The oxymoronic title of Benjamin Cohen’s Pure Adulteration. Cheating on Nature in the Age of Manufactured Food captures the central premise of the book: the meaning of „purity“ and „adulteration“ was both relative and fluid at the dawn of the industrial food system. With this premise, Cohen explains how the ideal of purity and the sin of adulteration came to shape, which foods Americans viewed as acceptable and which as unacceptable at a time when they had decreasing control over how food was produced. Such a judgment, Cohen argues, inevitably came down to trust; who or what did you trust when it came to food? This is a difficult question whose answer was not self-evident, in part because it was asked in the midst of what Cohen calls a „century-long shift from a producer-oriented culture of food and agriculture to a consumerist one“ (p. 44).

Cohen divides his argument into three main sections which are comprised of two or three chapters each. The first part considers how nineteenth century Americans assumed a level of purity based on a web of local relations and mutual trust. Even those who did not produce their own food knew who did or certainly who sold it to them: “The sense of pure […] derived from the familiar interactions of local life” (p. 33). Yet importantly, at this early stage of food manufacturing, knowledge of chemistry was limited and most people trusted not just their neighbors, but their own senses to know whether or not food was pure, since „appearances matched realities“ (p. 35).

The second part of the book discusses the purity debates concerning three manufactured products as illustrated in an 1887 print of a fierce, multi-headed serpent: margarine, cotton seed oil, glucose. Margarine as a product has changed greatly from the late nineteenth century to today, formerly derived from dairy products, but later becoming a concoction of highly processed plant fats. In its early days, margarine was celebrated by some as an economical alternative to butter as well as an efficient use of all animal byproducts, and soon a profitable raw material in global food manufacturing. To its critics, though, margarine was „offensive and controversial from the start because it competed with prevailing agrarian practices [butter-making]“ (p. 78). Although butter was clearly a „manufactured“ product, the result of manipulating nature, margarine’s origins in a factory, perhaps confusing people about which was „pure“, invited denunciations and debate.

The controversies surrounding cotton seed oil involved similar issues. Cotton seed oil was also the efficient use of a naturally grown resource which had heretofore been wasted. It, too, evolved into an economically successful raw ingredient in global food manufacturing. And it, too, was in danger of confusing people about the purity of particular foods, e.g., was olive oil really olive oil if it was blended with cotton seed oil? The controversies over glucose went in a slightly different direction. The complexity of the large industrial operation that created „glucose“ as an unfamiliar ingredient in manufactured foods incited fear as well as legal challenges regarding the nature of adulterants. Cohen observes that the challenges were laid to rest amid the proliferation of glucose embedded in an increasing number of products.

The last part of Cohen’s book examines how Americans came to redefine what was pure and what was adulterated if they did not know who produced their food and could no longer trust their senses. In short, Cohen explains that the new border between purity and adulteration would be policed by scientific experts who analyzed beyond appearances to chemical components. At the dawn of this new age, the role of scientists was ambiguous: they were both distrusted as those skilled in manufacturing manipulation, as well as the only professionals qualified to issue a stamp of purity. Cohen indicates that the latter role came to predominate, especially as chemists moved into government service helping to regulate the ever-expanding industrial food system.

If citizens had been seeking the reassurance of clear borders between the pure and the impure, the rise of chemical analysis did not provide it. Instead, the analysts made clear that „there was no preordained, natural (as in nonhuman) standard that defined purity. It had to be built and defended […].Their answers were not absolute, they were negotiated“ (p. 196). Cohen makes clear that his story of the pure food debates from the late nineteenth and early twentieth centuries raises questions still relevant today, as many continue to consider whether food is pure or not: „All foods are the result of human manipulation. Some are lightly manipulated […] others are heavily manipulated […]. Because of this, we will always have to differentiate between what is proper intervention and what is not“ (p. 240).

Cohen’s thoughtful argument is made stronger by his cogent writing as well as numerous illustrations. His writing is clear and precise, striking an enjoyable balance between the formal and the informal. It has become common for historians to make more use of the first person to give readers entrée into a complex narrative, but not everyone weaves together the different tones with the skill that Cohen does. In addition, the author’s narrative is propelled along by a judicious use of short declarative sentences to identify a key theme or argument, such as his deceptively simple opening to chapter two: „Appearances matter“ (p. 23).

The visuals used in Pure Adulteration – cartoons, document covers, tables of chemical components, advertisements, photos, and maps – are chosen with care, and illustrate key aspects of Cohen’s argument. Cohen also invites readers to find more, enhanced maps on a website linked to the book. The details of these electronic maps are welcome, though not necessary to absorb the book’s argument. My only question about this electronic link is that it perhaps encouraged the editors to include a few small, hard-to-read maps in the print edition that only end up frustrating the reader. I wish these maps had been reprinted larger and with more clarity, otherwise why include them at all in print?

Benjamin Cohen begins his book with a reference to the passage of the Pure Food and Drug Act and the establishment of the Food and Drug Administration in 1906. As with many historical turning points which we use to structure our stories of the past, 1906 represented a touchstone for the pure food debates that had been taking place for several decades, rather than the start of a new era. Pure Adulteration considers the complicated changes that took place before 1906, revealing how Americans’ understanding of food was remade by the industrial age.