UNIVERSITY OF CALIFORNIA.
| c ; IA.
INVESTIGATIONS MADE 15V AUTHORITY OF
THE COMMISSIONER OF AGRICULTURE,
UNDER DIRECTION OF
LARD AND LARD ADULTERATIONS.
H. W. WILEY.
GOVERNMENT PRINTING OFFICE.
J. M. RUSK,
U. S. DEPARTMENT OF AGRICULTURE.
DIVISION OF CHEMISTRY.
BULLETIN No. 13.
INVESTIGATIONS MADE BY AUTHORITY OF
THE COMMISSIONER OF AGRICULTURE,
UNDER DIRECTION OF
LARD AND LARD ADULTERATIONS.
II. W. WILEY.
GOVERNMENT PRINTING OFFICE.
17319 pt. 4 1
[BULLETIN No. 13]
PART 4.-LARD AND LARD ADULTERATIONS
U. S. DEPARTMENT OF AGRICULTURE,
DIVISION OF CHEMISTRY,
Washington, D. (?., February 7, 1889.
SIR: With many interruptions, clue to the experiments ia tke manu-
facture of sugar, carried on under the supervision of this division, I have
completed our studies on lard and lard adulterations, and now have the
honor to lay before you the results obtained for your inspection and
I have endeavored to shaw the character of true lard, how it is made,
and how it may be distinguished from its imitations. In the same man.
ner the substances used in adulterating lard viz, stearines and cotton
oil have been studied and their properties described. Also the charac-
teristics of the mixed lards have been pointed out, and the best methods
of analytical research illustrated.
Abstracts of similar studies by others have been given, and it is be-
lieved that the present state of our knowledge of lard and its com-
pounds is fully set forth.
Some delay in submitting the manuscript to the Public Printer has
been experienced on account of failure to arrange for printing the illus-
trations. To facilitate this matter, it has been decided to omit nearly all
illustrations of methods of making and refining lard and cotton oil, and
print only a few photo-micrographs showing the crystalline appearance
of pure lard and stearines and mixtures thereof.
H. W. WILEY,
Hon. NORMAN J. COLMAN,
Commissioner of Agriculture.
LARD AND LARD ADULTERATIONS.
(a) Lard is a term applied to the fat of the slaughtered hog, sepa-
rated from the other tissues of the animal by the aid of heat.
In the crude state it is composed chiefly of the glycerides of the fatty
acids, oleic and. stearic or palmitic, with small portions of the connect-
ive tissues, animal gelatine, and other organic matters.
(b) Kinds of lard. According to the parts of the fat used and the
methods of rendering it lard is divided into several classes. According
to methods of rendering lard is classified as kettle and steam. From
material used the following classification may be made:
(c) Neutral lard. Neutral lard is composed of the fats derived from
the leaf of the slaughtered animal, taken in a perfectly fresh state. The
leaf is either chilled in a cold atmosphere or treated with cold water to
remove the animal heat. It is then reduced to a pulp in a grinder and
passed at once to the rendering kettle. The fat is rendered at a tem-
perature 105 to 1200 F. (400-50 O.). Only a part of the lard is sep-
arated at this temperature and the rest is sent toother rendering tanks
to be made into another kind of product. The lard obtained as above
is washed in a melted state with water containing a trace of sodium
carbonate, sodium chloride, or a dilute acid. The lard thus formed is
almost neutral, containing not to exceed .25 per cent, free acid; but it
may contain a considerable quantity of water and some salt. This neu-
tral lard is used almost exclusively for making butterine (oleomarga-
(d) Leaf lard. The residue unrendered in the above process is sub-
jected to steam heat under pressure and the fat thus obtained is called
leaf lard. Formerly this was the only kind of lard recognized in the
Chicago Board of Trade, and was then made of the whole leaf.
(e) Choice kettle-rendered lard; Choice lard. The quantity of lard
required for butterine does not include all of the leaf produced. The
remaining portions of the leaf, together with the fat cut from the backs,
are rendered in steam-jacketed open kettles and produce a choice va-
riety of lard known as " kettle-rendered." The hide is removed from
406 FOODS AND FOOD ADULTERANTS.
the back fat before rendering and both leaf and back fat are passed
through a pulping machine before they enter the kettle. Choice lard
is thus defined by the regulations of the Chicago Board of Trade :
Choice lard. Choice lard to bo made from leaf and trimmings ouly, either steam
or kettle rondered r tho manner of rendering to be branded on each tierce.
(/) Prime steam lard. The prime steam lard of commerce is made
as follows: The whole head of the hog, after the removal of the jowl,
is used for rendering. The heads are placed in the bottom of the ren-
dering tank. The fat is pulled off of the small intestines and also
placed in the tank. Any fat that may be attached to the heart of the
animal is also used. In houses where kettle- rendered lard is not made
the back fat and trimmings are also used. When there is no demand
for leaf lard the leaf is also put into the rendering tank with the other
portions of the body mentioned. It is thus seen that prime steam lard
may be taken to represent the fat of the whole animal, or only portions
thereof. The quantity of fat afforded by each animal varies with the
market to which the meat is to be sent. A hog trimmed for the do-
mestic market will give an average of about 40 pounds, while from
one destined for the English market only about 20 pounds of lard will
be made. Prime steam lard is thus defined by the Chicago Board of
Prime steam lard. Standard prime steam lard shall be solely the product of the
trimmings and other fat parts of hogs, rendered in tanks by the direct application of
steam, and without subsequent change in grain or character by the use of agitators
or other machinery, except as such change may unavoidably come from transporta-
tion. It shall have proper color, flavor, and soundness for keeping, and no material
which has been salted shall be included. The name and location of the Tenderer and
the grade of the lard shall be plainly branded on each package at the time of pack-
This lard is passed solely on inspection ;'the inspector having no au-
thority to supervise rendering establishments in order to secure a proper
control of the kettles. According to the printed regulations, any part
of the hog containing fat can be legally used.
Since much uncertainty exists in regard to the disposition which is
made of the guts of the hog I have had the subject carefully investi-
gated. Following are the results of the study :
(g) Guts. The definition of the term as used by hog packers is: Ev-
erything inside of a kog except the lungs and hearts, or, in other words,
the abdominal viscera complete. The material is handled as follows :
When the hog is split open the viscera are separated by cutting out
the portion of flesh surrounding the anus and taking a strip containing
the external urino-generative organs. The whole viscera are thrown
u a table and divided as fallows : The heart is thrown to one side and
the fatty portion trimmed off for lard. The rest goes into the offal tank
or sausage. Tho lungs and liver go into the offal tank (or sausage).
LARD AND LARD ADULTERATIONS. 407
The rectum and large intestines are pulled from the intestinal fat and
peritoneum and, along with the adhering flesh and geuito-uriuary organs,
sent to the trimmer. All flesh and the above-mentioned organs are
trimmed off and the intestine proper is used for sausage casings. The
trimmings, including the genito urinary organs, are washed and dumped
into the rendering tank. The small intestine is also pulled from the fatty
membrane surrounding it and saved for sausage casings. The remain-
ing material, consisting of the peritoneum, diaphragm, stomach, and
adhering membranes, together with the intestinal fat, constitute the
"guts" which are seen undergoing the process of washing, which is
usually conducted in three or four different tanks. As the "guts" pass
into the first tank the stomach and peritoneum are split open and also
any portion of the intestines which sometimes adhere to the peritoneum.
After receiving a rough wash they are passed from tank to tank, when,
after the third or fourth wash, they are ready for the rendering tank.
The oraenturn fat is cut from the kidneys and the kidneys with a little
adhering fat go into the rendering tank. Spleen and pancreas go into
the rendering tanks, as do also the trachea, vocal chords, and ossopha-
To sum up, it is safe to say that everything goes into the rendering
tank, with the following exceptions:
(1) The intestines proper, which are saved for sausage-casings.
(2) The liver and lungs.
(3) That part of the heart free from fat.
I have been^told that in killing small hogs, and also when there is
small demand for sausage-casings, it is frequently the practice to split
the intestines, so as to save expense of pulling from the fat, and after
washing, fat and all go into the tank. Of course it will often happen
that the intestines break off and portions adhere to the enveloping tis-
sue, and consequently get into the tank after washing.
It is a commercial fact that sausage- casings are worth more than the
small amount of adhering fat, and consequently packers will save them.
Small hogs produce small casings difficult to pull, and it is reasonable
to believe that they will be handled in the simpler manner. They break
so easily that they are hardly worth saving separately. It is stated by
lard manufacturers that the grease made from the parts of the intes-
tines mentioned above is used for the manufacture of lard oil and soap,
and does not enter into the lard of commerce.
(h) Butchers' lard. The small quantities of lard made by butchers are
usually "kettle-rendered," after the manner practiced by small farmers
in making lard for home consumption. Often the scraps are saved up
for a considerable length of time by the butchers before rendering, and
that is likely to increase the free acid present. This lard is also fre-
quently dark colored, and contains a considerable quantity of glue. In
New York this lard is known as " New York Citv Lard."
FOODS AND FOOD ADULTERANTS.
In this figure is represented the type of apparatus used for rendering
lard, etc., under pressure. The rendering vessel is made of boiler iron
or steel, and varies in size according to the magnitude of the establish-
ment. A very common size is 10 to 12 feet in length and 3 to 5 feet in
diameter. The heads, scraps, and other materials are put in at M.
When the tank is full M is closed. Steam is admitted through the pipe
thus marked, and condensed water drawn oil* through the water-pipe.
Through the cocks at D the depth of lard in the taiik can be determined
LARU AND LARD ADULTERATIONS. 409
and the lard drawn off. When the process is finished and the lard
drawn off the bottom G is opened and the ''tankage" withdrawn and
dried for fertilizing purposes.
(B) OTHEU HOG-FAT PRODUCTS.
There are many other hog-fat products not used in the manufacture
of lard or compound lard, a description of which, however, may prove
(a) White grease. Tins grease is made chiefly from hogs which die in
transit, by being smothered or frozen. Formerly it was also made from
animals dead of disease; but this prod net has of late been diminished
on account of certain State laws requiring the carcasses of hogs which
have died of cholera to be buried. This grease is made from the whole
animal with the exception of the intestines. The latter are rendered
separately and make " brown grease". The rendering is done in closed
tanks at a high pressure. The residue is used in the manufacture of
fertilizer. White and brown grease are used chiefly in the manufacture
of low-grade lard oils and soap.
(1} Yellow grease. Yellow grease is made by packers. All the refuse
materials of the packing-houses go into the yellow-grease tank, together
with any hogs which may die on the packers' hands. Yellow grease is
intermediate in value between white and brown. It is used for the
(c) Pigs' -foot grease. This grease is obtained chiefly from" the glue
factories, and is used for making lard oils and soap.
The stearines are the more solid portions of the animal fats remain-
ing after the more fluid portions have been removed by pressure. The
steariues used in the manufacture of compound lard are lard stearine,
derived from lard, and olco s'.earine, derived from a certain quality of
beef tallow. Cotton-oil stearine is used chiefly in the manufacture of
A. LAUD STEARINE.
The lard stearine used in compound lard is made as follows:
The prime steam lard, if properly crystallized and of the right tem-
perature (from 45 to 55 F., winter; 55 to C5, summer), is sent at
once to the presses. If not properly grained, it is melted and kept in
a crystallizing room at 50 to CO F., until the proper grain is formed.
The lard is then wrapped in cakes with cloth, each cake containing 10
to 20 pounds. The cakes are then placed in a large press, with suitable
septa to facilitate the egress of the oil. These presses are sometimes 40
to 50 feet in length, and when first filled 12 to 18 feet high. The press-
ure is applied very gradually at first by means of a lever working a cap-
stan, about which the chain is wrapped, attached to the upper movable
part of the press.
410 FOODS AND FOOD ADULTERANTS.
The oil expressed, prime or extra lard oil, is used for illuminating and
lubricating purposes. The resulting stearine is used for making com-
pouud lard and is worth more than the lard. It has about .5 per cent.
free fatty acid (less than the lard oil), and crystallizes in long needles,
making the texture tough.
This product is made chiefly from the caul fat of beeves. This fat is
rendered in open kettles a*t a low temperature. The resulting tallow
is placed in cars in a granulating room, where it is allowed to remain
foi thirty six to forty-eight hours at a temperature 80 to 90 Fab.
The contents of the cars are then mixed and placed on a revolving ta-
ble, where they are made into cakes. These are wrapped with strong
cotton cloth and placed in a strong press, where a gradual pressure
at 90 F., becoming very strong at the end, is applied for one or two
hours. The expressed oil, known as oleo-oil, is used in the manu-
facture of btitterine. The stearine is removed from the press as white
hard cakes, and is used for adulterating lard. The oil is sometimes
filtered with a small percentage of fuller's earth, to improve its color
C. MUTTOX TALLOW.
A fine article of mutton tallow is also sometimes used in lard, but the
objection to the flavor is sufficient to limit its use to a small amount.
* D. BEEF FAT.
The following general remarks on beef fat will be found instructive:
Before the day of the oleomargarine industry all fat rendered from the
tissues of cattle was known commercially as tallow. Since then differ-
entiation has taken place and the term tallow is no longer sufficient to
designate the several products obtained from the rendered fat of the
beef. We have first " butter stock," which is rendered from the caul fat
at a low temperature and from which is manufactured by means of
(2) Oleo-steariue (beef stearine).
The kidney fat as a rule is lejft with the carcass and constitutes what
is known as suet. Marrow stock, as its name implies, is rendered mar-
row fat, and when properly prepared is almost equal to butter stock in
quality. Tallow is made from the trimmings and portions of the viscera.
Its color varies from white to yellow according to the portions of the
a.nimal which have been used and the care with which they have been
prepared for rendering and the temperature at which rendered. When
freshly and carefully rendered tallow should show less than 1.5 percent,
of free fatty acid. The tallow on the market will show anywhere from
2 to 10 per cent. Its flavor varies, never being good enough for lard.
Tallow grease corresponds to the yellow grease of the hog-packer. It
is of a dark color and often contains as much as 50 per cent, of free acid.
It is made into low-grade soaps.
LARD AND LARD ADULTERATIONS. 411
(3) COTTON OIL.
(a) The cotton seed from various sources is put through a screen to
take out the bolls and coarse material. The seed is then put through
a gin to remove as far as possible any remaining lint, of which about 20
pounds per ton of seed are obtained.
The clean seed is next sent to a huller composed of revolving cylin-
ders covered with knives, which cut up both seed and hull. The chips
are then conveyed to a screen placed on a vibrating frame, through
which the kernels fall. The hulls are carried by an endless belt to the
furnaces, where they are burned. The kernels of the seed are conveyed
to crusher rolls, where they are ground to a fine meal. The meal is then
sent to a heater, where it remains from twenty to forty minutes. These
heaters have a temperature of 210 to 215 F. The hot meal is formed
into cakes by machinery ; these are wrapped in cloth and placed in the
press. About 16 pounds of meal are put in each cake. The cakes are
placed in a hydraulic press, where a pressure of from 3,000 to 4,000
pounds per square inch is applied. The press is also kept warm. The
expressed cakes contain only about 10 per cent, of oil. The cake is
sold as cattle food or for fertilizing purposes. The crude oil as thus
expressed contains about 1.5 per cent, of free acid. The chief cotton-
seed presses of the country are located at the following points:
Cotton-seed oil milling points.
Arkansas: Illinois: North Carolina :
Little Rock. Cairo. Charlotte.
Argenta. Louisiana : Raleigh.
Fort Smith. New Orleans. Tennessee :
Texarkana. Shreveport. Memphis.
Brinkley. Baton Rouge. Jackson.
Helena. Monroe. Nashville.
Alabama: Missouri: Dyersburgh.
Selina. Saint Louis. Texas :
Mobile. Mississippi : Brenham.
Montgomery. Clarksdale. Dallas.
Eufaula. Columbus. Galveston.
Huntsville. Canton. Houston.
Georgia : Grenada. Palestine.
Atlanta. Greenville. Waco.
Macon. West Point.
The oil is chiefly pressed in winter, since it is difficult to keep the seed
for summer work. Some mills are, however, operated during the sum-
mer. The crude oil is shipped in tanks holding from 30,000 to 45,000
pounds each. When the oil is shipped North in winter it usually becomes
solidified. In order to get it out of the tanks they are placed on switches
and a jet of steam is introduced into the tank and the oil gradually
412 FOODS AND FOOD ADULTERANTS.
melted out. Another method consists in covering the tank with wood,
forming a chamber into which exhausted steam is introduced. Gutters
are provided along the railroad tracks into which the oil flows and
is conducted into the receiving tanks. From the receiving tanks it is
pumped into large receivers called scale tanks, where the crude oil is
(&) Refining process. After weighing, the oil is pumped into refining
kettles. These are of various sizes, the largest ones being 20 to 25 feet
deep and 15 feet in diameter. These tanks are furnished with steam-
coils for the purpose of heating the oil and with appropriate machinery
for keeping it in motion. A solution of caustic soda is used for refin-
ing. This solution is made from 10 to 28 Beaume in strength, and
varying quantities are used according to the nature of the oil operated
upon. After the addition of the caustic soda the mixture is agitated
for forty-five minutes and kept at a temperature of 100 to 110 F.
The contents of the tank are then allowed to stand six >to thirty-six
hours, when the solid matters, soap and substances precipitated by the
caustic alkali gather at the bottom. This mixture is called " foots,"
and is used for making soap. The yellow oil resulting by this proc-
ess is further purified by being heated and allowed to settle again or
by filtration and is called summer yellow oil. Winter yellow oil is
made from the above material by chilling it until it partially crystal-
lizes and separating the steariue formed, about 25 per cent., in presses
similar to those used for lard. This cotton-oil stearine is used for
making butteriue and soap.
(c) White oil. The yellow oil obtained as above is treated with from
2 to 3 per cent, of fuller's earth in a tank furnished with apparatus for
keeping the mixture in motion. When the fuller's earth has been thus
thoroughly mixed with the oil, the whole is sent to the filter press.
The fuller's earth has the property of absorbing or holding back the
yellow coloring matter, so that the oil which issues from the press is
almost white. This white oil is the one which is chiefly used for mak-
ing compound lard.
Cotton oil is obtained from the seeds of Gossypium hcrbaccum. The
percentage of oil varies in the seed from 10 to 30.
In 1882 it was estimated that the oil industry was represented by the
following data : *
410,000 tons of seed, yielding 35 gallons of crude oil to the ton, are
14,1550,000 gallons, worth 30 cents per gallon $1,305,000
Same amount of seed, yielding 22 pounds cotton lint to the ton, 189,090,000
pounds cotton, worth 8 cents per pound 721, di't)
And yielding also 750 pounds of oil-cake to the ton (2,2-10 pounds) is 137,277
tons of cake at $20 per ton 2,745, ;>}ii
Deduct the sum paid for the seed, say 4, 100, < >D
And there remains for value gained in niauipulati > i of s:< 1 :!, (IT. 1 , 1 I'l
'Brant. Vegetable and Animal Oils. Phil. II. ('. 1 laird &, Co.
LARD AND LARD ADULTERATIONS. 413
From September 1, 1883, to September 1, 1886, there were exported from New York
88,871 barrels, and from New Orleans 186,720 barrels, making a total .of 275,591 bar-
rels from the two ports. These figures show conclusively that American cotton-seed
oil is growing rapidly in favor in foreign countries.
When well stored and properly ventilated, cotton seed keeps sweet for twelve
mouths. If allowed to become damp, or stored too long in bulk, it grows heated, and
is liable to spontaneous combustion.
Manufacture of cotton-seed oil. The seed when landed at the mill is first examined
If too damp or wet it is dried by spreading it over a floor with free access of air, ex-
posing it on frames to the sunlight in warm weather, or by kiln-drying. Drying is
the exception rather than the rule in the United States. Cotton ginning is so care-
fully done that the seeds have little or no opportunity to become wet. Besides this,
the seed is generally held at the gins for some time before it is sold to the oil manu-
The first process in preparing the dry seed for the mill is to free it from dust. This
is effected by shaking it in a screen or in drums lined with a fine metallic net and
containing a strong magnet to which any iron nails will adhere, which are frequently
present. From the drums the seeds drop into a gutter leading to a machine which
removes the lint left by the gin. This is done by a gin constructed for the purpose,
with saws closer together than Ihc ordinary cotton-gin. An average of twenty-two
pounds of short lint is taken from a ton of the seed. This product, called "linters,"
is used in the manufacture of cotton batting. The clean seeds are then transferred
to the sholler, which consists of a revolving cylinder containing twenty-four cylin-
drical knives and four back knives. The sheller revolves at great speed, and as the
seed is forced between the knives the pericarp or hull is broken and forced from the
kernel. The mixed shells and kernels are separated in a winnowing machine by a
strong blast of air. This removal of the husk makes a vast difference in the meal
cake, a dessicated or decorticated cake being five times more nutritious and whole-
some than an undecorticated cake.
Doing thus cleaned, shelled, and separated, the kernels are carried by a system of
elevators to the upper story and then pass clown into the crusher- rolls to be ground
Cold pressure produces a very good salad oil, and this is the method generally pur-