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====Yeast Washing====
Yeast washing is the practice of exposing a yeast slurry to extreme acidic conditions in order to destroy bacteria contaminants in the slurry, and it has been used for over a century in the brewing industry to help reduce the potential for lactic acid bacteria spoilage. Although techniques might vary throughout the brewing industry, the most typical technique is to add phosphoric acid to a slurry of yeast until a pH of 2 is reached, and then the slurry is stored for 2 hours at 5°C (41°F). While phosphoric acid is a good choice for acid washing because of being inexpensive compared to other acids, its tendency to not kill yeast, and its lack of affecting beer flavor, it also does not kill some contaminants such as ''Shimwellia pseudoproteus''. It has also been proposed that chlorine dioxide, a disinfectant that is often used in the vegetable, meat, and water treatment industries, can be successfully used to wash a yeast slurry, with the first study on this reporting that a concentration of 78 mg/L (concentration value is for the entire slurry) and stored for 30 minutes at 8°C (46.4°F) <ref>[https://link.springer.com/article/10.1007/s00253-020-10534-x Modeling the inactivation of Lactobacillus brevis DSM 6235 and retaining the viability of brewing pitching yeast submitted to acid and chlorine washing. Munford, A.R.G., Chaves, R.D., Granato, D. et al. Appl Microbiol Biotechnol (2020). https://doi.org/10.1007/s00253-020-10534-x.]</ref>.
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 suggested as an enzyme that can help spoilage bacteria in beer and wine <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. 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 <ref>[https://biblio.ugent.be/publication/1023389 Anti-bacterial activity of lysozyme in pitching yeast and effect of lysozyme on yeast fermentation. </ref>.
===Cleaning and Sanitizing===