Shellfish transport unit, particularly for oysters
The packaging method with a support, lid, and reduced pressure maintains shellfish integrity and hydration, addressing the shelf life issues in existing methods by ensuring oysters remain closed and alive for extended periods.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2024-02-06
- Publication Date
- 2026-03-27
AI Technical Summary
Existing packaging methods for live shellfish, such as oysters, fail to maintain their freshness and shelf life due to high temperature processing and inadequate preservation, leading to premature death during transport and storage.
A packaging method involving a support with indentations for shell placement, a lid for immobilization, and a pressure reduction to below atmospheric pressure to maintain shell closure and integrity, using a deformable film for secure sealing.
The method extends the shelf life of shellfish by maintaining their closed state and hydration, allowing them to survive for at least 20 days without heat treatment, reducing stress and leakage risks.
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Abstract
Description
Title of the invention: Shellfish transport unit, particularly for oysters technical field
[0001] The invention relates to the packaging of live shellfish such as oyster products in packaging. STATE OF THE ART
[0002] In oyster farming, it is common practice to use wooden, plywood, or wicker baskets for packaging and transporting live shellfish for sale. However, there are certain constraints on the packaging of oyster products. After being harvested, the oysters are placed flat inside the basket to retain as much water as possible and preserve their flavor. The basket is then closed with a lid.
[0003] A basket containing live shellfish can then be sold individually in a sales area.
[0004] Other types of packaging for live shellfish can be used. For example, document FR 3 066 180 describes a polymer plate with a shellfish-receiving surface that has several predefined slots. An oyster can be placed in each slot. The plate is then covered with a micro-perforated plastic film, and the assembly of the plate and the oysters is placed at a temperature between 170°C and 190°C to heat-shrink the film over the oysters.
[0005] However, this process involves subjecting the oysters to a high temperature. Furthermore, the shelf life of the shellfish remains insufficient because the packaging offered does not allow the shellfish to remain alive long enough. Description of the invention
[0006] One aim of the present application is to remedy the aforementioned drawbacks by proposing a conditioning process which makes it possible to further increase the lifespan of shellfish, and therefore their shelf life.
[0007] To this end, according to a first aspect, a method for packaging shellfish, such as oysters, is proposed, comprising the following steps: - provide a support for the shells, the support comprising an upper face in which is formed at least one indentation configured to house at least partially a shell so as to hold the shell in position relative to the support; - place a seashell in each indentation of the support; - place the container containing the shell(s) in a waterproof enclosure; - reduce the pressure in the enclosure until a storage pressure lower than atmospheric pressure is reached; - to fix a lid securely to the support so as to immobilize the shell(s) between the lid and the support and to maintain a pressure in at least one cavity substantially equal to the preservation pressure.
[0008] Some preferred but non-limiting features of the conditioning process according to the first aspect are the following, taken individually or in combination: - the storage pressure is between 100 mbar and 800 mbar, for example equal to 500 mbar; - the pressure reduction step is carried out at a speed between 50 mbar / s and 500 mbar / s, for example 200 mbar / s; - the pressure reduction step is carried out at ambient temperature; - the lid includes a deformable plastic film, and the step of fixing the lid to the support includes applying the film in contact with at least one shell; - The lid attachment step includes welding the film to the backing; and / or - the shell(s) include an asymmetrical bivalve shell comprising a lower valve and an upper valve, the lower valve being more convex than the upper valve, the step of placing the shell in the imprint including the placement of the lower valve at the bottom of the imprint.
[0009] According to a second aspect, a shell transport unit is proposed comprising: - a support comprising an upper face in which at least one indentation is formed, each indentation being configured to at least partially house a shell so as to hold the shell in position relative to the support; - at least one seashell, each seashell being placed in a corresponding imprint; - a lid fixed tightly to the support, the lid being in contact with at least one shell in order to hold at least one shell in position relative to the support; a pressure in the transport unit being lower than atmospheric pressure.
[0010] Some preferred but non-limiting characteristics of the transport unit according to the first aspect are the following, taken individually or in combination: - at least one shellfish includes an oyster; - the pressure in the transport unit is between 400 mbar and 600 mbar, for example equal to 500 mbar; - the lid includes a deformable plastic film applied in contact with at least one shell, the plastic film being welded to the support; - the shell(s) include an asymmetrical bivalve shell comprising a lower valve and an upper valve, the lower valve being more convex than the upper valve, the lower valve being placed at the bottom of the imprint; and / or - the transport unit further includes at least one blotter placed at the bottom of the imprint. DESCRIPTION OF THE FIGURES
[0011] Other features, objectives and advantages of the invention will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which:
[0012] Fig. 1 illustrates an example of an embodiment of a transport unit conforming to one embodiment, with the shells omitted;
[0013] The [Fig.2] is a top view of the support of the transport unit of the [Fig.1];
[0014] Fig. 3 is a top view of the support of Fig. 2 with shells placed in the prints; and
[0015] The [Fig.4] is a flowchart of steps of a packaging process according to an embodiment.
[0016] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION OF THE INVENTION
[0017] The present description relates to a method for packaging a transport unit 1 of live shellfish 2 and the corresponding transport unit 1. By "shellfish 2" or "live shellfish 2" is meant, here and throughout the description below, live animals of the marine or freshwater mollusc type, typically bivalve molluscs or gastropods.
[0018] Living shellfish 2 include, for example, bivalve shellfish 2 such as oysters. Each shellfish 2 may comprise a lower valve and an upper valve, the lower valve being more domed (hollow) than the upper valve.
[0019] It will be understood, however, that the invention could be carried out, with the same advantages, in combination with any other type of consumable content packaged in the same packaging, in particular live content whose integrity and safety must be ensured during transport and sale.
[0020] In order to improve the shelf life of shellfish 2, it is proposed to place the 2 shells in a transport unit 1 comprising a support 3 and a Lid 4 is configured to immobilize the shells 2, preventing them from turning over and opening. Furthermore, the pressure in the transport unit 1 is lower than atmospheric pressure to reinforce the immobilization of the shells 2 in the support 3 and increase their shelf life. Indeed, shells 2, and in particular bivalve mollusks, feed by filtering water. Opening the shells 2 during transport or storage therefore presents the risk that they will lose all or part of their water, thus limiting their shelf life. Conversely, the transport unit 1, as described herein, ensures that the shell 2 remains closed, thus drastically increasing its shelf life.For example, the applicant noted that oysters packaged in a transport unit 1 comprising a support 3 on which a lid 4 is mounted in a hermetically sealed manner at a pressure lower than atmospheric pressure could be kept for at least 20 days, or even up to 40 days.
[0021] For this purpose, the support 3 includes an upper face 5 in which one or more cavities 6 are formed, configured to at least partially house a shell 2 so as to maintain the shell 2 in position relative to the support 3. The shell 2 is placed so that its lower valve is at the bottom of the cavity 6, the upper valve being able to protrude from the cavity 6. This effectively ensures that the mollusc is bathed in the water of the shell and reduces the risk of leakage.
[0022] The opening of the impressions 6 extends substantially in the same plane (within 5 mm) in order to improve the blocking of the shells 2 by the lid 4. The depth of the impressions 6 can, on the other hand, vary in order to take into account the thickness of the shell 2 intended to be placed in the impression 6 (when different shells 2 are placed in the transport unit 1).
[0023] Preferably, the cavity 6 houses at least partially the lower valve of the shell 2. The shape and dimensions of the cavity 6 are chosen so that, when the upper face 5 of the support 3 is horizontal and the support 3 is moved in a horizontal plane, the shell 2 placed in the cavity 6 cannot overturn.
[0024] In one embodiment, the shape and dimensions of the cavity 6 correspond to the shape and dimensions of all or part of the lower valve of the shell 2 so as to conform to the shape of its lower valve. The shell 2 can, for example, be tightly fitted into the cavity 6.
[0025] Alternatively, the imprint 6 may have a larger volume than the part of the lower valve that it receives and include shims configured to bear against the lower valve in order to hold the shell 2 in position.
[0026] The support 3 may comprise a solid part in which the cavities 6 are cut or molded. For example, the support 3 may comprise a solid rigid block (e.g., a block of plastic or wood) in the upper face 5 of which the cavities 6 are cut. Alternatively, as illustrated in Figures 1 to 3, the support 3 may comprise a hollow box having a bottom wall whose upper face 5 corresponds to the upper face 5 of the support 3 and side walls extending from the bottom, the cavities 6 being defined by deformation of the bottom (by molding or stamping) of the box. This embodiment has the advantage of being lighter and requiring less material compared to the solid part. The support 3 is also stackable.
[0027] The support 3 is made of a material suitable for food packaging, typically the plastic materials used in packaging fresh meat products. The material constituting the upper face 5 of the support 3 is further airtight and watertight in order to maintain constant pressure in the transport unit 1. In one embodiment, the support 3 may be made of a single material. For example, the support 3 may be made of amorphous polyethylene terephthalate (APET), which is a strong and low-cost thermoplastic material, of crystalline polyethylene terephthalate (PEC), or of polystyrene.
[0028] Optionally, a blotter 7 is placed at the bottom of each cavity 6, or alternatively over the entire upper surface 5 of the support 3, in order to absorb condensation in the transport unit 1. The blotter(s) 7 are preferably positioned so that the lower valve of each shell is in contact with blotter 7.
[0029] The blotting paper may, for example, comprise a paper having an absorption of between 3 and 7 L / m2, for example of the order of 5 L / m2.
[0030] The cover 4 is configured to be fixed in a watertight manner on the support 3 so as to immobilize the shell(s) 2 between the cover 4 and the support 3. The cover 4 therefore comes into contact with the upper valve so as to keep the shell 2 in contact with the support 3.
[0031] Preferably, the lid 4 is mounted on the support 3 so as to apply force to the shell 2 in order to keep it closed. The lid 4 may be transparent to allow the shells 2 to be viewed without opening the transport unit 1. The lid 4 is also made of a watertight and airtight material in order to maintain constant pressure in the transport unit 1 when the lid 4 is fixed against the support 3.
[0032] In one embodiment, the lid 4 comprises a deformable thermoplastic film 4 which is applied against the upper valve of the shells 2 and all or part of the upper face 5 of the support 3 (see [Fig. 1]). Furthermore, since the pressure in the transport unit 1 is lower than atmospheric pressure, the film 4 conforms to the shape of the shells 2, thus ensuring its functions of immobilizing the shells 2. The pressure in the transport unit 1 being lower than atmospheric pressure, the deformable film 4 comes into contact with a large part of the surface of the upper valve of the shells 2, or even where appropriate a part of the surface of the lower valve, and also partially penetrates the imprint 6 on either side of the shell 2, thus increasing the contact area between the film 4 and the shell 2 and thus reducing the risks of leaks and untimely opening of the shell 2.
[0033] The film 4 is then fixed to the support 3 in a sealed manner on the support 3, for example along the periphery of the support 3 and / or around the indentations 6, in order to maintain a constant pressure in the transport unit 1.
[0034] The film 4 may comprise any suitable material capable of deforming to conform to the shape of the shells 2 and ensuring the watertightness of the transport unit 1. If necessary, the material constituting the film 4 may also be weldable to the upper surface 5 of the support 3. For example, the film 4 may be made of a thermoplastic material such as polyethylene, low-density polyethylene, high-density polyethylene, or polypropylene. The thickness of the film 4 is further selected to withstand external stresses during the transport and storage of the transport unit 1, while ensuring its deformation to conform to the shape of the shells 2. For example, the film 4 may have a thickness of between 70 µm and 250 µm.As a non-limiting example, a transparent, three-layer polyethylene / ethylene vinyl alcohol / polyethylene (PE / EVOH / PE) film with a thickness between 80 µm and 150 µm exhibits very good puncture resistance, is weldable onto APET and CPET type materials (which can be used for substrate 3), and is airtight and watertight. An example of a PE / EVOH / PE type three-layer material is marketed by MULTIVAC under the name "MULTIFRESH ST20 PT 4-skin film with EVOH barrier".
[0035] Advantageously, since the pressure in the transport unit 1 is lower than atmospheric pressure, the deformable film 4 remains in contact with the shells 2 as long as the sealing of the unit is ensured, i.e. until the film 4 breaks (or where applicable, the support 3 is damaged).
[0036] The pressure in the transport unit 1 is lower than atmospheric pressure. Advantageously, reducing the pressure in the processing unit relative to atmospheric pressure allows: - to the lid 4 to de facto apply a force on the upper valve of the shell 2 thus ensuring that it remains closed during transport and storage; - to reinforce the retention of the lid 4 in position on the support 3; and - where applicable, when the lid 4 includes a deformable film 4, to allow the film 4 to conform to the shape of the shells 2 without requiring heat treatment, This further reduces the risk of shells opening 2 and reduces the stress applied to shells 2 during conditioning.
[0037] The gas contained in the transport unit 1 comprises ambient air. The shellfish 2 are therefore not under a controlled atmosphere but simply under ambient air, which simplifies their packaging and reduces associated costs. Ambient air here refers to the gas naturally present at the packaging location of the transport unit 1, which is breathed by the operators and the shellfish 2 during the packaging process. Ambient air is thus composed mainly (99%) of nitrogen and oxygen, the proportion of oxygen potentially varying depending on the geographical location of the packaging location.
[0038] The number of shells that can be packed in a transport unit 1 depends on the size of the transport unit 1 (and the tooling used for packing), bearing in mind that it is preferable that the shells be placed side by side, without overlapping or superimposing, to ensure that the lid 4, and in particular the film 4, is held against the shells 2 during transport and storage of the transport unit 1. Packaging process P
[0039] In what follows, a conditioning process P will be described in the case of a transport unit 1 comprising several shells 2. However, as specified above, this description also applies when the transport unit 1 comprises only one shell 2. Furthermore, the same tooling can condition several transport units 1 simultaneously.
[0040] The process P can be implemented semi-automatically or automatically using tooling which will be described below, at room temperature.
[0041] During a step E1, a support 3 is provided. The support 3 can be obtained by molding or stamping. Optionally, the support 3 can be manufactured by tooling, for example by stamping and forming a sheet of plastic material.
[0042] Optionally, a blotter 7 can be placed at the bottom of each impression 6, or alternatively, against the upper surface 5 of the support 3.
[0043] During step E2, a shell 2 is placed in each cavity 6 of the support 3. The shells 2 may be of the same species (only oysters, for example), of the same family (fines de claire, spéciales, etc.) and of the same size. Alternatively, the shells 2 may be different, i.e., of different species (oysters, mussels, clams, etc.), different families and / or different sizes. It should be noted that, in the case of different shells 2, the shape and dimensions (length, width, depth) of each cavity 6 may be adapted to the type of shell 2 received by each imprint 6 in order to guarantee the proper hold of each shell 2.
[0044] The shells 2 can be placed manually on the support 3 by an operator or, alternatively, automatically by the tooling.
[0045] During step E3, the support 3, including the shells 2, is placed in a sealed enclosure. For example, the tooling includes a receptacle configured to receive the support 3, a hood configured to cooperate with the receptacle to form a sealed enclosure, and a pump configured to draw air from the enclosure to reduce the pressure within it. The dimensions of the hood and the receptacle can, for example, be adapted to the dimensions of the support 3. During step E3, the support 3 is therefore placed on the tooling's receptacle, and then the hood is closed to form the sealed enclosure. The air contained within the enclosure is therefore ambient air.
[0046] During step E4, the pressure in the container is reduced to a storage pressure lower than atmospheric pressure. The storage pressure is chosen based on the size of the shell(s) 2 and the number of shell(s) 2 contained in the container, and, where applicable, the rigidity of the support 3 to prevent its deformation under pressure (and thus the risk of leakage). In one embodiment, the storage pressure is between 100 mbar and 800 mbar, preferably between 300 mbar and 650 mbar. For example, the pressure could be 500 mbar. It should be noted that, when the shell(s) 2 include oysters, a pressure of 500 mbar ensures the survival of the oysters while maintaining the lid 4 in place on the support 3.
[0047] The pressure can in particular be reduced in the enclosure by suction of the air contained in the enclosure by the pump of the tooling.
[0048] The pressure is preferably reduced in the enclosure at a rate between 50 mbar / s and 500 mbar / s, preferably between 50 mbar / s and 250 mbar / s, for example 200 mbar / s. This rate avoids stressing the shellfish 2 and therefore contributes to improving the shelf life of the shellfish 2.
[0049] During a step E5, the lid 4 is placed on the support 3. The lid 4 is in particular positioned so as to come into contact with each shell 2.
[0050] When the cover 4 includes a waterproof plastic film, step E5 can be carried out by unrolling the film 4 and then positioning the film 4 on the support 3 and the shells 2. The film 4 is positioned on the upper face 5 of the support 3 so as to cover all the shells 2 by overhanging on the upper face 5.
[0051] Where appropriate, steps E4 and E5 can be carried out simultaneously.
[0052] During a step E6, the cover 4 is fixed tightly to the support 3 so as to immobilize the shells 2 between the lid 4 and the support 3. The The airtight attachment of the lid 4 to the support 3 also ensures that the pressure in the transport unit 1 remains constant (and equal to the storage pressure obtained in step E4). The attachment can be achieved by welding, bonding, and / or mechanical fastening.
[0053] When the cover 4 includes a weldable, waterproof plastic film, the film 4 can be attached to the support 3 by welding. Alternatively, the film 4 can be glued to the support 3 using a suitable adhesive.
[0054] It should be noted that, when several transport units 1 are conditioned simultaneously in accordance with this description, the supports 3 of the transport units 1 are preferably placed side by side on the tooling receptacle during conditioning (and not stacked one on top of the other). Alternatively, when the tooling comprises several receptacles, one or more transport units 1 may be placed side by side on each receptacle. Examples
[0055] In one embodiment, an oyster transport unit 1 comprises a support 3 in the form of a hollow crate made of 700 µm thick transparent (crystal) APET obtained by stamping. The thickness of the bottom wall of the crate is substantially constant and equal to 700 µm. The support 3 comprises four cavities 6, which were obtained by deforming the bottom wall of the crate.
[0056] Each impression 6 comprises a lower wall surrounded by four lateral faces. The lower wall includes a recess, formed in a central area of the lower wall, and an inclined peripheral area extending between the recess and the lateral wall. Where applicable, the recess extends across the entire width of the impression 6, the peripheral area comprising only two parts extending on either side of the recess. The depth (distance in a plane normal to the upper face 5 of the support 3) of the impression 6 is greatest in the area of the recess, then gradually decreases in the peripheral area towards the lateral wall of the impression 6. The impression 6 is thus shaped so that the most convex part of the lower valve of the oyster rests against the recess, the remainder of the lower valve resting against the peripheral area.
[0057] A blotting paper 7 is placed at the bottom of each recess. The blotting paper comprises a sheet of paper having an absorption of 5 L / m² and is glued to the bottom of the recess using a hot-melt adhesive. In particular, a B256T blotting paper, marketed by the company Plastoloir, was used.
[0058] Where appropriate, as illustrated in [Fig.2], the indentations of two adjacent impressions can extend in line with each other and be substantially continuous, so that the same blotter 7 can be used for two impressions 6.
[0059] This embodiment of the support 3 allows the same mold shape 6 to be used for different families and / or sizes of oysters, for example, for Fine de Claire oysters no. 0 to 5, while ensuring that the oysters remain in position. Indeed, the oysters can be placed against the indentation and rest against the inclined peripheral area of the molds 6 and held in position within the molds 6 by the film, which conforms to their shape thanks to the reduced pressure in the transport unit. If necessary, the size of the molds 6 can be adapted to the size of the oysters.
[0060] The cover 4 comprises a three-layer film 4 “MULTIFRESH ST20 PT film 4 skin with Evoh barrier” having a thickness of 150 µm, which is fixed along the periphery of the upper face 5 of the support 3 by a weld bead.
[0061] The pressure in transport unit 1 is equal to 500 mbar. The pressure reduction step was carried out at ambient temperature and air at a rate of 200 mbar / s.
[0062] The gas in transport unit 1 is ambient air.
[0063] The Applicant has found that a transport unit 1 conforming to this example allows oysters to be kept for a minimum period of 20 days.
Claims
Demands
1. A method for packaging (P) shellfish (2), such as oysters, comprising the following steps: - providing (E1) a support (3) for the shellfish (2), the support (3) comprising an upper face in which is formed at least one cavity (6) configured to at least partially house a shellfish so as to maintain the shellfish in position relative to the support (3); - placing (E2) a shellfish in each cavity (6) of the support (3); - placing (E3) the support (3) comprising the shellfish (2) in a sealed enclosure; - reducing (E4), at a rate between 50 mbar / s and 500 mbar / s, the pressure in the enclosure until a storage pressure lower than atmospheric pressure is reached;- to fix (E5, E6) in a hermetic manner a lid (4) on the support (3) so as to immobilize the shell(s) (2) between the lid (4) and the support (3) and to maintain a pressure in at least one cavity (6) substantially equal to the preservation pressure.;
2. Conditioning method (P) according to claim 1, wherein the storage pressure is between 100 mbar and 800 mbar, for example equal to 500 mbar.
3. Conditioning method (P) according to any one of claims 1 and 2, wherein the pressure reduction step (E4) is carried out at a speed of 200 mbar / s.
4. Conditioning method (P) according to any one of claims 1 to 3, wherein the pressure reduction step (E4) is carried out at ambient temperature.
5. Packaging method (P) according to any one of claims 1 and 4, wherein the lid (4) comprises a deformable plastic film, and the step of fixing the lid (4) to the support (3) comprises applying the film to the contact of at least one shell.
6. Packaging method (P) according to claim 5, wherein the lid fixing step (4) includes welding the film onto the support (3).
7. Packaging method (P) according to any one of claims 1 to 6, wherein the shell(s) (2) comprise an asymmetric bivalve shell comprising a lower valve and an upper valve, the lower valve being more convex than the upper valve, the step of placing (E2) the shell in the cavity (6) comprising placing the lower valve at the bottom of the cavity (6).
8. Shellfish (2) transport unit (1) obtained by means of a packaging process according to any one of claims 1 to 7, comprising: - a support (3) having an upper face in which at least one cavity (6) is formed, each cavity (6) being configured to at least partially house a shellfish so as to maintain the shellfish in position relative to the support (3); - at least one shellfish (2), each shellfish being placed in a corresponding cavity (6); - a lid (4) fixed hermetically to the support (3), the lid (4) being in contact with at least one shellfish in order to maintain at least one shellfish (2) in position relative to the support (3); a pressure in the transport unit (1) being lower than atmospheric pressure.
9. Transport unit (1) according to claim 8, wherein at least one shell (2) comprises an oyster.
10. Transport unit (1) according to any one of claims 8 and 9, wherein the pressure in the transport unit (1) is between 400 mbar and 600 mbar, for example equal to 500 mbar.
11. Transport unit (1) according to any one of claims 8 to 10, wherein the cover (4) comprises a deformable plastic film applied in contact with at least one shell (2), the plastic film being welded to the support (3).
12. Transport unit (1) according to any one of claims 8 to 11, wherein the shell(s) (2) comprise an asymmetric bivalve shell (2) comprising a lower valve and an upper valve, the lower valve being more convex than the upper valve, the lower valve being placed at the bottom of the cavity (6).
13. Transport unit (1) according to any one of claims 8 to 12, further comprising at least one blotter (7) placed at the bottom of the imprint (6).