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Lysozyme, an enzyme that is often extracted from hen egg whites, is known to inhibit Gram-negative bacteria such as ''Lactobacillus'' but not Gram-positive bacteria such as ''Acetobacter'', and has been shown to be an enzyme that can help inhibit spoilage bacteria in wine and cider fermentations <ref>[https://en.wikipedia.org/wiki/Lysozyme "Lysozyme". Wikipedia. Retrieved 0319/2020.]</ref>. Lysozyme is normally added to wine with a stuck fermentation or to limit malolactic fermentation, and several yeast companies offer a lysozyme-based product <ref>[https://scottlab.com/content/files/Documents/Handbooks/ScottlabsHandbook2018.pdf 2018 Fermentation Handbook. Scott Laboratories. Retrieved 03/19/2020.]</ref>. It has also been suggested to be useful for limiting lactic acid bacteria in yeast slurries, but one experiment reported that the sensitivity of different species of lactic acid bacteria varies, with ''Pediococcus inopinatus'', ''Lactobacillus brevis'', ''Lactobacillus brevisimilis'' showing similar levels of sensitivity, but ''L. linderi'' showing less sensitivity. Bacteria were inhibited more at 22°C than at 4°C. At 300 mg/L, although lactic acid bacteria was inhibited, it was not killed cimpletely <ref>[https://www.researchgate.net/publication/293048096_Antibacterial_properties_of_hen_egg_white_lysozyme_against_beer_spoilage_bacteria_and_effect_of_lysozyme_on_yeast_fermentation/citation/download Van Landschoot, Anita & Villa, A. (2005). Antibacterial properties of hen egg white lysozyme against beer spoilage bacteria and effect of lysozyme on yeast fermentation.]</ref>.
The homebrew practice of adding distilled or sanitized water to a yeast slurry, letting the slurry settle into three layers, and then removing the bottom and top layer and re-pitching or saving the middle layer, is different than "yeast washing". This process is known as "yeast rinsing", and is primarily employed by homebrewers who wish to separate trub material from their yeast slurries before reusing the yeast slurry. This might have the benefit of removing unwanted flavors from the slurry or hop material that could inhibit yeast growth, but it does not inhibit lactic acid bacteria or any other contaminants (in fact, this process increases the chances of contaminating the yeast slurry). See [https://www.homebrewersassociation.org/how-to-brew/yeast-washing-yeast-rinsing-whats-difference/ this AHA article] for more details on yeast rinsing.
===Cleaning and Sanitizing===