Kerry Foods has moved to boost the health credentials of its Cheestrings kids' cheese by increasing the calcium content and fortifying it with vitamin D.

Starting this month, Cheestrings will contain 25% of children's recommended daily allowance of calcium, compared with 18% of RDA at the moment. Kerry is also fortifying Cheestrings with vitamin D for the first time.

"The rollout will begin this month and we aim to have all Cheestrings products containing 25% calcium and Vitamin D on shelf by early 2012," a spokeswoman for Kerry said.

The front of the new packs will read 'rich in calcium'. Kerry said it was considering an additional flash highlighting Cheestring's vitamin D content once the rollout was complete.

The company has already reduced the salt content of Cheestrings by 25% over the past eight years, but said it was looking to reduce this even further.