Preservatives, food boric acid

Boric acid is used in medicine as an antiseptic and large quantities have been used as a food preservative. Its use for this purpose is now prohibited in many countries. Boric acid is also used in the manuf of glazes, particularly for enamels to be used on metals(Ref 3). Boric acid has been used in expls, such as Boritines(qv). 

Boric acid, H3BO3, occurs in the volcanic steam jets of central Italy, The substance is a white crystalline solid, which.is sufficiently volatile to be carried along with a stream of steam. It is a very weak acid, and is used in medicine as a mild antiseptic. It is an excellent preservative for foods, but this use is illegal because of its toxicity. 

Boric acid is used as an antimicrobial preservative in eye drops,cosmetic products, ointments, and topical creams. It is also used as an antimicrobial preservative in foods. 

Some of the more important preservatives used in foods are benzoate of soda, boric acid, salicylic acid, alcohol, formaldehyde, sulphuric acid, potassium nitrate or saltpeter. 

Wiley HW (1904) Influence of food preservatives and artificial colors on digestion and health. I. Boric acid and borax. U S Department of Agriculture Bulletin No 84, Pt 1, Government Printing Office,... 

Boron compounds are also used as food preservatives, and boron compounds such as sodium octaborate are used to fireproof fabrics. Boric acid is also used as an insecticide, in particular for ants and cockroaches in the home. Compounds of borate are used in many other applications (e.g., as fertilisers, in face powders to add a lustre and a silky feel, and so on). 

Boron compounds are also nsed as food preservatives, and boron compounds such as sodium octaborate are used to fireproof fabrics. Boric acid is also used as insecticide, in particular for ants and cockroaches in homes. 

Boric acid is used in the manufacture of glass (borosilicate glass), glazes and enamels, leather, paper, adhesives, and explosives. It is widely used (particularly in the USA) in detergents, and because of the ability of fused boric acid to dissolve other metal oxides it is used as a flux in brazing and welding. Because of its mild antiseptic properties it is used in the pharmaceutical Industry and as a food preservative. 

In the EC list of preservatives, provisionally allowed for cosmetics, boric acid is listed with a maximum authorized concentration of 0-5% for products for oral hygiene and 3% for other products. As a food preservative boric acid is no longer of importance because of its toxicological properties. 

Boric acid and borax (ADI = 0.1 mg/kg body weight) resorb rapidly in the body and are slowly excreted. In comparison with other acids, which act as preservatives, these compounds are more toxic, but no side effects are known from foods. Concentrations of boric acid (borates) in pharmaceutical preparations are much higher and may cause several side effects. Chronic administration causes bleeding, dermatitis and anaemia. 

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