A food additive slurry composition which comprises 100 parts by weight of at least one magnesium ingredient selected from the group consisting of magnesium hydroxide, magnesium silicate, magnesium oxide, magnesium phosphate and magnesium hydrogen phosphate, and 2 to 55 parts by weight of at least one emulsion stabilizer selected from the group consisting of polyglycerol fatty acid ester, gum arabic, processed starch, sucrose fatty acid ester having an HLB of 8 or higher, carboxymethyl cellulose (hereinafter, referred to as CMC), methyl cellulose (hereinafter, referred to as MC), propylene glycol alginate (hereinafter, referred to as PGA), water-soluble soybean polysaccharide, condensed phosphate, gum ghatti, phospholipid and arabino galactan is provided. The food additive composition can be highly concentrated and is excellent in flavor as well as dispersibility in liquid.