GB2356387A

GB2356387A - Packaging of cut flowers

Info

Publication number: GB2356387A
Application number: GB9927569A
Authority: GB
Inventors: Nichole Paula Edgington; Simon Pearson; Juliette Isabelle Cornai
Original assignee: Marks and Spencer PLC; Danisco Flexible Ltd
Current assignee: Amcor Flexibles UK Ltd; Marks and Spencer PLC
Priority date: 1999-11-22
Filing date: 1999-11-22
Publication date: 2001-05-23
Anticipated expiration: 2019-11-22
Also published as: GB2356387B; GB9927569D0

Abstract

Cut flowers are enclosed in a sealed bag of plastics film with a carbon dioxide absorber to reduce the carbon dioxide level within the bag, the gas permeability of the film being such that respiration of the flowers produces a modified atmosphere within the bag with a reduced oxygen level compared to levels outside the bag. Preferably, the plastics film comprises a micro perforated film and the total area of perforations is adapted to give the required oxygen permeability for the flowers to produce the modified atmosphere. The perforations are typically 200 microns or less in diameter and have a density up to 1000 perforations/m<SP>2</SP>. Perforations less than 150 or 100 microns in diameter at densities between 10 to 1000 perforations/m<SP>2</SP> may be used. The film will have an inherent gas permeability determined by the polymer used, but this is supplemented by the effect of the perforations in the film. The carbon dioxide absorber may be a sachet of soda lime. Such packaging allows flowers to be transported and displayed without the need for water.

Description

2356387 0-\SPECS\JKH\Sid24utLlwp PACKAGING This invention relates to the

packaging of cut flowers.

Most flowers for the cut flower market in the United Kingdom are grown overseas in preferred climatic conditions and are imported by air. The flowers when harvested are cut with their stems about 5cm longer than the final length required for marketing, and are gathered in bunches of 6, 10 or 12 and wrapped in a sleeve of plastics film with open ends and a sachet of flower food. These bunches are then packed flat and dry in boxes and transported by air to the United Kingdom. Once in the United Kingdom, the bunches are processed by special machinery which cuts the stems of each bunch to final length under water, and the bunches are then stood in buckets of water containing antibacterial agents. The buckets of flowers are then transported by road to the shops where they are placed on display with the flowers standing in water.

The above packaging and distribution process requires further processing of the flowers once they arrive in the United Kingdom, and a supply of water to keep the flowers fresh in transit and on display in shops. These further processes increase the distribution costs, and the need for water creates limitations as to how the flowers are displayed for sale. An object of the invention is to provide an improved process for packaging flowers which avoids these disadvantages.

According to the invention, cut flowers are enclosed in a sealed bag of polymeric film with a carbon dioxide absorber serving to reduce the carbon dioxide level within the bag, the gas permeability of the film being such that respiration of the flowers produces a modified atmosphere within the bag with a reduced oxygen level compared to levels outside the bag.

Preferably, the film comprises a micro perforated film in which the total area of perforations in the film used to form the bag is adapted to give the oxygen permeability required for the flowers to produce the modified atmosphere within the bag.The 2 perforations are typically 200 microns or less in diameter and have a density up to 1000 perforationS/M2. Perforations less than 150 or 100 microns in diameter at densities between 10 to 1000 perforations/m' or more particularly, 10 to 400 or 10 to 200 perforations/m', may be used. The film will have an inherent oxygen permeability determined by the polymer used, but this is supplemented by the effect of the perforations in the film, which therefore serves as the control parameter that determines the final oxygen permeability of the film.

The film will also have an inherent water vapour permeability determined principally by the polymer and its thickness, and this is selected to best preserve the freshness of the flowers in storage.

We have now shown that if the modified atmosphere in the bag becomes too rich in carbon dioxide, this can impair the ability of the flowers to open fully subsequently when unwrapped. This can happen if the gas permeability of an imperforate film is too low or if the perforation area of a perforated film is too small. Therefore the carbon dioxide absorber according to the invention plays a vital role in reducing the carbon dioxide level in the bag. The absorber may comprise a sachet of soda lime.

The invention therefore provides a process for packaging cut flowers which allows them to be packed, transported and displayed in a dry state, and therefore avoids the need for secondary processing or the provision of water. Without the need for water, bags of flowers can be displayed in shops in new more interesting ways.

It will be appreciated that the term "flowers" as used above should be taken to include decorative foliage such as ferns which may not have flower heads as such, but which may also benefit from the invention.

The invention will now be described by way of example with reference to the accompanying drawings, in which:

3 Figure 1 is a graph showing the oxygen levels present in a bunch of roses packaged according to the invention; Figure 2 is a graph showing the carbon dioxide levels present in a bunch of roses packaged according to the invention; and Figures 3 to 5 are histograms showing the development of head diameter of roses packaged according to the invention following different storage periods of 2,4 and 5 days, including comparative results for other packaging processes.

Packaging tests were carried out using a variety of rose known as "Surprise". These were grown, harvested and packed in Kenya and flown back to the United Kingdom, where they were tested after different periods of storage. The roses were packed in three different ways for the purpose of comparative tests as follows.

PACK I A bunch of 6 roses was packed with a sachet of flower food in a transparent bag of polymeric film, and the bag was sealed. The bag consisted of a folded film sealed by hot wires along one side and the bottom. The film was a micro-perforated polypropylene film sold by Danisco Flexible under their trademark (P-PLUS), type 35PA80 having perforations on average 90 - 100 micron diameter and a frequency of 56 to 60 per square meter. The bag had dimensions 250min by 500min and had an oxygen permeability of approximately 2250cc/bag/day/atmosphere.

PACK 2 A bunch of roses as in Pack 1 above, but with the addition of a sachet of 5 grains of soda lime packed in the bag with the flowers.

PACK 3 A control pack of the same number of roses as in Packs I and 2 above, but comprising a transparent sleeve of polymeric film surrounding the flowers, the sleeve being open top and bottom and containing a sachet of flower food.

4 The test packs were all stored flat in boxes for transport to the United Kingdom and were kept at temperatures of 181C to 20'C for different periods of time (2,4 and 5 days) before being unwrapped and placed in vases of water containing the flower food, in ambient conditions. The control packs were additionally processed on arrival in the UK in the known manner by cutting the stems to length under water and standing the packs in buckets of water.

All packs were tested as to the oxygen and carbon dioxide levels within the packs during a storage period of six days, and the results are shown in Figures I and 2. The gas analysis of Packs I and 2 showed that the atmosphere therein reached equilibrium levels of oxygen and carbon dioxide throughout the maximum storage period of six days. In Pack 1, the oxygen levels decreased by more than half compared to norinal air, and the carbon dioxide level reached 8 to 10 percent. In Pack 2, the oxygen level remained between 12 to 14 per cent, and the addition of the carbon dioxide absorber removed virtually all of the carbon dioxide from the atmosphere within the pack, as shown in Figure 2. These results confirm that a modified gas atmosphere was produced within Packs I and 2 as a result of the respiration of the roses. The diameter of the flower heads were measured whilst packed and subsequently over a period of several days when unpacked and stood in vases of water containing flower food. Different sample packs were unpacked after different periods of storage, and the results compared in Figures 3 to 5.

In Figures I to 5, the scale graduations "P + n" and "V + n" refer, respectively to, the number of days "n" in a packed state, and the number of days "n" since being unpacked and stood in vases of water.

Figure 3 shows how the diameter of the heads of the roses developed when they were unpacked after two days and kept in vases over a further eight days. This shows that the flowers in Packs I and 2 opened more slowly than the control Pack 3 whilst wrapped, but recovered quickly once unwrapped. Furthermore, the roses in Pack 2 containing the carbon dioxide absorber, opened better than both Pack I and the control Pack 3 over the following eight days in the vases.

Figure 4 shows how the diameter of the roses developed when stored in packs for a period of four days before being opened and placed in vases for a ftirther eight days. Again, like the previous results, this shows that the opening of the roses in Packs I and 2 was delayed whilst stored in the pack, but subsequently when unpacked, the roses quickly opened and caught up the control roses of Pack 3 within two days in the vases.

Figure 5 shows how the diameter of the roses developed after an initial period of storage of five days before being unpacked and placed in vases for a further eight days. Again, like the tests of Figure 4, the roses in Packs I and 2 were delayed in opening but quickly caught up the roses of the control Pack 3 within two days of being placed in the vases. The roses of Pack 2 with the carbon dioxide absorber produced the best performance for most of the vase life.

In a pack according to the invention the perforations may be distributed uniformly over the whole of the film or may be formed in only part of the film. For example, Pack 1 would typically have a total of 14 to 15 perforations in the bag, these could be distributed uniformly over the whole of the film or could be formed in only one of the two folded halves of the film.

The polymeric film according to the invention might be composed of polypropylene, polyester, polyvinylchloride, polystyrene, polyethylene, cellulose acetate or regenerated cellulose, or a combination of those materials either as a laminate or a co-extrusion.

In an alternative embodiment of the invention, the bag may be a conical shaped bag constructed of two webs of plastics film scaled by hot wires at the sides and bottom. The web may be non-perforated orientated polypropylene OPP 35 micron thick with an anti-mist surface treatment, and the other web may be a micro-perforated polypropylene film such as the type 35 PA 80 described above. Such a bag would have typical dimensions 120mm. wide at the bottom, 315mm wide at the top and 650mm. long, and have an oxygen permeability of approximately 3600cc/bag/day/atmosphere.

6

Claims

1. A method of packaging cut flowers comprising enclosing them in a sealed bag of a polymeric film with a carbon dioxide absorber serving to reduce the carbon dioxide level within the bag, the gas permeability of the film being such that respiration of the flowers produces a modified atmosphere within the bag with a reduced oxygen level compared levels outside the bag.

2. A method as claimed in claim I in which the film comprises a micro perforated film.

3. A method as claimed in claim 2 in which the film is formed with perforations with a mean diameter of 200 microns or less and with a density up to 1000/m.

4. A method as claimed in claim 3 in which the perforations have a mean diameter of 100 microns or less.

5. A method as claimed in claim 3 or 4 in which the density of perforations in the film ranges from 10 to 400/m'.

6. A method as claimed in claim 5 in which the density of perforations in the film ranges from 10 to 200/m'.

7. A method as claimed in any one of the preceding claims in which at least a part of the bag is transparent.

8. A method as claimed in any one of the preceding claims in which at least a part of the bag is treated with an anti-mist coating.

9. A pack of cut flowers comprising a sealed bag of polymeric film enclosing the flowers and a carbon dioxide absorber.

7

10. A pack as claimed in claim 9 in which the film comprises a micro perforated film.

11. A pack as claimed in claim 10 in which the film is formed with perforations with a mean diameter of 200 microns or less and with a density up to 1 000/m'.

12. A pack as claimed in claim I I in which the perforations have a mean diameter of 100 microns or less.

13. A pack as claimed in claim I I or 12 in which the density of perforations in the film ranges from 10 to 400/M2.

14. A pack as claimed in claim 13 in which the density of perforations in the film ranges from 10 to 200/mI.

15. A pack as claimed in any one of claims 9 to 14 in which at least a part of the bag is transparent.

16. A pack as claimed in any one of claims 9 to 15 in which at least a part of the bag is treated with an anti-mist coating.