This worker in a dairy factory is about to tip a bucket of salt into a large butter churn. At the time, in 1947, salt was added to butter at a rate of 1.5–2% by weight. Before refrigeration, salt was an important addition: salted butter lasted much longer than the unsalted variety. In 2005, blocks of butter still had the same percentage of added salt. The dairy industry remains a heavy user of salt, mainly in its butter and cheesemaking processes.
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Permission of the Alexander Turnbull Library, National Library of New Zealand, Te Puna Mātauranga o Aotearoa, must be obtained before any re-use of this image.