BEVERAGES
COFFEE
Coffee is often colored with such substances as Scheele’s green, chrome
yellow, iron oxide, Prussian blue, indigo and turmeric. Imitation coffee
beans have been made of wheat flour, bran, rye, chicory and peas.
_Allen’s Preliminary Test._--A good preliminary test for ground coffee
is to sprinkle some of it on the surface of cold water. The oil of true
coffee prevents the particles from being readily soaked, and so they
float for some time. Chicory and most of the other adulterants of coffee
contain no oil, but do contain caramel, which is quickly extracted by
the water producing a zone of brown color about such particles. They
become soaked and quickly sink. The liquid containing pure coffee
diffuses uniformly without coloring the water to any perceptible degree.
Chicory and similar roots give a dark brown, turbid infusion. Roasted
cereals do not impart so distinct a color to water.
COLORING MATTER
Shake the coffee beans in cold water and make the regular qualitative
tests for the inorganic coloring matters--Scheele’s green may be
identified by testing for copper and arsenic; chrome yellow, by testing
for lead chromate; iron oxide may be detected by its characteristic
tests.
Organic coloring matter is best extracted with alcohol. Prussian blue
may be detected by dissolving it from the sediment with hot caustic
alkali, acidifying with hydrochloric acid, treating it with a drop of
ferric chlorid. If present, ferric ferrocyanide, a blue precipitate,
will be formed. Indigo is not discharged by sodium hydroxid, while
Prussian-blue is. It will form a deep blue solution with sulfuric acid.
Test for turmeric as under mustard.
IMITATION COFFEE BEANS
Most imitation coffee, as already stated, is heavier than water. Coffee
contains no starch, so the imitation beans made of cereals may be
detected by testing for starch.
STARCH
_Allen’s Method._--Boil the coffee in 10 parts of water. When perfectly
cold add to it a little sulfuric acid, then a strong solution of
potassium permanganate, drop by drop, with constant shaking, till the
liquid is almost decolorized; strain or decant and add to the solution a
solution of iodin. If 1 per cent or more of starch is present, a blue
coloration will be produced.
CHICORY
_Rimmington’s Test._--Boil a portion of the sample with water which
contains a little sodium carbonate; decant, wash and treat the residue
with a weak solution of bleaching powder for several hours. The solution
will be decolorized. The coffee will be at the bottom as a dark layer
while the chicory will be a light layer above it.
_Albert Smith’s Test._--Boil 10 grams of the sample in 250 cc. of water;
strain and add basic lead acetate in slight excess. A precipitate forms,
and when it has settled the supernatant liquid will be colorless if the
coffee is pure, but more or less colored if chicory is present.
TEA
Tea is adulterated by the substitution of inferior grades for those of
better quality, by the addition of exhausted leaves and foreign leaves,
by the use of coloring matter or “facing” such as Prussian blue, indigo,
or turmeric to color green tea, and sometimes graphite to color black
tea. Foreign astringents (generally catechu) are added to conceal the
presence of exhausted leaves. An imitation tea, “lie tea,” is made of
the stems and dust with mineral matter, and some starch or gum to hold
these together.
FOREIGN LEAVES
Though there are several chemical tests for foreign leaves, none are as
satisfactory as a microscopical examination. Soften the leaves by
soaking in hot water, unroll carefully and examine with a hand lens or
low power of the microscope. Compare with a genuine leaf--the shape,
margin, and venation.
EXHAUSTED TEA LEAVES
Sometimes such leaves may be detected by a physical examination. They
are often more or less unrolled and broken on the edges. But the only
certain way of ascertaining their presence is to determine the soluble
ash which is from 2.5 to 4 per cent in pure tea and usually less than
0.8 per cent in exhausted tea.
LIE TEA
This imitation tea is easily detected by pouring hot water over the
leaves. If they are artificial, they will break down into the fragments
of which they were made.
FACING
Organic coloring matter may be detected by the same method used for
detecting such colors in coffee.
CATECHU
_Hager’s Test._--Boil a little of the tea in water, and add to the
extract an excess of lead monoxid. If the tea is pure the addition of a
solution of silver nitrate produces only a slight grayish precipitate,
but when catechu is present a yellow flocculent precipitate forms.
A FEW OF THE BEST BOOKS ON FOOD ANALYSIS
ALLEN, A. H., Commercial Organic Analysis, 1898. Price, $29.50.
BLYTH, A. W., Foods, their Composition and Analysis, 1903. Price,
$8.40.
HASSALL, A. H., Food, its Adulterations and the Methods for their
Detection, 1874.
LEACH, A. E., Food, Inspection and Analysis, 1905. Price, $7.50.
LEFFMANN, H., and BEAM, W., Select Methods of Food Analysis, 1905.
Price, $2.50.
U. S. Dept. of Agr., Bureau of Chem., Bulletin 13, Parts 1-10, Food
and Food Adulterants, 1887-1902. (Some of these are out of print.)
Bulletin 46, Methods of Analysis of Foods, 1899; Bulletin 65,
Provisional Methods for the Analysis of Foods, 1902.
WILEY, H. W., Foods and their Adulteration, 1907. Price, $4.00.
CHEMICALS
The following are the chemicals used in making all the tests in this
book. Most of these are found in every chemical laboratory.[1]
Acetic acid
Ammonium carbonate
Ammonium chlorid
Ammonium hydroxid
Ammonium sulfid
Amyl alcohol
Aniline
Barium chlorid
Barium peroxide
Boric acid
Bromine
Calcium carbonate
Calcium chlorid
Calcium sulfate
Cane sugar
Carbon bisulfid
Castor oil
Chloroform
Diphenylamine
Ether
Ethyl alcohol
Ferric chlorid
Formalin
Fuchsin
Gelatin
Glycerol
Hydrochloric acid
Iodin
Lead acetate (basic)
Lead oxide
Lime water
Litmus paper
Logwood chips
Mercury (metallic)
Mercury sulfate
Methyl alcohol
Molybdic oxide
Nitric acid (sp. gr. 1.42)
Oxalic acid
Petroleum spirit
Phenolphthalein
Phenylhydrazine hydrochlorid
Phosphoric acid
Potassium bichromate
Potassium carbonate
Potassium chromate
Potassium ferrocyanid
Potassium hydroxid
Potassium iodate
Potassium iodid
Potassium nitrate
Potassium permanganate
Pyrogallic acid
Resorcin
Silver nitrate
Sodium acetate
Sodium acid sulfite
Sodium carbonate
Sodium chlorid
Sodium hydroxid
Sulfur
Sulfuric acid
Tannic acid
Turmeric paper
Zinc (arsenic free)
[1] The more uncommon ones may be obtained from Eimer and Amend, 205-211
Third Avenue, New York.
INDEX OF AUTHORS AND TESTS
PAGE
Allen, A. H., Heavy metals in fruits and fruit products, 37
in meat, 11
in vinegar, 58
Sulfuric Acid (distinguished from Sulfates) in
vinegar, 57
Tartar in vinegar, 59
Amthor, Caramel in fruit and fruit products, 36
Ashby, Free mineral acids in vinegar, 56
Beckmann, Starch in jellies, 38
Bell and Carter, Alum in flour, 16
Boettger, Ergot in rye flour, 18
Bornstein, Saccharin in canned vegetables, 27
Blyth, Alum in bread, 19
Courley and Coremon, Horseflesh in other meats, 14
Ebers, Diseased meat, 14
Frear, Sulfuric acid in vinegar, 57
Geisler, Coal-tar colors in butter, 6
Girard and Dupre, Acid magenta in catsups and tomatoes, 35
Cochineal in catsups and tomatoes, 29
Cochineal in canned vegetables, 29
Gutzeit, Arsenic in canned fruits, 39
Hehner, Formaldehyde in milk, 3
Henzold, Starch in jellies, 6
Hess and Doolittle, Process or renovated butter, test for, 49
Kämmerer, Sulfurous acid in meat, 9
Kleeburg, Wheat in rye flour, 18
Klinger and Bujard, Cochineal carmine in meat, 13
Kraemer, Corn meal in wheat flour, 17
Leach, Caramel in milk, 1
Malic acid in vinegar, 57
Salicylic acid in milk, 4
Salicylic acid in meat, 10
Lythgoe, Coal-tar colors in milk, 2
Marsh, Arsenic in canned fruits, 38
Martin, Coloring matter in butter, 5
Mohler, Benzoic acid in meat, 10
Benzoic acid in fruit and fruit products, 33
Peter, Benzoic acid in canned vegetables, 28
Richards, Mrs., Alum in baking powders, 22
Rimmington, chicory in coffee, 66
Schmidt, Saccharin in canned vegetables, 27
Smith, chicory in coffee, 66
Sostegni and Carpentieri, Coal-tar dyes in canned vegetables, 29
Stoke, Gelatin in milk, 2
Tocher, sesame oil in olive oil, 64
Vanderplanken, Alum in sour bread, 19
Vogel, Substituted flours, 17
Wynter Blyth, alum in flour, 16
Wolff, Tartaric acid (free or combined) in baking powders, 20
INDEX
PAGE
Acid magenta in fruit and fruit products, 35
Agar agar in fruit and fruit products, 37
Alkali in vanilla extract, 45
Allen, A. H., heavy metals in fruit and fruit products, 37
in meat, 11
in vinegar, 58
sulfuric acid in vinegar, 57
tartar in vinegar, 59
test of coffee, 65
Alum in baking powders, 22
in bread, 18
in flour, 16
in pickles, 31
Aluminium salts in cream of tartar, 23
Ammonia in cream of tartar, 23
Ammonium salts in baking powders, 21
Amthor, caramel in fruit and fruit products, 36
Annatto in butter, 5
in milk, 1
Aniline red in meat, 13
Apple juice in jellies made from small fruits, 36
Arsenic in fruit and fruit products, 38
Ashby, free mineral acids in vinegar, 56
Bach, test of olive oil, 62
Baking powders, 20
Adulterations of, 20
Alum, 22
Ammonium salts, 21
Gypsum, 21
Sulfates (calcium, etc.), 21
Tartaric acid (free), 21
Tartaric acid (free or combined), 20
Beckmann, gelatin in jellies, 38
Bell and Carter, alum in flour, 16
Beef stearin in lard, 61
Benzoic acid in meat, 10
in canned vegetables, 27
in fruit and fruit products, 34
Blyth, alum in bread, 19
Boettger, Ergot in rye flour, 18
Borax in fish and oysters, 13
in meats, 9
Boric acid in fish and oysters, 13
in meat, 9
in milk, 4
Bornstein, saccharin in canned vegetables, 27
Bread, 18
Adulterations of, 18
Alum, 18
Copper sulfate, 19
Butter, 5
Adulterations of, 5
Coloring matter, 5
Annatto, 5
Coal-tar colors, 5
Marigold, 6
Saffron, 6
Turmeric, 6
Cottonseed oil, 7
Oleomargarine, 7
Process or renovated butter, 6
Cane sugar in honey, 49
Canned and bottled vegetables, 24
Adulterations of, 24
Alum in pickles, 31
Coal-tar colors, 29
Cochineal, 29
Coloring matter, 29
Copper salts in green pickles, beans, peas, etc., 30
Turmeric in mixed pickles, 30
Examination of can or box, 31
Heavy metals other than copper (see under meats), 11
Preservatives, 25
Benzoic acid, 27
Formaldehyde, 25
Saccharin, 26
Salicylic acid, 26
Sulfurous acid, 26
Soaked vegetables, peas, beans, and corn, 30
Caramel in fruit and fruit products, 36
in milk, 1
in vanilla extract, 47
in vinegar, 58
Catechu in tea, 68
Cayenne pepper in black pepper, 54
in mustard, 53
Cereal products, 16
Chicory in coffee, 66
Citral in lemon extract, 42
Citric acid in lemon extract, 43
Coal-tar colors in butter, 5
in canned vegetables, 29
in fruit and fruit products, 35
in lemon extract, 45
in milk, 2
in vinegar, 58
Cochineal carmine in canned vegetables, 29
in fruit and fruit products, 35
in meat, 13
Coffee, 65
Adulterations of, 65
Chicory, 66
Coloring matter, 65
Imitation coffee beans, 66
Starch, 66
Coloring matters
Acid magenta in fruit and fruit products, 35
Annatto in butter, 5
in milk, 1
Aniline red in meat, 13
Caramel in fruit and fruit products, 36
in milk, 1
in vanilla extract, 47
in vinegar, 58
Copper salts in canned vegetables, 30
Coumarin in vanilla extract, 48
Copper sulfate in bread, 19
in flour, 17
Copper salts in canned vegetables, 30
Cottonseed oil in butter, 7
in lard, 60
in olive oil, 62
stearin in lard, 60
Courley and Coremon, horseflesh in other meats, 14
Cream of tartar, 22
Adulterations of, 22
Aluminium salts, 23
Ammonia, 23
Earthy materials, 23
Tartaric acid (free or combined), 22
Dairy products, 1
Ebers, diseased meat, 14
Eggs, test for freshness, 14
Elaiden test, 62
Exhausted tea leaves in tea, 67
Facing in tea, 68
Fats and Oils, 60
Lard, 60
Adulterations of, 60
Beef stearin, 61
Cottonseed oil, 60
stearin, 60
Olive oil, 61
Adulterations of, 61
Cottonseed oil, 62
Peanut oil, 63
Rape oil, 64
Sesame oil, 64
Fish, preservatives in, 13
Flavoring extracts, 42
Flour, 16
Adulterations of, 16
Alum, 16
Copper sulfate, 17
Substituted flours, 17
Corn meal in wheat flour, 17
Ergot in rye flour, 18
Wheat flour in rye flour, 18
Flour in mustard, 51
Formaldehyde in canned vegetables, 25
in milk, 3
Frear, sulfuric acid in vinegar, 57
Fruit and Fruit Products, 33
Adulterations of, 33
Agar agar, 38
Apple juice in jellies made from small fruits, 36
Arsenic, 38
Coloring matter, 35
Acid magenta, 35
Caramel, 36
Coal-tar dyes, 35
Cochineal, 35
Gelatin in jellies, 37
Heavy metals, 38
Preservatives, 33
Benzoic acid, 34
Saccharin, 34
Salicylic acid, 34
Starch in jellies, jams, and such products, 37
Gelatin in honey, 50
in jellies, 37
in milk, 2
Geisler, coal-tar colors in butter, 6
Ginger cake, stannous chlorid in, 19
Girard and Dupre, acid magenta in fruit and fruit products, 35
cochineal in catsups and tomatoes, 29
in canned vegetables, 29
Glucose in honey, 50
in maple syrup, 50
Gutzeit, arsenic in canned fruits, 39
Gypsum in baking powders, 21
Heavy metals in canned vegetables, 11
in fruit and fruit products, 38
in meat, 11
Hehner, formaldehyde in milk, 3
Henzold, gelatin in jellies, 37
Hess and Doolittle, test for process butter, 6
Honey, 49
Adulterations of, 49
Cane sugar, 49
Commercial glucose, 50
Gelatin, 50
Horseflesh in sausage and mince-meat, 14
Hydrochloric acid in vinegar, 57
test for formaldehyde, 3, 25
Imitation coffee beans, 66
Kämmerer, sulfurous acid in meat, 9
Kleeburg, wheat in rye flour, 18
Klinger and Bujard, cochineal-carmine in meat, 13
Kraemer, corn meal in wheat flour, 17
Lard, 60
Adulterations of, 60
Beef stearin, 61
Cottonseed oil, 60
stearin, 60
Leach, caramel in milk, 1
malic acid in vinegar, 57
salicylic acid in meat, 10
in milk, 4
Lemon extract, 42
Adulterations of, 42
Citral, 42
Coloring matter, 45
Coal-tar dyes, 45
Turmeric, 45
Lemon oil, 42
Methyl alcohol, 43
Oil of citronella, 43
Tartaric or citric acid, 43
Lemon oil in lemon extract, 42
Lie tea in tea, 67
Lythgoe, coal-tar colors in milk, 2
Malic acid in vinegar, 57
Maple syrup, 50
Adulterations of, 50
Glucose, 50
Marigold in butter, 6
Marsh, arsenic in fruit and fruit products, 38
Martin, coloring matter in butter, 5
Martius yellow in mustard, 52
Meats, 8
Adulterations of, 8
Canned, 11
Coloring matter (see under sausages, etc.), 13
Heavy metals, 11
Preservatives (same tests as under smoked and fresh meat), 11
Coloring matter, 13
Aniline red and cochineal-carmine in sausage chopped meat
preparations, and corned meat, 13
Diseased meat, 14
Fresh and smoked, 8
Preservatives, 8
Benzoic acid, 10
Boric acid, 9
Potassium nitrate, 8
Salicylic acid, 10
Sulfurous acid, 9
Fish, salt, dried and oysters, 13
Preservatives, 13
Borax (same as under fresh meat), 13
Boric acid (same as under fresh meat), 13
Horse-flesh in sausage and in mince-meat, 14
Starch in sausage, deviled meat and similar products, 13
Metallic impurities in vinegar, 58
Methyl alcohol in lemon extract, 43
Mineral acids in vinegar, 56
Milk, 1
Adulterations of, 1
Coloring matter, 1
Annatto, 1
Caramel, 1
Coal-tar dyes, 2
Gelatin, 2
Preservatives, 3
Boric acid, 4
Formaldehyde, 3
Salicylic acid, 4
Starch, 2
Mohler, benzoic acid in meat, 10
in fruit and fruit products, 34
Mustard, 51
Adulterations of, 51
Cayenne pepper, 53
Coloring matter, 51
Martius yellow or analogous coal-tar dyes, 52
Turmeric, 52
Flour, 51
Oil of citronella in lemon extract, 43
Oleomargarine in butter, 7
Olive oil, 61
Adulterations of, 61
Cottonseed oil, 62
Peanut oil, 63
Rape oil, 64
Sesame oil, 64
Olive stones in pepper, 53
Oysters, preservatives in, 13
Peanut oil in olive oil, 63
Pepper (common), 53
Adulterations of, 53
Cayenne pepper, 54
Ground olive stones, 53
Peter, benzoic acid in canned vegetables, 28
Pontet, general test of olive oil, 62
Potassium nitrate in meat, 8
Preservatives:
Benzoic acid in canned vegetables, 27
in fruit and fruit products, 34
in meat, 10
Boric acid in fish and oysters, 13
in meat, 9
in milk, 4
Formaldehyde in canned vegetables, 25
in milk, 3
Potassium nitrate in meat, 8
Saccharin in canned vegetables, 26
in fruit and fruit products, 34
Salicylic acid in canned vegetables, 26
in fruit and fruit products, 34
in meat, 10
in milk, 4
Sulfites in canned vegetables, 26
Sulfurous acid in canned vegetables, 26
Process or renovated butter, 6
Rape oil in olive oil, 64
Resins, foreign, in vanilla extract, 46
Richards, Mrs., alum in baking powders, 22
Rimmington, chicory in coffee, 66
Saccharin in canned vegetables, 26
in fruit and fruit products, 34
Saffron in butter, 6
Salicylic acid in canned vegetables, 26
in fruit and fruit products, 34
in meat, 10
in milk, 4
Schmidt, saccharin in canned vegetables, 27
Schmidt, Albert, chicory in coffee, 66
Soaked vegetables, 30
Sostegni and Carpentieri, coal-tar dyes in canned vegetables, 29
Spices in vinegar, 59
Stoke, gelatin in milk, 2
Substituted flours, 17
Corn meal in wheat, 17
General test for, 17
Wheat flour in rye, 18
Sulfates in baking powders, 21
Sulfuric acid in vinegar, 56
Sulfurous acid in meat, 9
Stannous chlorid in ginger cake, 19
Starch in fruit and fruit products, 37
in milk, 2
Tannin in vanilla extracts, 47
Tartar in vinegar, 59
Tartaric acid in baking powders, 20, 21
in cream of tartar, 22
in lemon extract, 43
in wine vinegar, 59
Tea, 67
Adulterations of, 67
Catechu, 68
Exhausted tea leaves, 67
Facing, 68
Foreign leaves, 67
Lie tea, 67
Tocher, sesame oil in olive oil, 64
Turmeric in butter, 6
in lemon extract, 45
in mixed pickles, 30
in mustard, 52
Vanilla extract, 45
Adulterations of, 45
Alkali, 46
Caramel, 47
Coumarin, 48
Foreign resins, 46
Tannin, 46
Vanderplanken, alum in sour bread, 19
Vinegar, 55
Adulterations of, 55
Coloring matter, 58
Caramel, 58
Coal-tar colors in wine vinegar, 58
Glucose, 59
Malic acid, 57
Metallic impurities, 58
Mineral acids (free), 56
Hydrochloric acid, 57
Sulfuric acid, 56
Spices, 59
Tartar in wine vinegar, 59
Tartaric acid (free) in wine vinegar, 59
Vogel, substituted flours, 17
Wynter Blyth, alum in flour, 16
Wolff, tartaric acid free or combined in baking powders, 20
Transcriber’s Notes
This text follows the source document in spelling and hyphenation,
including inconsistencies, except as mentioned below. Inconsistencies in
section heading have been retained as well.
The index entries are not always in alphabetical order; this has not been
changed.
Changes made to the text:
Some missing or wrong punctuation has been corrected silently.
Ratios have been changed to x : y where relevant.
Minor typographical errors corrected:
Page vii: Commerical to Commercial
Page 16: oelomargarine to oleamargarine
Page 49: invert suger to invert sugar
Page 62: ... (about 3 cc. of this ... to ... (about 3 cc.) of this ...
Page 71: seasame to sesame
Page 68: A FEW OF THE BEST BOOKS ON FOOD ANALYSIS has been considered a
separate chapter.
Page 69: the page header CHEMICALS has been used as the chapter heading.
The following words in the indexes have been changed to conform to those
in the text: Bechman to Beckmann; Kammerer to Kämmerer; Klingler to
Klinger; Winter-Blyth and Winter Blyth to Wynter Blyth.