Food giant Heinz is launching a green coloured version of one of its most famous products - tomato ketchup.The staple of thousands of British dinner tables is as famous for its bright red appearance as it is for taking an age to pour from the bottle. But in a bid to capture more of the younger market, the American firm will bring in a spinach-coloured version of the classic sauce in the US this October.British teams will be monitoring the launch to see if they should follow suit over here.Red tomato ketchup was one of the first products to be made by the company and has been on sale in its present form for 125 years. A spokesman for Heinz said: 'Whereas Heinz baked beans are very much associated as a British product, ketchup has a global market.'They also added 'We like to think of ourselves as an innovative company so in the US trials were carried out with child focus groups and the kids said they wanted to see the red sauce in a new colour.'Blue was tried out first but deep green was settled on as it was considered to have more 'kitchen logic'. The green ketchup is also expected to be a hit on St Patrick's Day (17 March).'It is hoped that the product will appeal to more youngsters when it turns green, by making meal-time fun. Although spinach-coloured it will be made from green tomatoes and also contain added vitamin C.The manufacturers have assured adults that despite being the colour of cowpats the green ketchup will taste just like their old favourite. However, it will be dispensed in a stream so thin that Heinz hopes children will draw with it.