Iron Oxides

Identifiers

INS No. 172(i); Iron oxide, black
INS No. 172(ii); Iron oxide, red
INS No. 172(iii); Iron oxide, yellow
Synthetic iron oxide
E 172; Iron oxides and hydroxides

Physical Description

Synthetic iron oxide consists of any one or any combination of synthetically prepared iron oxides, including the hydrated forms. Iron oxides are produced from ferrous sulfate by heat soaking, removal of water, decomposition, washing, filtration, drying, and grinding. They are produced in either anhydrous or hydrated forms. The range of hues for synthetic iron oxide includes yellows, reds, browns and blacks.

Common Uses

Typical applications include cosmetics, and pharmaceuticals, and foods, including confectionery, cereals, edible ices, sausage casings, dietary supplements, flavored milk and water based drinks, soups and broths, and fruit preparations.

Specifications

Regulatory Approvals

JECFA: ADI of 0-0.5 mg/kg body weight (23rd meeting, 1979). Iron oxides (INS Nos. 172(i-iii)) are added to foods and beverages at concentrations up to maximum permitted levels (MPLs) as established by the Codex Alimentarius Commission and adopted in the General Standard of Food Additives (GSFA). The 32 provisions are defined at the additive group level, and thus apply to the total content of the additives participating in this group: Iron oxide, black (172(i)); Iron oxide, red (172(ii)); and Iron oxide, yellow (172 (iii)).

USA: Synthetic iron oxides were permanently listed as exempt from certification for use in ingested and topical drugs in 1966, in food in 1968 and in cosmetics in 1976. The listing for food use has been amended, including in 1994, 2015, and 2018 and may be safely used in sausage casings intended for human consumption in an amount not exceeding 0.10% by weight of the finished food; in hard and soft candy, mints and chewing gum at levels consistent with GMP; in dietary supplement tablets and capsules, including coatings and printing inks, such that the total amount of elemental iron per day for labeled dosages does not exceed 5 mgs; for the coloring of dog and cat foods in an amount not exceeding 0.25% by weight of the finished food (21 CFR 73.200), to color ingested or topically applied drugs generally, with the amount of elemental iron for ingested drugs not to exceed 5 mg per day (21 CFR 73.1200) and iron oxides are safe for use in coloring cosmetics generally, including cosmetics applied to the area of the eye, in amounts consistent with GMP (21 CFR 73.2250).

EU: No ADI allocated (EFSA, 2015). Maximum levels of iron oxides and hydroxides have been defined in Annex II to Regulation (EC) No 1333/2008 on food additives, as amended.  Currently, iron oxides and hydroxides are authorized food additives and permitted to be used in specified foodstuffs at quantum satis.

 

Safety Reviews

Evaluation of certain food additives (23rd Report of the Joint FAO/WHO Expert Committee on Food Additives) WHO Technical Report Series No 648, 1980. Available online

ANS Panel (EFSA Panel on Food Additives and Nutrient Sources added to Food), 2015. Scientific Opinion on the re-evaluation of iron oxides and hydroxides (E 172) as food additives. EFSA Journal 2015;13(12):4317, 57 pp. Available online

FDA Final Rule (Ingested and topical drugs generally). 28 FR 3693; Apr 16, 1963. Available online

FDA Final Rule (Cosmetics generally including eye area use). 41 FR 52445; Nov 30, 1976. Available online

FDA Final Rule (Food use, soft and hard candy, mints and chewing gum). 80 FR 14839; Mar 20, 2015. Available online