GB2248599A

GB2248599A - Filling and sealing sterilised containers

Info

Publication number: GB2248599A
Application number: GB9022053A
Authority: GB
Inventors: Damian Killen
Original assignee: SOUS CHEF Ltd
Current assignee: SOUS CHEF Ltd
Priority date: 1990-10-10
Filing date: 1990-10-10
Publication date: 1992-04-15
Also published as: GB9022053D0; WO1992006892A1; AU8644891A

Abstract

A method of filling and sealing a sterilised container with aseptically processed matter through a sealable inlet provided with a neck portion (4) to receive a filling nozzle is disclosed. The method comprises the steps of inserting the filling nozzle into theinlet neck portion, filling the container with said aseptically processed matter, flushing the inlet to remove any residual aseptically processed matter therefrom prior to sealing, sealing the inlet and at least partially filling the inlet with a hot melt adhesive (16) to form a seal therewith which will prevent ingress of bacteria to the interior of the container. The inlet is preferably flushed with superheated steam to remove any food particles therefrom prior to closing the inlet with the hot melt adhesive.

Description

METHOD OF FILLING AND SEALING AN ASEPTIC FOOD CONTAINER AND CONTAINER FILLED THEREBY DESCRIPTION This invention relates to an improved method for filling and sealing an aseptic food or beverage container and also to a container filled in accordance with the method of the invention.

One of the more common containers into which food or drink is aseptically packaged is a flexible bag which incorporates a filling valve called a back membrane sealing gland. This gland consists of a rigid plastics neck from the bottom of which extends a radial shoulder which is secured to the interior face of the bag to be filled. A back membrane is attached to the lower face of the shoulder to provide two or more passage ways for product to flow into the bag. The bag is filled by attaching a filling nozzle to the neck of the sealing gland and pumping aseptically prepared food or drink into the bag under pressure until such time as the bag is full. The filling nozzle is then removed and the sealing gland is flushed with superheated steam to remove any particulate debris from the neck portion.

The back membrane is then heat sealed to the underside of the shoulder of the sealing gland to hermetically seal the contents of the bag therein.

One of the problems with an arrangement such as this i that if any debris is left in the region of the neck portion, a perfect seal cannot be made. For instance, if a food particle bridges the area where the annular seal is made between the back membrane and the gland shoulder, bacteria can get into the interior of the bag as the food particle provides a bridge across the seal area . This problem is exacerbated because both the neck and the contents of the bag contain moisture so the food particle acts as a wick and draws bacteria into the interior of the container. In order to overcome this problem, extra care has to be taken to ensure that all food debris is removed from the sealing gland during flushing .This is normally done using superheated steam or sterile water under pressure but there is no guarantee that all the food particles will have been removed to ensure that a proper seal can be made every time.

Various attempts have been made to overcome these problems by improving the flushing step or using expensive equipment to check to see if the seal has been bridged but they have all proved to be unsatisfactory. It is therefore an object of the invention to provide an improved method of filling a container with aseptic food or beverage whereby the contents of the container are guaranteed to be sealed therein in such a way that bacteria cannot enter the container at a later date.

According to one aspect of the invention there is provided a method of filling and sealing a sterilised container with aseptically processed matter through a sealable inlet provided with a neck portion to receive a filling nozzle, the method comprising the steps of:a) inserting the filling nozzle into the inlet neck portion; b) filling the container with said aseptically processed matter; c) flushing the inlet to remove any residual aseptically processed matter therefrom prior to sealing; d) sealing the inlet and; e) at least partially filling the inlet with a hot melt adhesive to form a seal therewith which will prevent ingress of bacteria to the interior of the container.

Preferably the inlet is flushed with superheated steam to remove any food or beverage particles therefrom.

Desirably the superheated steam is at a temperature of approximately 1450C so that it scours as well as flushes the inlet.

Preferably the inlet includes an annular shoulder attached to the interior of the container wall, the inlet further including a membrane attached to the lower face of said shoulder in such a way that aseptically processed matter can be admitted to the container between said membrane and the shoulder following which the membrane is secured to the shoulder to seal the inlet. Conveniently the membrane is heat sealed to the shoulder, the material of the membrane and the shoulder being compatible to enable them to be heat sealed together but sealing at a different temperature to that of the bag wall material.

Conveniently the inlet includes a neck portion which is substantially filled with said hot melt adhesive. Any suitable hot melt a adhesive can be used provided that it is non-toxic and suitable for use with food products.

For instance, an adhesive normally used for glueing food grade cardboard packaging can be used . If desired, the adhesive can also include a bacteriocidal agent for increased security.

The hot melt adhesive is preferably admitted to the neck portion at a temperature in the range from 1400C-2000C so that it will vapourise any moisture present in the gland neck. The adhesive can be admitted to the inlet either manually or automatically.

According to another aspect of the invention there is provided an aseptic food or beverage container provided with a hermetically sealed filling inlet which is additionally sealed with a hot melt adhesive.

Preferably the container is a flexible bag but any other form of container such as a box could be used.

Conveniently the inlet includes a neck portion attached to the container, the hot melt adhesive being located in said neck portion.

In a preferred embodiment, the inlet comprises a back membrane sealing gland wherein said neck portion is attached to a shoulder portion located inside the container and attached to the interior wall of the container, said back membrane being attached to said shoulder portion in such a way that food or beverage can be admitted to the interior of the container until the container is full at which time the back membrane is hermetically sealed to the shoulder to close the inlet.

A preferred method and container of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a cross-section through a container in accordance with the present invention; Figures 2A and 2B are plan views of alternative filling glands for use with the container shown in Figure 1, and; Figure 3 is a view of the container shown in Figure 1 just prior to the inlet gland being sealed.

Referring to the drawings, there is shown in Figure 1 a container in the form of a flexible bag having an upper wall la and a lower wall 1b joined at their periphery by means of a hermetic seal 2. A filling gland 3 moulded from a rigid plastics material is fitted to the bag and comprises an inlet or neck 4 attached to a radially extending shoulder 5. Spaced annular lips 9 and 10 define a collar 11 on the neck whose purpose will be explained hereafter.

The shoulder 5 is shaped as shown in Figures 2A and 2B.

A back membrane 6 is attached to the shoulder 5 in such a way that food or drink can be admitted to the interior of the container between the shoulder 5 and back membrane 6. For instance, the back membrane 6 can be line welded at 7 along opposite edges of the shoulder 5 as shown in Figure 2A. With this arrangement, product will flow into the container in the two directions indicated by the arrows.

Alternatively, the back membrane 6 can be attached to the shoulder 5 by four spot welds 8 located adjacent each corner of the shoulder 5. With this arrangement, product can flow into the container in the four directions indicated by the arrows.

Filling of the container with product is achieved by means of the nozzle 15 (see Figure 3). A clamp 14 engages the collar 11 on the sealing gland and raises the neck 4 up towards the nozzle 15. The mouth of the neck 4 is cpvered with a sealing membrane (not shown) which is pierced by the nozzle 15. The chamber within the neck 4 above the back membrane 6 is then flushed with steam supplied from the nozzle 15 to sterlise the chamber.

Aseptically processed food or beverage is then pumped from the nozzle 15 into the interior of the container between the shoulder 5 and the back membrane 6. Once the container is full, the supply of product to the nozzle 15 is cut off and the upper surface of the back membrane 6 is cleared of any food or beverage debris by a combination of flexing the gland mechanically and flushing the surface of the membrane 6 with superheated steam supplied from the nozzle 15 at a temperature of the order of 1450C. This flashes off or vapourises any moisture present in the neck gland and also washes away any food or other particulate material from the membrane which could impair the effectiveness of the seal of the back membrane 6 to the shoulder 5 in the manner to be described.

After completion of the flushing and scouring step, a heated annular sealing die 13 is raised to press the membrane 6 against the shoulder 5 to form an annular seal therewith around the neck 4 . The material of the membrane 6 and the shoulder 5 are compatible in terms of being heat sealed together but seal at a different temperature to that of the wall material la, 1b so there is nor risk of damage to the bag wall 1b during sealing of the back membrane 6 to the shoulder 5.

Once this step has been completed, the nozzle 15 is removed from the neck 4 and the filling gland is pressure tested to make sure that the inlet has been properly hermetically sealed. If it passes this test, then a hot melt adhesive 16 inserted into the neck 4 at a temperature of between 1400C and 2000C. This vapourises or flashes off any moisture which may be present in the neck and also forms a bacteria impervious external seal within the neck 4 of the gland. If a food or drink particle or fibre has been left in the annular seal area between the membrane 6 and the shoulder 5, moisture in the neck or interior of the container would tend to hydrate the particle bridging the seal and create a "wicking" effect which would draw the microoganisms into the container.By using the hot melt adhesive 16, even if there is debris bridging the seal between the shoulder 5 and the back membrane 6, the additional external seal provided by the hot melt adhesive 16 will provide the necessary security to prevent the ingress of any microbiological material such as air borne organisms, bacteria, yeasts or moulds.

By means of this simple a very effective seal can be formed in the back membrane sealing gland which does not require complicated machinery or testing procedures to ensure complete safety of the aseptic product in the container from attack by external microbiological organisms.

Containers filled by the method of the present invention have been tested by creating faulty seals whereby food material is trapped in the seal between the back membrane 6 and the shoulder 5. Hot melt adhesive 16 was then inserted into the neck 4 of the sealing gland to externally seal the inlet. Known bacteria suspended in solution was introduced into the necks of the glands and the containers were transit tested in known manner and then incubated for 21 days at a temperature of 300C. Despite the faulty seal between the back membrane 6 and the shoulder 5, none of the bags tested showed any contamination of the product inside the container.

The hot melt adhesive 16 can be inserted in the neck 4 either manually or automatically and can also include a bacteriocidal agent to further increase security.

A suitable hot melt adhesive would comprise a polymer such as EVA, a resin (hydrogerated hydrocarbon), a plasticiser such as polybutene and an antioxidant such as butylated hydroxy toluene. Such an adhesive is sold by Swift Adhesives Limited under their product No.

B640/67SF which has been found to be particularly suitable for use with the method of the present invention. Details are as follows: Description B640/67SF is a long open time, medium tack holt melt adhesive which is suitable for use in applications which require good adhesion to plastics. B640/67SF will bond polyethylene, polypropylene and polystyrene and uses no silicone in any of its manufacturing or processing.

Method of Application B640/67SF will run cleanly on wheel and jetting applicators.

Application Temperature: 1600C - 1800C Typical Properties Viscosity (ICI Cone and Plate) 1400-1580 mPa.s at 1750C Softening point - 77 - 820C (Ring & Ball) Colour - White (These values represent typical production data)

Claims

CLAIMS 1. A method of filling and sealing a sterlised container with aseptically processed matter through a sealable inlet provided with a neck portion to receive a filling nozzle, the method comprising the steps of: a) inserting the filling nozzle into the inlet neck portion; b) filling the container with said aseptically processed matter; c) flushing the inlet to remove any residual aseptically processed matter therefrom prior to sealing; d) sealing the inlet and; e) at least partially filling the inlet with a hot melt adhesive to form a seal therewith which will prevent ingress of bacteria to the interior of the container.
2. A method as claimed in Claim 1 wherein the inlet is flushed with superheated steam to remove any food or beverage particles therefrom.
3. A method as claimed in Claim 2 wherein the superheated steam is at a temperature of approximately 1450C so that it scours as well as flushes the inlet.
4. A method as claimed in any preceding claim wherein the inlet includes an annular shoulder attached to the interior of the container wall, the inlet further including a membrane attached to the lower face of said shoulder in such a way that aseptically processed matter can be admitted to the container between said membrane and the shoulder following which the membrane is secured to the shoulder to seal the inlet.
5. A method as claimed in Claim 3 wherein the membrane is heat sealed to the shoulder, the material of the membrane and the shoulder being compatible to enable them to be heat sealed together but sealing at a different temperature to that of the bag wall material.
6. A method as claimed in any preceding claim wherein the inlet includes a neck portion which is substantially filled with said hot melt adhesive.
7. A method as claimed in any preceding claim wherein the hot melt adhesive is non-toxic and suitable for use with food products.
8. A method as claimed in any preceding claim wherein the adhesive includes a bacteriocidal agent.
9. A method as claimed in any preceding claim wherein the hot melt adhesive is admitted to the neck portion at a temperature in the range from 1400C-2000C so that it will vapourise any moisture present in the gland neck.
10. A method substantially as herein described with reference to the accompanying drawings.
11. An aseptic food or beverage container provided with a hermetically sealed filling inlet which is additionally sealed with a hot melt adhesive.
12. A container as claimed in Claim 11 wherein the container is a flexible bag.
13. A container as claimed in Claim 11 or Claim 12 wherein the inlet includes a neck portion attached to the container, the hot melt adhesive being located in said neck portion.
14. A container as claimed in any of Claims 11-13 wherein the inlet comprises a back membrane sealing gland and said neck portion is attached to a shoulder portion located inside the container and attached to the interior wall of the container, said back membrane being attached to the shoulder portion in such a way that food or beverage can be admitted to the interior of the container until the container is full at which time the back membrane is hermetically sealed to the shoulder to close the inlet.
15. An aseptic food or beverage container substantially as herein described with reference to the accompanying drawings.