stored or handled at a certain temperature for a limited period in order to prevent quality degradation. Particularly well-known examples of such products are foodstuffs, such as refrigerated foods, e.g. milk, vege- tables, shellfish such as shrimps and the like, fish, minced meet etc, or frozen foods, e.g. meat, fish, icecream etc. For example, in order that a deep-frozen product should have a satisfactory quality when reaching the shop, it should not be subjected to a temperature exceed- ing e.g. about -18 °C after departure from the producer and until the time of arrival in the shop. For refrige^¬ rated foods, the corresponding temperature is about +4 to +8°C. On its way from the producer to the consumer, a frozen food passes through a large number of handling steps, such as storage with the producer, transportation from the producer to the wholesaler, storage with the wholesaler, transportation from the wholesaler to the retailer, and storage with the retailer. In all these partial steps, the deep-frozen food must be handled cor- rectly, i.e. at a temperature which does not exceed about -18 °C, in order to prevent its quality from degrading. To this end, the temperature of the product is checked at regular intervals in each partial step, i.e. during transport and storage. Refrigerated products are checked correspondingly. It should be pointed out that such monitoring or checking does not involve any checking of the initial quality of the product, but a checking of the handling to which the product is subjected before reach- ing the consumer, thereby making it possible to demonstrate if the product has been "maltreated" in an unacceptable fashion during this handling. For certain products, such maltreatment may consist in the product being temporarily subjected to a certain, undesired high tempe- rature, while the maltreatment for other products usually consists of a combination of temperature and time, i.e. that the product has been handled at an undesirably high temperature for a certain period, in which case the temperature as a function of time, and not merely the tempe- rature, decides whether the quality of the product has been degraded.

It is known to monitor the handling conditions for temperature-sensitive products by indicators of different kinds, i.e. devices which, by a visual change, such as a change of colour, indicate a change of the handling conditions of a product.

One type of temperature-sensitive indicators is disclosed in British Patent 1,557,742. This patent concerns a temperature-sensitive, water-based composition with controlled colour change and pH shift upon freezing or at a selected temperature below the freezing point. The composition has a first component including an aqueous solution which contains a buffer and which upon change of its temperature between a first temperature above its freez- ing point and a second temperature at or below its freezing point exhibits a pH shift, the composition containing as additional components a regulator entailing a change of the proton conductivity of the frozen aqueous solution so as to affect the pH shift upon freezing, and at least one pH indicator exhibiting colour change upon pH shift. The regulator may be an alcohol, a carboxylic acid or a precursor thereof. Particular examples of alcohols are methanol, ethanol, glycols and glycerol. Particular examples of carboxylic acids are formic acid, acetic acid, succinic acid, citric acid or glutamic acid. Examples of precursors of alcohols or carboxylic acids are enzyme- substrate mixtures which by enzymatic reaction produce, respectively, alcohol and carboxylic acid, e.g. lipase- esterase-glyceryltricapronate . To form a temperature-sensitive indicator, the temperature-sensitive, water-based composition is enclosed in a transparent plastic ampoule, which is in turn inserted in a wrapping, e.g. of paper. The wrapping is provided with an opening, through which the ampoule and its colour can be observed, and in connection with the opening there is printed information on the wrapping indicating how to interpret the colour of the ampoule, for instance "Best when green" and "Do not use when yellow". Moreover the wrapping is preferably formed as a label with an adhesive layer on the back, by means of which the indicator may be attached to the product that is to be checked. A further, and preferred type of indicator is an indicator which, as described above, indicates the temperature as a function of time, i.e. integrates the temperature over time. A number of such time-temperature- sensitive indicators are known, but a preferred type is a time-temperature-sensitive enzymatic indicator, as disclosed in US Patents 4,043,871 and 4,284,719. As stated in the latter patent, such an indicator may comprise two small, closed plastic ampoules separated by a common, rupturable partition. One plastic ampoule contains an aqueous solution of enzyme and pH indicator, while the other plastic ampoule contains a substrate suspended in an aqueous medium. When the monitoring of the handling conditions of a product, i.e. the indication of the temperature as a function of time, is to commence, the rup- turable partition is broken by the exertion of a compres- sive force on one of the plastic ampoules. In this way, the contents of the plastic ampoules will communicate with each other so that the contents of the ampoules are mixed and an enzymatic reaction is started. This enzymatic reaction proceeds with the production of a reaction product, such as caproic acid if the substrate is tri- caproin and the enzyme is a lipase, depending on temperature and time. The pH indicator present is intended, by colouring, to indicate the excess of a certain amount of reaction product, such as fatty acid. Like the above- described indicator, the enzymatic indicator comprises, in addition to the enzymatic composition enclosed in plastic ampoules, a surrounding wrapping, for instance made of paper, which is provided with an opening, through which the colour of the ampoule can be observed. Further the wrapping is provided with printed information in con- nection with the opening, as indicated above. Besides, the wrapping is preferably formed as a label, the back of the wrapping being provided with an adhesive layer with a protective release layer. After pulling off the release layer, the indicator can, by means of the adhesive layer, be attached to the product, the handling of which is to be monitored.

Even if the prior-art indicators function in a satisfactory manner, they have a number of drawbacks, which has entailed that they have not reached the ex- pected commercial use.

A critical factor in the context is the cost of the indicator. For an indicator to come into extended use, it must be easy and inexpensive to manufacture, such that its price does not significantly affect the price of the product that is to be monitored. As appears from that stated above, the prior-art indicators are complicated, containing a number of different components such as plas- tic ampoules with an indicator solution, a paper wrapping with printed information, and an adhesive layer with a release layer. This complicated construction makes the indicator comparatively expensive, resulting in its use being limited to wholesaler packages and the like. To monitor individual consumer packages, simpler and less expensive indicators are necessary.

A further important factor is that when the indicator is attached to the product that is to be monitored, it should not be possible later to tamper with the indicator. For instance, it should not be possible later to remove an indicator attached to a product and replace it with a new indicator.

Further there must be no risk that the indicator affects or contaminates the product that is to be monitored, e.g. by indicator solution flowing out and penetrating into the product and destroying it. This is particularly important in connection with the monitoring of foodstuffs . As is evident from that stated above, there is a need, especially when monitoring individual consumer packages containing temperature-sensitive products, of an indicator which is simple and inexpensive to manufacture and which can be attached to a product with no risk of affecting it and which cannot be tampered with, e.g. be removed, after being attached to the product. Summary of the Invention

The object of the present invention is to alleviate or obviate the drawbacks of prior-art indicators and to provide a simple and inexpensive indicator, which is arranged in connection with the product, but is separated therefrom, such that the indicator does not contaminate or otherwise undesirably affect the product, and which indicator is attached in such a manner to the product that the indicator cannot be tampered with, for instance cannot later be removed and replaced. According to the invention, this object is achieved by a package with an integrated indicator, i.e. the indicator forms a unit with the package.

More specifically, the invention provides a package including a temperature-sensitive product, which is enclosed in a surrounding casing, the package being combined with a temperature-sensitive indicator, characterised in that a) the casing is provided with printed information about the indicator, b) the indicator is arranged inside the casing, but separated from the product, c) the casing containing the product and the indicator is sealed, d) the indicator and the printed information can be observed from the exterior of the package.

According to the invention, there is also provided a method of making a package including a temperature-sensitive product, which is enclosed in a surrounding cas- ing, the package being combined with a temperature-sensitive indicator, the method being characterised in that the product and the temperature-sensitive indicator are enclosed separated from each other in the casing, which is sealed, the casing being provided with printed infor- mation about the indicator and being at least partially transparent such that the indicator and the printed information can be observed from the exterior of the package .

Further features and advantages of the invention will appear from the following description and the appended claims. Brief Description of the Drawings

To facilitate the understanding of the invention, it will be described hereinafter with reference to a prefer- red embodiment thereof which is illustrated in the accom^¬ panying drawings. In the drawings, Fig. 1 is a schematic side view of a plant for making a package according to the invention; and

Fig. 2 is a partial view of a package according to Fig. 1, seen from above in the direction of arrow II. Detailed Description of the Invention

The following description concerns specifically a fish package and the making of such a package according to the invention, but it will be appreciated that the invention is not to be considered restricted hereto, but the invention is equally applicable to other types of packages containing other kinds of sensitive products.

As indicated in Fig. 1, the sensitive product 1, which in this case is fish, for instance smoked salmon, is wrapped in a plastic package in such a manner that a bottom foil 2 of plastic is deep-drawn in a prior-art manner by means of heat and vacuum for the forming of depressions 3, which are adapted to accommodate fish. While forming the depressions 3, also smaller depressions 4 are formed by deep-drawing the foil 2. These depres- sions 4 are each adapted to accommodate an indicator 5, which is of the type described above, preferably a time- temperature-sensitive enzymatic indicator. The bottom foil 2 with the depressions 3 and 4 as well as the fish 1 and the indicators 5 arranged therein are fed to a weld- ing station 6, in which a top foil 7 from a storage roll 8 is supplied via a guide roll 9 above the bottom foil 2 and is welded thereto by means of heat and pressure from the welding plates 10 and 11 of the welding station 6. The temperature during welding is, as a rule, about 120-140 °C and the welding time about 1-4 s depending on the plastic material that is used for the bottom foil 2 and the top foil 7.

In the welding operation, the bottom foil 2 and the top foil 7 form a sealed casing around the product, i.e. the fish 1, and the indicator 5. The welding is carried out in such manner that the top foil 7 is welded to the bottom foil 2 along the edge portion around the depres- sion 3 containing the fish 1, and along the edge portion around the depression 4 containing the indicator 5. To prevent the depressions 3, 4 with the fish 1 and the indicator 5 from being damaged during welding, the lower welding plate 10 is formed with a recess conforming with the depressions 3, 4. By the welding process, welded or sealed portions 12 (see Fig. 2) are thus formed, which surround on the one hand the depression 3 with the fish 1 and, on the other hand, the depression 4 with the indica- tor 5. As a result, both the fish 1 and the indicator 5 are sealed inside the casing formed of the bottom foil 2 and the top foil 7, while at the same time the fish 1 and the indicator 5 are separated from each other.

In order to make it possible to observe the indi- cator 5 and its colour from the exterior of the package, either one of the bottom foil 2 and the top foil 7, or both, preferably at least the top foil 7, are made of transparent plastic.

If there is a risk that the indicator used is damag- ed when subjected to excessive temperatures, as is the case with time-temperature-sensitive enzymatic indicators, it should be arranged for the indicator, in the above-described welding operation, not to be exposed to a temperature of more than about 30-40 °C. This may be ensured on the one hand by making the welding time as short as possible and, on the other hand, by so designing the package and the welding plates that the indicator is not subjected to inappropriate thermal action by the welding plates. To this end, for instance, the indicator can be arranged in a depression 4, as described above, and further the upper welding plate 11 can be formed with a recess (not shown) conforming with the depression 4, such that the hot welding plates 10, 11 only contact the foils 2, 7 in those portions in which welding is to take place, i.e. in the portion 12 surrounding the depression 4, but not in that area which is occupied by the depression 4 and the indicator 5. Besides, the sealed or welded portion 12 should be arranged at a sufficient distance from the indicator 5, i.e. the depression 4 should be made sufficiently large to prevent the indicator 5 from being exposed to unacceptably high heat. After the sealing operation in the welding station 6, the package containing the fish 1, the indicator 5 and a surrounding, sealed casing which consists of the bottom foil 2 and the top foil 7 is discharged, and the package formed is separated by means of a cutting device (not shown) from the subsequent package.

In connection with welding in the welding station 6, preferably the atmosphere inside the package is evacuated and replaced by vacuum or a protective gas, which, for instance, can be selected among nitrogen and/or carbon dioxide, optionally in combination with oxygen.

By integrating the indicator with the package in the manner described above, it is in the invention not necessary for the indicator, as was previously the case according to prior art, to consist of an ampoule contain- ing an indicator solution and provided with an external label with text and an adhesive layer with a release foil on the underside. Instead, it is sufficient in the invention for the indicator that is integrated into the package to consist of a plastic ampoule containing an indica- tor solution, i.e. the label with printed information and the adhesive layer with a release foil can be excluded from the indicator according to the invention. This implies an essential simplification and saving in costs in the invention. By the indicator being integrated into the package, for instance by sealing the package casing, as described above, an adhesive layer with a release foil is not necessary. By the indicator of the invention being integrated into the package, further the separate, printed information about the indicator, which was previously arranged on a special indicator label, can be replaced by printed information directly on the package itself, for instance on the top foil 7 in the embodiment described above. Since normally the package, such as the top foil 7, is in any case provided with printed information about the packed product, such as the fish 1, providing the package with printed information 13 about the indicator as well will not cause any additional cost. Also in this respect, the present invention thus results in a simplification and saving in costs. The printed information about the indicator is suitably arranged adjacent to or in the position of the package, where the indicator 5 is arranged. The printed information, however, is not allowed to be positioned so as to completely conceal the indicator, but it must be possible to observe the indicator and its colour from the exterior of the package. This is achieved either by the printed information 13 being arranged beside the indicator or, as shown in Fig. 2, on top of the indicator, but with an opening 14, such that the indicator can be observed therethrough.

As stated above, the indicator, which is integrat- ed into the package according to the present invention, consists of a plastic ampoule containing an indicator composition. In reversible, temperature-sensitive indicators of the type described in the above British Patent 1,557,742, the indicator ampoule is inserted as it is in the depression 4 when making the package, whereas in connection with irreversible indicators, such as the time- temperature-sensitive enzymatic type as disclosed in the above US Patents 4,043,871 and 4,284,719, the indicator must first be activated before being inserted into the depression 4. In connection with an enzymatic indicator of the described type, activation takes place by breaking the rupturable partition between the enzyme solution and the substrate solution of the indicator ampoule. In practical terms, the operation can take place in such manner that the manufacturer of the package at issue, for instance the fish package described above, obtains from an indicator manufacturer non-activated indicators, which are activated immediately before inserting the indicator into the depression 4 when making the package. Alternatively, an activated indicator can be manufactured in direct connection with the making of the fish package by discharging from a storage container an enzymatic solution and a substrate solution which are supplied to a plastic ampoule, which is then sealed. Independently of which of these alternatives is selected, the indicator which is inserted in the depression 4 should be able to correctly monitoring and recording the handling conditions to which the product is subjected.

As is also indicated in Fig. 2, the indicator 5 can suitably be arranged in a welded portion 12 at an edge portion of the package, this edge portion besides having, for instance, an aperture 15, by means of which the package can be suspended from a hook (not shown) for sale in a shop. By arranging the indicator in this fashion in the package, it does not intrude upon the space occupied by the product, i.e. in this case the fish 1. A further important advantage of the integration of the indicator into the inventive package is that the indicator is tamper-proof, i.e. it is not possible to remove the indicator and replace it by another indicator without first breaking the package. This is of essential importance for the provision of a safe and reliable monitoring of the handling conditions.

By the indicator according to the present invention being integrated into the package, separated from the product that is to be monitored, which in the embodiment described above is achieved by the sealed or welded portion 12 that separates the depressions 3 and 4, the risk that the indicator can affect or contaminate the product to be monitored is eliminated. Even if the indicator is arranged separated from the product, the integration of the indicator into the same package as the product implies that the indicator is subjected to the same handling conditions as does the product, i.e. that the correct handling conditions are monitored.

The fish package described above with reference to the drawings concerns a preferred embodiment of the invention, and it will be realised that the invention may be varied within the scope of the appended claims.

Instead of integrating the indicator into a package which comprises a plastic casing sealed by heat welding, the package may include a carton, in which case the indi- cator ampoule is attached to the interior of the carton, which is formed with an opening such that the indicator and its colour can be observed from the exterior of the carton. The temperature-sensitive product, the handling conditions of which are to be monitored, is arranged in a conventional manner in, for instance, a plastic bag inside the carton. When packing the product in the carton, the carton is folded and sealed, for instance by gluing, whereby the indicator is integrated into the package in such a manner that it cannot be tampered with without breaking the package. Moreover, the outside of the carton is in conventional manner provided with print about the product contained in the package, and at the same time the carton has also been provided with printed information about the indicator. This printed information is preferably arranged in connection with the opening, through which the indicator can be observed.

Claims

1. A package including a temperature-sensitive pro- duct, which is enclosed in a surrounding casing, the package being combined with a temperature-sensitive indicator, c h a r a c t e r i s e d in that a) the casing (2, 7) is provided with printed information about the indicator, b) the indicator (5) is arranged inside the casing (2, 7), but separated from the product (1), c) the casing (2, 7) containing the product (1) and the indicator (5) is sealed (12), d) the indicator (5) and the printed information can be observed from the exterior of the package.

2. A package as claimed in claim 1, c h a r a c t e r i s e d in that the product (1) and the indicator

(5) are enclosed in a heat-sealed casing (2, 7) made of a heat-sealable, at least partially transparent plastic, the hot seal (12) separating the product and the indicator.

3. A package as claimed in claim 1 or 2, c h a r a c t e r i s e d in that the product (1) is arranged in one depression (3) in the casing (2) and the indicator (5) in another depression (4) in the casing (2).

4. A package as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the casing (2, 7) consists of a bottom part (2) and a top part (7), the bottom part (2) being formed with spaced-apart depres- sions (3, 4), and the product (1) which is a foodstuff being placed in one depression (3) , and the indicator (5) which is a time-temperature-sensitive enzymatic indicator being placed in another depression (4), that the top part (7), which is a transparent plastic sheeting provided with printed information about the indicator (5), is placed on top of the bottom part (2) such that the printed information about the indicator is arranged adjacent to the depression (4) containing the indicator, and that the top part (7) and the bottom part (2) are heat-sealed to each other along portions (12) surrounding the depressions (3, 4) for said product and said indicator.

5. A package as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the atmosphere in the casing (2, 7) is vacuum or a protective gas.

6. A method of making a package including a temperature-sensitive product, which is enclosed in a surround- ing casing, the package being combined with a temperature-sensitive indicator, c h a r a c t e r i s e d in that the product and the temperature-sensitive indicator are enclosed separated in the casing, which is sealed, the casing being provided with printed information about the indicator and being at least partially transparent such that the indicator and the printed information can be observed from the exterior of the package.

7. A method as claimed in claim 6, c h a r a c t e r i s e d in that the casing is a heat-sealable, at least partially transparent plastic.

8. A method as claimed in claim 6 or 7, c h a r a c t e r i s e d in that the casing is formed with depressions, and that the product and the indicator are each placed in a depression before heat sealing.

9. A method as claimed in any one of claims 6-8, c h a r a c t e r i s e d in that the casing consists of a bottom part and a top part, the bottom part, by deep- drawing, being formed with separated depressions, whereupon the product, which is a foodstuff, is placed in one depression, and the indicator, which is a time-temperature-sensitive enzymatic indicator, is placed in another depression, and that subsequently the top part, which is a transparent plastic sheeting provided with printed information about the indicator, is placed on top of the bottom part, such that the printed information about the indicator is arranged adjacent to the depression containing the indicator, and that the top part and the bottom part are then heat-sealed to each other along portions surrounding the depressions for said product and said indicator .

10. A method as claimed in any one of claims 6-9, > cha r a ct e r i s e d in that the atmosphere in the casing, before heat sealing, is evacuated and replaced by vacuum or a protective gas.