AU685330B2

AU685330B2 - Packaging and method of packaging improvements

Info

Publication number: AU685330B2
Application number: AU39158/95A
Authority: AU
Inventors: Jim Raptis
Original assignee: Raptis & Sons Pty Ltd A
Current assignee: A Raptis & Sons Pty Ltd
Priority date: 1994-12-02
Filing date: 1995-12-01
Publication date: 1998-01-15
Anticipated expiration: 2015-12-01
Also published as: AU3915895A

Description

44730 HKS:DP:MH P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant: A. RAPTIS SONS PTY. LTD.

00 Name of inventor: JIM RAPTIS Address for Service: COLLISON CO.,117 King William Street, Adelaide, S.A. 5000 Invention Title: PACKAGING AND METHOD OF PACKAGING IMPROVEMENTS Details of Associated Provisional Applications: PM9790 dated 2nd December 1994 The following statement is a full description of this invention, including the best method of performing it known to us: lllw This invention relates to packaging and a method of packaging and this particular application with respect to packaging of crustaceans and other seafood products destined to be sold in a frozen condition.

While reference will be made throughout this specification to prawns, it is to be understood that the reference is used as a matter of convenience and that the comments apply equally in respect of all seafood products and crustaceans sold in a frozen form. The invention is of general applicability in this area and should not be regarded as being limited to prawns or shrimp.

The present invention is related to the problems encountered in the packaging 1 0 and presentation of prawns and frozen marine products for sale and display purposes.

It is true that in a cooked and prepared state seafood products generally have an attractive and appetising appearance. However, in the uncooked and frozen state the appearance is usually less desirable than the cooked state.

1 5 Further, packaging processes that presently exist have the result of causing still more deterioration in the appearance of the product. The result being that a potential purchaser, associating the appearance of the packaged product with the quality of the product, could be discouraged from purchasing the product. In the case of premium quality, and therefore premium price 2 0 products, the appearance is of further importance.

Premium quality products are size graded and selected for packaging. To package the products they have hitherto been vacuum sealed in the chilled state and frozen for sale.

There are several disadvantages to such a process.

25 First, vacuum packing soft products in the chilled state flattens the underside of the product against the packing tray.

S"Second, the head of the prawn is depressed against the tray which detracts from the attractiveness of the product and therefore the quality of the pack.

Third, products which are vacuum sealed, frozen and thawed for use do not recover the original shape when compared with products frozen and thawed under natural atmospheric conditions.

Fourilfi, subjecting products in a chilled state to such vacuum pressure has been found to have a substantial adverse affect on the flesh texture of the product.

These difficulties have been addressed by hardfreezing the products before applying the sealing material. In such a manner it has been hoped to avoid the problems associated with subjecting soft shrimp body tissue to the vacuum 1 0 sealing process. This process is, unfortunately not entirely satisfactory as the large temperature differential between the sealing material, which is typically heated to 800C or above, and the surface of the shrimp product which is typically in the region of -20°C, causes the film to lift from the surface of the product adversely affecting the appearance of the package and the keeping 1 5 qualities of the product.

The inventors of the present invention have therefore sought to resolve the abovementioned conflicting situation by the invention of a method of packaging a frozen marine food product which allows the product to be adequately sealed in a vacuum pack without adversely affecting the appearance of the product.

Further, it has been attempted to package the product in such a way that the appearance will be improved so as to be beneficial to the sale of the product.

00 A surprising technique has been discovered in that if a shrimp or other seafood having firstly been frozen is subjected to a high temperature over an 2 5 exposed outer surface compared with the frozen interior, for a ,,hort time prior to being covered with film, then there are two beneficial results. The first being that a plastic film applied by vacuum drawing the film over the product whilst the film is heated produces improved adherence of the film to the product and .eooo) secondly such a short heating, rather than harming a shrimp or other seafood, 3 0 appeared to give its surface a better colour which assisted significantly the resulting appearance of the product for display purposes. resulting appearance of the product for display purposes.

L~ Therefore according to one aspect of the present invention there is provided a method of packaging seafood products comprising the steps of: i) laying one or more seafood products on a tray; ii) freezing the product or products, either before or after location on the tray; iii) subjecting the product or products to a heating process over an exposed upper outer surface so as to raise the temperature of the surface of the or each seafood products to at least OOC; and iv) then effecting a coating of a transparent packing film over the product 1 0 the film being drawn into close contact with the product by reason of reduced air pressure.

The step of heating the product over an exposed upper outer surface is important in several respects. The plastic packing film is applied using commercially available equipment. The equipment draws a vacuum while the 1 5 film is in contact with a heated surface, which heats the film, generally to the extent that the film is near liquid in behaviour. The film in the semi-molten stat- is then drawn onto the surface of the product and its associated tray.

It has been found that the large difference in temperature between the film and the product affects the ability of the film to achieve a successful seal. More 2 0 specifically, where the surface temperature of the product is below freezing the film will not seal effectively and the problem of lifting discussed above S-occurs.

Thus by raising the surface temperature of the frozen product to between OC :and 200C, the differential between the temperature of the product and that of 2 5 the film is reduced. Moreover, by applying the film to the slightly heated surface it is possible to achieve good adherence of the film to the product, which enhances the visual appeal of the product, the surface of the product having acquired a slightly glazed surface as a result of the heating process.

The outer surface of the product also acquires a hint of pinkish 'blush' which adds to the visual appearance of the product. 3 0 adds to the visual appearance of the product.

c c II The heating process takes into account two considerations. The absolute temperature of the surface of the product and the differential temperature between the packing film and the product. The raised temperature of the product should for reasons of longevity of the product not exceed 200C and preferably be around 00C. The temperature differential should as far as possible be minimised within this constraint.

The time required to achieve the raised surface temperature should also be taken into account.

For both speed of processing and product longevity it is preferable that the 1 0 desired surface temperature be achieved as swiftly as is possible and, at least within 30 seconds. For this purpose hot air has been found to be useful.

To produce a product with an improved appearance and also to reduce possible dehydration of the product it is advantageous to hard freeze the products in a plate freezer operation rather than an air-blast freezer operation.

1 5 One of the disadvantages of such packaging is that if conducted in the conventional way with conventional materials, ar would be substantially excluded from being in contact with the product. It has been discovered that even though seafood are substantially preserved by freezing, nonetheless there are still bacterial colonies active on and around the product.

20 Preferably, the plastic film is at least partially permeable to air. The use of an permeable film substantially prevents the occurrence of anaerobic •bacteria.

Preferably, the tray has an irregular surface such that the shrimp each will lie only on protrusions from the tray surface. Such an arrangement assists in 25 maintaining the correct position of the product.

Preferably, the packing tray is arranged to include a floor on which the shrimp are laid and a rim which is extended around the floor so as to provide a substantial uppermost surface on which the plastic film can adhere at the perimeter. Given the presence of extensive feelers found in many crustacean 3 0 it is important to provides a packing tray which allows all the feelers to be contained in the tray and also a tray which has a sufficient surface for the film to adhere to. The floor and the rim are connected by an inclined sloping side.

Preferably, the height of the sides of the tray are such that they are within the range of 1/3 to 2/3 of the height of the shrimp when within the tray and being laid on their s.Jes.

The attractiveness of the packaging process of the present invention can be enhanced by locating the package in an outer carton on which, in substantially full size, and in a colour that replicates the original shrimp or other seafood there is a picture of at least one shrimp of substantially the same variety and size as those in the package and there is a transparent 1 0 panel through the same side of the carton through which at least substantially the head and body of at least one of the shrimp within the carton can be seen.

In one form of the invention the shrimp rests on protuberances extending upwardly from the floor of the tray.

The invention therefore also provides a package of seafood wherein there is a 1 5 tray upon which seafood products are laid in adjacent relationship, and the products are held in place by a film of transparent plastics material where the film is located in close conformity to the shape of the products with negligible air between the film and the products.

It is advantageous that the plastic film is of an air permeable type such that 20 some air will pass through the film. Experimental evidence has also shown that it is preferable for the film to be of sufficient toughness to withstand S" °penetration by sharp elements of seafood products. A thickness of 150 lum o °has been found to be acceptable. This reduces the unsightly problem of black spot (or melanosis) and dehydration.

The height of the sides of the tray are such that they are within the range of 1/3 to 2/3 of the height of the shrimp when within the tray and being laid on their sides.

S° The present invention will now be described, by way of non-limiting examples, with reference to the accompanying drawings in which: FIG 1 illustrates in expanded view a marine food package in accordance with one aspect of the present invention; FIG 2 shows a vertical cross-sectional view of the package of FIG 1.

Shown in the drawings is a marine food package 10, in this embodiment a package of shrimp. The package 10 comprises a tray 12 having a floor 14, inclined sides 16 and an outer rim 18.

The tray is conveniently made of a polypropylene material able to withstand temperatures of -45°C. The dimensions of the tray are: Length: 335 mm overall, which includes 10 mm lip and slope.

1 0 Width: 233 mm overall, which includes 10 mm lip and slope.

Depth: 15 mm.

The tray has a 10 mm flat lip, which slopes inwards at a 450 angle.

Resting on the tray are a plurality of frozen shrimps 20, the shrimps being covered by an air permeable plastic film 22 which has been applied by a 1 5 conventional vacuum sealing process. As will be appreciated from FIG 2 the floor 14 is not planar but has a series of ridges 24 extending through the surface. The ridges 24 allow for increased strength in the package and also assist in maintaining the position of the product on the tray 12.

Using 150 pam film, the film is applied using conventional equipment applying a vacuum time of 15 seconds, vent time 0.5 seconds at between 800C and 10000.

1 oo•C' o a The package 10 of the present invention is prepared according to the S- following process: .4.5.5 first, laying each shrimp 20 on the tray 12, freezing the shrimps S 2 5 either before or after location on the tray 12, subjecting the shrimps 20 to a heating process over their exposed upper outer surface for a short period of I a~pe 8 time and then effecting a coating of the plastic packing 22 film over the product the film being drawn into close contact with the product by reason of reduced air pressure.

It is clear that the shape and dimensions of the tray may be varied to suit the shape and dimensions of the products to be packaged.

Modifications and variations of the present invention, such as would be apparent to a skilled addressee are deemed to be within the scope of the present invention.

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Claims

1. A method of packaging seafood products comprising the steps of: i) laying one or more seafood products on a tray; ii) freezing the product or products, either before or after location on the tray; iii) subjecting the product or products to a heating process over an exposed upper outer surface so as to raise the temperature of the surface of the or each seafood products to at least OOC; and iv) then effecting a coating of a transparent packing film over the product 1 0 the film being drawn into close contact with the product by reason of reduced air pressure.

2. A method of packaging seafood products according to claim 1, wherein the transparent packing film is applied using vacuum drawing equipment, the equipment being operated so as to draw a vacuum while the film is in contact 1 5 with a heated surface which heats the film, to the extent that the film is near liquid in behaviour, the film in a semi-molten state being drawn onto the surface of the product or products and the associated tray.

3. A method of packaging seafood products according to claim 1 or claim 2, wherein the surface temperature of the frozen product is raised to between 0 00C and 200C, to thereby to achieve good adherence of the film to the So product.

A method of packaging seafood products according to any one of the preceding claims, in which the step of subjecting the product or products to a heating process is continued until the surface of the product or products has 25 acquired a slightly glazed appearance.

5. A method of packaging seafood products according to any one of the .ooooi preceding claims, in which the surface temperature of the product or products does not exceed 200C and is preferably be around 00C. dl~L ~el II

6. A method of packaging seafood products according to any one of the preceding claims, wherein the step of subjecting the product or products to a heating process is completed within 30 seconds.

7. A method of packaging seafood products according to any one of the preceding claims, further including the step of hard freezing the product or products in a plate freezer operation prior to the step of subjecting the product or products to a heating process.

8. A method of packaging seafood products according to any one of the preceding claims, wherein the plastic film is at least partially permeable to air. 1 0

9. A method of packaging seafood products according to any one of the preceding claims, in which the tray has an irregular surface such that the product or products each will lie only on protrusions from the tray surface.

A method of packaging seafood products according to any one of the preceding claims, in which the packing tray is arranged to include a floor on 1 5 which the product or products are laid and a rim which is extended around the floor so as to provide a substantial uppermost surface on which the plastic film can adhere at the perimeter and wherein the floor and the rim are connected by an inclined sloping side.

11. A method of packaging seafood products according to claim 2 0 wherein the height of the sides of the tray are such that they are within the range of 1/3 to 2/3 of the height of the shrimp when within the tray and being laid on their sides.

12. A method of packaging seafood products according to any one of the preceding claims, including the further step of locating the package in an outer 25 carton on which, in substantially full size, and in a colour that replicates the original shrimp there is a picture of at least one of the product or products of substantially the same variety and size as those in the package and there is a transparent panel through the same side of the carton through which at least substantially the head and body of at least one of the product or products 3 0 within the carton can be seen. 11

13. A method of packaging seafood products according to any one of the preceding claims wherein there is a tray upon which at least two prefrozen seafood products are laid in adjacent relationship, and the products are held in place by a film of transparent plastics material where the film is located in close conformity to the shape of the products with negligible air between the film and the products.

14. A method of packaging seafood products according to any one of the preceding claims, wherein the film is of sufficient toughness to withstand penetration by sharp elements of seafood products.

15. A method of packaging seafood products according to any one of the preceding claims, wherein the thickness of the packing film is 100-200 mm.

16. A method of packaging seafood products according to any one of the preceding claims substantially as herein before described, with reference to and as illustrated in the accompanying drawings. Dated this 1st day of December 1995 A. RAPTIS SONS PTY. LTD. By their Patent Attorneys, 20 COLLISON CO. .55.55 S w P~aas~l~iI~~ ABSTRACT This invention relates to packaging and a method of packaging and this particular application with respect to packaging of crustaceans and other seafood products destined to be sold in a frozen condition. The method of packaging seafood prcducts includes a step in which a frozen product is subjected to a heating process over an exposed upper outer surface of the product so as to raise the temperature of the surface of the products to at least 0°C. By raising the surface temperature of the frozen product to between O°C and 1 0 20°C, the differential between the temperature of the product and that of the film is reduced, and by applying the film to the slightly heated surface it is possible to achieve good adherence of the film to the product, which enhances the visual appeal of the product. The surface of the pro'" ':laving acquired a slightly glazed surface as a result of the heating process. The 1 5 outer surface of the product also acquires a hint of pinkish 'blush' which adds to the visual appearance of the product. 9* 0 0 6I i ~a