Science seems to have an answer for everything, even for such weighty issues as how to keep your pizza delivery hot on its way from the store. One company with branches in 65 countries and 210 outlets in Britain and Ireland drafted in a US energy technology firm to overcome this pressing problem.

"We never get complaints about a pizza being too hot," admitted Ms Bernadette Eddisford of Domino's Pizza. The company is spending £1 million on new technology that it says will keep its products roasting hot until the deliveryman arrives with the goods.

Domino's is one of a growing number of pizza delivery companies doing business here, along with firms such as Apache Pizza, Four Star Pizza and Mizzoni Pizza & Pasta Co. The company has six outlets, four in Dublin, one in Limerick and one opened earlier this month in Waterford. It has three outlets in the North and 201 in Britain.

"Predominately the stores are franchised but we are increasing the number of corporate stores because we are growing aggressively," Ms Eddisford said. All of the Irish outlets are franchised and there are plans to open another 10 within the next 12 months.

Domino's is also a huge international operation with a presence in 65 countries. It has around 120,000 employees and produces about a million pizzas every day. It has been in business for about 40 years.

The company also expects to open a pizza dough manufacturing plant in Naas, Co Kildare later next month Ms Eddisford said. Dough manufacture is a big part of what the company does and 260 are employed at a UK plant in Milton Keynes. "We make all our own dough. They get live dough delivered to the stores every other day," Ms Eddisford said.

Dough for the Irish outlets currently arrives via ferry, but she added, "it is by no means optimum if we are to expand." The Naas plant will supply the local demand and employ between 20 and 30 as it gears up to full production.

The company's answer to lukewarm pizza, trademarked as "HeatWave", first arose as an idea from a company employee in 1997, Ms Eddisford said. What was needed was a system that would keep freshly baked pizzas warm for the 10 to 40 minutes it took to get them boxed, out of the shop and into the waiting hands of the customer.

"The roots of the system was in the 1970s energy crisis in the US," she said. US firm, AcuTemp worked at the time with the US Departments of Transport and Energy on alternative sources of heating for buildings and also did contract work for NASA and other clients, she said. A product was developed that was used in commercial buildings, in car seats and in gypsum wallboard for home heating, she explained.

When the company won a contract to develop a portable pizza heating system, it developed the earlier technology, modifying it to suit use in a food-handling context. It had to be safe, non-toxic and reliable, as well as simple to use.

The company developed a composite material made up of a heat sensitive hydrocarbon material locked into a silicon matrix. The disc is electrically conductive and when a current is passed through it, the hydrocarbon rubberises, a process triggered by the heat-sensitive chemical.

In effect the chemical locked inside the matrix melts and will give off heat for about 40 minutes until it returns to a solid state.

The composite material, called "phase change" by AcuTemp, is formed into a disc about 25 centimetres across and two or three centimetres thick. It is plugged into a rack like a "giant toaster" at the shop, Ms Eddisford explained and a current is applied. It comes out of the rack with a temperature of about 77C, more than hot enough to keep the pizza pleasantly toasty.

"The other problem we have had is soggy pizza," Ms Eddisford added. This was overcome by using a breathable bag that includes a slot for the HeatWave and which is porous enough to allow steam to escape. "There are no chemicals sparking off to create the energy in the disc," she said. It does not affect the food in any way other than heating it, and the disc can be used over and over.

"We trialed it in 50 stores and all of the stores reported a near 100 per cent decline in customers reporting cold pizza," she said. Development costs reached several million dollars and the company is now spending another £1 million to bring the technology to all its Irish and UK outlets.

"Our incentive for investing £1 million in this is where we have seen trials in other countries sales have increased phenomenally," she said.