MECHANISM ANALYSIS OF BACTERIOSTATIC EFFECT ON FOOD WASTE ANAEROBIC PRESERVATION

Food waste tends to rot and stink for high levels of water and organic matter, thus affecting its resource utilization and urban environment seriously. In this paper, natural sealing and anaerobic preservation methods of food waste were used to investigate the effect of different preservation methods on bacteriostatic effect with the increase of fermentation duration. The results showed that the order of Escherichia coli quantity in samples under different preservation methods was the anaerobic preservation without adding lactobacillus＜the anaerobic preservation group after adding lactobacillus＜the natural preservation group, which was consistent with the concentration of hydrolytic acidification products (organic carboxylic acid and ethanol, etc.) and the percentage of lactic acid+acetic acid to the hydrolytic products, from high to low, during sample preservation. To explore bacteriostatic effect of organic acid in the process of anaerobic preservation, Escherichia coli was chosen as the spoilage organisms to carry out Oxford cup bacteriostatic experiment and 96 orifice synergy bacteriostatic experiment. The results showed that the main inhibitory action was acetic acid molecule and lactic acid molecule rather than H⁺. The minimum inhibitory concentrations of lactic acid, acetic acid and ethanol were 2.5, 1.25, 35 g/L, respectively, and the FIC indexes of lactic acid+acetic acid, lactic acid+ethanol and acetic acid+ethanol were 0.12, 0.03, 0.22, respectively, indicating that each pair of the three hydrolytic products had synergistic bacteriostatic effect.