Propylene glycol alginate

What this is

Propylene glycol alginate, often abbreviated PGA, is one of the alginate-family food additives. Chemically, it is an alginic-acid ester in which some carboxyl groups are esterified with propylene glycol, while others remain free or neutralized. The key safety context is that regulators evaluate both the polymer and the propylene-glycol portion released after hydrolysis. EFSA’s 2018 re-evaluation set an ADI of 55 mg/kg bw/day for E405, found no genotoxicity or carcinogenicity concern, and concluded authorized-use exposure did not exceed the ADI. JECFA uses a different numerical ADI, 0–70 mg/kg bw, and maintains identity and purity specifications. In practice, the regulatory picture is ordinary additive control rather than prohibition: FDA, Codex, the European Commission, Health Canada, and the UK list PGA/E405/INS 405 as permitted only within category-specific limits, GMP conditions, or specifications. EFSA did ask for tighter impurity specifications and better use-level data, so the remaining concern is mainly specification/data quality, not a verified toxicity signal.

Safety Review

The critical endpoints experts review in safety assessments. This is not a prediction of harm.

EFSA evaluates both the polymer and the propylene-glycol portion released after hydrolysis and found authorized-use exposure below the ADI with no genotoxicity or carcinogenicity concern. The remaining issue is specification and data quality: EFSA asked for tighter impurity limits and better use-level data, not because of a verified toxicity signal.