GB2200091A

GB2200091A - Vacuum packaging

Info

Publication number: GB2200091A
Application number: GB08801292A
Authority: GB
Inventors: Bernard John Bourke
Original assignee: TRIGON PACKAGING SYSTEMS
Current assignee: TRIGON PACKAGING SYSTEMS
Priority date: 1987-01-22
Filing date: 1988-01-21
Publication date: 1988-07-27
Anticipated expiration: 2008-01-21
Also published as: GB8801292D0; GB2200091B; NZ219039A; AU1066588A; AU616165B2

Abstract

Meat cuts or other products 2 are packed within dual ply packages 1;1.1. An inner ply package 1 is evacuated and the surfaces of an outer ply package (1.1) are able to slip relative to the inner ply with less likelihood of damage occuring to the package prior to use. The outer ply is constituted by a bag or sleeve enclosing an inner bag constituting the inner ply, the bags having a common opening which is sealed after the inner bag has been loaded and evacuated. Openings 7 (Fig. 4) are provided in the outer bag to allow air into the bags' interspace. <IMAGE>

Description

'Vacuum Packaging' This invention concerns a method of vacuum packaging food and a pack for the same.

The invention will be described with reference to meat but those working-in this technology will appreciate that the invention is applicable to other foods or articles which are vacuum packed. Packers of multiple portions of the same cuts of meat for retail and wholesale now make greater use of vacuum packs whereas once it was common only for bacon and specialty meats.

The packs may be 300 x 200 and may contain for example several steaks. These are sealed in a vacuum packing machine using the following method. A bag the size described above is supplied ready sealed on three sides. The bag is filled and loaded into a vacuum chamber with the mouth of the bag lying between a pair of sealing bars or similar closure devices which after the bag is evacuated are activated to seal the pack on the fourth side.

A vaccum pack for bony cuts for example chops may have to endure handling in a butchers shop, supermarket or restaurant freezer. It is not uncommon for the sharp corner or point of a chop bone to pierce the film of the pack and destroy the vacuum. This leads to the incursion of air and the build up of a telltale ice layer which spoils the appearance of the meat. This may lead to unsaleability even though the meat may still be palatable and in a edible condition, or can cause contamination.

Puncture occurs for several reasons. Firstly, because the film loses some of its yeild capability as the storage temperature falls. Secondly, the vacuum ensures that the film is already tightly drawn around the outer surface of the meat including any protruding bone. Loin, neck and rump chops are particularly likely to present bony protrusions in this respect. Thirdly, the force available for penetration is increased by the stacking of meat packs one on top of the other in a freezer coupled with the hardness of the contents and the tendency of salespersons to jam the packs where ever they will fit.

A method aspect of this invention provides a method of making a vacuum pack comprising forming a flat inner bag within a flat outer bag while leaving an opening in a common side of both bags through which the inner bag may be filled.

The inner and outer bags may be united around their common perimeter except for the opening. Alternatively the inner and outer bags may be made separately and one inserted inside the other either before filling or after filling.

Another alternative is to have the inner bag sealed along the sides and bottom, and the outer bag sealed only at the sides forming a jacket.

Another method aspect of the invention provides a method of packing an article in a pack as described above comprising placing the article in the inner bag, evacuating the pack in a vacuum chamber and sealing the four film plies constituting the common side or opening of both bags while within the chamber.

The final- seal may unite the two plies which constitute the inner bag.

Alternatively the final seal may unite all four plies. When the latter method operates, the two outer plies are perforated to allow air ingress between the inner and outer bag so that the outer plies will separate from the plies making up the inner bag so that some sliding movement between the plies is possible despite their being united along the remainder of their common perimeter.

A product aspect of the invention provides a vacuum pack for articles for example meat comprising an inner flat film bag within an outer flat film bag with an opening along a common side of both bags.

The bags may be rectangular and united on three sides by a continuous seal. The inner bag may protrude on the fourth side from the mouth of the outer bag so that only the protruding border is sealed after filling and vacuum treatment. One bag is preferably of a film which is selected for tear strength and pliability at freezer temperatures or a compromise between these properties while the other bag film may be thinner and have a glossy surface to provide slip between the first bag and the second bag and secondly, between the three bags and other external contact for example, other packs. Either or both of the bags may bear print.

Embodiments of the present invention are now described by way of example only with reference to the accompanying drawings in which: Figure 1: is a diagrammatic section of a vacuum package in accordance with the present invention after loading, Figure 2: is a diagrammatice section of the vacuum package of Figure 1 with the open ends thereof having been nipped by a clamp, and Figure 3: is a diagrammatic section of the clamped bag of Figure 2 after the inner bag has been evacuated, and - Figure 4: is a perspective view of an exacuated and sealed package in accordance with one possible embodiment of the present invention, and Figure 5: is a perspective view of an unsealed pack in accordance with another embodiment of the present invention, and Figure 6: is a perspective view of the pack of Figure 5 after sealing.

Firstly, with respect to Figures 1 to 4 of the drawings, in accordance with one possible embodiment of the present invention bags 1 and 1.1 of known construction namely rectangular polythene bags are filled with meat cuts 2, the inner bag 1 then being evacuated and a common opening sealed.

The inner bag 1 is lose within the outer bag 1.1 and the open end 4 of the inner bag may, at least initially, extend beyond the equivalent opening 5 of the outer bag 1.1.

The inner bag 1 is placed within the outer bag 1.1 and filled with product such as meat cuts 2 as illustrated by Figure 1. The openings 4, 5 of the bags are then clamped by clamp 6 of a vacuum forming apparatus (not shown) which may be a chamber-type apparatus or a non-chamber apparatus such as the CORR-VAC machine manufactured by M-Tek of the U.S.A.

Figure 3 illustratesga package formed from the two bags 1, 1.1 in which the inner bag 1 has been evacuated using a vacuum probe 7 which extends between clamp 6, and the openings 3 sealed by seal bars (not shown) associated with the clamp 6.

After evacuation the inner bag 1 is closely formed about the meat cuts 2 whilst the outer bag 1.1 is a lose fit on the inner bag 1 with the bags being united about one edge, that is, the opening 3.

The outer bag 1.1 is provided with a plurality of apertures 7 therein which may be along one edge of the outer bag or elsewhere (not shown) so that the air space between the outer bag 1.1 and the inner bag 1.1 is subject to atmospheric conditions. This means that the outer bag 1.1 is able to slip with respect to the inner bag 1 with the risk of a puncture of both of the plies of the bags being substantially reduced.

Figures 5 and 6 of the drawings illustrate a possible alternative construction for a package in accordance with the present invention. The bag 8 is made of four super-imposed rectangular plies of film. The two inner plies 9, 10 form the inner bag 11 while two outer plies 12, 13 form the outer bag 14. All the plies are joined by a continuous seal 20 around the three sides as shown but the inner plies are longer than the outer plies leaving a mouth 21 to which the bag can be filled. The bag is evacuated and then sealed in the same manner as previously described, the final closing being achieved by establishing seal 22 as shown in Figure 6.

Aspects of the present invention have been described by way of example only and it would be appreciated that modifications and additions thereto may be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. A method of packaging comprising the steps of making a vacuum pack comprising inner and outer bags with a common opening, filling the inner bag with a product and closing the opening.

2. A method as claimed in claim 1 comprising the additional step of evacuating the inner bag prior to closing the opening.

3. A method as claimed in claim or claim 2 wherein the outer bag is provided with apertures therein to allow the ingress of air into the outer bag.

4. A method as claimed in anyone of claims 1 to 3 wherein the inner and outer bags have one or more common edges.

5. A method as claimed in anyone of claims 1 to 4 comprising the further step of forcing air into the outer bag after or prior to sealing to separate plies of the bags.

6. A package for a product comprising an inner bag and an outer bag having a common opening wherein the inner bag has been evacuated after loading and the opening closed so that the product is protected by the inner bag which is a close fit on the product and -the outer bag which is a loose fit on the inner bag.

7. A package as claimed in claim 6 wherein the outer bag is provided with at least one aperture therein to allow the ingress of air into the outer bag.

8. A package as claimed in claim 6 wherein the inner and outer bags are united along one or more common edges.

9. A package as claimed in anyone of claims 6 to 8 wherein the outer package is provided with one or more apertures therein positioned on edge or edges of the bag.

10. A method of packaging substantially as herein described with reference to the accompanying drawings.

11. A package substantially as herein described with reference to the accompanying drawings.