Walk down the pet aisle and you will see wet cat and dog food in three main packs: round metal cans, flexible pouches, and shallow aluminum trays with a peel-off foil lid. The tray is popular for single-serve portions and premium recipes, because it opens without a can opener and presents the food neatly in the bowl.
For a manufacturer, though, the tray is not just a different-shaped can. It changes how the container is fed, how product is dosed, how the pack is closed, and how it behaves in the retort. This article looks at aluminum tray wet pet food as a product and at the production steps behind it.
What goes into an aluminum tray
The same families of recipes that are canned can also be packed in trays. Published configurations for tray lines cover:
Wet cat food: smooth meat pâté and mousse, minced and shredded meat, meat chunks in gravy, meat-and-jelly recipes, and mixed meat formulations.
Wet dog food: meat-based recipes with chicken, beef, or fish, minced meat and chunks, meat paste with gravy, and mixed-ingredient formulations.
What changes is the presentation. A tray is wide and shallow, so the top surface of the food is what the pet owner sees when the lid comes off. A smooth pâté should look level and clean at the edges; chunks in gravy should show distinct pieces, not a pile on one side. That makes fill weight, fill height, and product spread across the tray important quality targets, not just net content.
Can, tray, or pouch: decide the pack before the machines
Cans, trays, and pouches are separate package routes. Each raises its own equipment questions:
Package routes and key questions to resolve:
• Metal can — Can and end compatibility; empty-can feed; filling; double seaming; inspection; retort interface.
• Aluminum tray — Tray presentation; filling method; lidding material and heat sealing; handling; process requirements.
• Pouch — Pouch orientation; filling; seal design; handling; process and inspection requirements.
A line built around metal cans should not be assumed to run trays or pouches without a separate equipment assessment. Before asking for quotations, define the product presentation, target markets, the tray supplier and its specification, net content, the SKU list, and the checks the finished pack must pass.
The production steps on a tray line
An aluminum tray wet pet food production line connects product preparation with tray packaging. A typical sequence looks like this:
- 1.
Raw material preparation. Fresh or frozen meat, poultry, and fish are ground or cut according to the incoming material and the recipe.
- 2.
Mixing and formulation. Ingredients are combined in mixing tanks to reach the required distribution and consistency.
- 3.
Cooking and product processing. Cooking kettles, heating, and emulsifying equipment are chosen by texture: a fine pâté needs different processing from shredded meat or chunks in gravy.
- 4.
Automatic tray feeding. Empty trays are separated, positioned, and transferred to the filler. Tray dimensions, shape, and depth set the feeding mechanism.
- 5.
Quantitative filling. The filler doses product into each tray. The dosing technology is selected by viscosity, particle size, solid content, and target weight.
- 6.
Foil lid feeding and heat sealing. Lids or sealing film are placed over the filled trays, and a sealing head applies controlled temperature and pressure.
- 7.
Sterilization and cooling. For shelf-stable products, a retort sterilization and cooling stage is integrated.
- 8.
Inspection and packing. Trays move on to drying, coding, labeling, cartoning, and final packing.
Filling: keep the seal area clean
In a can, the seal is formed mechanically by the double seam. In a tray, the seal is a heat-sealed flange, and product or gravy on that flange is a direct threat to seal integrity. That is why the filling method and the product's flow behavior matter so much on a tray line. Thick pâté, loose minced meat, and gravy each need a dosing approach that puts product in the cavity and not on the rim.
Sealing: match the lid to the tray
The heat-sealing system is configured to the tray construction and the lid or film specification. The tray and lid supplier, the sealing temperature and pressure, and the required seal checks should be agreed together. A change of lid material is a change to the package and should be reviewed as one.
Retort processing: why trays need pressure control
Shelf-stable wet pet food is heat-treated after sealing to reach commercial sterility. Trays and pouches are more sensitive to pressure differences than rigid cans: as the product heats, internal pressure rises, and without enough external pressure the lid can bulge or the seal can be stressed.
This is where overpressure processing comes in. An overpressure water spray retort recirculates heated water over the load while controlling vessel pressure independently of temperature. During cooling, air overpressure helps protect container shape. HSYL's published equipment data for this retort lists a design temperature of 147 °C (working range 80–145 °C), lists tinplate and aluminum cans, retort pouches, and trays among the validated container formats, and states a temperature uniformity of ±0.5 °C, heat-distribution tested before shipment.
Two cautions apply to any tray project:
There is no universal recipe. Temperature, pressure profile, F0 target, and cycle time must be established by qualified thermal-process specialists for the actual recipe, tray, fill weight, and cold-point behavior.
Baskets and loading matter. Trays must be held so that spray water reaches every pack and the load does not shift or deform during the cycle. Basket design is part of the retort scope, not an afterthought.
Quality checks for the finished tray
Typical checks to define before the line is built include:
Fill weight and, for chunk recipes, the meat-to-gravy ratio.
Clean seal flange before sealing, and seal integrity after sealing and after retort.
Lid and tray appearance after retort (no bulging, wrinkling, or deformation).
Coding and label accuracy, and case-pack counts.
Batch records from the retort for traceability.
Planning summary
- 1.
Fix the recipe, texture, and tray specification first.
- 2.
Choose filling technology from the product's viscosity and particle size, with the sealing flange in mind.
- 3.
Agree the lid material and sealing parameters with the tray supplier.
- 4.
Plan the retort around trays: overpressure control, basket design, and a validated process.
- 5.
Size feeding, filling, sealing, and retort capacity together so no stage becomes the bottleneck.
Done in that order, the aluminum tray becomes a reliable premium pack rather than a can-line adaptation that never quite fits.