Abstract:

To investigate the antibacterial effects of citric acid and lactic acid under different concentrations and compounding conditions against Escherichia coli and Staphylococcus aureus, we determined the optimal antibacterial proportion by evaluating inhibition zones, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and growth-killing curves. When the stock solution concentration of citric acid was 4.0% and lactic acid was 2.0%, mixed in a volume ratio of 3:1, the antibacterial effect against E. coli and S. aureus was the best, with inhibition zone diameters reaching 13.5 mm and 14.2 mm respectively, and the synergistic bacteriostasis effect was significantly better than that of single components. Finally, the optimal citric acid/lactic acid compound was applied to beef preservation. By evaluating indicators such as total bacterial count, texture, color difference, and water-holding capacity of beef, the results showed that the total bacterial count of chilled beef during storage was significantly lower than that of the control group, the color L value reduced by 2.3, the a value decreased by 1.5, and the water-holding capacity was significantly improved, effectively extending the shelf life. This study provides a theoretical basis and technical reference for the industrial application of natural organic-acid composite preservatives in chilled meat processing, and has good market application potential and promotion prospects.

Key words: citric acid, lacti cacid, synergistic bacteriostasis, beef preservation