- Tray sealing applies a film lid to a pre-formed tray using heat and pressure — delivering airtight seals for MAP, standard atmosphere and VSP formats.
- Peelable and non-peelable seal types serve different end-use requirements: peelable for consumer convenience, non-peelable for integrity-critical applications.
- Tray material — CPET, APET, PP, paperboard/PE — determines ovenable suitability, recyclability and seal layer compatibility.
- Inline tray sealing lines integrate filling, sealing, labelling and inspection in a single pass at rates of 20–100 cycles per minute.
- EU PPWR recyclability requirements are driving rapid adoption of paper-based and mono-material tray-lidding combinations in 2026.
Table of Contents
- What Is Tray Sealing Packaging?
- Types of Tray Sealers
- Tray Materials and Film Lidding
- Seal Types: Peelable vs Non-Peelable
- Tray Sealing vs Alternative Food Packaging Formats
- Technical Specifications
- Industry Insight: MAP + Tray Sealing in 2026
- Frequently Asked Questions
What Is Tray Sealing Packaging?
Tray sealing packaging — also called tray lidding or heat-seal tray packaging — is a process in which a pre-formed tray filled with product is sealed with a flexible or semi-rigid film lid applied under controlled heat and pressure. The seal is formed between the inner heat-seal coating of the lidding film and the flange of the tray, creating an airtight closure that protects the product from contamination, moisture loss and atmospheric oxidation.
Tray sealing is the predominant packaging format for chilled ready meals, fresh meat and poultry, deli products, fresh pasta, salads and dairy portions across the food service and retail sectors. The format's ability to combine precise atmosphere control — via Modified Atmosphere Packaging (MAP) gas flushing — with consumer-friendly peel-open convenience makes it one of the most versatile food packaging systems available.
The global tray sealing market was valued at approximately USD 3.4 billion in 2025 and is forecast to grow at 4.8% CAGR through 2030. Growth is driven by expanding demand for convenience food, the shift from butcher-counter to pre-packed retail formats, and the increasing use of high-oxygen MAP for fresh protein products.
Types of Tray Sealers
Manual and Semi-Automatic Tray Sealers
Entry-level tray sealers require an operator to load trays into a nest tool, close the machine lid and initiate the seal cycle. Output is typically 5–20 cycles per minute. These machines are suitable for artisan food producers, small-scale food service operations, catering and pilot production environments. Capital cost is low — entry models start from USD 2,000–5,000 — and tooling changeover for different tray formats takes 10–20 minutes.
Automatic Inline Tray Sealers
Automatic tray sealers use a conveyor system to continuously advance trays through the sealing tooling. The operator loads empty trays at the infeed; filling, sealing and discharge happen automatically at rates of 20–100 cycles per minute depending on the number of tool nests per cycle. Inline sealers are integrated with gas flushing heads for MAP, film tracking systems and downstream checkweighers and labellers.
Rotary Tray Sealers
High-volume production lines use rotary tray sealing platforms in which the tool — carrying multiple nest positions — rotates continuously. This format maximises the dwell time available for sealing without reducing line speed, achieving outputs of 80–200 cycles per minute for multi-nest tools. Rotary tray sealing is the format of choice for large-scale chilled protein and ready meal production lines running three shifts.
Skin Tray Sealers (VSP on Tray)
Skin packaging on a rigid tray combines the structural support of a tray with the premium appearance of Vacuum Skin Packaging (VSP). A heated top film drapes tightly over the product surface, conforming to its shape and adhering to the tray flange under vacuum. The result is a pack with exceptional shelf impact and extended shelf life. VSP tray sealers operate at lower speeds than standard tray sealers due to the additional vacuum cycle required.
Tray Materials and Film Lidding
Tray Substrate Materials
CPET (Crystallised PET): Dual-ovenable tray for ready meals. Withstands conventional oven temperatures up to 220°C and microwave use. Off-white or black in appearance. Recyclable in PET streams where lidding is removed. Widely used for chilled and frozen ready meals across UK, European and US retail.
APET (Amorphous PET): Clear or tinted tray for chilled fresh foods. High clarity maximises product visibility. Microwave-safe but not conventional-oven-safe. Recyclable in PET streams. Standard format for fresh salads, sushi, deli portions and snacking products.
PP (Polypropylene): Microwave- and conventional-oven-safe at up to 160°C (PP homopolymer). Good chemical resistance. Available in black, white and natural. Commonly used for ready meals, soups and sauce pots. Recyclable in PP streams.
Paperboard/PE and Moulded Fibre: Fibre-based trays with heat-seal coating are increasingly adopted as recyclable alternatives to plastic trays. Compatible with standard tray sealing tooling but require validated sealing parameters — the porous fibre substrate absorbs more heat than plastic. Moulded fibre trays are used for eggs, fresh produce and premium ready meals in sustainability-focused retail.
Lidding Films
Lidding films for tray sealing are laminates designed to bond to the specific tray material under defined temperature, pressure and dwell time parameters. A standard lidding construction for CPET/APET trays is PET/PE — 12 µm PET outer layer (printable, stiff, heat-resistant) laminated to a 60–80 µm PE sealant. For MAP applications, an additional EVOH barrier layer is included to reduce oxygen transmission.
Anti-fog lidding incorporates a surfactant coating on the inner film surface that prevents condensation droplets forming on the inside of the lid — maintaining clear product visibility for chilled, high-moisture products like fresh salads and cut fruit.
- The product requires structural support in the pack (fresh meat, ready meals, fish portions)
- MAP gas flushing is needed to extend shelf life
- Consumer-facing presentation and product visibility are important
- The tray format matches existing retail fixtures, shelf space or delivery containers
- The product is irregular in shape and better suited to VSP or flow wrapping
- The product is free-flowing and can be packaged in a pillow bag on a VFFS line
- Very long shelf life (>12 months) at ambient temperature makes thermoformed retort or flexible pouch more appropriate
Seal Types: Peelable vs Non-Peelable
The seal integrity and opening behaviour of a tray-sealed pack is determined by the relationship between the lidding film's sealant layer and the tray flange material. Two fundamental seal types exist:
Peelable seals use a controlled-peel lacquer that allows the film to be separated from the tray by hand with a consistent, clean peel force — typically 8–20 N/15 mm. Consumer convenience is the primary driver. The peel lacquer is engineered to delaminate from one substrate surface rather than cohesively tear through the film. For MAP packs, peel strength must be high enough to maintain seal integrity throughout distribution but low enough for easy consumer opening.
Non-peelable (weld) seals fuse the lidding film and tray flange into a single material mass — the seal can only be broken by tearing the film or tray material itself. Non-peelable seals are used where tamper evidence and maximum seal integrity are required: sterile medical trays, certain pharmaceutical unit doses and high-pressure-distribution frozen food packs.
Technical Specifications
| Parameter | Semi-auto | Automatic Inline | Rotary |
|---|---|---|---|
| Speed (cycles/min) | 5–20 | 20–60 | 80–200 |
| Tool nests per cycle | 1–4 | 2–16 | 4–24 |
| Sealing temperature range | 120–200°C | 120–220°C | 130–220°C |
| MAP capability | Optional | Standard | Standard |
| Indicative CAPEX | USD 3,000–15,000 | USD 40,000–150,000 | USD 200,000–600,000+ |
Frequently Asked Questions
What is a tray sealer machine?
A tray sealer — also called a tray lidding machine or heat seal tray machine — is a piece of packaging equipment that applies a film lid to a pre-filled tray using controlled heat and pressure. The sealing tooling presses the lid against the tray flange for a set dwell time, forming an airtight seal. Tray sealers range from small semi-automatic bench-top units for artisan producers to fully automated rotary lines for large-scale industrial food production.
What is the difference between tray sealing and thermoforming?
In thermoforming packaging, both the tray and the lid web are formed from a flat film roll on the same machine — the bottom web is thermoformed into a tray, filled, and then sealed with the top web in one continuous process. In tray sealing, the tray is a separately supplied pre-formed component — the sealing machine only applies the lidding film. Tray sealing lines offer faster format changeover (change the tool nest rather than the forming tooling) and easier integration of complex tray shapes, but require a separate tray supply chain.
What foods are packaged using tray sealing?
Tray sealing is used across a very wide range of chilled, frozen and ambient food products. Fresh and processed meat, poultry, fish and seafood are the largest volume application globally. Ready meals — including chilled and frozen single portions — are a major tray sealing segment. Other common applications include fresh produce (salads, cut vegetables, mushrooms), dairy portions (cheese, butter pats), deli products, fresh pasta, soups and dessert pots.
Can tray sealers work with MAP?
Yes — MAP-capable tray sealers incorporate a gas flushing system that evacuates and re-gasses the tray headspace before the seal cycle is completed. The gas mix — typically nitrogen and carbon dioxide for fresh produce, high-oxygen mixes for red meat — is delivered through nozzles in the sealing tool. The residual oxygen level in the sealed pack is a critical quality parameter and is monitored by sampling or, on advanced lines, by 100% inline laser headspace analysis.
What is the shelf life extension from tray sealing with MAP?
Shelf life extension from MAP tray sealing varies significantly by product type and gas mix. Fresh red meat in high-O₂ MAP achieves 8–12 days retail display shelf life versus 2–3 days for overwrapped equivalent. Cooked sliced meats in CO₂/N₂ MAP achieve 28–42 days. Fresh pasta in CO₂/N₂ achieves 30–60 days. Fresh-cut salads in a low-O₂ / high-CO₂ mix achieve 10–14 days. Exact shelf life depends on starting microbial load, temperature control throughout the chain and specific gas composition optimisation.
What tray materials are compatible with tray sealing?
Almost all rigid and semi-rigid tray materials are compatible with tray sealing, provided the tray flange has an appropriate heat-sealable surface. Common materials include CPET (dual-ovenable), APET (clear, microwave), PP (oven- and microwave-safe), HIPS (general food), PS foam (low-cost ambient), aluminium foil trays and paperboard/PE fibre-based trays. Each requires a matching lidding film with the correct sealant chemistry.
How is tray seal integrity tested?
Seal integrity is verified using a combination of visual inspection, peel force testing (destructive — typically 8–20 N/15 mm for peelable seals) and non-destructive methods including dye penetration tests, vacuum bubble emission tests and pressure decay testing. On production lines, statistical sampling is standard; 100% inline testing using headspace laser gas analysis or flexible pack deflection sensors is increasingly deployed on high-volume chilled protein lines.
For more on the gas mixtures used in tray-sealed MAP packs, see the full guide on Modified Atmosphere Packaging. For an overview of sustainable tray and lidding material options that meet EU PPWR recyclability requirements, see the Sustainable Packaging Materials Guide.
Sources: Crawford Packaging — Tray Sealing 101 | Packaging World — AI, Automation, and Sustainability Lead Packaging Trends