Amendment to the Enforcement Ordinance of the Food Sanitation Law and the 
Standards and Specifications for Foods and Food Additives 
 
The government of Japan will designate Sodi um Selenite as an authorized food 
additive. 
 Summary 
Under Article 10 of the Food Sanitation Law (hereinafter referred to as the “Law”), 
food additives shall not be used or marketed  without authorization by the Minister of 
Health, Labour and Welfare (hereinafter referred to as “the Minister”). In addition, when 
specifications or standards are established for f ood additives based on Article 11 of the Law and 
stipulated in the Ministry of Health, Labour a nd Welfare Notification (Ministry of Health and 
Welfare Notification No. 370, 1959), those additiv es shall not be used or marketed unless they 
meet the standards or specifications. 
 
In response to a request from the Minister, the Committee on Food Additives of the 
Food Sanitation Council that is establishe d under the Pharmaceutical Affairs and Food 
Sanitation Council has discussed the adequacy of the designation of Sodium Selenite as 
a food additive. The conclusion of the committee is outlined below.  Outline of conclusion  
The Minister, based on Article 10 of the Law, should designate Sodium Selenite, as a 
food additive unlikely to harm human health, and establish standards for use and compositional specifications, based on Ar ticle 11 of the Law (see Attachment). 
    Attachment 
Sodium Selenite  
亜セレン酸ナトリウム  
 
 Standards for use 
Sodium Selenite is permitte d only in powdered formulat ed breast milk substitutes 
[(cow’s milk-based powdered formulated m ilk (infant formula an d follow-up formula) 
and other breast milk substitutes*]. 
When used in other breast milk substitute s, it shall not be contained at a level 
exceeding 5.5 μg as Se per 100 kcal for each product. 
*Other breast milk substitutes include no n-milk based formula, such as soy milk 
  Compositional specifications 
Substance name  Sodium Selenite 
Molecular formula  Na2SeO 3･5H2O  
Molecular weight  263.01 
Chemical name [CAS number]      
Disodium Selenite Pentahydrate  [ 26970-82-1] 
Content  Sodium Selenite contains 98.5–1 01.5% of sodium selenite (Na 2SeO 3･5H2O ).  
Description   Sodium Selenite occurs as a white crystalline powder.  
Identification   
(1) Dissolve 0.05 g of Sodium Selenite by addi ng 2.5 ml of water and 2.5 ml of dilute 
hydrochloric acid, and boil. When 0.05 g of L-ascorbic acid is added, the resulting 
solution produces a red precipitate. When left to stand for a few minutes, the color of the precipitate changes to red-brown to black.  
(2) Dissolve 0.05 g of Sodium Selenite by a dding 5 ml of water and 1 ml of dilute 
hydrochloric acid. When 1 ml of barium chlo ride solution (3 in 50) is added, no 
precipitate is produced.   
(3)  Sodium selenite responds to all tests fo r Sodium Salt in the Qualitative Tests.    
Purity  
(1)  Clarity of solution  Colorless and clea r (2.0 g, carbon dioxide-free water 20 ml). (2)  pH  9.8–10.8  (2.0 g, carb on dioxide-free water 20 ml). 
(3)  Chloride  Not mo re than 0.005% as Cl. 
Sample Solution  Place 2.0 g of sodium selenite in to a Nessler tube, and dissolve it 
by adding about 30 ml of water. Add 4 ml of nitric acid and mix.  
Control Solution  Use 0.30 ml of 0.01 mo l/L hydrochloric acid. 
(4)  Sulfate  Not more than 0.03% as SO 4 (0.8 g, Control solution: 0.005 mol/L 
sulfuric acid 0.50 ml). 
(5)  Lead  Not more than 2.0 g/g as Pb. 
Standard Solution  Measure exactly 2 ml of Lead Standard Stock Solution into a 
100-ml volumetric flask, and add nitric  acid (1 in 200) to volume.    
Test Solution  Weigh 1.00 g of sodium selenite into  a 10-ml volumetric flask, dissolve 
it by adding nitric acid (1 in 200) to make 10 ml. 
Standard Test Solutions   Weigh 1.00 g of sodium selenite into each of three 10-ml 
volumetric flasks.  To the flasks, add 0.5 ml, 1 ml, and 2 ml of the standard solution separately, and dissolve them by adding nitric  acid (1 in 200) to make 10 ml of each 
solution. 
Procedure   Determine the emission intensity of lead in the test solution and 
standard test solutions by inductive couple d plasma-atomic emission spectrometry. Plot 
the values obtained on a graph, with the amount ( μg) in each solution on the x axis and 
emission intensity on the y axis, to prepare regression lines for the three elements. Determine the amount of lead in the sample  from the distance between the origin and 
the intersection of the regression line and the x axis.       
    
(6)  Iron  Not more than 50 g/g as Fe.  
Standard Solution  Measure exactly 5 ml of Iron Standard Stock Solution) into a 
100-ml volumetric flask, and add ni tric acid (1 in 200) to volume. 
Test Solution  Weigh 1.00 g of sodium selenite into  a 10-ml volumetric flask, dissolve 
it by adding nitric acid (1 in 200) to make 10 ml. 
Standard Test Solutions   Weigh 1.00 g of sodium selenite into each of three 10-ml 
volumetric flasks.  To the flasks, add 0.5 ml, 1 ml, and 2 ml of the standard solution separately, and dissolve them by adding nitric  acid (1 in 200) to make 10 ml of each 
solution. 
Procedure   Determine the emission intensity of iron in the test solution and 
standard test solutions by inductive coupled plasma-atomic emission spectrometry. Plot the values obtained on a graph, with the amount ( μg) in each solution on the x 
axis and emission intensity on the y axis, to prepare regression lines for the three elements. Determine the amount of iron in the sample from the distance between the origin and the intersection of the regression line and the x axis.     
(7)  Arsenic  No t more than 4.0 g/g as As 2O3.  
Standard Solution  Measure exactly 3 ml of Arsenic Standard Stock Solution (for 
inductive coupled plasma-atomic emission spec trometry) into a 100-ml volumetric flask, 
and add nitric acid (1 in 200) to volume.    
Test Solution  Weigh 1.00 g of sodium selenite into  a 10-ml volumetric flask, dissolve 
it by adding nitric acid (1 in 200) to make 10 ml. 
Standard Test Solutions   Weigh 1.00 g of sodium selenite into each of three 10-ml 
volumetric flasks.  To the flasks, add 0.5 ml, 1 ml, and 2 ml of the standard solution separately, and dissolve them by adding nitric  acid (1 in 200) to make 10 ml of each 
solution. 
Procedure  Determine the emission intensity of  arsenic in the test solution and 
standard test solutions by inductive couple d plasma-atomic emission spectrometry. Plot 
the values obtained on a graph, with the amount ( μg) in each solution on the x axis and 
emission intensity on the y axis, to prepare regression lines for the three elements. Determine the amount of arsenic in the sample from the distance between the origin and the intersection of the regression line and the x axis. 
 
Assay   Weigh accurately about 0.1 g of sodium  selenite into a st oppered flask, and 
dissolve it by adding 100 ml of water. To this solution, add 3 g of potassium iodide and 5 ml of diluted hydrochloric acid (2 in 3), i mmediately stopper tightly, and allow to stand 
in a dark place for 5 minutes. Titrate th e liberated iodine wit h 0.1 mol/L sodium 
thiosulfate (indicator: 3 ml of starch TS).  Add starch TS near the endpoint of the titration, when the solution is pale yellow-red. The endpoint is when the blue color produced disappears. Separately perform a blank test to make a correction.  
Each ml of 0.1 mol/L sodium thiosulfate = 6.575 mg of Na
2SeO 3･5H2O     
 
Reagents and Test Solutions (TS)  
Arsenic Standard Stock Solution (for in ductive coupled plasma-atomic emission 
spectrometry)    Weigh exactly 0.10 g of arsenic trioxide, previously powdered finely 
and dried for 4 hours at 105 ºC, dissolve it by adding 6 ml of sodium hydroxide solution 
(1 in 10), and add 500 ml of water. Adjust the pH to 3 to 5 with dilu ted hydrochloric acid 
(1 in 4), and add water to make exactly 1000 ml . Each ml of this solution contains 0.1 
mg of arsenic trioxide (As 2O3).  
Iron Standard Stock Solution   Weigh exactly 8.63 g of ammonium iron(III) sulfate dodecahydrate, dissolve it by adding 25 ml of diluted nitric acid (1 in 3) and water, and 
add water to this solution to  make exactly 1000 ml. Each ml of this solution contains 1 
mg of iron (Fe). Store, protected from light.