BHA

Butylated hydroxyanisole (BHA, E320) is a synthetic antioxidant consisting of a mixture of two isomers — 2-BHA and 3-BHA — used to prevent oxidative rancidity in fats, oils, and lipid-containing foods including snack foods, breakfast cereals, dehydrated soups, and chewing gum. It is particularly effective as a carry-through antioxidant that remains active after food processing at high temperatures, which makes it valuable in fried snack products. BHA is often used in combination with BHT (E321) or propyl gallate because of synergistic antioxidant activity in mixed systems.

JECFA has established an ADI of 0.5 mg/kg body weight per day for BHA (evaluated 1997), based on long-term rodent studies showing forestomach hyperplasia and squamous cell carcinomas at high doses in rats and hamsters. This anatomical site (the rodent forestomach) has no human counterpart, which has been a significant point of scientific debate in interpreting the carcinogenicity data for human risk assessment. IARC classified BHA as Group 2B (possibly carcinogenic to humans) in 1986, based primarily on these rodent forestomach findings. The European Food Safety Authority has not completed a full re-evaluation under current systematic standards; the existing EU ADI is based on older JECFA assessments.

BHA is authorised in the European Union under Regulation (EC) No 1333/2008 at maximum levels of 100–200 mg/kg (calculated on fat content) and is GRAS-listed in the United States under 21 CFR §182.3169. It is not permitted in Japan as a direct food additive. California's Proposition 65 lists BHA as a chemical known to cause cancer, based on the IARC classification. Given these regulatory and consumer perception concerns, many manufacturers have reformulated products to use tocopherol-based or rosemary extract antioxidant systems, particularly for products marketed in health-conscious retail channels.