Scientific Opinion on the re-evaluation of boric acid (E 284) and sodium tetraborate (borax) (E 285) as food additives

The Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of boric acid (E 284) and sodium tetraborate (borax) (E 285) as food additives in the EU. These additives are authorised in EU for use as preservatives of sturgeon eggs (caviar) up to a maximum concentration of 4 g boric acid/kg. Previous evaluations have been performed by the Scientific Committee for Food (SCF) in 1979, 1988 and 1992, Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1962, EFSA (2004, 2005a, b, 2012) and TemaNord (2002). The Panel concluded that boric acid and sodium tetraborate do not raise concern for genotoxicity. Feeding studies in rats, mice and dogs have demonstrated that the male reproductive system is adversely affected by boric acid and sodium tetraborate. The adverse effects found with boric acid are similar to those obtained from other borates indicating that the boron is the toxicologically active species. The data on toxicokinetics do not indicate differences between laboratory animals and humans. The Panel concluded that based on the NOAEL of 9.6 mg boron/kg bw/day, derived from a developmental toxicity study in rats, and application of an uncertainty factor of 60, a group ADI of 0.16 mg boron/kg bw/day can be established. Exposure to boron from its use as food additive at the highest is 0.04 mg boron/kg bw/day for children, 0.01 mg boron/kg bw/day for adolescents, 0.01 mg boron/kg bw/day for adults, and 0.01 mg boron/kg bw/day for the elderly. Exposure estimates to boron from its use as food additive at the highest 95th percentile for consumers only, for children, adolescents, adults and the elderly would be 0.56, 0.37, 0.13 and 0.15 mg/kg bw/day, respectively. The Panel concluded that it is unlikely that a regular exceedance of the ADI occurs.