Kraft, which is the largest US food company, made the announcement at an obesity summit arranged by California governor Arnold Schwarzenegger.
Kraft chief executive Roger Deromedi said that after studying children's websites, the company had recognised that children are increasingly spending more time in front of computers.
The company runs a brand website aimed at children aged six to 11 for its Dairylea brand, www.getmoovin.co.uk, which features games and promotions in which its brands are prominently displayed.
The move comes following the announcement a year ago that Kraft would be joining firms in the US food industry by making a commitment to stop advertising certain junk foods on TV to under 12s.
In May, Kraft unveiled a UK website focused on healthy eating as part of its global plan to change the way it markets it product.
Kraft has revealed that by the end of 2006, only products that meet its "Sensible Solution" nutrition standards will appear on its websites that primarily reach children ages six to 11.
The company also is working with others in the food industry to strengthen self-regulation of food and beverage marketing to younger children.
Kraft revealed its new ad strategy in January, which involves adding logos to the packaging of "better-for-you" products and changing ads aimed at children.
Ofcom's review on food ads and the government's stance on labelling have encouraged firms to take a more serious look at how they market their products, against a backdrop of increasing numbers of obese children.
Yesterday, Schwarzenegger signed a California school nutrition law that means that by 2007 all public schools in the state will only sell bottled water, low-fat milk, drinks with at least 50% fruit juice, and foods and snacks that meet strict fat, sugar and calorie restrictions.
At the end of July, Kraft apointed Lexington Communications to its UK public affairs account to deal with proposals to implement a ban on food ads during family-viewing programmes.
The firm opposes this idea strongly and claims it would affect entire food groups such as its range of cheeses, including children's favourite Dairylea.
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