Water-soluble monostearin-derived carbon dots with enhanced antibacterial capacity for food preservations

Effectively controlling spoilage remains a critical challenge for maintaining safety and quality of food products. Here, we tested the hypothesis that carbonization of monostearin, a safe but weak antimicrobial emulsifier, can yield monostearin-derived carbon dots (MCDs) with enhanced antibacterial properties suitable as coating ingredients for food preservation . Although the hydrothermally synthesized MCDs are composed solely of C, O, and H, they exhibit strong antibacterial activity against E. coli and S. aureus, with minimal inhibitory concentrations as low as 0.01 mg/mL and 0.08 mg/mL, respectively. Mechanistic studies revealed that MCDs disrupt the structural integrity of both bacterial species and interfere with cellular metabolism. RT-qPCR analysis showed both upregulation and downregulation of gene expression in E. coli , whereas only downregulation occurred in S. aureus . For practical applications, MCDs were dispersed in alginate solution as the coating solutions, providing a safe and effective platform for extending shelf life of strawberries and meats. After 8 days of storage, the MCDs-alginate coating significantly reduced absolute weight loss relative to the control, from 37.4% to 26.7% in strawberries and from 16.4% to 11.8% in pork, while lowering the absolute rotting rate from 83.3% to 33.4% and from 66.3% to 37.6%, respectively. These improvements effectively preserved key sensory attributes, including color, odor, texture, and overall acceptability. This work establishes a strategy for engineering non-preservative food additives into antimicrobial agents, opening avenues for developing next-generation food preservatives.