I just learned about the Frederik Accum's 1820 book A Treatise on Adulteration of Food and Culinary Poisons from Public Domain Review:
This groundbreaking work — written in English by a German scientist named Frederik Accum who lived in London from 1793 to 1821 — marked the beginning of an awareness of need for food safety oversight. Accum was the first person to tackle the subject and to reach a wide audience through his activities. His book, controversial at the time, found a wide audience and sold well – a thousand copies in the first month – and a second edition (featured here) was published in the same year. Although popular, the book threatened established practices within the food processing industry and it earned him many enemies among London food manufactures — not least because Accum took the brave step of mentioning companies by name which had been caught carrying out the nefarious practises he details. Only a year after publication Accum left England after a lawsuit was brought against him, living out the rest of his life as a teacher at an industrial institution in Berlin.
The first-edition cover, with its spiderwebs and snakes and the skull-faced warning "There is death in the pot," is particularly appetizing.
More details from Wikipedia:
The various chapters of the book alternate between harmless forgeries such as mixing dried pea grounds in coffee, and much more dangerous contamination by truly poisonous substances. Accum explained to his readers that there was a high lead content in Spanish olive oil, caused by the lead containers used to clear the oil, and recommended using oil from other countries such as France and Italy, where this was not practiced. He warned against bright green sweets sold by itinerant merchants in the streets of London as the colour was produced with "sapgreen", a colorant with high copper content. "Vinegar", he explained to his readers, "was frequently mixed with sulphuric acid in order to increase its acidity."
Accum paid particular attention to beer, introducing the subject with the comment: "Malt beverages, and especially port, the preferred drink of the inhabitants of London and other large cities, is among the items which is most frequently adulterated in the course of supply." He claimed that English beer was occasionally mixed with molasses, honey, vitriol, pepper and even opium. Among the most shocking customs he pointed out was the practice of adding fishberries, part of the family Menispermaceae, to port. It became evident during the French Revolutionary Wars that the practice was getting out of hand, and Accum attributed the intoxicating power of the drink to the addition of this plant matter.