FR2856657A1 - Food products e.g. raw fruit, conditioning method, involves modifying atmosphere near container and cover by introducing gaseous mixture rare in oxygen e.g. mixture of nitrogen and carbon dioxide gases, and sealing packing - Google Patents

Abstract

The method involves maintaining a cover (3) that is separated from a container (2) with help of a wedge (61). The wedge is provided in an interface zone (6) of the container and the cover. The atmosphere near the container and the cover is modified, by introducing gaseous mixture rare in oxygen e.g. mixture of nitrogen and carbon dioxide gases. Packing (1) is sealed, and the wedge is then crushed. An independent claim is also included for an installation for conditioning the food product.

Description

The present invention relates to a method and an installation for the packaging of food products under a modified atmosphere.
In particular, it involves packaging fresh food products, possibly prepared and / or cooked, to give them a shelf life longer than a week.
For this, it is known to place such fresh products in a modified atmosphere, low in oxygen. Nitrogen or carbon dioxide is advantageously used alone or as a mixture. With these gases, conditions are created which are unfavorable for microbial growth.
However, in the known packaging processes, one begins by filling a container with a food product, then a lid is placed on the container, before sealing the package. However, it is necessary to seal this package after having injected into the packaging the gas chosen to produce the modified atmosphere. This step therefore presents difficulties when the lid is already placed on the container, without being sealed yet.
It is known to solve this problem, a machine comprising a suction device used to manipulate the lid of the package and keep it at least ajar during the injection of the chosen gas.
The object of the invention is to provide a packaging method and an installation, which overcomes the aforementioned drawbacks.
Another object of the invention is to provide a packaging installation whose operation is simplified compared to that of the machines of the prior art.
Another object of the invention is to provide a packaging method and an installation for saving time during the packaging of a food product in a modified atmosphere and to increase the rate of production.
Another object of the present invention is to provide a modified atmosphere food product packaging whose opening is facilitated, without prejudice to its sealing.
Other aims and advantages of the invention will become apparent from the description which follows, which is given for information only and which is not intended to limit it.
Firstly, the invention relates to a method of packaging food products under modified atmosphere, in a package consisting of a container closed by a lid, comprising the following steps: - the lid is held away from the container using spikes provided in the interface zone of the container and the lid, the atmosphere is modified in the vicinity of the container and the lid, the package is sealed and the spikes are crushed.
The invention also relates to a food packaging installation under modified atmosphere, in a package consisting of a container closed by a lid, said package being provided with means for keeping the container and the lid apart, said installation comprising at least: - means for forming a modified atmosphere chamber, - a lower tool housed inside said chamber and adapted to support said package, - an upper tool housed inside said chamber and adapted to cooperate with said lower tool for sealing said package and crushing said means to keep apart the container and the lid.
The invention further relates to a package obtained by the implementation of such a packaging method or manufactured using such a packaging plant.
The invention will be better understood on reading the description, accompanied by the appended figures, among which: FIG. 1 is a sectional view along the line 1-1 of FIG. 2, of a half-open package before sealing. according to the invention, - Figure 2 is a top view of a first variant of the container of a package according to the invention, - Figure 3 is a view similar to that of Figure 2, a second variant of the container of a packaging according to the invention, - Figures 4a, 4b and 4c are sectional views of an installation according to the invention, showing three successive stages of the operation of such an installation, FIG. 5 is a view of detail V of FIG. 1, or according to section VV of FIG. 3. As illustrated in the various figures, the invention relates to a package 1 consisting of a container 2 and a lid 3. adapted to cooperate with the container 2 to close the package. Said container contains, for example, a food product 4 under modified atmosphere 5.
Examples of food products include fresh food products such as mixtures of various seasoned vegetables. These food products may also contain, inter alia, eggs, meat, fish, seafood, or others. However, it may be a mono food product, such as raw vegetables for example.
Advantageously, the food product is maintained at a temperature below 4 ° C. and the modified atmosphere consists of a gas mixture that is low in oxygen. For example, the gas mixture contains N2 nitrogen and / or CO2 carbon dioxide. Nitrogen has the property of being a neutral gas unfavorable to microbial growth. Carbon dioxide is an antioxidant, acid, which prevents the rancidity of food products.
Under these conditions, one can consider keeping fresh products between 20 and 30 days. Indeed, these conditions make it possible to limit microbial growth, in particular bacterial growth, and thus to retard the degradation of food products.
For example, the container is a tray, as shown in Figure 2, or a pot, illustrated in Figure 3. Naturally, other forms of packaging are possible, depending on technical considerations, such as for example the shape of the food product to be packaged, or of purely commercial considerations, depending in this case on advertising aspects for example.
In any event, the container 2 is traditionally constituted by a bottom 21, substantially horizontal, side walls 22 extending substantially vertically or slightly inclined relative to the vertical and a peripheral flange 23, extending substantially horizontally, towards the outside of the container 2.
The lid 3 consists of a sheet 31 completely covering the container 2 and whose edge 32 is adapted to cooperate with the rim 23 of the container, to participate in the closure and sealing of the packaging.
According to various methods, the rim 23 of the container 2 and the rim 32 of the lid 3 are sealed together, for example by welding under the effect of heat and / or pressure, by ultrasound, by gluing, crimping or any other method known to those skilled in the art, resulting in sealing the sealed package.
In particular, the container 2 and the lid 3 are made of a rigid or semi-rigid material, such as a plastic material, authorized for food applications. In this case, the package can be sealed by heat sealing.
Moreover, it is possible to usefully provide means for easy opening of the lid according to various variants known to those skilled in the art, at its internal part. For example, it is a weakening of the thickness of the lid associated with a pull tab, according to the principle widely used in the field of cans.
However, during the packaging process, the main stages of which are illustrated in FIGS. 4a, 4b and 4c, the lid 3 is held away from the container 2 by means of pins 61 provided in the interface zone 6 of the container. 2 and lid 3.
Thus, as illustrated in FIG. 5, one-off spikes 61 are provided, for example at the upper face 63 of the flange 23 of the container 2. Alternatively, the spikes 61 may be provided at the lower face 62 of FIG. the border 32 of the lid 3.
So that the lid 3 is stably spaced from the container 2, at least three pins 61 are provided in said interface zone 6.
For example, as illustrated in Figure 2, for a substantially rectangular tray, four pins 61 are arranged at the vertices of a rectangle. As illustrated in FIG. 3, for a frustoconical pot, three pins 61 were placed on a circle, separated from each other by an angle of 120 [deg].
However, it is not absolutely necessary that the pins 61 are evenly spaced from each other, but it is sufficient that they are sufficiently spaced to define a plane. Advantageously, said pins 61 are oriented substantially perpendicular to the bottom 21 of the container 2.
As illustrated, said pins 61 are cylindrical and solid and of the same material as, or compatible with, the lid and / or the container.
It is nevertheless possible to use hollow pins. Thus, crashing such hollow spikes could turn around like a glove. To implement this variant, it is simply necessary that said hollow pins are able to support the lid 3 as the conditioning operations are in progress.
Thus, it is possible to keep apart the container 2 and the cover 3, at least in the interface zone 6, by a distance or gap D substantially equal to the height of the pins 61.
In the following process, after filling the container of the food products to be packaged, and arranged the lid above the container, the latter being kept apart as described above, oh changes the atmosphere in the vicinity of the container and lid so as to replace it with a previously selected gas (FIG. 4b). Finally, sealing the package and crushing said pins (Figure 4c) Advantageously, the package is sealed by heat sealing, the pins 61 being crushed under the effect of heat and / or pressure.
The invention also relates to a packaging installation 7 of food products 4 under modified atmosphere 5, in a package 1. It is as described above a package consisting of a container 2 closed by a lid 3, said packaging being provided with means for keeping apart the container 2 and the lid 3.
Said installation 7 comprises at least means 8 for forming a modified atmosphere chamber, a lower tool 9 housed inside said chamber and adapted to support said package 1 and an upper tool 10 housed inside of said chamber and adapted to cooperate with said lower tool 9 to seal said package 1 and crush said means to hold apart the container 2 and the lid 3.
Advantageously, the evacuation chamber 8 consists of two half-shells 81, 82 adapted to cooperate with each other at a seal 83 to form said chamber 84. In addition, one of the half-shells, the upper half-shell 82 for the illustrated examples, is provided with a pipe 85 communicating between the inside and the outside of the chamber 84.
Furthermore, there are provided means, not shown, for putting the chamber 84 under vacuum as well as means, not illustrated, for injecting a gaseous conditioning mixture. Advantageously, said means for evacuating and injecting a gaseous mixture cooperate with the pipe 85 to effect gas exchange between the inside and the outside of the chamber 84.
Said lower tool 9 and said upper tool 10 are in the form of a jaw whose jaws 91, 101, are able to cooperate with one another on the one hand, to crush said pins 61, and on the other hand, to realize the sealing the lid 3 to the container 2. In particular, said jaws 91, 101, each constitute an electrode. Said jaws can be actuated by means of a press device, to apply a high pressure at the interface zone 6 between the container 2 and the lid 3. It will be for example a pressure of several tonnes, especially eight tonnes, applied hot.
By combining, the effects of heat and pressure can crush the pins 61 and seal the package 1.
In this regard, the use of an easy opening system, as mentioned above, allows the use of high pressures favoring the crushing of said pins and the realization of the seal between the lid and the container.
The operation of the packaging plant, illustrated in Figures 4a, 4b and 4c is as follows.
Firstly, at the level of the lower tool 9, there is a container 2 filled with the food product 4 and on which the lid 3 is placed. Thanks to the pins 61, the lid 3 and the container 2 are separated one by one. on the other a distance D.
In the next step, the means 8 are closed to form a modified atmosphere chamber 84. The sealing of the chamber 84 is ensured by means of the seal 83. Vacuuming is then carried out by means of evacuation means communicating with the pipe 85. The gaseous conditioning mixture 5 is then injected. , for example through the pipe 85. The gaseous mixture 5 spreads inside the chamber 84 and in particular in the volume defined between the container 2 and the lid 3.
The next step is to seal the package by bringing the jaws closer to the lower tool 9 and the upper tool 10. For example, heat and pressure are applied to isolate the volume. inside the packaging of that of the chamber 84 by crushing the pins 61 and secondly to make the sealed package by performing a heat seal.
Once the sealing has been carried out, either the excess injected gas mixture can be recycled back into the chamber 84, or these means 8 can simply be opened to constitute said chamber 84.
Finally, the sealed package is removed from the installation to make room for a new, unsealed package.
Of course, other modes of implementation, within the reach of those skilled in the art, could still be envisaged without departing from the scope of the invention.

Claims (7)

2. A method of packaging according to claim 1, wherein there is provided a device (33) for easy opening at the lid (3). 3. Method according to claim 1 or 2, wherein there is provided at least three pins (61) spaced apart in the interface area. (6) the container (2) and the lid (3), said pins (61) being oriented substantially perpendicularly to the bottom (21) of the container. 4. A method of packaging according to any one of the preceding claims, wherein the container (2) and the lid (3) are made of a rigid or semi-rigid material. The method of packaging according to claim 4, wherein said material is a plastic material. 6. A method of packaging according to any one of the preceding claims, wherein the package is sealed (1) by heat sealing, said pins (61) being crushed under the effect of heat and / or pressure. 7. Installation (7) for packaging a food product (4) under modified atmosphere (5), in a package (1) consisting of a container (2) closed by a lid (3), said package (1) being provided with means (61) for keeping the container apart ( 2) and the cover (3), said installation (7) comprising at least: means (8) for forming a modified atmosphere chamber (84), a lower tool (9) housed inside said chamber (84) and able to support said package (1), an upper tool (10) housed inside said chamber (84) and adapted to cooperate with said lower tool (9) for sealing said package (1) and crushing said means (61) to keep the container apart (2); ) and the lid (3). 8. Installation (7) of conditioning according to claim 7, wherein said lower tool (9) and said upper tool (10) each constitute an electrode in the form of a jaw (91, 101), able to cooperate between them to crush said pins (61) and seal the lid (3) on the container (2). 9. Installation (7) for packaging according to claim 7 or 8, wherein said chamber (84) of modified atmosphere is constituted by two half-shells (81, 82) adapted to cooperate with each other at a joint (83) provided with sealing means and means for injecting a gaseous conditioning mixture. 10. Packaging (1) obtained by the implementation of a method according to any one of claims 1 to 6 or manufactured using an installation according to any one of claims 7 to 9.