Hygiene refers to the health practices that minimize the spread of infectious microorganisms between people or between other living things and people. Inanimate objects and surfaces, such as contaminated cutlery or a cutting board, may be a secondary part of this process.

One of the bedrock fundamentals of hygiene is handwashing. The recognition of the link between handwashing and reduction in microbial illness dates back to the mid-nineteenth century. Then, Florence Nightingale, based on her nursing experiences during the Crimean War, wrote about her perceived relationship between unsanitary conditions and disease. At about the same time, the Viennese physician Ignaz Philipp Semmelweis noted the connection between mortalities in hospital patients and the movement of physicians from patient to patient without an intervening washing of their hands. After Semmelweis introduced hand washing with a solution containing chloride, the incidence of mortality due to puerperal fever (infection after childbirth) diminished...