Johns Hopkins University Press
  • Pure White Bread?Bleached Flour, Contestations, and Regulation in Great Britain, 1900–50

Why was bleaching—despite early concerns about this new food technology—left unregulated for over half a century? This article focuses on the processes developed to artificially whiten flour in the first half of the twentieth century. It shows how, instead of circumscribing adulteration to practices that they could identify precisely, most scientists in fact foregrounded the limits of their expertise and called for a precautionary approach when dealing with new food technologies and the attendant risks. Setting the British case within a more international context provides a window into the difficulties that regulatory regimes faced, narrowing their definition of adulteration to demonstrably harmful practices. This type of regime led to legitimizing the use of new, potentially dangerous products and processes and made further regulation much more complicated once these technologies became widespread.

adulteration, food history, bleaching, bread


While there has never been so much research into food safety and toxicity, establishing standards of safety remains as complex and contested as ever. A telling case of the disparities in standards is offered by flour bleaching. This process applies various chemical agents—nowadays mostly chlorine and benzoyl peroxide—not only to give a whiter hue to flour but also to accelerate its natural aging. These processes also make for a softer texture. That is why the biscuit and baking industries prefer bleached flour. Concerns about the potential toxicity of bleaching agents led the European Community to forbid their use in the 1990s, while China and Turkey have also banned them in recent years. Still, benzoyl peroxide remains legal in many other countries, [End Page 149] such as Canada and the United States.1 These variations in the regulation of flour bleaching agents illustrate a key food safety issue: if so many countries still allow the use of benzoyl peroxide, the reason is not simply because it seems to meet consumer demand, but because the evidence demonstrating its toxicity in the doses typically used is mostly controversial. But in the countries where these processes are banned, the rationale is that in the absence of conclusive evidence, it is easier to take a precautionary approach and allow only a narrow range of additives and processes.

These current concerns and considerations have been around for a long time, as this article shows by tracing the origins of flour bleaching to the early twentieth century.2 If flour bleaching is occasionally mentioned in milling histories, it rarely features in the history of food regulation. This omission is surprising because flour bleaching raised important questions over how purity and adulteration were defined in the first half of the twentieth century: it was seen as the epitome of newer forms of scientific and industrial adulteration. From the very beginning, scientists widely condemned bleaching processes, but their concerns were marginalized. It would often take several decades before the more criticized processes were forbidden. Far from naively embracing the idea that whiteness equaled purity, many contemporaries expressed concern over what they saw as artificial manipulation of a staple food. The case of bleaching thus opens an interesting window into wider twentieth-century discussions about food safety, especially regarding processes whose impact on food and health remained difficult to ascertain.

This article contributes to the growing scholarship on the history of risk and regulation of new, potentially hazardous technologies. Over the past two decades, historians have shown that it is fruitless to look for a radical break between our supposedly modern and reflexive "risk society" and previous risk regimes; they have documented the long history of concerns and attempts to evaluate and regulate new technological processes.3 Uncovering this long history has also questioned the notion of an ever more stringent legislative apparatus of the state whose only aim was to protect the public and consumers. Regulation was not just about restricting the use of potentially toxic products and processes; it was often also a means of legitimizing new processes, either formally or by instigating more demanding standards of [End Page 150] proof to demonstrate harm or nuisance.4 The turn of the twentieth century was an important period in which the state established a new regulatory framework to rebuild consumer "trust" in a food system that increasingly called on scientists to participate. Defining safety standards, however, was by no means straightforward.5 A simple and linear "chronological inventory" of food and technological regulations cannot do justice to the complexity of this new regulatory framework and the diverse, often contested definitions of purity and safety.6 Carolyn Cobbold and Benjamin Cohen show how the emergence of industrial food processes considerably changed the meaning of what could be considered "food" and how the boundary between what was and was not pure and safe food became increasingly blurry and contested.7

To understand this important shift, fine-grained empirical analyses are needed of how food technologies were incorporated into our food systems. The history of flour bleaching is one such story. It sheds light on how new synthetics and food processing methods raised important concerns, in particular around the injurious nature of exposure to unknown substances, even in low doses. The article focuses in particular on the British debate, where numerous calls for regulation went largely unheeded. The British case offers a striking illustration of how early food regulation systems impinged rather than facilitated the prohibition of new products and processes. According to Sébastien Rioux, late nineteenth-century British food regulations—long considered the starting point of a "trend towards safer, better quality food"—in fact favored the rise of "legal adulteration" by narrowing down its very meaning to only practices that could be proven injurious.8 Bleachers are a prime example: although widely condemned by scientists as potentially harmful and definitely unnecessary, banning bleachers was severely hampered owing to the evolution of British food laws, which imposed high standards of proof regarding the deleterious nature of new food additives and processes. This article provides novel perspectives on the history of negotiating new technological risks, showing that once new food products and processes became widespread, banning them was a very long and difficult undertaking. [End Page 151]

Manufacturing Whiteness

Consumer demand for white wheaten bread, deemed easy to digest and imbued with great symbolic and cultural value, grew steadily in Britain from the mid-eighteenth century, first in cities and then throughout the country, gradually becoming a "necessary luxury" alongside tea and sugar. To meet this increasing demand, bakers used various products, in particular alum, to whiten flours deemed of lesser quality ("seconds"). In his 1820 Treatise on Adulteration, Fredrick Accum described the addition of alum to bread as one of the most common food "sophistications," and of all the samples examined by the Lancet's Sanitary Commission in the 1850s, not a single one was free of alum.9 By the end of the nineteenth century, new legislation (in particular the 1875 Sale of Food and Drugs Act) and powers of inspection had progressively eradicated the use of alum.10 Though the use of alum by bakers gradually came to a halt, the search for processes to artificially whiten flour picked up in the 1880s and 1890s, moving upstream in the wheat-flourbread chain, from the baking to the milling trade. An initial process, using chlorine gas, was patented in Britain in 1879, while in France, a miller called Frichot invented a process to bleach flour using ozone.11 Neither process was ever used industrially. Later major attempts to develop new bleaching methods included the Andrews process first patented in Belfast (1901) and the Alsop process in the United States (1903).

The exact nature of the chemical change bleaching produced remained unclear.12 Some proponents claimed that bleaching not only "sterilized" and "purified" the flour but also increased its nutritional value, and they touted other benefits of bleached flours such as their ability to keep longer and produce a "stronger" and larger loaf.13 An uncontroversial aspect of these processes was their potential to produce "any degree of whiteness desired." Bleaching advocates argued that this was a way to meet the seemingly relentless consumer demand, as the taste for "white" bread had become almost universal in Britain by 1900.14 Though bleaching was often presented as merely a way of meeting consumer demand, it was much more than just altering the color of flour. Bleaching was not like adding a color additive; it accelerated [End Page 152] the natural aging process and engineered flour to produce more rapidly a consistent and predictable product out of heterogenous raw materials. It was, in other words, a way to mimic and accelerate natural processes through chemical technology. Far from being reducible to a matter of "universal" color preferences, the development of these new bleaching processes should be seen against the backdrop of technological, economic, and ecological transformations in the British food system. By the late nineteenth century, British millers were increasingly relying on "hard" Russian and American wheats with better baking value, enabled through agrarian changes in these countries, reduced shipping costs, and the very rapid development of Britain's steel roller mills in the 1880s and 1890s.15 Yet even with these roller mills, the flour made from harder wheats had to be stored for weeks not only to lose its yellow hue but also to attain its full potential in terms of water absorption, gas retention, and ability to produce larger and better-shaped loaves.16

Bleaching was thus never used solely for its coloring properties but because its effects resembled aging flour for several weeks or months. Another reason for bleaching's particular appeal was that British millers, unlike their Hungarian or American counterparts who processed more uniform raw materials, had to deal with a wide range of wheat varieties, with very different characteristics. The British miller's work thus consisted of "skilfully blending" diverse wheat varieties and "the products of various siftings," a very complex process entailing inevitable variations in quality. Mechanization of the baking industry made the "production of flour of uniform baking properties" a priority, and the invention of bleaching processes enabled millers to "obtain consistency between flours" and manufacture "a uniform product" much more easily.17 This took place at a time when millers faced growing competition. The 1860s and 1870s had seen rapid increases in wheat imports, unlike the still marginal import of flour. The subsequent roller process radically altered the situation: removing the germ that made the flour turn rancid if stored too long allowed flour to be transported and stored for long periods. In the 1880s, British millers faced increasing competition from abroad—and by 1901, more than 30 percent of wheat imports to the United Kingdom were in the form of flour. The competition from the United States was particularly fierce, with flour representing 40 percent of all wheat imports in 1901.18 Flour bleaching was thus crucial for British millers to [End Page 153] compete with these rising U.S. flour imports: if the wheat was milled before leaving U.S. ports, it could age during shipping, but if it was milled in the United Kingdom, it would have to be stored for several weeks to attain the required properties, incurring additional costs and immobilization of capital. Bleaching processes thus not only played an important role in conforming to alleged timeless chromatic preferences but also had wider implications for the industrialization of the British food system and the changing materiality and economy of the wheat grain chain.

Artificiality and Safety

Some millers hailed the new bleaching processes as the application of scientific principles replacing the time-consuming and costly procedures involved in natural aging.19 Yet, from its inception, many condemned bleaching: bakers in particular opposed it, arguing that bleaching allowed unscrupulous millers to "hide" lower-quality flour. For example, in 1906, bakers in Glasgow issued a circular protesting against bleaching, and the National Association of Master Bakers also called for systematic disclosure of the practice.20 Bakers were not the only ones to voice concerns. Some millers criticized and derided as "nonsense" the idea that bleaching produced larger or more nutritious loaves. They also felt that the practice reflected badly on the entire profession and distorted the competition by allowing unscrupulous millers to disguise an inferior product as a more alluring one.21 More importantly, if "white" flour was generally held as the highest and most profitable grade of flour, the term "white" covered various nuances not all attributed the same qualities. It is important to emphasize that, for contemporaries, "whiteness" encompassed several meanings, and its alimentary superiority was controversial. In the case of milk, Londoners preferred it yellowish, which led to the use of dyes to give milk a "creamy color." "Pure" whiteness was often seen as a sign of artificiality and unwholesomeness, whether in milk or in bread.22 Bleaching thus often faced criticism from millers for producing the wrong type of white, a "dirty white" with "the hue of chalk not of cream," and creating a "pale sickly loaf," not one with the "bloom" to which the British public was accustomed.23 The medical profession was also vocal, with the Lancet describing the practice of bleaching flour as a threat to the "purity of bread."24 [End Page 154]

These criticisms may be seen as new enunciations of the traditional discourse on working-class food consumption: commentators and health experts, from the late eighteenth century, frequently lamented poor people's increasing consumption of white bread and advocated a return to the robust simplicity and nutritional superiority (albeit far from consensual) of less "refined" bread.25 Yet concerns about bleaching also reflected rising fears about the "new food dangers" posed by highly processed and "artificial" foods. Such anxieties were highlighted at the time of the Boer War (1899–1902), when the poor physical health of the working class, which physicians blamed on "the craze for white bread," gave cause for alarm.26 The bleaching of flour was seen as a paradigmatic example of the new "refinements of adulteration" created by modern science and industrialization.27 Far from being a marginal issue, the debate about bleaching became interwoven not only with earlier debates about the nutritional and cultural value of white bread but also with the opportunities and risks created by modern science's "artificialization" of food.28 The 1900s thus saw mounting opposition to bleaching, and official food analysts called on those in charge, the Local Government Board, to legislate. The issue was also raised in the British Parliament's House of Commons, where one member argued that "the manufacturers who practice these methods are reaping a financial advantage at the risk of the consumer."29

These calls for action paralleled developments in the United States, where scientific studies and political action on the bleaching issue had gotten off to an early start. The 1906 Pure Food and Drug Act was an ambitious piece of consumer protection legislation, yet the law still left many questions unanswered and significant room for interpretation over what was "pure" food and what was not.30 Chief of the U.S. Bureau of Chemistry, Harvey Wiley, aimed to enforce a strict interpretation of the law and use it to have many additives and food processes banned; securing a ban on bleachers was one of his priorities. For Wiley, bleached flour was a symbol of modern adulteration: consumers were both cheated by paying a higher price for flour disguised as a superior product and potentially poisoned by the residues from the bleaching processes. Wiley came under attack from the milling industry, especially as scientific evidence of bleaching's actual toxicity was not forthcoming given [End Page 155] the very small doses used. Nevertheless, thanks to the importance of flour as a staple product, and in line with decisions restricting the use of other food additives (dyes in particular), the U.S. secretary of agriculture sided with Wiley. The Board of Food and Drug Inspection ruled that bleached flour was an adulterated product and therefore that selling or transporting it in interstate commerce was illegal.31 A few months later, in April 1910, Wiley made his first move against bleached flour by charging a Nebraska milling company for selling "adulterated and misbranded" flour. The trial in Missouri (where the flour had been shipped, and thus fell under federal law) ruled that bleached flour was indeed an adulterated product and the substances added as a result of bleaching were "of a poisonous and deleterious character."32 New Zealand and several states in Australia also passed Pure Food Acts in the 1900s that specifically barred the use of bleachers, showing a rising trend of regulatory activity, which British authorities were called on to emulate.

White Bread under Attack

The London Government Board ordered a report on bleaching and the use of various "improvers," and the findings were published a year later at an auspicious time.33 In January 1911, amid wider debates on the merits and dangers of Britain's ubiquitous white bread, the Daily Mail had published a manifesto calling for legislation to ensure that all bread in Britain met "standard bread" requirements: it should contain wheat germ and at least 80 percent whole grain flour (not the usual 70 percent at the time). The Daily Mail then ran a series of articles over six months to promote "standard bread." This was the first time the white bread issue had received so much coverage in the press and in medical circles.

The 1911 campaign has already undergone close historical analysis, but it is noteworthy that the debate over white versus brown dovetailed with purity and adulteration considerations.34 Both sides of the argument mobilized the "purity" factor, showing how the whiteness issue intersected in several ways with notions of purity and safety. Millers and critics of "standard bread" opposed any form of regulation on the rate of extraction (the proportion of grain made into flour), emphasizing the links between whiteness and purity and agitating the threat of a return to the dark ages of adulteration. They argued that compulsory whole meal bread might be used to conceal [End Page 156] "imperfectly cleaned" products, while whiter flour offered the greatest visual guarantee of no fraudulent additions.35 But for the Lancet, the standard bread campaign vindicated its long opposition to the "dazzling white and tasteless rolls and slices" and reducing "bread to a mere mass of bleached starch."36 This highlighted once again the different meanings attributed to whiteness, ranging from a sign of purity to a symbol of unhealthy artificiality.

The bread issue's already high public profile in 1911 meant that the London Government Board reports attracted considerable public attention and were widely quoted in the press.37 Dr. J. M. Hamill's main report, "On the Bleaching of Flour and the Addition of So-Called 'Improvers' to Flour," was very critical. First, he argued that bleaching was commercial fraud: it artificially modified the color of flour and allowed millers to use "cheaper wheats" while artificially maintaining "uniformity in the appearance of flour milled." Importantly, Hamill insisted "that bleaching by nitrogen peroxide [could not] be regarded as free from risk to the consumer." His condemnation was unequivocal: it was undesirable that "such an indispensable foodstuff as flour, the purity and wholesomeness of which are of first importance to the community, should be manipulated and treated with foreign substances." His experiments led him to believe that, in large quantities, bleaching inhibited digestion and could even result in heart disturbances. Though acknowledging that with small quantities there was no way of proving that bleaching processes were immediately harmful, Hamill argued that it could not "be regarded as desirable that minute doses should be ingested day by day of a drug which in larger single doses has a marked action on the vascular system."38

Particularly interesting in Hamill's report is his insistence on how the prolonged ingestion of small doses of unknown substances had unpredictable effects. Hamill was writing at a time when the science of nutrition was undergoing important changes and paying more attention to the importance of "countless substances" as yet little known but nonetheless deemed fundamental to health and good nutrition.39 In emphasizing the importance of "unrecognised food substances" in February 1911, the Daily Mail mentioned the work of F. G. Hopkins, a reader in chemical physiology at Cambridge, who, along with scientists like Casimir Funk, was conducting research on the nutritional importance of unknown "accessory factors," later called vitamins.40 Although what the Daily Mail described as this "revolution in the [End Page 157] science of food" was only nascent in 1911, it certainly was known to Hamill and encouraged scientists to adopt epistemological caution when making pronouncements on dietary matters. As Hamill stated in another report, there were still "numerous points of uncertainty" in nutrition science, and all the "inferences which may now be drawn from observed facts" were therefore "liable to require considerable modification as knowledge of the physiology and chemistry of nutrition advances."41 Arguably, Hamill's indictment of bleaching relied on a proto-precautionary principle: in light of constantly evolving knowledge about the importance and influence, positive or negative, of minute doses of alimentary substances, "it would in present knowledge be unwise to conclude that the process [was] attended by absolute freedom from risk."42

The publication of the report led to several calls in the press for the process to be banned.43 In response, representatives of the milling trade vilified their opponents as "cranks" and deplored the "exaggeration and misrepresentation of the conduct of the trade by a certain portion of the Press."44 Not all millers were in favor of bleaching, however. Many had not yet adopted bleaching processes and felt that at least compulsory labeling of bleached flour would make their "untreated produce" more competitive. Moreover, the Daily Mail campaign had attained such public prominence that many in the milling trade feared that legislation enforcing some "standard" on the rate of extraction was now inevitable. Almost all millers opposed such infringement on their commercial freedom, but some felt that the bleaching issue gave opponents powerful ammunition. A move against bleaching and other "improving" treatments would show their goodwill and put them in a better position to fight what was seen as the important battle, against the standardization of bread, and thus a large portion of the milling industry favored some kind of regulation.45

Agitation in the press and Parliament drove the London Government Board to take action and legislate in view of the Hamill report conclusions and bans in various countries.46 The time seemed ripe for some form of legislation, and in July 1911, two Conservative MPs even introduced a "Pure Flour" bill, to "prohibit the artificial bleaching of flour."47 A second reading [End Page 158] of the bill scheduled a few days later was adjourned for unrelated reasons, and the bill was not discussed subsequently.48 Despite indications that the London Government Board was working on a British "Pure Food Bill" to deal with the bread issue, the outbreak of war in 1914 shattered any attempt at regulations that could have lowered food availability or raised prices, and while wartime saw increasing control over food supplies, controls over quality and safety and concerns over bleaching became rather muted.49

Purity and Precaution

After World War I, a new process, initially developed in America, spread rapidly in Britain. Known as "Agene" (because it "aged" flour artificially), this new process introduced air "containing 1 per cent, of nitrogen trichloride (NCl3), into a forcibly agitated flour."50 Agene and other forms of bleaching flour were again denounced in the press, in medical journals, and at bakers' congresses.51 Regulation, however, was a complex process, as shown by how uneven it was in different countries. Laws in some states of Australia like New South Wales and South Australia banned bleaching, but Victoria and Queensland still used electrical bleaching processes, and in New Zealand it was forbidden to bleach flour, but importations of bleached flour were not.52 Germany and the Netherlands had no regulations concerning bleaching, while Switzerland had taken steps to eradicate it.53 In the United States, the Supreme Court had reversed the ban on bleaching in 1914. The court ruling was based on the argument that bleached flour could not be considered adulterated without demonstrating the toxicity of typical doses. The Supreme Court decision thus lay the onus of proof on the authorities or suing parties, who had to demonstrate unequivocally that the residues from the bleaching process were harmful to health.54 [End Page 159]

The situation in France is an interesting example of how significant gray areas regarding flour whiteners marred consumer protection. Before World War I, the French widely condemned bleaching practices and passed legislation (a law in 1905 reinforced by a decree in 1912) to combat adulteration, but there were no specific regulations concerning bleaching products.55 By the interwar years, millers were still bleaching flour with various products, including nitrogen trichloride (Agene), despite heavy criticism. Both food chemists and doctors accused millers of robbing flour of vitamin A and expressed general concerns over adding substances whose properties and long-term effects were unknown.56 Given the growing consensus among French health and food experts concerning the nutritional deficiencies of overrefined white bread, bleaching was a clear case of a process that reduced production costs but presented no benefits for consumers and bore potential risks to public health. Bleaching's opponents, such as the Academy of Medicine, argued that it was impossible to devise experiments to test the long-term effect of these substances and therefore safer to abstain from using any of them in flour treatment.57 But given the absence of specific regulations, many uncertainties remained, and there were numerous "administrative tolerances." Court decisions were not always clear on the legality of bleaching: in one case tried in Amiens in 1931, a miller who had been bleaching his product with potassium bromate and ammonium persulfate was cleared of any wrongdoing, while in a second judgment the appellate court found him guilty of adulteration.58 Following the Council of National Hygiene and the Academy of Medicine's call for a total ban, France formally prohibited the use of bleachers and other improvers, but some millers and bakers continued to use them illegally. This even led to a significant controversy after World War II over "cursed bread," when a village in the South of France was afflicted with cases of food poisoning, causing several deaths and an even greater number of psychiatric disorders. The poisoned bread incident has still not been solved, with various alleged causes—from rye ergot fungus to CIA experiments with LSD, as well as bleaching with Agene—showing that the controversy over this practice had not fully died out in the 1950s.59 The broader point here is that flour bleaching was a case in point of the complexity involved in regulating new processes, but as we shall see, the British food safety system set up in the late nineteenth century made it particularly hard to formally ban products as long as their toxicity had not been clearly demonstrated. [End Page 160]

In Britain, the issue gained increasing resonance as part of a broader movement of investigation and legislation on food preservatives and coloring in the early 1920s. Despite its general reluctance to introduce new wide-ranging legislation on food regulations, Britain's new Ministry of Health was pressured into setting up a preservatives committee in 1923.60 The Monro Committee's final report, advocating more stringent legislation, appeared a year later, but the committee was not disbanded; its terms of reference broadened to address the issue of treating flour with chemical substances. Apart from the committee's chair, the other members were scientists and public analysts, including high-profile figures like former director of the Rothamsted research station A. D. Hall, Cambridge professor and soon-to-be Nobel laureate F. G. Hopkins, and J. M. Hamill, now a senior medical officer at the Ministry of Health.

The Monro Committee's 1927 report was another clear indictment of chemical treatment in general and Agene in particular. The report emphasized that it should be a state priority to maintain "the purity of the flour supply" and ensure that flour was "a product of the milling of wheat without the addition of any foreign substance." Interestingly, the committee's decision was not based on "direct evidence of injury to the health of the consumer from the use of these added substances," as this was very difficult to demonstrate with certainty. Instead, the committee's case was based, like Hamill's sixteen years before, on the idea that, even in minute quantities, chemicals in such an important food item as flour could result in alterations that science was not yet able to detect but might prove detrimental in the longer term. The committee members had received conflicting evidence on the kind of chemical changes produced by adding chemicals to flour, which, they thought, illustrated "the incompleteness of existing knowledge of the action of the substances at present used." At a time of important discoveries in nutrition science, the report argued that the lack of direct evidence of a substance's deleterious character could not be considered as "proof that the material tested [was] certainly innocuous" and was perhaps due to the "imperfect" nature of current "methods of detection." The committee members again favored a precautionary principle, arguing that, with such an "important foodstuff as flour," it was safer to rely on the "sound instinct" of nineteenth-century bread regulations aimed at "maintaining inviolate the purity of the flour supply," and thus called for a ban on chlorine and nitrogen trichloride.61

The publication of the report heightened the focus on the bleaching issue, with frequent discussions in the medical and general press, as well as in the House of Commons, as there was also an economic case against [End Page 161] bleaching.62 British farmers, too, were concerned about the use of bleachers. While millers had traditionally relied on a blend of American and British wheats to produce the type of flour sought by bakers and consumers, the new bleaching processes enabled them to use any type of wheat. This led, allegedly, to the rise in imports of "the lowest grades of foreign wheats," thus reducing the price of wheat to unprofitable levels for British farmers.63 The Ministry of Health, however, was reluctant to act. Apart from general caution and reluctance to legislate on food issues, the minister's refusal was probably due to a retreat after the 1927 preservatives regulation. As some scholars argue, this regulation led to "inactivity on other fronts," as the Department of Health believed that "industry deserved a break from new measures."64

Inadequate Legislation

But the main reason for inaction in Britain was that the existing legislation provided uncertain foundations for an outright ban. Theoretically, since the 1822 and 1836 Bread Acts, it was illegal "to put into flour any ingredient or mixture not the real and genuine produce of the corn or grain."65 Yet nineteenth-century legislation was no longer applied, and common law precedents had reinforced the view that the Bread Acts were unable to deal with new technological developments. Starting in the late 1900s, court cases explored the safety of bleaching processes. At a case tried in the High Court of Justice of England in March 1909, the judge, although presented with several indictments from British and American scientists, decided that there was insufficient evidence to prove that bleached bread was toxic or that its nutritive qualities were impaired.66 Other test cases in 1912 all deemed bleaching legal. At one of these, the sheriff in charge stressed that his "natural sympathies" were against bleaching, but he argued that the law compelled him to authorize the use of bleachers. In his view, bleaching agents could not be declared an offense under the 1875 Sale of Food and Drugs Act, whereby it was illegal "to mix, colour, stain or powder any article of food with any ingredient or material so as to render the article injurious to health," thus obliging the plaintiffs to "demonstrate unequivocally" the existence of [End Page 162] "deleterious results."67 Later cases on bleaching and other improving agents confirmed that if no harm to health could be proved, it was impossible to forbid the use of such processes and additives.68 These decisions illustrate how the regulatory system had indeed evolved from one where any additive to flour was illegal to one where an improver or added substance could not be considered as adulteration unless it was positively proven injurious. Sébastien Rioux argues that the late nineteenth-century food regulations, traditionally viewed as enhancing consumer protection, may have introduced "legal adulteration" and can be seen as "normalizing and expanding the domain of socially acceptable adulterations, while simultaneously narrowing down the very meaning of adulteration to injurious and deceitful practices." The bleaching issue thus strikingly illustrates the limitations of a regulatory system established in the late nineteenth century: although bleachers were widely condemned by scientists and deemed potentially harmful and definitely unnecessary, their ban was seriously hampered by the evolution of British food laws, which had both narrowed the definition of adulteration (practices positively proven as harmful) and widened the meaning of food to include various additives and processes.69

In Britain, the nineteenth-century regulations became even more flexible after the 1922 (Bread Acts) Amendment Act, which removed the ban on baking powder, used widely since the mid-1800s. The 1928 Food and Drugs (Adulteration) Act may have prohibited "the mixing, colouring, staining or powdering of any article of food with any material or ingredient so as to render the article injurious to health," but it did not address the issue of how to define "injurious." The existing legislative framework provided "no statutory authority under which the agents may be banned," thus sidelining the 1927 Monro Committee recommendations once again.70

An opportunity emerged in the late 1930s, with the 1938 Food and Drugs Act, which gathered and updated all preexisting legislation but also allowed new regulations governing the "standard" composition of items such as bread and flour. As early twentieth-century standards in British food legislation only covered milk and butter, the introduction of standards for bread and flour was highly significant since their absence had made it impossible to implement the 1927 Monro Committee recommendations.71 The new act thus theoretically enabled the Ministry of Health to prohibit "the addition of any substance, or the application of any treatment, to flour intended for sale," and the Ministry of Health was keen to set strict limitations on the [End Page 163] type of substances and processes allowed. Stringent regulations were deemed necessary since, by formally repealing the nineteenth-century Bread Acts, the 1938 Food and Drugs Act involved removing "an important safeguard to the consumer." Ministry officials were fully aware that "failure to deal with the improver question [would] be tantamount to recognition of the whole range of improvers," once again showing how successive food regulations did not necessarily imply tighter consumer protection.72 The original draft of the bread regulations, in March 1939, was thus a big step toward "tightening up the regulations": the Ministry of Health favored following the 1927 Monro Committee recommendations and issued a list of authorized substances, excluding chlorine and Agene. At last, it seemed that the campaign against bleachers had borne fruit.73

Lobbying and Delaying

Yet, as the archives show, the milling profession was deeply opposed to these provisions, claiming that there was "no case for modifying current practice in the milling industry." Millers argued that there was "no scientific evidence to support the exclusion of so many flour treatments" and that a restricted list of authorized treatments would exclude "the use of newly discovered substances."74 More importantly, they argued, such regulations would inevitably lead to a distortion of competition in favor of imported flour and "would unjustifiably disturb and injure the home-milling trade."75 The ministry had expected such a reaction, yet the strength of opposition from the milling industry led it to quickly drop the idea of prohibiting Agene. This retreat was for several reasons: while the millers had been very divided on the issue before World War I, the milling industry had undergone a huge concentration—the three largest firms now accounted for around 40 percent of Britain's flour output—and spoke with a much more united voice.76 There was also the sense that Agene was now too big to fail. Since 90 percent of the mills used bleaching, an outright ban would have been highly disruptive, incidentally showing how delays made further regulation much more [End Page 164] complicated once processes and products became widespread. Timing was probably the most important factor, since this discussion took place in May 1939, and with war looming, people felt that "in these days of emergency, it [was] highly dangerous to cause disorganization in the milling industry."77 There was a suggestion that including Agene on the permitted list might be temporary and reviewed after a period of five years. Even that provision was eventually dropped. Manufacturers of rival processes and substances also used the authorization of Agene to argue that their products should be authorized as well, and in any case, work on the draft was interrupted when war broke out.78

World War II saw unprecedented bread regulations regarding the extraction rate, with the notable introduction of the wholemeal "National Loaf" in 1942, but there were no provisions concerning bleachers and improvers, which remained legal despite calls by the Medical Research Council to formally prohibit them.79 If anything, the use of bleaching probably increased during the war, since a higher rate of extraction, imposed by wartime regulations, was believed to require a more intensive use of bleachers to produce a more palatable and enticing product.80 At the end of the war, the committee reporting on the bread and flour regulation situation acknowledged the limitations of the entire food legislation system. This system allowed local authorities to counteract the "grosser forms of adulteration" but provided very limited tools to offset the more sophisticated and complex cases, where injury to health or to the purse was harder to define.81 The controversy over Agene resurfaced in 1946, when British doctor Edward Mellanby, from the National Institute for Medical Research, published a paper showing that dogs fed with biscuits made from agenized flour suffered forms of epileptic fits.82 Mellanby's paper preceded a string of publications in Britain and the United States confirming that Agene led to convulsions in animals such as ferrets, rabbits, and cats (but not, interestingly, in rats, the only animals tested at the time of the Monro Committee).83 These publications led to a rapid ban on [End Page 165] Agene in the United States and its replacement with other bleaching agents, mostly chlorine dioxide.84

In light of these findings, the British medical profession strongly favored banning Agene even though its toxicity in humans had not yet been proven.85 However, other interests were involved, and while the Ministry of Health pushed for regulation, the Ministry of Agriculture, Fisheries and Food was adamant that a solution be achieved "with a minimum of disturbance of trade" at a time when Britain was still suffering from food shortages and rationing.86 This meant that more than ten years elapsed between the publication of Mellanby's findings and the decision to ban Agene.87 The milling industry stalled as much as possible, reluctant to invest in new replacement processes if there was any possibility that they might also be deemed harmful and banned, once again demonstrating how difficult it had become to ban a product once its use was so widespread.88 Ultimately, Agene was replaced with chlorine dioxide, which was used in 80 percent of the flour Britain produced in the 1960s, despite concerns that it impaired the nutritional value of treated flour.89 The use of chlorine dioxide to bleach flours prevailed until the 1990s, when the incorporation of European Economic Community food regulations into British law led to a ban on all bleaching agents.90


The history of flour bleaching in Britain shows that, beyond consumers' alleged aesthetic and taste preferences, new processes such as bleaching were embedded within widespread economic and ecological transformations of food systems and aimed to manufacture as quickly as possible a uniform product out of increasingly heterogenous raw materials. These latest additives and processes posed new threats to food safety, but they also made definitions and regulations of risk and purity more complicated. This complexity highlights the need to study precisely how such innovations were accommodated in national contexts. Studying flour bleaching exemplifies [End Page 166] that Britain's history of food legislation is not one of straightforward gradual improvement; new legislation actually widened what was defined as "food" and legitimized the use of new industrial products and processes to manufacture flour. This example highlights the piecemeal nature of a regulatory framework: it allowed considerable room for interpretation and placed the burden of proof on suing parties, who, in the absence of clear standards, had to demonstrate a definative relationship between a chemical additive and the alleged harm it caused. As many contemporary scientists argued, however, allowing all substances and processes as long as their harmful nature could not be proven was highly problematic, especially in such a widespread staple as wheaten flour. Report after report emphasized that the innocuous nature of a given additive necessarily depended on the limited knowledge available at the time, as it was very difficult to devise experiments ascertaining the long-term and interactional effects of minute doses of unknown substances. Instead of falling back on what "science" could prove, the reports suggested a precautionary approach to food purity. The two world wars undoubtedly delayed regulation, but the example of bleaching also shows the strength of industrial lobbying and how, once new substances and processes became widespread, regulating their use faced increasing and more organized resistance. This case study highlights that scientists had different ways of framing purity and safety and that widespread transformations in modern food systems required much more than the straightforward application of "science" to govern new industrial substances and processes.

Arnaud Page

Arnaud Page is an assistant professor of British history at Sorbonne University, Paris. His work is at the intersection of food history, environmental history, and the history of science, and he is currently preparing a monograph on the history of plant, animal, and human nutrition in the second half of the nineteenth century. The author wishes to thank Neil Davie, Maxime Guesnon, Chris Otter, the anonymous reviewers, and Hermione Giffard and Ruth Oldenziel at Technology and Culture.


Archival Material, Parliamentary Debates, and Trade Journals

British Medical Journal, 1900–1960
House of Commons, Hansard Parliamentary Debates, 1900–1960
The Lancet, 1900–1960
The Miller, 1900–1939
The National Archives, Kew, United Kingdom (TNA)

Published Sources

Accum, Fredrick. A Treatise on Adulteration of Food and Culinary Poisons. London: Longman, 1820.
Anonymous. "Attitude of Foreign Governments on Bleaching of Flour." Food and Drug Review 7, no. 1 (1923): 26–27.
Anonymous. "Cereal Flours and Related Products." Federal Register 13, no. 231 (1948): 6969–70.
Anonymous. "Farines améliorées." Revue des Fraudes 7, no. 65–66 (1931): 161–67.
Atkins, Peter J. Liquid Materialities: A History of Milk, Science and the Law. Farnham: Ashgate, 2010.
Atkins, Peter J. "The Retail Milk Trade in London, c. 1790–1914." Economic History Review 33, no. 4 (1980): 522–37.
Bobrown-Strain, Aaron. White Bread: A Social History of the Store-Bought Loaf. Boston: Beacon, 2012.
Boudia, Soraya, and Nathalie Jas. "Risk and 'Risk Society' in Historical Perspective." History and Technology 23, no. 4 (2007): 317–31.
Burnett, John. Plenty and Want: A Social History of Food in England from 1815 to the Present. London: Routledge, 1989.
Carpenter, Kenneth J. "A Short History of Nutritional Science: Part 3 (1912–1944)." Journal of Nutrition 133, no. 10 (2003): 3023–32.
Cobbold, Carolyn. A Rainbow Palate: How Chemical Dyes Changed the West's Relationship with Food. Chicago: University of Chicago Press, 2020.
Cohen, Benjamin R. Pure Adulteration: Cheating on Nature in the Age of Manufactured Food. Chicago: University of Chicago Press, 2019.
Collins, E. J. T. "Dietary Change and Cereal Consumption in Britain in the Nineteenth Century." Agricultural History Review 23, no. 2 (1975): 97–115.
Collins, E. J. T. "Food Adulteration and Food Safety in Britain in the 19th and Early 20th Centuries." Food Policy 18, no. 2 (1993): 95–109.
Dessaux, Pierre-Antoine. "Comment définir les produits alimentaires? L'élaboration des références pour l'application de la loi du 1er août 1905 entre expertise et consensus professionnel." Histoire, Économie et Société 25, no. 1 (2006): 83–108.
Fleurent, Emile, "Sur le blanchiment des farines." Bulletin de la Société Chimique de Paris 35 (1906): 381–96.
Folin, Otto. Preservatives and Other Chemicals in Food: Their Use and Abuse. Cambridge, MA: Harvard University Press, 1914.
Fouser, David. "A Biography of Modern British Bread." In Acquired Tastes: Stories about the Origins of Modern Food, edited by Benjamin R. Cohen, Michael S. Kideckel, and Anna Zeide, 35–50. Cambridge, MA: MIT Press, 2021.
French, Michael, and Jim Phillips. "Adulteration and Food Law." Twentieth Century British History 9, no. 3 (1998): 350–69.
French, Michael, and Jim Phillips. Cheated Not Poisoned: Food Regulation in the United Kingdom, 1875–1938. Manchester: Manchester University Press, 2000.
Fressoz, Jean-Baptiste. "Beck Back in the 19th Century: Towards a Genealogy of Risk Society." History and Technology 23, no. 4 (2007): 333–50.
Giedion, Siegfried. Mechanization Takes Command: A Contribution to Anonymous History. New York: Oxford University Press, 1948.
Hamill, J. M. "On the Bleaching of Flour and the Addition of So-Called 'Improvers' to Flour." In Reports to the Local Government Board on Public Health and Medical Subjects no. 49, Food Reports no. 12, 1–33. London: HMSO, 1911.
Hamill, J. M. "On the Nutritive Value of Bread Made from Different Varieties of Wheat Flour." In Reports to the Local Government Board on Public Health and Medical Subjects no. 55, Food Reports no. 14, 1–53. London: HMSO, 1911.
Hassall, Arthur Hill. Food and Its Adulterations. London: Longman, 1855.
Hopkins, F. G. "Feeding Experiments Illustrating the Importance of Accessory Food Factors in Normal Dietaries." Journal of Physiology (London) 44, no. 5–6 (1912): 425–60.
Humphries, A. E. "Modern Development of Flour Milling." Journal of the Society of Arts 55 (1906): 109–26.
Hutchinson, Robert. Food and the Principles of Dietetics. 3rd ed. London: Edward Arnold, 1911.
Inter-departmental Committee on Physical Deterioration. Report of the Inter-departmental Committee on Physical Deterioration. London: HMSO, 1904.
Jago, William. "The Bleaching and Conditioning of Flour." In Seventh International Congress of Applied Chemistry, 1909, Section VI A: Starch Industry, 39–44. London: Partridge and Cooper, 1910.
Jago, William, and William C. Jago. The Technology of Bread Making. London: Simpkin, 1911.
Jas, Nathalie. "Public Health and Pesticide Regulation in France before and after Silent Spring." History and Technology 23, no. 4 (2007): 369–88.
Javillier, M. "Doit on décolorer et maturer artificiellement les farines?" Annales des Falsifications et des Fraudes 18, no. 204 (1925): 580–95.
Jones, Glyn. The Millers: A Story of Technological Endeavour and Industrial Success, 1870–2001. Lancaster: Carnegie, 2001.
Kaplan, Steven. Le Pain Maudit, Retour Sur La France des Années Oubliées, 1945–1958. Paris: Fayard, 2008.
Kent-Jones, D. W. and A. J. Amos. Modern Cereal Chemistry. Liverpool: Northern Publishing, 1947.
Ladd, E. F., and R. E. Stallings. "Bleaching of Flour." Bulletin of the Government Agricultural Experiment Station of North Dakota 72 (1906): 219–36.
Le Roux, Thomas. "Governing the Toxics and the Pollutants: France, Great Britain, 1750–1850." Endeavour 40, no. 2 (2016): 70–81.
Maunder, Peter. The Bread Industry in the United Kingdom: A Study in Market Structure, Conduct and Performance Analysis. Nottingham: University of Nottingham, 1935.
McCance, R., and E. Widdowson. Breads White and Brown. London: Pitman, 1956.
Ministry of Food (U.K.). Report of the Conference on the Post-War Loaf. London: HMSO, 1945.
Ministry of Health (U.K.). Report of the Departmental Committee on the Treatment of Flour with Chemical Substances. London: HMSO, 1927.
Monier-Williams, G. W. "On the Chemical Changes Produced in Flour by Bleaching." In Reports to the Local Government Board on Public Health and Medical Subjects no. 49, Food Reports no. 12, 34–65. London: HMSO, 1911.
Moore, Benjamin, and John T. Wilson. "The Effects of Nitrogen Peroxide on the Constituents of Flour in Relation to the Commercial Practice of Bleaching Flour with That Reagent." Journal of Hygiene (London) 13, no. 4 (1914): 438–66.
Nelson, Michael. "Social-Class Trends in British Diet, 1860–1900." In Food, Diet, and Economic Change Past and Present, edited by Catherine Geissler and Derek J. Oddy, 101–20. Leicester: Leicester University Press.
Otter, Chris. "Artificial Britain: Risks, Systems and Synthetics since 1800." In Governing Risks in Modern Britain: Danger, Safety and Accidents c. 1800–2000, edited by Tom Crook and Mike Esbester, 79–103. London: Palgrave Macmillan, 2016.
Otter, Chris. "Industrializing Diet, Industrializing Ourselves: Technology, Energy, and Food, 1750–2000." In The Routledge History of Food, edited by Carol Helstosky, 220–46. New York: Routledge, 2015.
Perren, Richard. "Structural Change and Market Growth in the Food Industry: Flour Milling in Britain, Europe, America, 1850–1914." Economic History Review, 2nd ser., 43, no. 3 (1990): 420–37.
Petersen, Christian. Bread and the British Economy. Aldershot: Scolar, 1995.
Privy Council for Medical Research. Report of the Medical Research Council for the Years 1945–1948. London: HMSO, 1949.
Radomski, Jack L., Geoffrey Woodard, and Arnold J. Lehman. "The Toxicity of Flours Treated with Various 'Improving' Agents." Journal of Nutrition 36, no. 1 (1948): 15–25.
Rees, Jonathan. The Chemistry of Fear: Harvey Wiley's Fight for Pure Food. Baltimore: Johns Hopkins University Press, 2021.
Rioux, Sébastien. "Capitalist Food Production and the Rise of Legal Adulteration: Regulating Food Standards in Nineteenth Century Britain." Journal of Agrarian Change 19, no. 1 (2019): 1–18.
Roberts, Michael T. "A Perspective on Emerging Law, Consumer Trust and Social Responsibility in China's Food Sector: The 'Bleaching' Case Study." Food and Drug Law Journal 66, no. 3 (2011): 405–15.
Royal Commission on Supply of Food and Raw Material in Time of War, Report of the Royal Commission on the Supply of Food and Raw Material in Time of War. Vol. 3. London: HMSO, 1905.
Scholliers, Peter. "Defining Food Risks and Food Anxieties throughout History." Appetite 51, no. 1 (2008): 3–6.
Silver, Maurice L., Robert E. Johnson, Robert M. Kark, J. Raymond Klein, Elmer P. Monahan, and Solomon S. Zevin. "White Bread and Epilepsy in Animals." Journal of the American Medical Association 135, no. 12 (1947): 757–60.
Smith, David F., and Jim Phillips. "Food Policy and Regulation: A Multiplicity of Actors and Experts." In Food, Science, Policy and Regulation in the Twentieth Century: International and Comparative Perspectives, edited by David F. Smith and Jim Phillips, 1–16. New York: Routledge, 2000.
Stanziani, Alessandro. Histoire de la qualité alimentaire (XIXe–XXe siècles). Paris: Seuil, 2005.
Tann, Jennifer, and Glyn Jones. "Technology and Transformation: The Diffusion of the Roller Mill in the British Flour Milling Industry, 1870–1907." Technology and Culture 37, no. 1 (1996): 36–69.
Trentmann, Frank. Free Trade Nation: Commerce, Consumption, and Civil Society in Modern Britain. Oxford: Oxford University Press, 2008.
Weatherall, Mark. "Bread and Newspapers: The Making of a 'A Revolution in the Science of Food.'" In The Science and Culture of Nutrition, 1840–1940, edited by Harmke Kamminga and Andrew Cunningham, 179–211. Amsterdam: Rodopi, 1995.
Wiley, Harvey. The History of a Crime against the Food Law. 1929. Reprint, Washington, D.C.: Wiley, 1955.
Zachmann. Karin. "Risk in Historical Perspective: Concepts, Contexts, and Conjunctions." In Risk: A Multidisciplinary Introduction, edited by Claudia Klüppelberg, Daniel Straub, and Isabell M. Welpe, 3–35. Heidelberg: Springer, 2014.
Zachmann, Karin, and Per Østby. "Food, Technology, and Trust: An Introduction." History and Technology 27, no. 1 (2011): 1–10.
Zweiniger-Bargielowska, Ina. "'Not a Complete Food for Man': The Controversy about White versus Wholemeal Bread in Interwar Britain." In Setting Nutritional Standards: Theory, Policies, Practices, edited by Elizabeth Neswald and David F. Smith, 142–64. Woodbridge: Boydell, 2017.


1. Hepeng Jia, "China Bans Whitening Additives in Flour," Chemistry World, March 14, 2011; Roberts, "A Perspective on Emerging Law, Consumer Trust and Social Responsibility in China's Food Sector."

2. On flour bleachers in Britain: Jones, The Millers; McCance and Widdowson, Breads White and Brown. This article is the first in-depth analysis.

13. Jago and Jago, The Technology of Bread Making, 377; advertisement for the Alsop process, Miller, November 7, 1904, xxix; "A New Flour Bleacher," Miller, May 2, 1904, 130.

19. "The Flour Bleaching Question," Miller, August 1, 1904, 306.

20. Hamill, "On the Bleaching of Flour and the addition of So-Called 'Improvers' to Flour," 15; "Protection against Bleached Flour," Belfast Newsletter, April 12, 1906.

21. Miller, July 4, 1904, 241.

23. Frank Dove, "On the Coming of the Bleacher," Miller, June 6, 1904, 187.

24. "The Purity of Bread," Lancet, November 19, 1904.

26. "White Bread," Times, August 5, 1904, 2. For a critique of white bread: Interdepartmental Committee on Physical Deterioration, Report of the Committee on Physical Deterioration, 40, 107, 406.

27. "Bleached Flour: Another Food Danger," Western Gazette, July 13, 1906; "Scientific Adulteration," Chelmsford Chronicle, September 2, 1910.

29. "A Harmful Practice: Notts County Analyst and the Bleaching of Flour," Nottingham Evening Post, April 26, 1910; "Flour Bleaching," House of Commons Debate, July 14, 1910, Hansard, vol. 19, c. 747.

35. Weatherall, "Bread and Newspapers," 197; "Standard Bread," Lancet, February 4, 1911, 454.

36. "Standard Bread," 316.

37. "Bread and Health," The Times, April 7, 1911; "Bleached Flour," Darlington and Stockton Times, April 8, 1911.

41. Hamill, "On the Nutritive Value of Bread Made from Different Varieties of Wheat Flour," 48.

43. "Wanted, A Pure Bread Bill," Nation, October 19, 1912, 127–29.

44. Miller, April 5, 1909, 71; Miller, June 6, 1910, 193; "Dr Hamill's Report," Miller, May 1, 1911, 127.

45. "Council Meeting of the National Association of British and Irish Millers," April 21, 1911, reported in Miller, May 1, 1911, 133.

46. House of Commons Debate, March 11, 1912, Hansard, vol. 35, c. 903; written answers (Commons), July 23, 1912, Hansard, vol. 5, cc. 1004.

47. House of Commons, July 19, 1911, Hansard, vol. 28, cc. 1047.

48. On July 24, 1911, when Prime Minister Asquith stated his intention to push through the original Parliament bill restricting the powers of the House of Lords, the Opposition created so much disturbance that the session had to be adjourned.

49. House of Commons Debates, Hansard, April 10, 1911, vol. 24, c. 31; April 7, 1913, vol. 51, cc. 797–98; May 11, 1914, vol. 62, c. 704; July 20, 1916, vol. 84, c. 1175. Also French and Phillips, Cheated Not Poisoned, 137.

51. "Bakers' Stand for Pure Flour," Western Morning News and Mercury, May 3, 1922, 5; "White Bread," Times, August 15, 1924, 11; "Flour Adulteration," Bath Chronicle and Herald, September 25, 1926.

52. "Bleached Flour," Australasian, January 20, 1923, 10; "Bleached Flour," Brisbane Courier, January 18, 1926, 4.

54. Bobrown-Strain, White Bread, 66–67; United States of America v. Lexington Mill and Elevator Company, 232 U.S. 399 (1914). Also Folin, Preservatives and Other Chemicals in Food, 45.

57. "Académie de Médecine, séance du 3 mars 1931," Gazette des Hôpitaux Civils et Militaires, March 7, 1931, 366.

62. House of Commons Debate, April 30, 1931, Hansard, vol. 251 cc. 1800–1801; "Letters, Notes, and Answers," British Medical Journal, December 8, 1934.

63. "Gassed Flour," Exeter and Plymouth Gazette, July 2, 1928, 7; "Preservatives in Food," Western Times, July 6, 1928.

65. Section 11 of the Bread Act, 1822; Section 9 of the Bread Act, 1836.

66. Jago and Jago, Technology of Bread Making, 394–95. Also "The Action against Nottingham Millers," Nottingham Evening Post, March 26, 1909; Ladd and Stallings, "Bleaching of Flour."

67. Moore and Wilson, "Effects of Nitrogen Peroxide," 451–52; Section 3 of the 1875 Sale of Food and Drugs Act, 1875, 38 and 39 Vict., c. 63.; emphasis added.

72. Letter R. B. Cross to Sir John Maude on Bread and Flour Regulations, March 10, 1939, and A. E. Hickinbotham, "Minute on Bread and Flour Regulations," December 5, 1938, Ministry of Health, "Food and Drugs Act 1938: Bread and Flour Regulations," MH 56/303, TNA.

73. Note by A. E. Hickinbotham on Minute by R. B. Cross to Sir John Maude, March 17, 1939, MH 56/303, TNA.

74. Ministry of Health, "Deputation from the National Association of British and Irish Miller, May 16, 1939: Note of Meeting," MH 56/303, TNA.

75. National Association of British and Irish Millers, "Memorandum on the draft of bread and flour regulations proposed to be made by the minister of Health," May 12, 1939, MH 56/303, TNA.

77. Letter A. E. Hickinbotham to H. Chambers, May 24, 1939, MH 56/303, TNA.

78. "Food and Drugs Act 1938: bread and flour regulations," MH 56/304, TNA.

79. Medical Research Council Accessory Food Factors Committee, "Memorandum on Bread," 1940, quoted in "Improved Quality of Bread," British Medical Journal, August 3, 1940, 164. Also House of Commons, written answers, August 21, 1940, Hansard, vol. 364, c. 1319; December 15, 1942, vol. 385, c. 1806.

80. "Note of Conference held on April 1, 1948, at the Ministry of Health with the National Association of British and Irish Millers," in Ministry of Health, "Flour improvers: particularly Agene," MH 56/296, TNA.

82. Edward Mellanby, "Diet and Canine Hysteria: Experimental Production by Treated Flour," British Medical Journal, December 14, 1946, 885–87.

86. "Note of conference held on 1st April 1948, at the ministry of Health with the National Association of British and Irish Millers," MH 56/296, TNA.

87. "Flour improvers (Agene)," written answer, House of Commons, December 21, 1954, Hansard, vol. 535 c. 272.

88. Note by E. G. Harwood on "Flour Improvers," October 14, 1951, and confidential note by Norman C. Wright, February 7, 1952, MH 56/296, TNA.

89. S. G. Impey and T. Moore, "Nutritive Value of Bread Made from Flour Treated with Chlorine Dioxide," British Medical Journal, August 26, 1961, 553–56.

90. Food Standards Agency (U.K.), "The Bread and Flour Regulations 1998 (As Amended): Guidance Notes," 2008, 6,