Gas flush high pressure pasteurization packaging and associated methods

The present disclosure is directed to systems and methods for packaging perishable foods. A packaging method in accordance with several embodiments of the disclosure can include, for example, mating a tray with a product. The tray can include a compartment having a generally similar shape as the shape of the product. The method can further include gas flushing an internal atmosphere around a product, and sealing the product and the internal atmosphere between a lid and the tray. Additionally, the method can include pasteurizing the product with an application of substantially uniform high pressure to a surface area of the package (e.g., high pressure pasteurization).

TECHNICAL FIELD

The present disclosure relates generally to packaging perishable products and, more particularly, to gas flush and high pressure pasteurization packaging.

BACKGROUND

Perishable products (e.g., meats, cheeses, fruits, medications, etc.) are generally packaged at a processing facility prior to shipment to retail outlets and/or consumers. Exposure of perishable products to ambient air (e.g., an oxygen-nitrogen atmosphere) results in spoilage. Thus, to extend the shelf lives of perishable products, conventional, packages confine perishable products in atmospheres that inhibit the growth of pathogens. For example, a conventional package includes two impermeable membranes that form a hermetic seal around a product. Such a package can also seal in a gas or gas mixture other than ambient air that extends the shelf life of the product more than a vacuumed package. The gas or gas mixture can be inserted into the package using gas flushing methods, e.g., modified atmosphere packaging (“MAP”) and controlled atmosphere packaging (“CAP”). MAP modifies the internal atmosphere of a package by injecting a desired gas mixture (e.g., nitrogen, carbon dioxide, etc.), whereas CAP controls a defined mix of gases with an external apparatus or internal chemical reactions.

More recently, processing facilities have implemented high pressure pasteurization (“HPP”) methods to package and preserve some perishable products. Conventional HPP methods include placing a package in an enclosure (e.g., a water tank) and applying a uniform pressure (e.g., hydraulic pressure) to a surface area of the package. With little to no heat treatment, the intensity and duration of pressure can effectively destroy pathogenic microorganisms in the product by interrupting their cellular functions. Thus, unlike traditional pasteurization, HPP can pasteurize heat sensitive products. Additionally, the absence of heat treatment during HPP can facilitate the retention of freshness, flavor, color, and nutrients of packaged foods. HPP also extends the shelf life of products compared to conventional gas flush packaging, and generally reduces the process time of traditional pasteurization. However, conventional HPP packages include little to no free space since the application of high pressure (e.g., 87,000 psi (5,998 bar)) compresses packaging materials. If the package includes free space, the high pressure can cause packaging materials and hermetic seals to rupture. Thus, conventional HPP packaging is generally suited for products having mostly homogenous consistencies (e.g., guacamole, applesauce, etc.) that do not require free space within packages for the separation of distinct sections and/or components.

DETAILED DESCRIPTION

The present disclosure describes methods and systems (collectively, “technology”) for gas flush high pressure pasteurization packaging. A packaging method configured in accordance with several embodiments of the disclosure can include, for example, positioning a perishable product in a compartment of a tray. The compartment and the product can have generally similar shapes, such that the tray mates with the product. The method can further include attaching a lid to a portion of the container and over the product to form a package. The package can be gas flushed, hermetically sealed, and undergo high pressure pasteurization (“HPP”) without rupturing the package or damaging the product. Perishable products packaged in accordance with the technology benefit from a longer shelf life than conventional gas flush packaged products (e.g., triple the shelf life). Additionally, packages configured in accordance with the technology can include more free space (e.g., greater than 10% free space) than conventional HPP packages. As an example, a package having a total volume exceeding 110 mL may contain a product having a volume of 100 mL. The additional free space can prevent HPP from crushing and/or smashing the product. Thus, despite the application of high pressure, packaged products configured in accordance with the present technology can preserve the separability of sections (e.g., slices of cheese) and/or the integrity of distinct components (e.g., fruit and nuts in fruitcake) of the product, while still benefiting from the advantages of HPP (e.g., an extended shelf life).

Certain details are set forth in the following description and inFIGS. 1A-4to provide a thorough understanding of various embodiments of the disclosure. For example, the term tray generally refers to any container (e.g., pre-formed tray, blister) configured to at least partially enclose or otherwise receive a product. Other well-known structures and systems often associated with packaging perishable products have not been shown or described in detail below to avoid unnecessarily obscuring the descriptions of the various embodiments of the technology. Additionally, a person of ordinary skill in the relevant art will understand that the technology may have additional embodiments that may be practiced without several of the details described below. In other instances, those of ordinary skill in the relevant art will appreciate that the methods and systems described can include additional details without departing from the spirit or scope of the disclosed embodiments.

In the Figures, identical reference numbers identify identical or at least generally similar elements. To facilitate the discussion of any particular element, the most significant digit or digits of any reference number refers to the Figure in which that element is first introduced. For example, element100is first introduced and discussed with reference toFIG. 1.

FIG. 1Ais a top view of a package100configured in accordance with several embodiments of the disclosure. In the illustrated embodiment, the package100includes a tray102having a compartment110that receives a perishable product108. The product108can be a perishable food, e.g., deli meat, cheese, peaches, applesauce, and/or other perishable products that can be pasteurized. The compartment110can be a cavity, indent, and/or other suitable portion of the tray102that can receive the product108. The tray102can mate with the product108. Two objects are said to mate when they have generally similar shapes, and one object can receive the other due to its larger size. InFIG. 1A, for example, the compartment110has larger dimensions than those of the product108and has a generally similar shape as the shape of the product108. Thus, the compartment110can receive and mate with the product108. In other embodiments, the compartment110can have a different shape that is generally similar to the shape of the product108it receives. In at least several embodiments, the correspondence between the shape of the compartment110and the shape of the product108need not be exact. It is generally sufficient that the overall outer bounds of the shape be at least approximately geometrically similar. In some embodiments, the tray102can include a plurality of compartments110having shapes generally similar to those of the products they contain, and dimensions larger than those of the products.

The tray102can be made from a flexible, semi-rigid, and/or rigid tray material that can be formed into a desired shape before the tray102receives the product108, and that can fully or partially recover to the initial shape of the tray after deformation during HPP. In some embodiments, for example, the tray material is a thermoplastic that can be formed into a shape and has enough resiliency to expand back to its initial shape after compression (e.g., approximately 15%) experienced during HPP. In other embodiments, the tray102can comprise other plastic materials, metals, and/or other suitable materials that have enough rigidity to form a desired shape and enough elasticity to recover after deformation from HPP.

The tray102can be formed using suitable tray forming methods known to those skilled in the art. In some embodiments, for example, a thermoform fill-seal (“TTFS”) machine can shape a thermoplastic into the tray102. Suitable TTFS machines include the R535 available from Multivac® of Kansas City, Mo., and the PowerPakNTfrom CFS of Bakel, the Netherlands. In other embodiments, a traysealer can be used to form a foamed material into the tray102. Suitable traysealing machines include, for example, the T800 from Multivac® and the Twinstar® 9 Traysealer from CFS.

In some embodiments, the tray102can be formed to have a shape corresponding to the dimensions and/or shape of a particular product. As an example, a TTFS machine can receive a material (e.g., a thermoplastic), heat the material, form the material into a tray having a compartment shaped like the shape of a product, and load the product into the tray. In some other embodiments, a machine can pre-form a tray such that a compartment of the tray has a shape that can adequately receive and mate with a product. As an example, a TTFS machine can shape pre-formed trays according to a design specification so compartments in the trays can mate with products having a specified size and shape.

The package100also includes a cover or lid104that can hermetically seal the product108within the compartment110. As illustrated inFIG. 1A, the lid104can be attached to an upper peripheral portion116of the tray102. The lid104can be attached to the upper peripheral portion116using an adhesive, a snap, heat seal, a mechanical interference between the tray102and the lid104, and/or other suitable attachment devices that can form a hermetic seal. For example, the Multivac® R535 machine described above can heat seal the lid104to the upper peripheral portion116. In other embodiments, the lid104can be sealed to another portion of the tray102.

The lid104can be made from a generally flexible and/or semi-rigid lidding material. For example, the lidding material can include plastic (e.g., styrene, PVC), film, paper, foil, and/or another suitable material that can be attached and sealed to the tray102. In various embodiments, the same material can be used to form the lid104and the tray102and/or the lid104and the tray102can be integrally formed.

Free space within the package100(e.g., the difference between the dimensions of the compartment110and the product108) can include an internal atmosphere106. The internal atmosphere106is a gas or gas mixture such as nitrogen, carbon dioxide, oxygen, and/or another suitable gas that can be hermetically sealed within the package100. In some embodiments, the internal atmosphere106can extend the shelf-life of the product108.

The internal atmosphere106can be added into the package100and sealed between the tray102and the lid104using suitable gas flushing methods. For example, a gas flushing machine can raise the tray102to a vacuum-tight seal chamber where the machine can remove the ambient air from the package100. The machine can then add the internal atmosphere106between the tray102and the product106using pins and/or a nozzle and apply heat and/or pressure to hermetically seal the lid104to the tray102. In other embodiments, a gas flushing machine can add the internal atmosphere106, then remove the ambient air, and seal the lid104to the tray102. Suitable gas flushing machines include, for example, the Twinstar® 9 Traysealer from CFS. In some other embodiments, gas flushing can include displacing the ambient air inside the package with the internal atmosphere106and sealing the lid104to the tray102. In yet other embodiments, the internal atmosphere106can be added between the sealed tray102and lid104using other suitable methods. For example, controlled atmosphere packaging (“CAP”) can control the internal atmosphere106with an external apparatus or internal chemical reactions.

As illustrated inFIGS. 1B and 1C, the internal atmosphere106can create a pressure within the package100that slightly collapses the lid104(e.g., deflect the lid104inwardly toward the compartment110) against the product108. As an example, gas flushing the package100with the internal atmosphere106can create a pressure of 2.901 psi (200 mbar) within the package. An external atmospheric pressure of 14.707 psi (1014 mbar) creates a net pressure of 11.806 psi (814 mbar) on the package100that slightly compresses the lid104against the product108. The collapsed lid104can restrict the movement of the product108within the package100to prevent damage to the product108during other manufacturing processes (e.g., HPP) and/or handling.

The internal atmosphere106can act as a padding around the product108that protects the product108from undesirable pressure. In some embodiments, for example, the internal atmosphere106can form a gas barrier that prevents the pressure exerted on the package100during HPP from crushing the product108. The internal atmosphere106can also protect the product108when the package100is exposed to an external atmosphere (e.g., a pressure of 14.707 psi (1014 mbarD. The volume of the internal atmosphere106necessary to provide adequate pressure relief can depend on the relationship between the size, shape, and depth of the tray and the size, shape, and height of the product. As an example, the internal atmosphere106can create a gas pressure within the tray102that can range from approximately 14.707 psi (150 mbar) to approximately 5.802 psi (400 mbar). In other embodiments, the gas pressure can be higher or lower.

The package100can undergo HPP to pasteurize the product108and extend the product's shelf life. Suitable HPP techniques are available from the American Pasteurization Company of Milwaukee, Wis. During HPP, the package100can be placed into an enclosure that applies high pressure to a surface area of the product108for a duration of time that pasteurizes the product108. For example, the package100can be placed in a tank of water and hydraulic pressure can be applied to the exterior surface of the package100. The level of pressure (e.g., approximately 80,000 psi (5,516 bar) to approximately 90,000 psi (6,205 bar)) and duration (e.g., 1 to 6 minutes) necessary to attain pasteurization can depend on the density, pH levels, and/or other attributes related to the product108. For example, HPP of a sliced deli meat product can include placing the package100in a tank of water and applying a pressure of 87,000 psi (5,998 bar) for 1.5 to 3 minutes. If the product108has a lower pH and/or a lower density than the deli meat, the HPP process can be carried out at a lower pressure and/or for a shorter period of time. The opposite can be true if a product has a higher pH level and/or is denser.

The package100can withstand HPP without rupturing the package100, despite having free space between the package100and the product108. Mating the tray102to the product108and gas flushing the package100with the internal atmosphere prevent the tray102from breaking under the high pressures of HPP. During conventional HPP, for example, the application of pressure may compress trays such that they collapse into any free space within the package. The high pressure can collapse the trays so far into the free space, that the trays rupture and/or cannot retain their original shape. However, the package100only allows the tray102to collapse until the tray102contacts the product108and/or the internal atmosphere106restricts the movement of the tray102. The product108and/or the internal atmosphere106can support the tray102and prevent the tray102from collapsing until failure. The generally similar shapes of the product108and the compartment110ensure that the package100reduces or eliminates the unsupported free space that would cause the tray material to fail or the hermetic seal between the tray102and the lid104to rupture. After HPP, the tray102can fully or substantially recover to its original shape. Advantageously, mating the tray102with the product108can also reduce the amount of liquid, known to those skilled in the art as “purge,” released from the product108during the application of high pressure. For example, the generally similar shapes of the tray102and the product108limit the voids within the package100in which the purge can rest.

Gas flushing the internal atmosphere106into the package100can also relieve some pressure on the product108before, during, and after HPP. For example, the internal atmosphere106can provide a barrier of free space around the product108that prevents HPP from smashing the product108. Additionally, gas flushing can slightly collapse the lid104to prevent the product108from moving substantially within the tray102. Slightly collapsing the lid104can also prevent the application of non-uniform pressure on the product108during HPP and subsequent handling.

The package can provide adequate free space (e.g., greater than 10%) within the package100to preserve the integrity of distinct portions and/or components of the product108during HPP. As an example, the package100can contain slices of a product108(e.g., cheese) and maintain the separability of the individual slices after HPP. As another example, the package100can contain a non-homogenous product108(e.g., fruitcake) and maintain the distinction between individual textures and particles of the product. The package100can also contain a homogeneous product (e.g., applesauce) and maintain its consistency.

As illustrated inFIG. 1A, in some embodiments, the package100can further include an easy open feature112. Packages that undergo HPP are generally difficult to open because they are often tightly sealed to prevent damage to the package during the application of high pressure. The package100, however, can include the easy open feature112that allows a consumer to open the package100without excessive force and/or tools (e.g., scissors, knives, etc.). The easy open feature112can be a tear tab, an easy-to-peel corner, a serrated cut, and/or another feature known to those skilled in the art that simplifies opening the package100.

As further illustrated inFIG. 1A, the package100can include a reseal feature114that can facilitate reclosing the package100after it has been opened (e.g., after partial use of the product108by a consumer) and seal the product108from further exposure to ambient air. In the embodiment illustrated inFIG. 1A, for example, the reseal feature114is an adhesive film that secures and at least substantially seals two portions (e.g., the lid104and the tray102) of the package100together. In other embodiments, the reseal feature114can include a Ziploc® closure, mechanical interference between the tray102and the lid104, and/or other suitable features that can reseal the package100. As illustrated inFIG. 1A, the reseal feature114and the easy open feature112can be a single feature. In other embodiments, the reseal feature114and the easy open feature112can be distinct features.

FIG. 2is a bottom isometric view of a package200configured in accordance with several embodiments of the disclosure. The package200illustrated inFIG. 2includes several features that are generally similar in structure and function to that of the corresponding features of the package100described above with reference toFIGS. 1A-C. For example, the package200includes a tray202, a lid204, a product208, an internal atmosphere206, and a compartment110. The compartment210is shaped generally similar to the product208(e.g., a cut of meat). The compartment210has larger dimensions than those of the product208it contains and can mate with the product208. The package200further includes an easy open feature212and a reseal feature214. In the embodiment illustrated inFIG. 2, the easy open feature212is a serrated edge on the lid104and the reseal feature214is a tear tab. In some embodiments, the package200can include different easy open features212and/or different reseal features214. Similar to the package100ofFIGS. 1A-C, the package200illustrated inFIG. 2can include more than 10% free space.

The package200can undergo gas flushing to insert the internal atmosphere206into at least a portion of the free space within the package200. The internal atmosphere206can have a volume that provides a barrier around the product208to at least partially relieve the product108from exposure to undesirable pressures. Additionally, the package200can undergo HPP without destroying the integrity of the sections, components, and/or consistencies of the product208.

FIG. 3is an isometric view of a tray302for a package configured in accordance with several embodiments of the disclosure. The tray302can have features generally similar to those of the tray102illustrated inFIGS. 1A-C. In the illustrated embodiment, however, the tray302includes two compartments310(identified individually as310aand310b), each shaped generally similar to the shapes of the products each compartment310is to contain. Each compartment310can mate with a product. In other embodiments, the tray302can include more than two compartments310and/or the individual compartments310can be shaped differently.

FIG. 4is a flow diagram illustrating a process400for packaging a perishable product configured in accordance with several embodiments of the disclosure. The process400can include decision block402to determine whether a pre-formed tray is provided. A pre-formed tray can have an indent, a cavity, or a compartment with a shape generally similar to the shape of the perishable product. If a pre-formed tray is provided, the process400can continue at block406. Alternatively, if a pre-formed tray is not provided, the process400can continue at block404. Block404includes forming a tray for one or more particular product(s) using suitable tray forming methods (e.g., the Multivac® TTFS machine described with reference toFIGS. 1A-C). The tray can comprise any suitable flexible, semi-rigid, and/or rigid material that can maintain a desired shape before the tray receives a product and can mate with the product in the manner described above.

Block406includes mating a product with the tray. In this step, the compartment of the tray can receive the product. The product and internal side walls of the tray can be separated by free space that allows the product to preserve the separability of pieces of the product (e.g. slices of meat or cheese), the consistency of the product (e.g., guacamole), and/or the distinct components of the product (e.g., fruit and nuts in fruitcake) during subsequent processing.

Block408includes gas flushing the tray with an internal atmosphere. Gas flushing can include placing the product and the tray in a sealed environment (e.g., hermetically sealed), removing ambient air (e.g., vacuuming) from around the product, and surrounding the product with the internal atmosphere. The internal atmosphere can comprise a volume of gas (e.g., nitrogen) or mixture of gases (e.g., carbon dioxide and nitrogen) that can form a barrier around the product and relieve the product from exposure to undesirable pressures. The gas flushing step can include methods known to those skilled in the art (e.g., CAP, MAP).

Block410includes attaching a cover or lid to a portion of the tray to hermetically seal the internal atmosphere and the product between the lid and the tray. The lid can be attached or bonded to the tray using suitable systems, e.g., the Multivac® R535 described above. The lid can comprise any suitable flexible, semi-rigid, and/or rigid material that can attach and seal to the tray.

In some embodiments, the internal atmosphere can create a low pressure within the package such that the lid slightly collapses inwardly on the product once the package is exposed to an external atmosphere. Collapsing the lid can restrict or prevent movement of the product within the tray to reduce damage from a pressure differential during subsequent processing and handling. As an example, if the external atmosphere is approximately 14.707 psi (1014 mbar), gas flushing can create approximately 14.707 psi (150 mbar) of pressure inside the package so that approximately 12.531 psi (864 mbar) can collapse the lid against the product. In other embodiments, other pressures may be used.

Block412includes applying HPP to the package. HPP can include placing the package in a tank and applying a high, uniform pressure (e.g., 87,000 psi (5,998 bar)) that inactivates harmful pathogens in the product. In various embodiments, other conventional methods of HPP can be applied to the package.

The process400can produce a package that includes more free space than conventional HPP packages to preserve distinct sections, components, and/or consistencies of the product. The process400can also produce a package that reduces the purge secreted from the product during HPP since the mated tray decreases voids within the package in which purge can rest. Additionally, the process400can substantially extend the shelf life of the product.

From the foregoing, it will be appreciated that specific embodiments of the present technology have been described herein for purposes of illustration, but that various modifications may be made without deviating from the technology. For example, the embodiments illustrated inFIGS. 1A-Cinclude an irregularly shape compartment. However, other embodiments of the new technology can include trays with compartments that have standard geometric shapes (e.g., circles, rectangles) that correspond to the shapes of the products they are to contain. Additionally, the lid described inFIGS. 1A-4can be any type of cover, shell, top, and/or membrane that can seal products and internal atmospheres within the package. Certain aspects of the new technology described in the context of particular embodiments may be combined or eliminated in other embodiments. For example, the trays and the lids described inFIGS. 1A-Ccan be integrally formed. Further, while advantages associated with certain embodiments of the new technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.