FR2779411A1 - Oyster packaging method and associated packaging - Google Patents

Abstract

The process involves vacuum packing the oysters in a suitable film (6,7,8) to ensure that the shells remain closed. This is achieved by flat packing the oysters in a film envelope, withdrawing the air, using for example a vacuum pump, and sealing the oysters within the bag. An Independent claim is included for the state of the oysters caused by the packaging and by the method.

Description

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  The present invention relates to a new process for packaging shellfish, in particular bivalve shellfish and in particular oysters, as well as packaging containing

  such shells obtained by this process.

  The present invention will be described with more specific reference to the packaging of oysters, but it applies to other shellfish species such as, for example, clams, cockles, meadows, almonds, mussels or clams, etc. Oysters are generally sold by being stacked one on top of the other in wooden baskets fitted with a lid to prevent their shells from opening during the time of marketing, thus causing a loss of

  the water which must remain inside the shell.

  The known packaging of this type is not entirely satisfactory, because, despite the precautions that are taken, it does not prevent the sanitary state of the oysters from degrading and making them unfit for consumption after a period of time which is of

around five to eight days.

  In addition, the packaging generally includes large quantities of oysters which are greater than the purchases of average consumers, which implies repackaging the oysters for their retail sale and which also contributes to the deterioration of

their health.

  The present invention aims to remedy these drawbacks and to allow the marketing of oysters in packages comprising a given quantity, for example a dozen or two dozen oysters, said packaging being carried out in a sealed manner at the place of shipment. In addition, the oysters can, if desired, be conditioned in the pre-opened state, i.e. after

breaking of their hinge.

  The present invention is based on the use of a pressure difference with respect to atmospheric pressure to keep the two half-shells of the shells applied against one another in a leaktight manner, while the said shells are

  enclosed in a sealed enclosure.

  In a first embodiment, the present invention relates to a method of packaging shellfish such as oysters, characterized in that the shellfish are placed in

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  the interior of a flexible container or pocket in which a vacuum is then created by sucking in the air so as to apply the walls of the flexible container or pocket to the shells, so as to maintain the two half shells of each shell applied against each other and which are then sealed

container or flexible pouch.

  In a completely surprising way, by proceeding in this way, one obtains not only that the shells do not open and do not lose their water under the effect of the depression but that on the contrary, the shells retain all their water while the walls of the container or of the pocket hold the two half-shells applied one on the other in a leaktight manner, which prevents them from any loss of water and ensures them an excellent conservation which can reach at least two to three weeks before the degradation of

  their state of health does not make them unfit for consumption.

  According to the invention, it is advantageous to place the shells in a first flexible or non-leak-proof pocket or container which is then introduced into a second flexible pocket inside.

which we empty.

  This way of proceeding has the advantage of avoiding that under the combined action of atmospheric pressure and the depression which prevails inside the flexible pocket, the cutting edges of the

  shells puncture the pocket which isolates them from the atmosphere.

  According to a particular embodiment of the invention, the shells are placed, for example oysters, in a deformable plastic box which corresponds substantially to the general shape of all the oysters which it is desired to condition, this box being provided of a lid which is folded down on the oysters after their setting

place in the box.

  The box thus filled is then introduced into a pocket

  made of flexible plastic, inside which a vacuum is created.

  The degree of vacuum which is produced inside the flexible bag must be sufficient to keep the two half-shells of each oyster pressed against each other in a leaktight manner

  during the entire shelf life.

  Absolute internal pressures of the order of a few hundred millibars, i.e. absolute internal pressures of

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  a few hundred grams per square centimeter are usually

  sufficient to implement the method according to the invention.

  In a second embodiment of the invention, the shellfish are packaged for marketing by placing them in a sealed container inside which a gas is sent to place the interior of the container under sufficient pressure to prevent shellfish from opening during

  the whole time they stay in the packaging.

  In a particular embodiment, the pressure inside the sealed container can be for example around 1.5 kg

at 2 kg per square centimeter.

  The enclosures used may be rigid such as boxes or containers or deformable, such as pockets

plastic material.

  The gas used to create the internal overpressure can for example be air or nitrogen which is preferably filtered and

sterilized before use.

  According to an improved variant of the method according to the invention before packaging the oysters, the hinge is fractured which ensures the mechanical connection of the two half-shells when the latter open and close under the action of the muscle which is located some distance from the hinge. In doing so, care must be taken not to damage the contact surfaces of the two half-shells in order to maintain the seal which exists.

  naturally when the oyster stays closed.

  In this case, it should be ensured at the time of packaging that the oysters remain arranged horizontally until the moment when a vacuum has been created in the flexible bag for

  prevent water from flowing out of the oysters.

  The fact of fracturing the hinge which connects the two half-shells makes it possible later to open the oysters with great ease since it suffices to introduce the blade of a knife between the two half-shells to cut the muscle without the '' we have to force the hinge which constitutes the most important obstacle to

the opening of an oyster.

  The present invention also relates to a packaging of shells such as oysters, characterized in that the shells are contained in a container or in a container.

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  deformable pocket inside which a vacuum has been created such that the walls of the container or of the pocket are applied to the half-shells

  oysters by keeping them closed.

  In a particular embodiment of the invention, the shells are contained in a deformable and non-waterproof container and itself placed inside a flexible pocket inside which

the vacuum is created.

  In a particular embodiment, this packaging is characterized in that the hinge connecting the two oyster half-shells was broken before the introduction of the

  shells in their packaging.

  Although the invention has been described with more particular reference to oysters, it can be applied to many shellfish which have the particularity of being able to close in a sealed manner by applying one against the other of their two half - shells, which prevents, when the shell is closed, the passage of water or air from the outside to the inside of the shell or from the inside of the shell to the outside and thus ensures conservation. The invention has the advantage of allowing packaging on the place of shipment which will be kept until the time of use by the consumer, this packaging

  containing a number of oysters which corresponds to a sales unit.

  The packaging thus produced according to the invention at the sender's may include a marking concerning in particular the origin and the expiry date which guarantees the consumer a perfect sanitary condition of the product and a certain knowledge of its origin. The invention also makes it possible to market self-service shellfish from the fresh produce department in a packaging which is perfectly clean and which, at the time of consumption, does not contain water, the latter having been stored inside.

  shells tightly.

  The method according to the invention also has the great advantage of allowing the marketing, in perfect sanitary condition, of oysters pre-opened at the place of dispatch, which is not

currently not possible.

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  After the opening of the flexible pouch, the consumer only has to cut the muscle to open the shell, the

  hinge was previously broken.

  In order to better understand the invention, we will describe below several non-limiting modes of implementation given by way of example with reference to the accompanying drawing in which: - Figure 1 is an elevational view of an oyster ajar, - Figure 2 is the top view of the oyster of Figure 1 after removal of the upper half-shell, - Figure 3 is a perspective view of an oyster package according to a first embodiment of the invention, - Figure 4 is a sectional view along IV-IV of Figure 3, - Figure 5 shows how, according to a second embodiment of the invention, first place the oysters in a deformable container, - Figure 6 shows how the container of Figure 5 is arranged inside a flexible pocket, inside which we are about to empty, - the Figure 7 is a cross-sectional view of the packaging of oysters obtained by the pro given in Figures 5 and 6, and Figure 8 is a schematic view showing an alternative embodiment of the invention, according to which the oysters are placed in a sealed container in which a gas is sent under

pressure.

  There is shown in Figure 1, an oyster shelled profile view which has a lower half-shell 1 containing the

  body of the mollusk, and an upper half-shell 2 forming a cover.

  The two half-shells are hinged together by a hinge 3 which allows their opening under the action of the muscle 4 while ensuring a tight closure of the two half-shells when

  muscle 4 applies them one against the other.

  FIG. 2 shows the oyster of FIG. 1 which was opened by cutting the muscle 4 and fracturing the hinge 3

  to move the upper half-shell away.

  We also see in Figure 2 the body 5 of the oyster.

  Like many other shells, the oyster has the particularity that the edges of the two half-shells can be

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  kept tightly in contact with each other, while the

  hinge 3 is located outside this sealing line.

  As a result, the tightness of the two half-shells can be maintained even after the hinge 3 has broken when the two half-shells are applied to each other. There is shown in Figure 3 a package of six

  oysters according to a first embodiment of the invention.

  This conditioning is obtained by the fact that the oysters are placed inside a flexible pocket, constituted by two sheets 6, 7 joined by a weld line 8, inside which a vacuum has been created by suction. air in there, then

  we have welded the periphery 8 of the two sheets.

  The vacuum thus created corresponds for example to an absolute pressure of approximately 300 grams per square centimeter, which means that atmospheric pressure exerts on the external surface of the flexible bag

  6.7 a force of about 700 grams per square centimeter.

  In Figure 4 which is a sectional view along IV-IV of Figure 3, there is the upper sheet 6, the lower sheet 7 and the weld line 8 which joins the periphery of the two sheets

  after vacuuming the space containing the oysters.

  It results from the depression which reigns inside the pocket thus constituted that the atmospheric pressure strongly applies the walls 6 and 7 of the pocket against the oysters which it contains by exerting a sufficient force to prevent that the two half-shells of each oyster do not open, as happens spontaneously

  when oysters are left in the open air for a while.

  Figures 5, 6 and 7 show a second embodiment of the invention, according to which the oysters are first placed in a flexible container (which is seen in section in Figure 5 in the state open) which comprises a body 9 and a cover 10 capable of fitting one into the other and which, in the embodiment described are joined by a fold line 11 forming a hinge. Such flexible containers obtained by deformation of plastic sheets are currently commonly used

in food.

  The obturation obtained by placing the cover 10 on the

  body 9 is not made in leaktight manner.

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  After placing the oysters in the flexible container of Figure 5 and having closed the latter, it is introduced as shown in Figure 6, in a flexible pocket consisting of two plastic sheets 6 and 7 welded in 8 around their edges , while an orifice comprising a cannula 12 makes it possible to suck out the air contained in the pocket, which gradually causes the walls 6 and 7 of the pocket to be applied strongly to the container of the figure, it deforms the walls to apply them to the oysters under

  the action of atmospheric pressure.

  When sufficient vacuum is obtained, it suffices with the aid of two heating tools 13 which are applied on either side to heat the corresponding zones of the sheets 6 and 7 to ensure a tight seal and obtain the packaging which is shown in

section in Figure 7.

  In this figure is shown in bold broken lines the walls 6 and 7 of the flexible bag whose edges are welded in 8, while there is shown in strong solid lines 9 and 10 the

  bottom and cover of the flexible container of figure 5.

  It is thus understood that in the embodiment of FIG. 7, as in that of FIG. 4, the atmospheric pressure which is applied to the oysters by means of the flexible boxes or pockets of the packaging ensures a perfectly sealed closure.

  two-half shells of each oyster.

  Schematically shown in Figure 8 the implementation of a variant of the invention which consists in placing the oysters in a container 14 provided with a lid 15 which can be fixed on it

  tightly by conventional means not shown.

  Said cover 15 is provided with a tube 16 which is connected to a source of compressed gas such as for example air or nitrogen, so as to reign inside the enclosure containing the sufficient pressure to prevent the two half-shells of each oyster from being stored during storage

move away from each other.

  The modes of implementation of FIGS. 3 to 7 allow individual packaging of quantities of oysters, for example twelve or twenty four oysters, which correspond to commercial quantities for consumers. These two types of packaging - 8 -

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  allow self-service sales like most products

  fresh found in large or medium-sized stores.

  This packaging is inexpensive because it uses materials which are plastic sheets produced in large quantities. The advantage of the mode of implementation of FIGS. 5 to 7 lies in the fact that the flexible container which contains the oysters provides protection of the bag inside which the vacuum is produced, thus avoiding that during transport the cutting edges of oysters do not pierce the flexible outer pocket and destroy the front void

the end use of the product.

  This packaging is particularly simple to use, because it suffices to cut, for example with scissors, a corner of the flexible pocket to bring air inside, which allows

clear the oysters.

  As explained above, with this packaging method, it is possible to fracture the hinge 3 of each oyster before packaging them, without in any way affecting their good preservation, while greatly facilitating opening.

  oysters of which it remains only to cut the muscle 4.

  According to the embodiment of Figure 8, this container, preferably metallic, is strong enough to withstand the internal overpressure which ensures the maintenance against each other of the

two half shells.

  This mode of implementation makes it possible to transport and keep a large number of oysters from the place of dispatch to the place of sale in perfect sanitary condition for a period of at least fifteen days, the marketing then being carried out in a manner

  conventional after opening the pressure vessel.

  As indicated above, the invention is not limited to the packaging of oysters, but it applies with the same advantages to the packaging of all shellfish comprising two half-shells which naturally apply one against the other. 'other

  tightly under the action of an external pressure.

  It is understood that the embodiments which have been described above are only given for information, and that they may receive any modifications without departing from the scope

of the invention.

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Claims (14)

  1. A method of packaging shells such as oysters, characterized in that a pressure difference is used with respect to atmospheric pressure to maintain the two half-shells (1,2) of the shells applied one against the other in a sealed manner, while said shells are   enclosed in a sealed enclosure (6.7; 8.9; 14.15).   2. A method of packaging shells according to claim 1, characterized in that the shells are placed inside a container or a flexible bag (6,7) in which a vacuum is created by vacuuming the air so as to apply the walls of the container or of the flexible pouch (1,2) to the shells so as to keep the two half-shells of each shell applied one against the other, and that one then tightly closes (8) the container or pocket (6,7).   3. Method according to claim 2, characterized in that the absolute pressure obtained inside the container or the flexible bag is about a few hundred grams per square centimeter. 4. Method according to claim 2, characterized in that the shells are placed in a first pocket or flexible and non-waterproof container (9,10), which is then introduced into a   second flexible pocket (6,7) inside which a vacuum is created.   5. Method according to claim 1, characterized in that the shells are conditioned by placing them in a sealed enclosure (14, 15) inside which a gas is sent to put the inside of the enclosure under sufficient pressure to prevent the shellfish from opening during the entire time they   stay in packaging.   6. Method according to claim 5, characterized in that the pressure created inside the sealed enclosure (14,15) is   from about 1.5 kg to 2 kg per square centimeter.   7. Method according to claim 4, characterized in that the gas used is air or nitrogen, preferably filtered or sterilized before use.   8. Method according to any one of claims   previous, characterized in that before proceeding to the packaging of the shells, their hinge (3) is fractured without 2779411   damage the edges of the half-shells (1,2) on which is carried out   sealing when the shell is in the closed state.   9. Packaging of shells such as oysters, characterized in that the shells are contained in an enclosure or a flexible pouch (6,7), inside which a relative vacuum prevails so that the half shells (1,2) shells remain pressed against each other in a sealed manner under the effect of atmospheric pressure which applies the enclosure or the flexible pocket on the shells.   10. Packaging according to claim 9, characterized in that the shells are surrounded by a deformable and non-waterproof wall (9,10) which protects the enclosure or the flexible bag (6,7) to   the interior of which the vacuum is created.   11. Packaging according to any one of the claims   9 and 10, characterized in that the absolute pressure inside the enclosure or the flexible bag (6,7) is approximately a few   hundreds of grams per square centimeter.   12. Packaging of shells such as oysters, characterized in that it consists of a closed container (14,15) containing the shells and a gas under sufficient pressure to maintain the half-shells (1,2) of the seashells   applied to each other in a leaktight manner.   13. Packaging according to claim 12, characterized in that the pressure prevailing inside the container   (14.15) is equal to about 1.5 kg to 2 kg per square centimeter.   14. Packaging according to any one of   Claims 9 to 13, characterized in that the hinges (3)   shells were broken beforehand without damaging the edges of the two half-shells by applying one to the other so waterproof.