In Upton Sinclair's "The Jungle," there is a vivid depiction of the unsanitary conditions in the meatpacking industry, including the mention of food contamination. While I can't provide the exact quote verbatim, the passage describes how workers in the meatpacking plants would find rat-infested environments, and how the food products, including sausage, could be tainted with dead rats and other unsanitary substances.
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