Today's quality control of the food and drinks industry is thanks to pioneering work started by chemist Frederick Accum and medic Arthur Hill Hassall in the 19th century

Today, food packages and drink cans or bottles must state their contents by law, but until 1875 there were few effective controls on the contents or quality of food and drink on sale to the public. That is, until chemist Frederick Accum and medic Arthur Hill Hassall confronted the problem.

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White bread - what's in it for you?

Some of the commonly used additives in the 19th century were poisonous. To whiten bread, for example, bakers sometimes added alum (K2SO4.Al2(SO4)3.24H2O) and chalk to the flour, while mashed potatoes, plaster of Paris (calcium sulphate), pipe clay and even sawdust could be added to increase the weight of their loaves. Rye flour or dried powdered beans could be used to replace wheat flour and the sour taste of stale flour could be disguised with ammonium carbonate. Brewers too, often added mixtures of bitter substances, some containing poisons like strychnine, to 'improve' the taste of the beer and save on the cost of hops (see Box 1). By the beginning of the 19th century the use of such substances in manufactured foods and drinks was so common that town dwellers had begun to develop a taste for adulterated foods and drinks; white bread and bitter beer were in great demand.

Enter Frederick Accum

Frederick Accum was the first to raise the alarm about food adulteration. Accum was a German chemist who had come to London in 1793 and who quickly established himself as a chemical analyst, consultant and teacher of chemistry (see Box 2). By 1820 Accum had become aware of the problem through his analytical work and this led him to publish A treatise on adulterations of food and culinary poisons - the first serious attempt to expose the nature, extent and dangers of food adulteration. The title page of the book bore a skull and a quotation from the Old Testament 'there is death in the pot' (II Kings chap.4, verse 40). The first edition sold out within a month; a US edition was published in the same year and a German translation was brought out in 1822. In his preface Accum remarked that the art of counterfeiting and adulteration had developed in England to such an extent that spurious articles of all kinds could be found everywhere, but he regarded the adulteration of food and drink as a criminal offence. 'The man who robs a fellow subject of a few shillings on the highway is sentenced to death', he wrote, but 'he who distributes a slow poison to the whole community escapes unpunished'.

By this time tea and coffee drinking had become popular in England but, being imported, both were expensive and as the fashion spread cheaper varieties were needed for sale to the masses. Many of these were not genuine tea and coffee but were made to look like the real thing by chemical treatment. Spent tea leaves and coffee grounds could be bought for a few pence per pound from London hotels and coffee shops. The used tea leaves were boiled with copperas (ferrous sulphate) and sheep's dung, then coloured with prussian blue (ferric ferrocyanide), verdigris (basic copper acetate), logwood, tannin or carbon black, before being resold. Some varieties of cheap teas contained or were made entirely from the dried leaves of other plants. Exhausted coffee grounds were treated in a similar way, adulterated with other roasted beans, sand/gravel, and mixed with chicory, the dried root of wild endive, a plant of the dandelion family. Chicory itself was sometimes adulterated with roasted carrots or turnips and the dark brown coffee colour was achieved by using 'black jack' (burnt sugar).

While the adulteration of tea and coffee was fraudulent, the products were not as dangerous as some of the substances added to beer and porter (stout). Accum described a substance called 'bittern' sold to brewers of bitter beer in large quantities. It contained copperas (ferrous sulphate), extracts of Cocculus indicus, quassia and liquorice juice. There was also a preparation of ground coriander seeds, with Nux vomica and quassia, again to impart bitterness to the brew. While the sale of such poisons was illegal under an Act of Parliament passed during the reign of George III, there were no reliable tests for these vegetable poisons before the 1820s and so the law was not rigorously applied and few offenders were caught.

By his analyses of many commodities Accum recognised the presence of lead and copper salts by the black precipitate they produced with hydrogen sulphide. Copper was further identified by the deep blue colour produced with ammonium hydroxide solution. The white precipitate of barium sulphate when barium chloride solution was added to liquids containing vitriol indicated the presence of sulphates. The starch in rice powder or wheat flour, often added to thicken cream, could be identified by the blue colour produced by a dilute solution of iodine in aqueous potassium iodide. Red wine adulterated with the juice of bilberries or elderberries produced a deep blue precipitate with lead acetate. Of all forms of adulteration the most reprehensible was the use of poisonous colouring matters in the manufacture of jellies and sweets. The bright colours used to attract children often contained lead, copper or mercury salts. Table 1 lists other adulterants identified by Accum. Incensed by the widespread use of all these practices, Accum published the names and addresses of traders convicted by the Courts of adulterating food and drink with poisonous additives. This made him some powerful enemies.

Accum often studied books in the library of the Royal Institution where some of the enemies he had made were also members. He was secretly watched as he worked and was accused of mutilating some of the books. His home was searched and pages torn from books were found, though whether he had torn them from his own books or from those belonging to the Royal Institution does not seem to have been established. The evidence was considered enough to charge him. He appeared before the magistrates and was released on bail pending his trial. With his reputation in ruins public opinion turned against him and, unwilling to face such public disgrace, he fled back to Germany in 1821. In Britain his analytical work on food adulteration was forgotten and during the next 30 years unsafe culinary practices continued to thrive.

Thomas Wakley and Arthur Hill Hassall

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Ten years later Thomas Wakley (1795-1862), surgeon, MP and editor of the medical weekly, The Lancet, started a new campaign against the adulteration of food and drugs. Wakley commissioned an article on poisonous confectionery in which the poisons contained in various items of coloured sweets, already condemned by Accum, were again identified. They included gamboge, a yellow gum that acts as a violent purge and irritant, and brightly coloured lead, copper and mercury compounds. The trade in highly coloured sweets had grown extensively in the decade since Accum first mentioned the problem. Even the sweet wrappers were often coloured with the same poisonous salts to make the sweets look more attractive. For Wakley this article was the first step in what would later become a long campaign to expose the dangers of adulteration and to secure legislation to protect the public.

In 1850 Sir Charles Wood, chancellor of the exchequer, speaking in parliament about the adulteration of coffee with chicory, said that he had been advised that neither chemical nor any other tests could show for certain whether coffee contained chicory or not. In quick response, Arthur Hill Hassall (1817-94), a London-based physician, knowing that this statement was untrue, set out to show just how false it was. He examined some samples of coffee purchased in London and wrote an article in which he showed that it was easy to identify chicory mixed with coffee using a good microscope. He followed his examination of coffee with one of common brown sugar in which he observed under the microscope large numbers of minute living insects - sugar mites.

Hassall's work on coffee was reported in several newspapers and this brought him to the notice of Thomas Wakley who dreamed up the impressive scheme of the Analytical Sanitary Commission. Hassall agreed to be the Commission's chief analyst and was the sole author of the analytical reports, though Henry Letheby, medical officer of Health for London, was also involved when adulterated drugs and medicines were analysed.

Between January 1851 and the end of 1854, Hassall bought some 2500 samples of food and drink for analysis, carefully recording the names and addresses of the vendors and the dates of purchase. He then did a detailed analysis of each sample and published the results in The Lancet as reports of the Analytical Sanitary Commission. These reports appeared weekly at first and later less frequently. For the first three months no indication of the provenance of adulterated samples was given, but vendors were warned that the names of tradesmen who sold adulterated samples would be published in future reports. Wakley undertook to bear any expenses that might be incurred as a result of legal action. From the beginning Hassall made sure that those who sold unadulterated foods were named with commendation.

Hassall analysed the samples first with a microscope, and then with chemical tests as necessary. Before Hassall's time the microscope had been ignored as an analytical tool, but it proved invaluable for identifying foreign vegetable matter, living or dead insects, minute traces of adulterants, and crystals of foreign organic matter for which no chemical tests were available.

The microscope allowed him to estimate the amounts of adulterants present by counting the particles of foreign bodies, even when there were only traces. In one sample of mustard, for example, he estimated that there was one part of turmeric powder in 547 parts of mustard. He used chemical analysis to identify alum in bread, and iron, lead and mercury compounds in cayenne pepper, copper salts in bottled fruits and pickles, or Venetian red (iron oxide Fe2O3) in sauces, potted meats and fish. He also used chemical methods in the analysis of coloured sweets and to test for alkaloids in beer. The latter were much more difficult to identify than the mineral salts and in Hassall's day the main qualitative tests were colour changes brought about by various reagents like sulphuric acid, potassium chromate, ferric, stannous or mercuric salts, usually in acid solutions. Wakley gave him complete freedom and published his reports without changes or additions. Hassall's name was rarely mentioned in these reports, but emboldened by the fact that no threat of litigation had been successful, he re-published his results separately in his own name in 1855 (see Table 2).

Hassall's work showed that adulteration was the rule rather than the exception and that adulterated articles were often sold as genuine. He was meticulous both in his scientific work and in accurately recording where and when the samples had been purchased. He presented a mass of evidence in support of his results and became widely recognised as an authority; he was even mentioned by Charles Kingsley in his children's book, The water babies, published in 1863. Kingsley wrote of those who 'invent poisons for little children and sell them at wakes, fairs and tuck shops. Dr Letheby and Dr Hassall cannot catch them...'.

Moves towards reform

With the publication of Hassall's book moves towards reform, which had been rumbling intermittently for years, began in earnest. A Parliamentary Committee of Inquiry was established to investigate the accuracy of Hassall's reports. Many witnesses were called and the information obtained by the inquiry confirmed Hassall's statements about the extent of adulteration and the practices employed. Thomas Blackwell of Crosse & Blackwell's gave evidence that the greening of preserved fruits and vegetables with copper salts and colouring of red sauces for potted meats with iron compounds were common. He admitted that his firm used these additives, not realising that they were so objectionable.

Hassall commented on the moral, social and financial effects of adulteration. He laid most blame on the big food manufacturers, since special manufacturing methods and machinery were usually needed. Yet, he realised that the retailer also played an important part. He said it would be impossible to be guilty of adulteration and yet be honest, though many of those who practised adulteration flattered themselves with the belief that they were. But the consumer was always the loser and this affected the lower classes most since cheaper foods were usually the most adulterated. (Note, however, that Hassall's work was done entirely in London and did not offer a national picture. That would come later.)

The first Food Adulteration Act was passed in 1860; though many of Hassall's recommendations regarding the treatment of convicted adulterators and the appointment of food inspectors were not taken on board. A popular household book, Enquire within upon everything, published in the 1860s, criticised Hassall's work and the Acts of Parliament for merely exposing adulteration and frightening everybody without producing a practical result. In contrast, this publication described simple ways of detecting adulterations in the home, suggesting for example that the housewife should grind her own pepper, flour, coffee and curry powder, use home-made bread and avoid items known to be adulterated in essentials like yellow custard and egg powders, coloured sweets and jellies. Good advice no doubt but almost impossible for every individual to follow.

In 1872 a revised Adulteration of Foods Act incorporated Hassall's proposals and also made provision for the appointment of public analysts. In 1874 the Society of Public Analysts was founded with Hassall as its first president and a select committee was set up to examine the working of the 1872 Act. Hassall again gave evidence and the report of this committee provided the basis for the Sale of Food and Drugs Act of 1875. Later amendments in 1879, the Margarine Act of 1887 and the Food Adulteration Act of 1899 at last produced considerable improvements.

Thus Hassall's investigations eventually resulted in the control of adulteration, the appointment of public analysts in all the counties and boroughs of Britain and the formation of the Society of Public Analysts to represent their interests and maintain their professional status. The use of poisonous additives in food and drink came to an end, though the complete elimination of all adulterants can never be achieved. Culinary colours, flavours and preservatives will always be needed in food manufacturing. The long-term safety of such additives may be difficult to ensure, but we can at least make certain that nothing commonly permitted for use in food manufacturing is known to be an active poison (see Box 3).

Box 1 - Improving the taste of beer

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In 1790, brewer Samuel Child published a book entitled Every man his own brewer: a practical treatise explaining the art and mystery of brewingin which he mentioned various plant extracts that he said were indispensable to the brewer. Child's book was one of several 'guides' available to home-brewers, all of which recommended several 'additives' for giving the beer a distinctive bitter taste, including:

  • Cocculus indicus - an extract of the South East Asian Fish berry - so-called because it was used to stun fish - which contains picrotoxin (C12H14O5), a poison related to curare;
  • Nux vomica - extracted from the seeds of an Indian tree (Strychno nux vomica), an important source of strychnine;
  • vitriol (sulphuric acid);
  • 'grains of paradise' - the pungent seeds of an African tree used as a spice similar to ginger;
  • quassia - a mixture of alkaloids extracted from wormwood, a family of flowering plants found in the tropical forests of the US and Africa. It has a bitter taste and in the 19th century was used as a pesticide; and
  • opium.

Box 2 - Frederick Accum (1769-1838)

For a time Accum was a laboratory assistant to Humphry Davy at the Royal Institution and later he lectured on chemistry at the Surrey Institution in Blackfriars Road, London. He became chemist to the Gas, Light and Coke Company and among his many books on chemical subjects he wrote an excellent account of the coal-gas industry. Besides all this Accum established a small firm selling laboratory chemicals and apparatus. As his trade expanded he took in Alexander Garden, one of his own students, as a business partner and the firm of Accum and Garden became well known. They shipped apparatus and chemicals to the US to equip the first chemical laboratories in the universities of Yale and Harvard after Benjamin Silliman, the first professor of chemistry at Yale, and William Peck, professor of chemistry at Harvard, attended Accum's chemical lectures in London. As the first chemist to make his living by teaching the subject and practising as a chemical analyst and consultant, he was well known and highly regarded.

Box 3 - Today's public analysts

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The Food and Safety Act 1990, the primary legislation in force today still requires local authorities to appoint one or more public analyst. As well as being members of the Royal Society of Chemistry, which administers the statutory qualification, allowing chemists to be appointed as public analysts, most public analysts are members of the Association of Public Analysts, which celebrated its 50th anniversary last year. The Association of Public Analysts of Scotland was 100 years old in 2002, and a short history is available at

 Far more additives are present in foods than ever before, but their use is monitored and controlled. It would be comforting to think that such gross adulterations as occurred in the 19th century are no more, but there have been reports of unscrupulous traders selling, for instance, 'vodka' made from diluted industrial methylated spirits and imported chilli powder, which contained a carcinogenic red dye called Sudan I, which is normally used in shoe polish.

Table 1 Some other adulterants identified by Accum (1820)
Food Adulterant
Red cheese Coloured with red lead (Pb3O4), and vermilion (mercury sulphide, HgS)
Cayenne pepper Coloured with red lead
Pickles Coloured green by copper salts
Vinegar 'Sharpened' with sulphuric acid; often contained tin and lead dissolved when boiled in pewter vessels
Confectionery White comfits often included Cornish clay
Red sweets were coloured with vermilion and red lead
Green sweets often contained copper salts (eg verdigris: basic copper acetate) and Scheele's or emerald green (copper arsenite)
Olive oil Often contained lead from the presses
Table 2 Other adulterants found by Hassall (1851-54)
Product Adulterants for bulk and weight Adulterants for colour, taste and smell
Custard powders Wheat, potato and rice flour Lead chromate, turmeric to enhance the yellow colour
Coffee Chicory, roasted wheat, rye and potato flour, roasted beans, acorns etc Burnt sugar (black jack) as a darkener
Tea Used tea leaves, dried leaves of other plants, starch, sand china clay, French chalk Plumbago, gum, indigo, Prussian blue for black tea, turmeric, chinese yellow, copper salts for green tea
Cocoa and chocolate Arrowroot, wheat, Indian corn, sago, potato, tapioca flour, chicory Venetian red, red ochre, iron compounds
Cayenne pepper Ground rice, mustard seed husks, sawdust, salt Red lead, vermilion, Venetian red, turmeric
Pickles   Copper salts for greening
Gin Water Cayenne, cassia, cinnamon, sugar, alum, salt of tartar (potassium tartrate)
Porter & stout Water Brown sugar, Cocculus indicus, copperas, salt, capsicum, ginger, wormwood, coriander and caraway seeds, liquorice, honey, Nux vomica, cream of tartar, hartshorn shavings, treacle

Dr Noel G. Coley, formerly reader in history of science at the Open University, can be contacted at 24 Kayemore Road, Sutton, Surrey SM2 5HT.

Further Reading

  • F. Accum, A treatise on adulterations of food and culinary poisons. London: Longman, 1820. 
  • C. A. Browne, The life and chemical services of Friedrich AccumJ. Chem. Educ., 1925, 2, 829, 1008, 1140. 
  • R. J. Cole, Friedrich Accum: a biographical studyAnnals Sci., 1951, 7, 128. 
  • A. H. Hassall, Food and its adulterations; comprising the reports of the analytical sanitary commission of 'The Lancet' for the years 1851 to 1854. London: Longman, 1855. 
  • W. Marcet, On the composition of food and how it is adulterated, with practical directions for its analysis. London: J. Churchill, 1856. 
  • A. H. Hassall, The narrative of a busy life. London: Longman, 1893. 
  • S. D. Smith, Coffee, microscopy, and The Lancet's analytical sanitary commissionSoc. Hist. Med., 2001, 14(2), 171. 
  • E. G. Clayton, Arthur Hill Hassall, physician and sanitary reformer, a short history of his work in public hygiene and of the movement against the adulteration of food and drugs. London: Ballière, Tindall and Cox, 1908. 
  • E. G. Clayton, A compendium of food microscopy with sections on drugs, water and tobacco, compiled with additions and revision, from the late Dr A. H. Hassall's work on food. London: Ballière, Tindall and Cox, 1909. 
  • J. Burnett, Plenty and want, a social history of diet in England from 1815 to the present day. London: Thomas Nelson, 1966.