Metal Packaging in the Microwave Oven

1. Metal Packaging in the Microwave Oven

2. Increasing Demand for Quick Meals • 26 % of the European consumers use the microwave oven to prepare quick meals at least once a day, while • 42 % use it 3 to 6 times a week. • 49 % of the American consumers use the microwave oven to make quick meals at least once a day, while • 13 % use the microwave oven 3 to 6 times a week. • (Source: Datamonitor Consumer Survey, 2006)

3. The Green Light to Use Metal Packaging in the Microwave Oven Tests made by the Frauenhofer Institute show that it is both possible and safe to use metal packaging when we heat up food in the microwave oven.

4. Safe Warming Many people believe that they cannot use metal packaging in the microwave oven because sparks may occur when warming up metal. Sparks may occur at strong field energy between two metal objects. However, there are no risk of sparks with a distance of at least 5 mm between metal packaging and other metals.

5. Safe Use When using metal packaging, always remember: • One must always remove the lid before warming up the food. • Only warm up one metal packaging at a time. • At least 2,5 cm to the sides and to the ceiling. • To put the metal packaging on a plate if not on the turnable glass plate of the microwave oven. For safety reasons, the metal packaging must always be followed by instructions of correct warming. And a recommendation to follow the microwave producer's instruction

6. Even Temperature • The use of metal packaging ensures a good distribution of the heat – better than with plastic materials. • Likewise there is less difference in temperature within the content of the metal packaging because you warm up the product through the gap. • This is possible as the metal functions as a shield towards the micro waves. Metal Plastic (Temperature measurements indicate the average temperature for top and bottom after warming in the microwave oven. Source: Frauenhofer Institute)

7. Time • The heating time of a food product in a metal container is two or three times as long as for a similar plastic container. • The larger the diameter and thereby open surface of the metal can the shorter time it takes to heat food to serving temperature. • We are still talking about a quick warm up of food, e.g. 3,5 minutes to heat up 250 g of food from 10 to 75 degrees Celsius. (The heating time of food in metal containers is longer because the content is only warmed up through the gap – food in plastic containers, on the contrary, is warmed from the sides.)

8. The Optimal Design for Microwave Ovens • Big and flat packaging with large openings compared to the volume is most suitable for a fast and good distribution of heat. • The optimal height of the packaging is 2 to 3 centimetres. Only fluent contents in very full cans so that you can mix it during warming. In that way you obtain a nice and even temperature of the food. • The food in metal packaging is warmed up through the gap which is why both time and distribution of heat is improved with metal packaging that is large and flat.

9. Glud & Marstrand Packaging for Microwave Ovens

10. Advantages of Metal Packaging in the Microwave Oven • Functionality – you can use metal packaging in both conventional and microwave ovens. • Rigidity – in particular when you have warmed the food – makes it easier to handle. • Less risk of overheating the food – no risk of melting as with plastic materials. • Even temperature – less difference in temperature of the contents than with plastic materials.