WO1995008480A1

WO1995008480A1 - Food product packaging

Info

Publication number: WO1995008480A1
Application number: PCT/AU1994/000570
Authority: WO
Inventors: Anthony Earl Flecknoe-Brown
Original assignee: Tetra Laval Holdings & Finance S.A.
Priority date: 1993-09-24
Filing date: 1994-09-23
Publication date: 1995-03-30

Abstract

A food product package (10) is disclosed which includes a substrate (12) having a plurality of protuberances (13) which form a plurality of spaced support surfaces (14) which are arranged to support a food product. The substrate (12) also includes a plurality of wells (15) located between the support surfaces and which are interconnected by channels (17) to enable fluid communication between adjacent wells. The food product package is arranged to contain and control any liquid discharge from the food product away from the surface of the food product.

Description

FOOD PRODUCT PACKAGING

TECHNICAL FIELD

This invention relates generally to the packaging of products such as wet solid foods, and in particular to a food product package and a method of packaging using such a package.

BACKGROUND ART

Foods such as fresh meats, fish and certain cheeses and other food preparations often discharge a liquid component, such as blood and blood serum in the case of meat and whey in the case of some cheeses for a considerable period of time after cutting and packaging for same to the consumer.

These products are usually distributed and sold in fresh, chilled condition and require specialised packaging to ensure that the liquid discharged is somewhat controlled and contained. For example, modern retail fresh meat packaging consists mostly of foamed polystyrene shallow trays overwrapped with a clear film. Such packaging suffers from a number of evident defects. The liquid can be spilled by seeping through the film overwrap, if the package is not kept horizontal and often the liquid pools at a visible point inside the package. This can be unsightly and unhygienic. Furthermore, in recent years the use of foamed polystyrene for meat packaging in particular, has become less environmentally acceptable, because chlorofluoro carbons are or were mostly used as the inert gas introduced into the polystyrene polymer to create the foam. Such packages are also difficult to collect and recycle and cannot be incinerated without liberating harmful gases. Whilst polystyrene foam continues to be used, but less widely in retail meat packaging, increasing centralisation in the preparation and packing of meat is also causing chilled meat to be kept in the consumer package between packing and sale, for a longer period of time than was hitherto the case.

As a result of these various changes, more meat is now being packed in thermoformed rigid plastic containers which are deeper than traditional foam trays and which may have a heat sealed transparent rigid or flexible closure.

Furthermore, a new class of packages designed to extend the shelf life of fresh meat is being slowly but progressively introduced. These packages involve the use of a rigid thermoformed plastic lower tray and a heat sealed clear or rigid thermoformed or flexible film cover. At the time of packing, the oxygen in the package is partially or wholly flushed out by a gas mixture designed to reduce the rate at which bacteria can develop and affect the meat. This may involve the use of an additional semi-porous membrane which further separates the meat packed under one gas from another gas in the lid space, in order to control the rate of exchange between the bases and the meat surface.

Over the last 3-5 years many meat retailers have also introduced a non-woven absorbent pad as an additional packaging component into the bottom of the tray to soak up the blood from the meat. This serves a number of purposes: to slow down that rate of bacteria development in the pack by reducing the amount of the surface of the meat which is in contact with the blood, an ideal bacteria growing medium; to keep the packed meat looking more attractive and particularly, to enable the tray to be displaced at an angle on a multi-level shelf. In this case, the blood can pool in the front lower part of the pack and the pad is used to prevent this form being so obvious. This type of display allows more packs to be presented per unit of supermarket floor space; to reduce the spillage of blood during transport from the supermarket to the consumers home and therefore to increase the convenience of the packaging.

The use of an absorbent pad is however, undesirable for the following reason:- the pad is an extra and costly component, which must be assembled into the package as a separate operation; - the pad remains wet and at all time is in contact with the underside of the meat, leading to earlier discolouration and odour; many consumers feel that the use of an absorbing pad is unhygienic.

DISCLOSURE OF THE INVENTION An aim of the present invention is to provide a food product package which at least ameliorates the problems associated with packaging foods that are prone to discharge a liquid component. A particular aim of the invention is to provide an improved substrate in which the food product may be supported which is better able to contain and control liquid discharge from the food product.

According to a first aspect, the present invention provides a food product package including a substrate having a plurality of protuberances forming a plurality of spaced support surfaces arranged to support a food product on the substrate.

Preferably, the substrate includes a plurality of wells adapted to contain liquid and which are located between the support surfaces and in a position wherein they are remote from the support surfaces. Preferably channels are provided to enable third communication between adjacent wells. An advantage of the food product package according to a preferred embodiment of the invention is that the substrate enables discharged liquid of the food product, such as blood from meat, to be retained and kept out of contact with the surface of the food product, in such a way the collected liquid is not prone to spill from the package or gather in one visible part of the package. A further advantage of a preferred form of the package is that it allows the underside of the food product to be ventilated and make contact with the air, gas or gas mixture enclosed within the package, with such contact not being inhibited by the food product being submerged in liquid. This arrangement has real practical benefit as it allows all parts of the surface area of the food product to be kept under essentially the same condition, so that the life of the food product in the pack is not shortened by that part of the food product which would otherwise be in contact with the discharged liquid, which is often an ideal bacteria culturing medium, causing earlier development of "off" colour or odour. This is particularly the case with meat products.

Preferably the protuberances each have an upwardly extending circumferential wall having a support surface formed at its respective upper ends. Preferably the wells are formed from downwardly extending circumferential walls having a base at its lower end.

Preferably, the wells and the protuberances are formed in a regular array with a portion of the circumferential wall of each protuberance being continuous with a part of the wall of its adjacent well.

Preferably the spacing between the wells is in the range 1 to 15 mm and their depth is in the range 0.5 to 8 mm. Preferably the average opening size of each individual well is in the range of 1 to 8 mm. Further, preferably the depth of each protuberance in relation to its average base dimension is in the range of 0.5 to 1.5.

Alternatively the substrate may be a perforated substrate which allows fluid to drain therethrough to a portion of the package separate from the product. An absorbent material may be provided in said separate portion.

Typically the food product package includes a side wall which extends around the perimeter of the substrate. In one form the substrate may be integrally formed with the side wall or alternatively the food product package may include a receptacle incorporating the side wall and wherein the substrate is in the form of an insert which is arranged to be located within the receptacle.

Preferably the substrate is formed by thermoforming a sheet of thermoplastic material and wherein the protuberances are formed as upwardly extending hollow projections and the wells are formed as downwardly extending hollow projections. Closure means may be provided to overwrap the product and substrate to provide a closed or sealed package.

Such closure means may comprise a thin separate flexible overwrapping sheet or a rigid assembly which can encapsulate the product and substrate.

The closure means may be formed integrally with the substrate and may take the form of a hinged lid adapted to bend over the product and attach to the opposite end of the substrate to close the package.

In a further aspect, the present invention provides a method of packaging a food product using the food product package as described above. Further, the method may include the step of applying a gas to the food product through the channels between the support surfaces of the substrate.

It will convenient hereinafter to describe embodiments of the food product package with reference to the accompanying drawings. However, it should be appreciated that the particularity of these drawings in the associated description is not to be understood as supercedingly the generality of the preceding broad description of the invention. BRIEF DESCRIPTION OF DRAWINGS

Figure 1 is a fragmentary perspective view of a food product package according to a first embodiment of the present invention having a detailed view of the substrate to an enlarged scale; Figure 2 is a plan view of the package of Figure 1 ;

Figure 3 is a schematic view of a thermoforming tool for use in the manufacture of a food product package according to an embodiment of the present invention;

Figure 4 is a detailed view of alternative substrate for a food product package of an embodiment of the invention; Figure 5 is a sectional view along V-V of Figure 4; and

Figure 6 is a schematic view along VI-VI of Figure 4.

DETAILED DESCRIPTION OF THE DRAWINGS.

Figures 1 and 2 illustrate a food product package 10 in the form of a substantially rectangular tray having a generally flat base 11 and a flanged or unflanged side wall 18.

The package 10 includes a substrate 12 which consists of an array of upwardly rising ridges or protuberances 13 forming a plurality of spaced support surfaces 14 and an array of downwardly directed hollows or wells 15. Figure 1 shows the substrate in an enlarged scale for ease of illustration. The protuberances 13 and the wells 15 are arranged alternatively on both sides of a neutral axis 16 which extends parallel to the base 11 of the package 10. With this arrangement, channels 17 are formed between the support surfaces 14 to enable fluid communication between adjacent wells 15.

The geometry of the substrate may vary widely provided the general principal is followed that the wells 15 have a closed shape so that they can contain fluid and that the protuberances 13 are arranged such that the respective support surfaces 14 are spaced from these wells 15. In this way, the support surfaces allow the food products supported thereon to be ventilated and to prevent the product from laying onto and sealing itself around the perimeter of any well 15 which perimeter is located at the neutral axis 16. It should further be appreciated that the shape of the respective protuberances and wells may vary widely. The shapes of the wells may be pyramidal, conical or some other regular or irregular shape. Further, the arrays used may be triangular, rectangular or hexagonal. The protuberances can be of a different shape to the hollows and may occur at different frequency.

The wells 15 are designed to collect and contain the blood or liquid which drains from a food product, such as meat or cheese, supported on the support surfaces 14. Each well can become gradually filled with liquid only up to the height of the neutral axis. Should some of the wells become filled, the liquid will overflow into the next adjacent well 15 via the channels 17. This process will continue until the fully or partially filled wells have contained all of the blood which is discharged from the meat and then no further flow of fluid will take place. Using meat as an example, in extreme cases, up to 5% by weight of blood and other liquid may be discharged from a cut of meat, so the wells 15 in the substrate 12 must be deep enough on average, over the total surface area of the base of the package 10 to contain all of the expected volume of liquid which may be discharged.

To illustrate this further, the specific example of a meat tray of 20 cm by 10 cm in plan size, containing a 250 gram cut of meat, is used. Using the geometry shown figure 1 , it is apparent that half of the total surface area of the flat base of the pack, ie. 75 sqr.cm of say, a total base surface area of 150 sqr.cm is made up of the wells 15 and the other half, of the protuberances 13. In addition, the shape of each well is that of a truncated pyramid with the volume of each well being about half that of a parallel sided well of the same base dimensions. Thus, in order to properly contain all of the possible 12.5 cc of liquid which may be discharged from the meat, when the tray is resting horizontally, the protuberances must be at least 2x12.5/75 = 0.33 cm in depth.

When the package 10 incorporating the substrate 12 is tilted, the liquid in the filled wells will normally be expected to immediately spill over the into less filled wells, but it is here that an unexpected benefit results when the size of each well is chosen within certain limits.

Due to surface tension, the fluid which has seeped into a well, may be retained there, even when the sheet is tilted by a large angle, or at the extreme, may even be retained when the sheet it held upside down, provided: - the well is large enough to allow the air bubble at the bottom of the well to be released as the liquid seeps into it. the well is small enough for the surface tension over the free surface of the volume of liquid held in the well, to exceed the mass of the liquid in the well, so that the liquid will be retained in the well by surface tension. Blood and blood serum has a different surface tension to plain water and this may vary within relatively wide limits. It may further vary in the presence of detergents, if such were used to pre-wash the tray.

By systematic study, the applicant has found that to take advantage of these benefits, it is preferably that the average base size of each individual well, when measured at the neutral axis, is within the range of 1 to 8 mm. Further, it is beneficial if the ratio of the depth of each protuberance in relation to its average base dimension is between the range of 0.5 to 1.5 mm.

In addition to accommodate expected liquid discharge, it is preferred that the spacing between respective wells 15, (measured at say, their centre lines 19) is in the range of 1 to 15 mm and their depth is in the range of 0.5 to 8 mm. The method of manufacture of such containers is not critical and may include injection moulding, compression moulding, thermoforming or moulding in a closed box with expanding materials.

In general, the container can be constructed of any thermoplastic or thermosetting material or of any metal which is capable of being pressed into such a relatively deeply embossed geometric form.

A preferred method of manufacture is however, to thermoform the complete package from a heat softened sheet of thermoplastic material.

Figure 3, illustrates a heat-softened thermoplastic sheet 20 and a thermoforming tool 21 consisting of a pressure box 22 for clamping and holding the heat softened sheet over an open shaped cavity mold 23 which has the form of a substrate surface 24 machined or cast into its base.

On the upper side of the sheet, shaft 25 attached to a non-metallic or metallic plug 26 can be operated to push this plug down into the mold 23 to stretch the aforesaid heat softened sheet. In order to ensure that the thickness of plastic at the base of the wells is sufficient to withstand the mechanical loads imposed on the package without collapse, the soft plastic is forced down into the each well 24 by solid metallic or non-metallic pins 27 each one of which coincides with one of the wells in the base of the mold. These pins are fitted to the underside of the plug 26 are operated together with the plug and are aligned with the receptacle wells. They have the same general cross sectional shape as these wells and are small enough in diameter to fully penetrate into the wells without touching their walls. The sequence of forming is that the hot formable sheet 20 is introduced between the mold and the pressure box 21. The plug 26 is then pushed into the sheet until the projections 27 travel to their full extend within the wells 24 and pressure is then applied inside the pressure box 21. Alternatively, vacuum may be introduce via the spigot 28 into the chamber 29 and thence into the mold via the small diameter holes 30 drilled through the base of the mold 23. This completes the overall forming of the final shape of a complete substrate.

Often the actual geometry of the substrate will depend on the ease of manufacture of the tooling to be used to form the shape. Figures 4 to 6 for example, illustrate a detail of an alternative metal substrate 31. The substrate incorporates a geometry comprising frusto-conical hollows 32 or wells formed by tooling which drilled a plurality of conical holes. Projections 33 which form the protuberances are of octagonal cross section and result from the metal pillars left between each four drilled holes. The channels 34 are formed between adjacent hollows 32 and are formed by removing the fine metal web left between adjacent holes by cross milling to a depth of one third to one half of the full depth of the holes.

An advantage of the food product packages of the present invention is that they are inexpensive to manufacture, yet are effective in collecting and retaining discharged liquid from the food product at a location away from the food product.

Finally, it is to be understood that various alterations, modifications or additions may be introduced into the construction and/or arrangement of the parts previously described without departing from the spirit or ambit of the invention.

Claims

CLAIMS:

1. A food product package including a substrate having a plurality of protuberances forming a plurality of spaced support surfaces arranged to support a food product on the substrate.

2. A food product package as claimed in claim 1 wherein the substrate includes a plurality of wells adapted to contain liquid, the wells being located between the support surfaces and being located remote from the support surfaces.

3. A food product package as claimed in claim 2 further including channels between the support surfaces to enable fluid communication between adjacent wells.

4. A food product package as claimed in either claim 2 or 3 wherein each well includes a downwardly extending circumferential wall having a base at its lower end.

5. A food product package as claimed in claim 4 wherein each protuberance includes an upwardly extending circumferential wall having a respective one of the support surfaces at its upper end.

6. A food product package as claimed in claim 5 wherein the wells and protuberances are formed in regular arrays with a portion of the circumferential wall of each protuberance being continuous with a portion of the circumferential wall of its adjacent well.

7. A food product package as claimed in claim 6 wherein the spacing between adjacent wells is in the range of 1 to 15 mm.

8. A food product package as claimed in either claims 6 or 7 wherein the depth of each well is in the range of 0.5 to 8 mm.

9. A food product package as claimed in any one of claims 6 to 8 wherein the average opening size of each well is in the range of 1 to 8 mm.

10. A food product package as claimed in any one of claims 6 to 9 wherein the ratio of the depth of each protuberance in relation to its base dimension is in the range of 0.5 to 1.5 mm.

11. A food product package as claimed in any one of the preceding claims further including a side wall extending around the perimeter of the substrate.

12. A food product package as claimed in claim 11 wherein the substrate and the side wall are integrally formed together.

13. A food product package as claimed in claim 11 further including a receptacle incorporating the side wall and wherein the substrate is in the form of an insert which is arranged to be located within the receptacle.

14. A food product package as claimed in any one of claims 2 to 13 wherein the substrate is formed by thermoforming a sheet of thermoplastic material and wherein the protuberances are formed as upwardly extending hollow projections and the wells are formed as downwardly extending hollow projections.

15. A food product package as claimed in any one of the preceding claims further including closure means cooperable with the package to enable food products supported on the substrate to be encased within the package and the closure means.

16. A method of packaging a food product including the steps of:

(a) providing a food product package as claimed in any one of the preceding claims; and

(b) locating the food product in the package such that the food product is supported on the support surfaces of the substrate.

17. A method of packaging a food product including the steps of:

(a) providing a food product package including, a substrate having a plurality of protuberances forming a plurality of spaced support surfaces and a plurality of wells located between the support surfaces, the wells being located remote from the support surfaces and the substrate further including channels between the support surfaces enabling fluid communication between adjacent wells; and

(b) locating the food product in the food package such that the food product is supported on the support surfaces of the substrate.

18. A method of packaging a food product as claimed in claim 17 further including the step of allowing fluid from the food product to drain from the food product and collect in the wells.

19. A method of packaging a food product as claimed in either claim 17 or 18 further including the step of applying a gas to the food product through the channels between the support surfaces.

20. A food product package substantially as herein described with reference to the accompanying drawings.

21. A method of packaging a food product substantially as herein described with reference to the accompanying drawings.