Thickeners include sodium alginate, carrageenan, gelatine, sodium bicarbonate, tetrasodium pyrophosphate, and alginic acid. Alginate, agar and carrageenan are gelatinous seaweed products collectively known as hydrocolloids or phycocolloids. Sugar polymers include agar, carboxymethyl cellulose, pectin and carrageenan. Iota carrageenan contains sodium chloride which improves gel formation. Other ingredients, such as starch, salt, carrageenan, vanilla, or artificial flavoring are sometimes added. Stabilizers such as carob bean gum and carrageenan are typically added in industrial production. Today, many marblers use powdered carrageenan extracted from various seaweeds. Two major derivitative products are Carrageenan and Agar. Carrageenan, from the red alga "Chondrus crispus", is used as a stabilizer in milk products. Farming methods affect the character of the carrageenan that can be extracted from the seaweed. After harvest, the seaweed is dried, baled, and sent to the carrageenan manufacturer. Poligeenan is produced by the harsh acid degradation of carrageenan. Technically carrageenan is considered a dietary fibre. Indonesia, the Philippines, and Chile are three main sources of raw material and extracted carrageenan. FDA also reviewed carrageenan safety for infant formula.