Frequently Asked Questions

What is a C-PET Tray?

C-PET (Crystallised Polyester Terephthalate) is a material that is suitable for use in microwaves or conventional ovens. C-PET Trays are freezable, suitable for MAP (Modified Atmosphere Packaging) and available in either black or white. C-PET Trays cannot be surface printed and are relatively expensive.

What is an A-PET Tray?

A-PET (Amorphous Polyester Terephthalate) is not suitable for use in microwaves or conventional ovens. A-PET Trays are freezable and suitable for MAP (Modified Atmosphere Packaging). They are available in any colour (including clear) and can be surface printed. A-PET Trays are less expensive than C-PET Trays.

What is a PP Tray?

PP (Polypropylene) is suitable for use in microwaves but not for use in conventional ovens. PP Trays are freezable and suitable for MAP (Modified Atmosphere Packaging). They are available in any colour (including clear) and can be surface printed. PP Trays are relatively inexpensive.

What is a PVC Tray?

PVC (Polyvinyl chloride) is not suitable for use in the microwave, conventional oven or freezer. PVC Trays are suitable for MAP (Modified Atmosphere Packaging), but performance will be improved with a PE coating. PVC Trays are available in any colour (including clear), can be surface printed and are relatively cheap.

What is a PS Tray?

PS (Polystyrene) is a very brittle material and is not suitable for use in the microwave, conventional oven or freezer. PS Trays are not suitable for MAP (Modified Atmosphere Packaging). PS Trays are inexpensive and are available in any colour.

What is an HIPS Tray?

HIPS (High Impact Polystyrene) is a material that is not suitable for use in microwave or conventional ovens. HIPS Trays are freezable but are not suitable for MAP (Modified Atmosphere Packaging). They are available in any colour, inexpensive and not as brittle as PS Trays.

What is an HDPE Tray?

HDPE (High Density Polyethylene) is not suitable for use in microwaves or conventional ovens but is suitable for freezing. HDPE Trays are suitable for MAP (Modified Atmosphere Packaging) and have very high barrier properties. HDPE Trays are limited to white, black or clear in colour and can be surface printed, but printing onto HDPE Trays is fairly expensive.

What is a Crinkle Wall Foil Tray?

Crinkle Wall Foil Trays are suitable for freezing but not suitable for MAP (Modified Atmosphere Packaging). They cannot be surface printed but they are fairly inexpensive. Crinkle Wall Foil Trays cannot be sealed hermetically and are mostly used with board lids and crimping.

What is a Smooth Wall Foil Tray?

Smooth Wall Foil Trays are suitable for use in the conventional ovens and most microwaves. They are also freezable and suitable for MAP (Modified Atmosphere Packaging) . Smooth Wall Foil Trays are available in different colours but cannot be surface printed. Smooth Wall Foil Trays can be difficult to seal unless they have been lacquered. Product contamination has to be carried out with an x-ray machine and they are relatively expensive.

What is a Dual Ovenable Board Tray?

Dual Ovenable Board Trays are suitable for use in conventional ovens, microwaves and freezers, but are not suitable for MAP (Modified Atmosphere Packaging) . They are available in various colours and can also be surface printed. Dual Ovenable Board Trays require a sealant layer to enable sealing and are reasonably inexpensive.

What is Polyester (PET) Lidding Film?

PET Lidding Film is the most common base material used for sealing; it is also the most heat resistant (up to 235°C). PET Lidding Film offers excellent clarity and can be supplied printed to customers' specific requirements.

What is Nylon (OPA) Lidding Film?

This is technically known as "Orientated Polyamide". It is heat resistant up to 190 degrees C and has to be laminated to Polyethylene. It is tear resistant, slightly opaque and can be supplied printed.

What is Polypropylene (OPP) Lidding Film?

Polypropylene (OPP) Lidding Film is technically known as 'Oriented Polypropylene', sometimes referred to as 'Orientated Polypropylene'. It is heat resistant up to 160°C and must be laminated to cast polypropylene. Polypropylene (OPP) Lidding Film can only seal to polypropylene and it can be supplied printed.

What is MAP (Modified Atmosphere Packaging)?

MAP (Modified Atmosphere Packaging) is a process used to extend the shelf life of a food product without the need to freeze. The product is first placed in a suitable tray and a vacuum is applied to remove the majority of the air. The vacuumed air is then replaced with a gas mixture that will prolong the shelf life of the product and also retain the appearance of the food. The tray is then heat-sealed with a suitable film to encapsulate the product and the gas mixture for a recommended duration.

What are the benefits of MAP (Modified Atmosphere Packaging)?

The benefits of MAP (Modified Atmosphere Packaging) include:

  • Extended shelf life. Depending on the product, the time an item can remain on display in a supermarket or shop can usually be extended by between 50% and 500% using MAP techniques.
  • Minimisation of waste. With MAP, food can be displayed for longer periods of time and therefore less chance of having to throw it away at the end of its usual shelf life.
  • Quality. There are obvious advantages for both retailer and consumer in having food which deteriorates at a slower rate, as it makes journey from place of production to the domestic kitchen, fridge or freezer.

    Presentation. Because MAP products are usually presented in a tray, retailers have the opportunity to package more attractively.

    All these benefits have wide-ranging applications but they are especially important to producers of ready meals and cook-chill products, as MAP can significantly extend the shelf life of a whole range of such products. Besides delaying microbial spoilage, the use of a carbon dioxide and nitrogen gas mix (2:1 ratio) has also been found to delay the development of oxidative warmed over flavour.

    Cook-chill means food is hygienically prepared, pasteurised and rapidly chilled to between zero and three degrees Centigrade. Food is then stored at similar temperatures before being reheated to 70 degrees Centigrade for a period prior to consumption.

    Under Department of Health guidelines issued in 1989 for cook-chill for the catering industry, the maximum recommended shelf life for products is five days. This period can be extended if the food is packed under modified atmosphere conditions or cooked under vacuum for the retail market. Tests have shown that for ready meals and cook-chill products with a shelf life of two to five days, modified atmosphere can increase this to between five and ten days.

    Ready prepared foods that can benefit from MAP include fish, game, meat, pasta, poultry and vegetables as well as casseroles, soups and sauces.

What is Gas Flushing?

Gas Flushing is another way of saying Modified Atmosphere Packaging or MAP

What Gas Should I Use?

MAP (Modified Atmosphere Packaging) gases for food use are available pre-mixed using either one, two or all three of the following:

  • Carbon Dioxide - improves the quality and shelf life of dairy and meat products.
  • Oxygen - aids respiration of fruit and vegetables, colour retention in red meat and avoids anaerobic conditions in white fish.
  • Nitrogen - prevents oxidation and increases shelf life, reducing the need for preservatives that are perceived by the consumer to be detrimental to nutrition and health.