Before we had government regulations to set safety standards for food, the American consumer was pretty much at the mercy of those who sold what we ate. In the late 19th century, the dairy industry was particularly egregious in selling low-quality and even dangerous milk to consumers. There were three basic problems. First, lack of sanitation led to bacterial contamination, causing the spread of disease. Second, milk was diluted with cheaper ingredients, such as water and chalk, or even calf brains.
Finally, if the milk was threatening to sour, dairymen added formaldehyde, an embalming compound long used by funeral parlors, to stop the decomposition, also relying on its slightly sweet taste to improve the flavor. In the late 1890s, formaldehyde was so widely used by the dairy and meat-packing industries that outbreaks of illnesses related to the preservative were routinely described by newspapers as “embalmed meat” or “embalmed milk” scandals.
Indiana's top public health officer John Newell Hurty fought for safer milk, but strangely, he was okay with adding formaldehyde for a time because it killed bacteria. Read about Hurty's part in the fight for safe milk at Undark. -via Digg