Lysozyme is a naturally occurring enzyme isolated from egg whites. It is used in wine to inhibit lactic acid bacteria. Lysozyme degrades the cell wall of gram-positive bacteria such as Oenococcus, Pediococcus, and Lactobacillus. Due to their protective external membranes, Lysozyme is not effective against gram-negative bacteria like Acetobacter. It also has no activity against yeast. Lysozyme’s effectiveness depends not only on the type of bacteria, but also the number of cells present. Unlike SO2, Lysozyme is more effective at higher pH’s when lactic acid bacteria growth is favored. Lysozyme does not replace SO2 because it has no anti-oxidative effect. It can, however, be used to help greatly reduce the amount of SO2 needed to achieve microbial stability over the life of both red and white wines.