CMC E number is E466

Carboxymethyl cellulose (CMC) is a cellulose derivative with carboxymethyl groups. It is often used as its sodium salt, sodium carboxymethyl cellulose. CMC E number is E466 is used in food science as a viscosity modifier or thickener. As a food additive, it has E number E466. It is also a constituent of many non-food products.
Carboxy methyl cellulose is a polymer derived from natural cellulose. CMC is biodegraded aerobically and anaerobically by bacteria commonly found in the environment. Biodegradation produces smaller CMC fragments and sugars. These groups form many hydrogen bonds among adjacent chains, regularly packing the chains together to form stable crystalline regions and giving a complete insolubility in water and in most of the organic solvents.
In laundry detergents it is used as a soil suspension polymer designed to deposit onto cotton and other cellulosic fabrics creating a negatively charged barrier to soils in the wash solution. CMC is also used in the oil drilling industry as an ingredient of drilling mud, where it acts as a viscosity modifier and water retention agent. Aqueous solutions CMC have also been used to disperse carbon nanotubes.
I personally believe that it is the responsibility of the parent to check the foods they are feeding their child and educate them about their food choices. we know that a certain food additive is not safe and one should avoid it, we are totally at a loss of doing anything- cause these days, food additives are found in almost all foodstuff sold anywhere.

Others: Pectin        Sodium Alginate