Lawrence Berkeley National Laboratory

Preservatives deter microbial growth, providing crucial functions of safety and durability in composite materials, formulated products, and food packaging. Concern for human health and the environmental impact of some preservatives has led to regulatory restrictions and public pressure to remove individual classes of compounds, such as parabens and chromated copper arsenate, from consumer products. Bans do not address the need for safe, effective alternative preservatives, which are critical for both product performance (including lifespan and therefore life cycle metrics) and consumer safety. In this work, we studied both the safety and efficacy of a series of phenolic preservatives and compared them to common preservatives found in personal care products and building materials. We quantified antimicrobial activity against Aspergillus brasiliensis (mold) and Pseudomonas aeruginosa (Gram negative bacteria), and we conducted a hazard assessment, complemented by computational modeling, to evaluate the human and environmental health impacts of these chemicals. We found that octyl gallate demonstrates better antimicrobial activity and comparable or lower hazards, compared to current-use preservatives. Therefore, octyl gallate may serve as a viable small-molecule preservative, particularly in conjunction with low concentrations of other preservatives that act through complementary mechanisms.