On the composition of food and how it is adulterated : with practical directions for its analysis

Front matter

22101840148

THE

COMPOSITION OF FOOD

Introduction

Few questions have lately engrossed so large a share of the public attention, as that which relates to the adulteration of our aliments. The time has now arrived when, thanks to the progress of chemical and microscopical analysis, the attempts so frequently made to adulterate food, are no longer capable of concealment, and we hail with gratitude and satisfaction, the recent efforts of Parliament to put a stop to a practice, so injurious to the best interests of the country.

With the view of attaining an end so important to the health of the population at large, but more particularly to that of the labouring classes, it appears to me that the first step to be taken, is to investigate carefully and without any exaggeration, the different modes employed for adulterating our food, with their effects upon health ; and next to determine the causes which have led to these

VI INTEODUCTION.

fraudulent practices. For, as a skilful physician, having to treat a dangerous disease, must, before he attempts to cure it, look carefully into its nature and principle, and ascertain the circumstances to which it owes its origin, so should the Government, before deciding on the legislative measures necessary for putting an end to the adulteration of food, first make itself thoroughly acquainted with the nature, extent, and cause of this most injurious practice. Then, only, can it expect to find a practical and effectual remedy.

Adulterations of food may be classed under three different heads :

1. An inferior kind of food may be mixed with a superior quality of the same article.

2. One or more of the constituents of an article of food, may be artificially increased or diminished.

3. An entirely foreign substance may be added to the genuine article.

The first class of adulterations, consists in the conversion of a better into an inferior article of food, and the greatest ingenuity is displayed in order to give to this often fraudulent mixture, the appearance of the genuine article, and thus enable it to be sold for much more than its real value. The result of this practice, is to supply

INTRODUCTION. vii

the market with a less nutritious and less valuable article of diet ; still no poison has been added to it, nothing that is likely to produce disease ; and, as Nature has ordained that there must be different classes of people, and different qualities of food, if the less opulent classes can live and thrive upon inferior bread and inferior meat, the mixture of these, vv^ith food of a superior quality, although in many cases contrary to the principles of a sound morality, can hardly be considered as seriously detrimental to the general health of the population.

The second mode of adulteration, that of increasing or diminishing one or more of the constituents of an article of food, is, no doubt, in all cases, objectionable ; still we must sometimes submit to it, on account of the impossibility of its being removed. Thus it is difficult, not to say impossible, to procure certain wines entirely free from alcohol added previously to importation ; the only inconvenience of the practice, in this case, when confined within certain limits, is that of altering, and in general deteriorating the taste and flavour of the wine. But, unluckily, this mode of adulteration is carried on to a considerable, and, in some cases, frightful extent, with other and more important articles of food within our own immediate reach ; and, though not introducing into the food any element of an actually deleterious nature, gives rise to fraudulent practices well deserving the attention of the Legislature.

viii INTRODUCTION.

The third class of adulterations is more important in a sanitary point of view. It frequently happens that certain substances, sometimes highly poisonous, are added to our food, with the view of increasing its weight, or imparting to it a bright and pleasing colour or aspect ; and this fraud has become in some cases so extensive, that very dangerous symptoms and even death, may supervene from the improper use of the very means. Providence has placed at our disposal for maintaining the body in a healthy condition. It also frequently happens that foreign ingredients find their way into our food, on account of some imperfection in the method employed for their manufacture or preparation, or from want of sufficient attention on the part of the manufacturer. This source of adulteration, although highly reprehensible, as denoting carelessness or want of skill, can hardly be viewed under the light of a fraudulent, and, still less, of a criminal practice.

The Analytical Sanitary Commission of the ' Lancet' has shown the public how different our daily bread is, from what it ought to be ; and the book recently published on the subject by Dr. Hassall, chief analyst to the Commission, is full of extensive and useful information. The time and labour expended on his work must have been very considerable, and the country is greatly indebted to his efforts for having placed, in so prominent a view, before the eyes of Government and of the public, the present impure

INTRODUCTION. ix

condition of various articles of food. Still, I may perhaps be allowed to add, after having perused Dr. HassalPs book with attention, that some of his descriptions appear to ine rather exaggerated. It is of the utmost importance, that the author of a work such as his, should not only be perfectly impartial, but most carefully avoid overstating his case ; he must remember that in no country in the world, has trade acquired such an extension as in Great Britain, and that many honest tradespeople might be seriously injured by an overcharged statement. Besides, Dr. Hassall's book, valuable as it will prove as a reference, and in any step the Legislature may think fit to adopt on this important subject, is rather to be considered as a collection of voluminous reports, than as a guide for the medical practitioner. It is under this impression, convinced by personal experience of the want of a text-book, containing the simplest, and, at the same time, most efficacious methods for detecting the nature of the adulterations, to which our food is daily exposed, and encouraged, moreover, by a few medical friends, that I beg leave to offer this fittle work to the public. It claims no originality, beyond the introduction of some chemical methods not hitherto employed in the analysis of food ; but I have endeavoured, as much as possible, to adopt a careful, and, I trust, clear and satisfactory classification of the subject, and, above all, to observe the most scrupulous accuracy in every statement of facts.

X INTRODUCTION.

The woodcuts, with but very few exceptions, have all been carefully drawn from nature, with the camera lucida, and under my direct superintendence, by Mr. Lens Aldous, and engraved by Mr. Hart.

Laboratoky of Physiological and Pathological Chemistry, 8, Cliapel Place, Belgrave Square ;

Chapter I. On Farinaceous And Saccharine Food And Its Adulterations

PAGE

Flour and bread . . . . . .1

Manufacture of flour . . . . . . 2

Qualitative analysis of flour : Water, starch, gluten, albumen, grape

sugar, bran, fats . . . . . . 7

Quantitative analysis of flour . . . . .10

Composition of wheat flour . . . . . 13

Composition of bran . . . . .14

Microscopical structure of starch (illustrations) . . . 15

Mineral adulterations of wheat flour : Carbonate of magnesia, carbonate

of lime, bone dust, phosphate of lime, sulphate of lime, clay, and

Synoptical table showing how to analyse flour . . . 22

Diseases of cereal grasses : the ergot, bunt, smut, rust, mildew, vibrio

tritici, wheat midge . . . . .23

Adulterations of bread: Alum, hards and stuff, sulphate of copper, arsenic,

Cocoa; its composition and microscopical structure . .27

Adulterations with animal fats and oils, starch, sugar, mineral substances . . . . . .28

Arrow-root (Maranta, Curcuma, Tacca, Arum, Mauihot, Potato) . 33

Adulteration with Sago Starch and Potato Plour . ,34 xu

CONTENTS.

PAGE

Revalenta . . . . . . . 35

Semolina . . . . . .35

Cane Sugar and Grape Sugar. Java, Havannali, Brazil, Bengal,

Mauritius, Cuba, Madras Sugars . . .36

Mechanical and chemical impurities of sugar . . . 37

Adulterations . . . . .39

Colours employed in Confectionary : Red, Yellow, Blue, Green, Brown,

Chapter II. On Spices And Their Adulterations

Malabar, Penang, Sumatra, Tellicheri, Common White, and English

Bleached . . . . . . 46

Adulterations with ground rice, pepper husks, &c. . . 48

Cayenne Pepper . . . . . .49

Composition . . . . . . 50

Adulterations with red lead, salt, brick-dust, red ochre, cinnabar,

ground rice . . . . .52

Mustard (Black and White) . ..... 58

Adulterations . . . . . . 55

Jamaica, Uncoated Malabar, and other varieties . . . 56

Analysis of ginger, and adulterations . . .57

Structure and adulterations . . . .60

Yarieties and adulterations . . . .62

Varieties . . . . . .63

Structure and adulterations . . " . . . 64

Mace : Varieties and structure . . . .65

CONTENTS.

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PAGE

Structure aud adulterations . . . . . 67

Pimento, or Allspice . . . . .69

Structure and adulterations . . . . . 70

Mixed Spice . . . . . .71

Curry Powder ; composition . . . . 71

Adulterations . . . . . . 74

Chapter III

ON INFUSION OF VEGETABLE SUBSTANCES. — OTHER FLUID VEGETABLE FOOD AND THEIR ADULTERATIONS : TEA, COFFEE, SAUCES, OLIVE OIL.

Botanical description . . . . . 75

Mode of preparing black tea . . . .77

Chemical composition . . . . .79

Adulterations of black tea : Leaves of British plants, exhausted tea-leaves (illustrations of tea-leaves j, catechu, la veno beno, Chinese botanical powder, gum, starch, sulphate of iron, rose pink, logwood, graphite, talc and soap stone, indigo, turmeric powder . . . . . .80

Report of the Commission of the ' Lancet' on the Adulterations of

Black Tea . . . . . . 90

Adulterations of green tea : Prussian blue, mineral green, verdigris, arsenite of copper, Dutch pink, chromate of potash, bichromate of potash, chromate of lead, chalk, gypsum, carbonate of magnesia, Chinese tea dye. Spurious green tea of

British fabrication . . . . .91

Beport of the Commission on the Adulterations of Green Tea . 96 Colfee . . . . . . .97

Different kinds : Mocha, Madras, Ceylon (native), Mysore, Brazil (Rio), Brazil (Bahia), Costa Rica, Ceylon (Plantation Peaberry), Ceylon (Plantation) . . . .100

Chemical composition and analysis of coffee . . . 101

Adulterations ..... 103

Structure of root ..... 105

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CONTENTS.

PAGE

Adulterations of chicory : Carrot, parsnip, mangold wurtzel, beans, coffina, roasted corn, biscuit powder, burnt sugar, oak-bark tan, mahogany, horse's and bullock's liver, Hamburg powder, red earth, and Venetian red, or sesquioxide of iron . . , 106

Report of the Commission of the ' Lancet' on the adulterations of chicory 108 Abstract from Messrs. Graham, Stenhouse, and Campbell's Report

Sauces and their adulterations ..... 109

Olive oil and its adulterations . . . . . 110

Chapter IV. On Fermented Beverages And Their Adulterations

Alcoholic and acetous fermentation .... 113 Wine : its acidity, sugar, alcohol, and salts . . . . 114

Spirits : Brandy, Gin, Whiskey, Rum, Arrack or Rack, Liqueurs and

Compounds . , . . . . 117

Analysis of alcoholic fluids . . . . .119

Determination of sugar by volumetric measurement . . . 121

„ „ with the saccharometer . . . 122

„ „ by fermentation . . . . 125

Table showing the different densities corresponding to mixtures of

alcohol and water . . . . . . 128

Adulterations of wine : acids and lees, colouring matters, alcohol.

Artificial wines . . . . .129

Adulterations of beer with water, sugar, burnt sugar or treacle, salt,

and sulphate of iron . . . . . 133

Adulteration of spirits with water, Cayenne pepper, cinnamon, cassia,

compounds containing sulphuric acid, and lead . . 135

Report of the Commission of the * Lancet' on the Adulterations of Spirits 136 Vinegar and its manufacture . . . . . 136

Chemical analysis of vinegar ..... 138 Adulterations of vinegar with water, sulphuric acid, burnt sugar, copper,

CONTENTS.

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CHA.PTER V.

ON ANIMAL FOOD — MEAT, PISH, MILK — AND ITS ADULTERATIONS.

PAGE

Chemical composition of flesh . . . . 142

Cooking of meat . . . . . . 143

Putrid meat : its poisonous effects .... 144

Diseased meat, not poisonous . . . . . 145

Milk ; its constituents . . . . .146

Different kinds of cheese, analysis of . . . . 147

Determination of the specific gravity, cream, fatty matters, cheese, sugar

and saline matters in milk . . . . . 148

Adulterations of milk : Water, flour, milk of almonds, gum, gum tragacanth, chalk, turmeric, sugar, cerebral matter, carbonate of soda,

Report of the Commission of the * Lancet' . . . . 152

Chapter VI. On Mineral Or Inorganic Food And Its Adulterations : Salt And Water

Salt, or chloride of sodium . . . • . 154

Extraction of salt . . . . . . 155

Adulterations of salt . . . . .156

Characteristic properties of the best drink-water, and examination of

water in order to detect its impurities . . .158

Professor Earaday's experiments on the muddiness of the Thames . 159

Chemical examination of water . . . . . 159 Carbonic acid, sulphuretted hydrogen, oxygen, nitrogen, and ammonia in

Detection of substances suspended in water . . . . 161

Microscopical examination of the deposit . . .162

Methods employed to purify water . . . . 163

Sources from which water derives its solid constituents . . 164

Thames water . . . . . . 165

Organic matters in Thames water (illustrations) . . .167

Results from the analysis of different waters . . . . 169

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CONTENTS.