NZ506628A - Method of packaging foodstuffs with an oxygen scavenger - Google Patents

Abstract

A method of packaging foodstuff comprising the sealing of an oxygen removing material inside a substantially oxygen impermeable container is described. The container is then opened and the foodstuff inserted and the container resealed, with both the foodstuff and the oxygen removing material contained within the container.

Description

INTELLECTUAL PROPERTY OFFICE OF NZ. 2 7 AUG 2001 Intellectual Property Office of New Zealand Te Fou R&huJ Hanga Hou PATENTS FORM NO. § Patents Act 1953 No 506628/a\ And 509947 Date: 3LAUG 2000 And 16 FEB 2001 COMPLETE SPECIFICATION (b) JMP.RQYEMENT. TO.A PACKAGE I (or WE), <c> J83. Windmill .Road, RD. 3,.HAMILTON, NE.W ZEALAND A citizen .of .New .Zealand hereby declare the invention, for which I (or wo) pray that a patent may be granted to me (or uio), and the method by which ft is to be performed, to be particularly described in and by the following statement (a) Where priority as provided by subsection (2) or subsection (3) of section 11 of the Patents Act 1953 is desired in respect of one or more provisional specifications, quote number or numbers and date or dates (b) Insert title of invention (c) State (in hill} name, address, and nationality of applicant or applicants as In application form (d) Here begin full description of Invention. The continuation of the specification should be upon paper of the same size as this form, on one side only, with the lines well spaced and with a margin of 2.5 cm on the left hand part of the paper.

The completion of the description should be followed by the words "What I (or we) claim is" after which should be written the claim or claims numbered consecutively. (See note below.) The specification and the duplicate thereof must be signed at the end NOTE.—The claims must relate to a single invention, must be clear and succinct, and must be fairly based on the matter disclosed In the specification. They should form in brief a clear statement of that which constitute the invention. Applicants should be careful that their claims Include neither more nor less than they desire to protect by their patent Any unnecessary multiplicity of claims or prolixity of language should be avoided. Claims should not be made for the efficiency or advantages of the invention. («0 • A-fkll ■description- follows on-the attached • 10 -pages' -.(11 pages-including this frontpage) 1 Field of invention The present invention concerns an improvement to a package by means of an improved method of packaging foodstuff.. It deals with oxygen absorbing (or scavenging) systems and a process to deliver these reactive systems to enable the use of a better package..

Background art It has been known for some time that one of the limits for storage of foodstuff is that the presence of oxygen is detrimental to the extended storage of foodstuffs.

Various methods are used and have been described to achieve a method of packaging perishable foodstuff so that the food will remain unspoiled for extended periods. One of the main methods relies on the removal of oxygen from the foodstuff by enclosing the foodstuff in an oxygen impermeable enclosure or package, removing the oxygen from the package and then hermetically sealing the package.

Vacuum packaging is a common method used but is not always suitable due to colour, nature or form of the product being packaged. In this method it is important that oxygen is removed prior to closing or sealing, and that the packaging material must be a barrier to the ingress of oxygen by being substantially oxygen impermeable. Vacuum packaging may also be considered unsuitable for practical reasons. Vacuum packaging exposes the foodstuff to some level of pressure which may be as high as atmospheric pressurei. This level of pressure will distort any material that is delicate or has a particular shape. In these types of application vacuum packaging is impractical.

There have been many methods described for packaging in an oxygen free environment by the use of chemical mixtures that react to remove oxygen from the package. In this situation the oxygen (in the form of air as air is more or less 20% oxygen contained in it) does not have to be substantially removed from the containing package.

There are examples of prior art that set out the possible methods of making an oxygen absorbing mixture that can then be used in a food package as described above.. These examples don't predict any particular method of package as they are directed towards the actual oxygen absorbing mixture. 2 1 4 NOV 2001 RECEIVED US patents 4113652 and 4166807 describe chemical mixtures that maybe used to achieve oxygen removal. Further examples are included in US patents 4992416, 5885481, 5725795 and 5262375.

A further example is contained in US 4762722 Here another chemical processe is included with the oxygen absorption system. In this case the other process is Carbon Dioxide generation.

Further examples concern the oxygen absorber in use in a package. US patent 5667863 describes a method for oxygen removal by incorporating the chemical mixture into an adhesive label and thus combining the function of labeling and oxygen removal into one operation. WO 00/28836 provides another example.

US patent 4055672 provides one example of a multi-compartment package that allows for oxygen removal during transit but the nature of the package to be changed for retail purposes.

A limit of using oxygen absorber chemical reactions for removing oxygen from packages is that the chemical will react with atmospheric oxygen in an effectively uncontrolled manner as soon as the chemical agents are given exposure to atmosphere or air. This is obviously a practical problem if used in a package to preserve food in that the oxygen absorber cannot be at any time exposed to the atmosphere before the time the foodstuff is sealed into the package. This is because its capacity to remove oxygen from the inside of the package will be impaired and the amount of reduced capacity left (if any) is not practically measurable. This has the practical effect that oxygen absorber items - often in the form of a small sachet type package but also in other forms - must be protected from atmospheric oxygen until such time they are required to be exposed to the atmosphere inside the package that also encloses the foodstuff.

This practical limit is usually achieved by keeping the oxygen absorber entity protected in a non-oxygen environment until just prior to the time it is required to be inserted into the food package and the package hermetically sealed. This imposes limits on efficiency and predicts that certain types of equipment must be used. There are also difficulties with wastage as any oxygen absorber entities that are exposed that are intended to be used maybe wasted if there are not the exact matching numbers of food packages to be processed. 3 INTELLECTUAL PROPERTY OFFICE OF N.Z. 1 4 NOV 2001 RECEIVED US Patent 4588561 describes one possible way to overcome this problem by incorporating the oxygen absorbing chemicals into the food package in such a way that the oxygen absorber can be activated at the required time by a particualr activation process.

US Patent 4702966 sets out a process with a similar activation mechanism.

These systems however do require the activation process to be carried out and this is often at extra cost and the process is often difficult and requires high levels of technical expertise.

These examples of an activation or trigger mechanism still fail to satisfactorily address the basic difficulty of using oxygen absorbers. Because these chemical mixtures react with any oxygen available to them, there is a need to prevent contact between the oxygen absorber and atmospheric oxygen until the time required by the packaging process.

Disclosure of invention.

The object of this invention is to provide a package that includes an oxygen absorbing chemical mixture within the package material that will be used to package the perishable product. The package material is substantially oxygen impermeable due to the required function that it has to carry out in preserving and protecting the perishable foodstuff. This property can also prevent oxygen from gaining access to the oxygen absorber contained within. This is achieved by fully sealing the package along all openings with the oxygen absorber contained therein. The sealed package is then ready for use at a later time to package the foodstuff. The oxygen absorber remains protected from atmospheric oxygen during this time and there is no need for activation mechanisms at the time the foodstuff is packaged.

Due to the effect of the absorber reacting with air and reducing the volume it is desirable that the package form be one that can easily change shape or preferably one that can be manipulated to contain very little air when assembled. The best form for this is known as a bag made from a tube of flexible plastic film and sealed at the ends. Another option is to form the container from opposed sheets of flexible film and sealed along the perimeter. 4 INTELLECTUAL PROPERTY OFFICE OF N.Z. 1 4 NOV 2001 RECEIVED At the required time of use the bag is opened along one or its^sideS3, me perishable product inserted and then the bag sealed again.

The oxygen absorber is, and has remained, fully active during transit and storage but due to protecting nature of the packaging material has been prevented from reacting.

As soon as the bag is opened and the foodstuff inserted some air will gain access to the inside of the package and the oxygen absorber will immediately begin to absorb it. No activation mechanism is required nor any protective layer need to be removed to allow the oxygen absorber to become active, nor any similar process needed.

Description of drawings.

Fig. 1 shows a bag made from flat opposing sheets of plastic film. The seals along the perimeter (1,2,3,4) and the oxygen absorber (5) inside the bag between the two opposing sheets of film (6,7).

Fig la shows a bag made from a folded sheet of film where the folded edge becomes one edge of the bag (8) Fig lb shows a bag made from a tube of plastic film where the flattened'tube has two sides (9,10) formed from the folded edge of the tube.

Fig 2 shows the part removal of the top of the bag (1 l)(in the form of fig. lb). This process of top removal allows for the insertion of the foodstuff. The location of the final seal following the insertion of the foodstuff is also indicated (12).

Removal of the bag end so that the foodstuff can be inserted is achieved by use of a sharp instrument. Alternatively the opposing sheets of film that make up the bag can be made from film known as peel seal and these materials, when sealed, can be peeled open. However the bag can be assembled in a many ways that takes advantage of the properties of oriented plastic films. In this situation the film will tear and tear propagate in a predictable direction. This can be used to enable easy opening of the bag. Fig 3 shows a bag which uses this property and the tear initiation point is indicated (13).

INTELLECTUAL PROPERTY OFFICE OF N.Z. 1 * NOV 2001 RECEIVED

Claims (22)

E ft /§ (S <*) Q gy § o £. y a Fig 4 shows a package which is assembled using peal seal film and an extra flap of film (15) that has upon it a layer of contact adhesive (14). This design variation allows for opening of the unused package by hand opening the top of the peel seal (16), thus not requiring any tools. After the foodstuff is inserted the package is then sealed with the flap of contact adhesive. Again, this enables tool-free sealing of the protective package. The package can also use just the peal seal film and use a heat seal bar to reseal it. This enables the package to be opened without tools. The packages described by way of example are characterised by the fact that the oxygen removing item is protectively contained within the package before the foodstuff is inserted and that there is no requirement for any specific triggering or activation process. Aspects of the present invention have been described by way of example only and it should be appreciated that modifications may be made to the invention without departing from the scope as defined in the following claims. WHAT I CLAIM IS

1. A method of packaging foodstuff comprising the sealing of an oxveen removing material inside a substantially oxveen impermeable container, and then sequentially opening of the container, inserting of the foodstuff in the container and then resealim of the container with both the foodstuff and the oxveen removing material contained within it.

2. A Method of packaging as claimed in claim 1 where the oxveen removing material contained within the package is protected from reaction with atmospheric oxygen by the package material before insertion of the foodstuff.

3. A Method of packaging as claimed in claim 1 where the package is assembled from flexible plastic film.

4. A Method of packaging as claimed in claim 1 where the oxygen removing material is attached to one of the layers of flexible film. 6 INTELLECTUAL PROPERTY OFFICE OF N.Z. 1 4 NOV 2001 RECEIVED k0e9fl t ?J ^ 0 y £ O

5. A Method of packaging as claimed in claim 1 where the oxveen removing material is contained within a second protective enclosure within the package.

6. A Method of packaging as claimed in claim 1 where the package is assembled from opposing sheets of flexible film.

7. A Method of packaging as claimed in claim 1 where the package is assembled from a folded sheet of flexible film.

8. A Method of packaging as claimed in claim 1 where the package is made form a tube of flexible film.

9. A Method of packaging as claimed in claim 1 where the package is assembled from film which has a directional tear propagation property.

10. A Method of packaging as claimed in claim 1 where the package is assembled from flexible film that has opposing layers that form a peal seal.

11. A Method of packaging as claimed in claim 1 where the package is resealed after the foodstuff is inserted using a heat seal device

12. A Method of packaging as claimed in claim 1 where the package is resealed after the foodstuff is inserted using a contact adhesive.

13. A Method of packaging as claimed in claim 2 where the package has remained hermetically sealed until just prior to inserting the foodstuff.

14. A Method of packaging as claimed in claim 2 where the package is assembled from flexible plastic film.

15. A Method of packaging as claimed in claim 2 where the oxveen removing material is attached to one of the layers of flexible film.

16. A Method of packaging as claimed in claim 2 where the oxveen removine material is contained within a second protective enclosure within the package.

17. A Method of packaging as claimed in claim 2 where the package is assembled from opposing sheets of flexible film.

18. A Method of packaging as claimed in claim 2 where the package is assembled from a folded sheet of flexible film.

19. A Method of packaging as claimed in claim 1 where the package is made form a tube of flexible film.

20. A Method of packaging as claimed in claim 2 where the package is assembled from film which has a directional tear propagation property.

21. A Method of packaging as claimed in claim 2 where the package is assembled from flexible film that has opposing layers that form a peal seal.

22. A package of foodstuff produced according to a method as claimed in any one of the preceding claims. INTELLECTUAL PROPERTY OFFICE OF N.Z. 1 4 NOV 2001 RECEIVED 8