Iron Oxides

 

Identifiers

Synthetic Iron Oxide
Iron oxides and hydroxides
E172

Iron Oxide Black
INS No. 172(i)
CAS No. 1317-61-9
CI No. 77499
CI Pigment Black 11

Iron Oxide Red
INS No. 172(ii)
CAS No. 1309-37-1
CI No. 77491
CI Pigment Red 101 and 102

Iron Oxide Yellow
INS No. 172(iii)
CAS No. 51274-00-1
CI No. 77492
CI Pigment Yellow 42 and 43

Physical Description

Iron oxides are naturally occurring pigments, ranging from black, yellow, red and brown in color. However, commercial forms are produced by synthesis. They impart pastel shades as opposed to some of the brighter and clean shades imparted by other colors.

Common Uses

Typical applications include pet foods, confectionery, cosmetics, and pharmaceuticals.

Specifications

US FDA
JECFA
EU Commission Regulation (EU) No 231/2012

Codex GSFA Provisions

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 published 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)).

Regulatory Approvals

USA: Synthetic iron oxide is exempt from certification 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).

JECFA: ADI of 0-0.5 mg/kg body weight (1980)

EC: 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 Assessment

JECFA last evaluated iron oxides at its 23rd meeting, noting that studies on the bioavailability of iron from these compounds suggest that ferric oxide is less available as a source of biologically active iron than are other forms of iron. A few studies on experimental animals indicate that levels of up to 10 g/kg of iron oxide in the diet do not result in adverse effects. It was also shown that rats consuming more than 50 mg/kg of body weight of iron oxide for 8 generations showed no effects on reproduction. An ADI of 0-0.5 mg/kg of body weight was established.

Safety Reviews

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

JECFA (1980). Toxicological evaluation of certain food additives. 23rd Report of the Joint FAO/WHO Expert Committee on Food Additives. WHO Food Additive Series No. 14. Available online