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Table of Content
An Introduction to Vacuum Sealing
The Key Differences Between Tray Sealing and Vacuum Sealing
The Best Applications for Each Method
How to Choose the Right Packaging Method for Your Product
Tray sealing and vacuum sealing have both earned their place as standard technologies in the modern food industry. Across fresh produce, meat, seafood, dairy, ready meals, and countless other categories, one or the other is responsible for the shelf life, safety, and presentation of nearly every packaged food product on the market today.
Understanding tray and vacuum sealing, what distinguishes them, and when each method is the appropriate choice, is fundamental to making sound packaging decisions. This guide provides a clear, detailed comparison of both, covering how each works, their respective advantages, their ideal applications, and the factors that should guide your choice.
Tray sealing is a packaging process in which food products are placed into pre-formed trays and sealed with a plastic film or rigid lid using heat and pressure. The result is a rigid or semi-rigid package that protects the product structurally, presents it cleanly for retail display, and can provide a meaningful barrier against oxygen, moisture, and contamination.
A standard tray sealing process follows a consistent sequence of steps:
Products are placed into pre-formed trays, either manually or through an automated loading system.
The loaded trays move into the sealing station of the tray sealer machine.
A lidding film is drawn from a roll and positioned over the tray opening.
Heat and pressure are applied to bond the film to the tray rim, creating a sealed package that is then discharged for labeling, inspection, and distribution.
On automated tray sealing lines, this process runs continuously with minimal operator intervention. Tray feeding, film indexing, sealing, and discharge all occur in a programmed cycle that can be adjusted for tray dimensions, film type, and sealing parameters. Modern tray sealers, including this semi-automatic food tray sealer from Hualian, can process high volumes per hour while maintaining seal consistency across every unit.
Tray sealing is not a single fixed process but a family of related techniques, each suited to different product and shelf-life requirements.
Standard tray sealing: The film is sealed to the tray under atmospheric conditions, providing physical protection and a tamper-evident closure.
Modified Atmosphere Packaging (MAP) tray sealing: Before the film is sealed, the air inside the tray is evacuated and replaced with a controlled gas mixture tailored to the specific product.
Skin packaging: A high-barrier film is heated until pliable and then drawn tightly around the product by vacuum, conforming closely to its contours before sealing to the tray.
Tray material selection affects barrier performance, sustainability profile, and compatibility with downstream processing and disposal.
The most widely used materials include:
PET (polyethylene terephthalate), which offers good clarity, rigidity, and recyclability
PP (polypropylene), which provides higher temperature resistance suitable for ready meals that will be reheated in the tray
Aluminum, which delivers excellent barrier performance and heat conductivity for cook-in and ovenable applications
Paper-based trays, which are gaining adoption as brands respond to consumer demand for more sustainable, fiber-based packaging. An Introduction to Vacuum Sealing
Vacuum sealing is a packaging process that removes air from inside a package before sealing it airtight. By eliminating or greatly reducing the oxygen present around the product, vacuum sealing directly attacks the two primary mechanisms responsible for most food spoilage: aerobic microbial growth and oxidative degradation of fats, proteins, and pigments.
The vacuum sealing process follows a straightforward sequence:
The food product is placed inside a vacuum bag; a flexible, multi-layer plastic film designed to maintain an airtight seal under vacuum conditions.
The open end of the bag is placed inside the vacuum chamber or positioned at the external vacuum nozzle. The machine then evacuates the air from inside the bag, reducing internal oxygen levels to near zero.
While the vacuum is still active, a heat sealing bar closes and seals the bag mouth. The vacuum is then released, and atmospheric pressure outside the bag presses the flexible film firmly around the product, creating the characteristic tightly-conforming appearance of vacuum-packaged food.
Vacuum sealing equipment is available in several configurations suited to different production scales and operational contexts.
Chamber vacuum sealers: The bag and product are placed entirely inside a sealed chamber, which is evacuated before sealing. Chamber machines provide the most complete and consistent vacuum and are the standard for commercial and industrial food packaging.
External vacuum sealers: The bag remains outside the machine while only its open end is connected to the vacuum system. External vacuum sealing machines are simpler and less expensive, but provide a less complete vacuum than chamber machines.
Double-chamber vacuum sealers: Two chambers alternate, with one evacuating and sealing while the other is being loaded. This maximizes throughput and minimizes idle time, making double-chamber machines the preferred solution for high-volume production environments.
Although both methods serve the purpose of preserving food for distribution and sale, they differ in fundamental ways that make each method better suited to specific products and contexts. Understanding these differences is the starting point for an informed packaging decision.
Tray sealing uses a rigid or semi-rigid tray as the primary container, sealed with a flexible or rigid lidding film. The tray provides structural protection for the product regardless of the film's properties.
Vacuum sealing uses a flexible bag that conforms to the shape of the product once the air is removed. There is no rigid structure, as the bag simply follows the product's contours.
Standard tray sealing does not remove air; the package contains the same atmospheric air present at the time of sealing. MAP tray sealing removes air and replaces it with a controlled gas mixture, but some residual gas remains by design to support the specific preservation function required.
Vacuum sealing removes the vast majority of the air inside the package. In fact, commercial chamber vacuum machines typically achieve residual oxygen levels below 1%.
Tray sealing preserves the product's natural shape and presentation. A fillet of salmon or a portion of fresh pasta in a tray looks exactly as it did before packaging since the product sits in the tray without compression or distortion, visible through the clear lidding film.
Vacuum sealing produces a package where the film conforms tightly to the product's surface. For many products, this is acceptable or even desirable, but for fragile or visually important products, the compression of vacuum packaging would cause unacceptable damage to appearance.
Standard tray sealing provides physical protection but limited additional shelf life beyond what the product's natural characteristics allow.
Vacuum sealing typically provides an even longer shelf life extension for products that tolerate it, because the near-total oxygen removal creates a more aggressive preservation environment than most MAP gas mixtures.
High-speed automated tray sealing systems are capable of very high throughput, processing multiple trays per cycle in fully continuous production lines.
Vacuum sealing speed varies significantly by machine type, from the relatively slow batch processing of single-chamber machines to the near-continuous throughput of double-chamber and thermoforming vacuum systems.
Tray sealing offers a distinct set of benefits that make it the preferred choice in specific market contexts, particularly where retail presentation and product protection are paramount.
Rigid trays allow products to be displayed in their natural, undisturbed form, visible through a clear film lid. This is particularly important for fresh meat, ready meals, fresh produce, and any product where visual appeal directly influences the consumer's purchasing decision.
The rigid tray structure protects fragile foods from compression, crushing, and deformation during transport and retail handling.
Tray sealing integrates naturally with MAP technology, allowing the gas mixture inside the tray to be precisely controlled for each product type. This combination delivers extended shelf life without sacrificing the product presentation advantages that make tray sealing attractive in retail.
The flat, rigid surfaces of sealed trays accept labels cleanly and consistently, providing a stable surface for product information, barcodes, and brand graphics.
Vacuum sealing's advantages center on its preservation power and operational economics, making it the dominant choice wherever maximum shelf life extension is the primary objective.
Near-total oxygen removal creates the most effective aerobic preservation environment achievable through packaging alone, without relying on chemical preservatives or additives. For products that tolerate the tight packaging format, vacuum sealing typically delivers the longest achievable refrigerated shelf life.
Vacuum packaging removes the air that would otherwise occupy space inside the package, resulting in a compact, dense package that significantly reduces the volume of storage space and shipping containers required.
An airtight vacuum seal provides a highly effective barrier against airborne bacteria, mold spores, and moisture ingress. Once sealed, the product is isolated from the external environment throughout its shelf life.
Vacuum bags are generally less expensive per unit than rigid trays, particularly when compared to multi-layer composite tray formats with high-barrier lidding films.
Tray sealing delivers its greatest value in retail-oriented food production, where product presentation, consumer convenience, and the ability to integrate MAP are the primary priorities.
Fresh meat and poultry: Trays maintain the product's shape and prevent liquid leakage in the retail environment.
Ready-to-eat and ready-to-cook meals: The tray serves as both the primary package and the cooking vessel for meal trays, making it the natural and nearly universal format for the convenience meals category.
Fresh fruits and vegetables: Rigid trays protect soft produce from the bruising and crushing that would occur in flexible packaging.
Bakery and confectionery items: Delicate baked goods require the structural protection that rigid tray packaging provides.
Retail-focused food products generally: Any product where the consumer's purchase decision is significantly influenced by the visibility and presentation of the product in its package is a strong candidate for tray sealing.
Vacuum sealing's superior preservation performance makes it the preferred choice for products where oxygen removal is the dominant packaging requirement, and where the compressed, tight packaging format is acceptable for the product type.
Processed and cured meats: Sausages, ham, salami, bacon, and cooked deli meats are all ideally suited to vacuum packaging.
Seafood: Vacuum sealing, by removing the oxygen that supports bacterial growth and the oxidation that produces the off-flavors associated with spoiled seafood, provides the strongest available shelf life extension for both fresh and smoked seafood products.
Cheese: The compressed packaging preserves the wedge or block format without distortion, while the oxygen-free environment prevents the surface mold growth that would otherwise limit shelf life.
Frozen foods: Vacuum sealing eliminates the air that causes freezer burn — the ice crystal formation and surface dehydration that degrade texture and flavor in frozen products over time.
Bulk food storage: For large quantities of products destined for foodservice use, catering, institutional supply, or long-term storage, vacuum sealing offers the most cost-effective combination of strong preservation, compact packaging, and relatively low material cost.
Selecting between tray sealing and vacuum sealing is rarely a choice made on a single criterion. In practice, it requires an honest assessment of several interconnected factors that together define what the packaging must achieve for a specific product in a specific market.
Fragile products that would be crushed, deformed, or made visually unacceptable by compression require the structural protection of tray sealing. Products that contain significant liquid or sauce cannot be vacuum-sealed without liquid being drawn out during the evacuation process, making trays the practical requirement.
Products that are structurally dense and robust can typically tolerate vacuum sealing without quality loss. Moisture content also matters: products with very high moisture content may interact with the vacuum process in ways that affect the integrity of the seal.
If the primary packaging objective is to maximize the refrigerated shelf life of a product without the use of chemical preservatives, vacuum sealing is typically the stronger performing method, provided the product is suitable for the format.
If the shelf life requirement is more moderate, or if MAP tray sealing can achieve the target shelf life while delivering superior presentation, then tray sealing may be the better overall choice. It is also worth considering the entire distribution chain: a product that moves quickly through a short retail cycle requires less shelf life extension than one that must survive international shipping and extended retail exposure.
For products sold directly to consumers through retail channels, the visual presentation of the package at point of sale is a significant commercial factor. Tray sealing maintains the product's natural appearance and provides a clean, professional retail format that is widely recognized and trusted by consumers.
Vacuum sealing produces a format that is immediately recognizable as a preservation-focused package; appropriate for cheese, cured meats, and similar products where this presentation is conventional and expected, but less suitable for premium or impulse-purchase products where visual appeal is a primary sales driver.
High-speed automated tray sealing systems are well-established in large-scale retail food production and can sustain very high continuous throughput. If your operation requires the highest possible packaging output per hour with minimal labor, automated tray sealing lines are designed for exactly that context.
For vacuum sealing at comparable volumes, double-chamber or continuous thermoforming vacuum systems are required. Smaller operations may find the lower capital cost and simpler operation of chamber vacuum sealers more appropriate, with the trade-off of lower throughput per hour.
Products destined for long-distance distribution generally benefit from the strongest available preservation method, which in most cases is vacuum sealing. The compact format also reduces shipping volume, which has direct cost implications at scale.
On the other hand, products distributed through shorter, faster retail supply chains, where they will be on sale within days of production, may not require the maximum preservation performance that vacuum sealing provides.
The honest answer to the question posed in this article's title is that neither tray sealing nor vacuum sealing is categorically better. Each is better for different products, different markets, and different operational requirements.
In many operations, both technologies are used in parallel for different product lines. And, for some product categories, hybrid approaches that combine elements of both (such as skin packaging over a tray) offer the best of each method simultaneously.
Hualian Machinery manufactures both tray sealers and vacuum packaging machines; from semi-automatic models for smaller operations to fully automated, high-throughput systems for large-scale food production. Whether you are evaluating tray sealing, vacuum sealing, or a combination of both for your product range, Hualian's technical expertise and broad equipment portfolio make them a reliable partner for the decision. Visit hualianmachinery.com to explore the full range or contact the team to discuss your specific packaging requirements.
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