Foods and Their Adulteration / Origin, Manufacture, and Composition of Food Products; Description of Common Adulterations, Food Standards, and National Food Laws and Regulations

by Harvey Washington Wiley

COMPOSITION OF THE FLESH OF PIGS.

Extensive investigation of the composition of the flesh of pigs has been made in the Bureau of Chemistry (Bulletin 53). The pigs upon which these examinations were made were specially bred and fattened at the Agricultural Experiment Station of Iowa, and were prepared for the market by the most approved modern style of feeding. They were slaughtered according to the approved method and immediately, after proper preparation, the carcasses were placed in cold storage, where they were kept until removal for the purpose of dissection and preparation of the samples for analyses. Expert butchers from Washington were secured for the dissecting and dressing of the pigs in the manner in which it would be done for the best market. The pigs were of different varieties, namely, Berkshire, No. 1; Tamworth, No. 2; Chester White, No. 3; Poland China, No. 4; Duroc Jersey, No. 5, No. 6, No. 7; Yorkshire, No. 8.

TABLE A.—WEIGHTS OF WHOLE CUTS AND DATA RELATING TO THE PREPARATION OF AIR-DRY SAMPLES.
PIG No. 1.—BERKSHIRE.

Names of Cuts.	Weights of Whole Cuts.									Direct Determinations on Original Material.		Preparation of Air-dry Samples.
	Chicago.						Washington.					Weight of fresh sample.	Air-dry sample of original material.	Weight of air-dry sample after extraction.	Weight of fat.	Air-dry sample plus fat.	Weight of water removed.	Removed in preparation of sample.
										Water.	Fat.							Water.	Fat.
	Lbs.		Oz.		Grams.		Lbs.	Oz.	Grams.	Per ct.	Per ct.	Grams.	Per ct.	Grams.	Grams.	Grams.	Grams.	Per ct.	Per ct.
Two American clear backs,	35	1⁄2	0		16,102.8		34	6	15,592.5	..	..	..	..	..	..	..	..	..	..
Meat,	..				..		..		..	31.33	58.21	833.0	13.16	109.6	458.0	567.6	265.4	31.86	54.98
Two clear bellies,	19	1⁄2	0		8,845.2		19	4	8,731.8	..	..	..	..	..	..	..	..	..	..
Meat,	..				..		..		..	36.09	52.69	741.2	14.33	106.2	362.1	468.3	272.9	36.82	48.84
Two short-cut hams,	23	1⁄2	0		10,659.6		23	5	10,574.6	..	..	..	..	..	..	..	..	..	..
Meat,	..				..		..		..	60.29	22.19	532.5	22.95	122.2	88.3	210.5	322.0	60.47	16.58
Two New York shoulders,	20	1⁄2	0		9,298.8		20	10	9,395.5	..	..	..	..	..	..	..	..	..	..
Meat,	..				..		..		..	54.97	29.01	532.5	17.65	94.0	152.9	246.9	285.6	53.64	28.71
Four feet (seven hoofs),	3	1⁄2	0	[3]	1,594.2	[4]	..		1,514.1	..	..	..	..	..	..	..	..	..	..
Meat,	..				..		..		..	59.78	17.04	221.1	25.10	55.5	33.7	89.2	131.9	59.66	15.24
Spareribs,	5		0		2,268.0		..		2,212.0	..	..	..	..	..	..	..	..	..	..
Meat,	..				..		..		..	50.33	30.05	359.9	20.81	74.9	98.6	173.5	186.4	51.78	27.39
Tenderloins,	1		0		453.6		..		470.8	67.14	9.14	427.9	27.11	116.0	26.6	142.6	285.3	66.67	6.21
Neck bones,	2		0		907.2		..		842.5	..	..	..	..	..	..	..	..	..	..
Meat,	..				..		..		..	53.82	28.72	390.6	20.02	78.2	100.5	178.7	211.9	54.25	25.73
Backbones,	3	1⁄2	0		1,587.6		..		1,580.0	..	..	..	..	..	..	..	..	..	..
Meat,	..				..		..		..	51.89	27.16	397.5	22.24	88.4	102.1	190.5	207.0	52.08	25.69
Trimmings,	18		0		8,164.8		16	9	7,512.8	..	..	..	..	..	..	..	..	..	..
Meat,	..				..		..		..	29.68	62.00	783.7	9.72	76.3	479.2	555.5	228.2	29.11	61.17
Tail,		1⁄4	0		113.4		..		363.0	..	..	..	..	..	..	..	..	..	..
Meat,	..				..		..		..	23.99	69.25	199.2	8.73	17.4	134.7	152.1	47.1	23.64	67.62
Total,	132	1⁄4	0		59,995.2		..		58,789.6	..	..	..	..	..	..	..	..	..	..

[3] Missing hoof, 6.6 grams.

[4] Corrected for missing hoof.

Preparation of Samples for Analyses.

—The meat obtained from all of the cuts of the same kind in each sample was passed through a meat chopper two or three times in order to get an even, finely divided condition. A portion of known weight was then placed in a dish and dried in a steam oven at a temperature of boiling water or slightly above and heated until the fat had well separated so that it could be poured off into a flask, with care not to remove any of the water which may have separated with it. Small samples were removed before drying for the determination of the exact quantity of fat and water therein, and the results of these analyses were used for calculating the relative portion of the large samples. Samples of skin, bones, marrow, spinal cord, tendons, hoofs, and other parts of the animal were also carefully secured and subjected to analyses. In this way the whole animal was subjected to examination for analytical data, and at the same time each particular part of it, in so far as its relation to the market is concerned, was kept separated. In Table A are found the weight of the whole cut and the data relative to the preparation of the air-dried sample.

The data show that there was a slight loss of water during the transit from Chicago to Washington. The part of the pig which has the largest percentage of fat is the meat of the tail, while the smallest percentage is found in the tenderloins. The largest percentage of water in any part of the meat is in the tenderloins and the smallest in the meat of the tail.

TABLE B.—WEIGHTS OF PARTS FROM EACH CUT AND DATA RELATING TO THE PREPARATION OF AIR-DRY SAMPLES.
PIG No. 1.—BERKSHIRE.

Names of Parts and Cuts.	Weights of Parts.
	From each cut.	Total.	Of entire pig.
Meat (fat and lean):	Grams.	Grams.	Percent.
Backs,	14,767.9	..	..
Bellies,	8,230.6	..	..
Hams,	9,407.9	..	..
Shoulders,	8,448.2	..	..
Feet,	325.3	..	..
Spareribs,	1,683.8	..	..
Tenderloins,	470.8	..	..
Neck bones,	493.2	..	..
Backbones,	704.0	..	..
Trimmings,	7,021.5	..	..
Tail,	291.7	..	..
		51,844.9	88.19
Bones:
Backs,	191.1	..	..
Bellies,	81.4	..	..
Hams,	879.6	..	..
Shoulders,	693.8	..	..
Feet,	802.6	..	..
Spareribs,	528.2	..	..
Neck bones,	336.1	..	..
Backbones,	833.5	..	..
Trimmings,	71.0	..	..
Tail,	27.1	..	..
Total,	..	4,444.4	..
Marrow,	69.7	69.7	0.12
Total bones less marrow,	..	4,374.7	7.44

TABLE C.—ANALYTICAL DATA FOR MEATS.
PIG No. 1.—BERKSHIRE.

Names of Cuts.	Air-dry sample: Percent of orig- inal mate- rial.	Percent Air-dry Material.								Percent Original Material.
		Water.	Fat.	Nitrogen.				Leci- thin.	Ash.	Water.			Fat.			Leci- thin.	Nitrogen.				Nitrogenous substances.				Ash.	Total.[5]
				Total.	Of pro- teids insol- uble in hot water.	Precip- itated by bromin.	Of flesh bases.			In pre- paring sample.	In steam- dry mate- rial.	Total.	In pre- paring sample.	In steam- dry mate- rial.	Total.		Total.	Of pro- teids insol- uble in hot water.	Precip- itated by bromin.	Of flesh bases.	Pro- teids insol- uble in hot water.	Gelati- noids.	Flesh bases.	Total.
Two American backs,	13.16	3.14	20.55	11.32	8.51	0.62	2.19	1.16	3.89	31.86	0.41	32.27	54.98	2.71	57.69	0.15	1.49	1.12	0.08	0.29	7.00	0.50	0.91	8.41	0.51	-		98.46 98.88
Two clear bellies,	14.33	3.14	21.59	11.15	7.78	0.65	2.72	0.99	3.85	36.82	0.45	37.27	48.84	3.09	51.93	0.14	1.60	1.12	0.09	0.39	7.00	0.56	1.22	8.78	0.55	-		98.11 98.53
Two short-cut hams,	22.95	4.14	15.43	11.85	9.77	0.48	1.60	1.10	4.18	60.47	0.95	61.42	16.58	3.54	20.12	0.25	2.72	2.24	0.11	0.37	14.00	0.69	1.15	15.84	0.96	-		99.28 98.34
(Fat extracted with ether),	16.58	..	..	0.22	..	..	..	2.43	..	..	..	..	..	..	..	0.40	0.04	..	..	..	..	..	..	..	..
																0.65
Two New York shoulders,	17.65	2.31	2.10	13.76	10.22	0.73	2.81	0.85	5.03	53.64	0.41	54.04	28.71	0.37	29.08	0.15	2.43	1.80	0.13	0.50	11.25	0.81	1.56	13.62	0.89	-		98.49 97.63
Four feet,	25.10	6.46	6.32	13.73	7.75	3.00	2.98	0.75	3.28	59.66	1.62	61.28	15.24	1.59	16.83	0.20	3.45	1.95	0.75	0.75	12.19	4.69	2.34	19.22	0.82	-		96.86 98.15
(Fat extracted with ether),	15.20	..	..	0.13	..	..	..	2.68	..	..	..	..	..	..	..	0.41	0.02	..	..	..	..	..	..	..	..
																0.61
Spareribs,	20.81	3.66	8.23	13.03	10.31	0.89	1.83	1.68	4.80	51.78	0.76	52.54	27.39	1.71	29.10	0.35	2.71	2.15	0.18	0.38	13.44	1.13	1.19	15.76	1.00	-		97.14 98.40
Tenderloins,	27.11	5.14	9.47	12.50	10.95	0.28	1.27	1.82	4.30	66.67	1.39	68.06	6.21	2.57	8.78	0.49	3.39	2.97	0.08	0.34	18.56	0.50	1.06	20.12	1.17	-		97.57 98.13
Neck bones,	20.02	7.23	10.93	12.25	9.97	0.59	1.69	1.33	4.02	54.25	1.45	55.70	25.73	2.19	27.92	0.27	2.45	1.99	0.12	0.34	12.44	0.75	1.06	14.25	0.81	-		97.60 98.68
(Fat extracted with ether),	18.69	..	..	0.21	..	..	..	2.17	..	..	..	..	..	..	..	0.41	0.04	..	..	..	..	..	..	..	..
																0.68
Backbones,	22.24	3.36	6.88	13.03	10.36	0.62	2.05	1.20	5.59	52.08	0.75	52.83	25.69	1.53	27.22	0.26	2.90	2.30	0.14	0.46	14.38	0.87	1.44	16.69	1.24	-		96.98 97.98
Trimmings,	9.72	3.69	8.34	13.09	8.54	1.11	3.44	1.16	4.23	29.11	0.36	29.47	61.17	0.81	61.98	0.11	1.27	0.83	0.11	0.33	5.19	0.69	1.03	6.91	0.41	-		99.00 98.77
Tail,	8.73	4.30	6.97	13.45	10.56	0.98	1.91	1.98	4.41	23.64	0.38	24.02	67.62	0.61	68.23	0.17	1.17	0.92	0.09	0.16	5.75	0.56	0.50	6.81	0.39	-		100.44 99.45

[5] In this column the totals obtained by both the direct and the indirect determination of water and fat are given. The upper number in each case was obtained by use of the results of direct determinations of these constituents; for the lower number in each case the results obtained during the preparation of the sample, and in the analysis of the dry-air sample, were used. Lecithin is not included in the totals given in this table.

TABLE D.—ANALYTICAL DATA FOR BONES, MARROW, SKIN, SPINAL CORD, TENDONS, AND HOOFS.
PIG No. 1.—BERKSHIRE.

Names of Parts.	Air-dry sample, percent of orig- inal mate- rial.	Percent Air-dry Material.								Percent Original Material.
		Water.	Fat.	Nitrogen.				Leci- thin.	Ash.	Water.			Fat.			Leci- thin.	Nitrogen.				Nitrogenous substances.				Ash.	Total.
				Total.	Of pro- teids insol- uble in hot water.	Precip- itated by bromin.	Of flesh bases.			In pre- paring sample.	In resid- ual mate- rial.	Total.	In pre- paring sample.	In resid- ual mate- rial.	Total.		Total.	Of pro- teids insol- uble in hot water.	Precip- itated by bromin.	Of flesh bases.	Pro- teids insol- uble in hot water.	Gelati- noids.	Flesh bases.	Total.
Bones,	52.67	5.72	0.52	6.18	5.32	0.11	0.75	0.84	49.59	35.93	3.01	38.94	11.40	0.27	11.67	0.44	3.26	2.80	0.06	0.40	17.50	0.38	1.25	19.13	26.12	95.86
(Fat extracted with ether),	11.40	(.61)	..	0.29	..	..	..	..	(.28)	..	(.07)	..	..	..	..	..	0.03	..	..	..	..	..	..	..	(.03)	..
Marrow,	4.44	6.68	0.19	8.31	7.08	0.65	0.48	..	..	14.06	0.30	14.36	81.50	0.01	81.51	..	0.37	0.32	0.03	0.02	2.00	0.19	0.06	2.25	..	98.12
(Fat extracted with ether),	17.36	..	..	0.07	..	..	..	2.64	..	..	..	..	..	..	..	0.46	0.01	..	..	..	..	..	..	..	..	..
Skin,	36.93	8.31	3.28	15.02	10.95	2.89	1.18	0.33	1.70	47.17	3.07	50.24	15.90	1.21	17.11	0.12	5.55	4.04	1.07	0.44	25.25	6.69	1.37	33.31	0.63	-		108.44 101.89
(Fat extracted with ether),	15.90	..	..	0.15	..	..	..	1.85	..	..	..	..	..	..	..	0.29	0.024	..	..	..	..	..	..	..	..	..
																0.41
Spinal cord,	8.80	6.01	8.28	8.85	7.02	1.26	0.57	..	..	65.17	0.53	65.70	26.03	0.73	26.76	..	0.78	0.62	0.11	0.05	3.88	0.69	0.16	4.73	..	97.19
Tendons,	31.93	10.23	1.53	14.10	11.26	2.22	0.62	0.39	3.71	55.16	3.27	58.43	12.91	0.49	13.40	0.13	4.50	3.59	0.71	0.20	22.44	4.44	0.62	27.50	1.18	100.51
(Fat extracted with ether),	4.81	..	..	0.23	..	..	..	6.65	..	..	..	..	..	..	..	0.32	0.01	..	..	..	..	..	..	..	..	..
																0.45
Hoofs,	63.44	7.14	1.35	14.63	..	..	..	..	1.46	36.56	4.53	41.09	..	..	0.86	..	9.28	..	..	..	..	..	..	58.00	0.93	100.88

Similar data were obtained for all of the other samples used, but the chemical composition is so nearly the same that it is not advisable to repeat the data for the other varieties. The Berkshire for which the data are given may be taken as a fair representative of the composition of the varied parts of the meat of pigs. The comparative weights of various parts of the Berkshire pig are given in [Table B].

The data show that 88.19 percent of the weight of the carcass, after dressing, is composed of meat, fat, and lean, and 7.56 percent of bone. The complete data for the variety of Berkshire pig may be taken as a type for the other varieties and is given in [Table C].

The composition of the bone, marrow, skin, spinal cord, tendons, and hoofs of the Berkshire pig is shown in [Table D].

The percentages of the various parts of the original material of the Berkshire pig are found in [Table E].

TABLE E.—REVISED ANALYTICAL DATA.
PIG No. 1.—BERKSHIRE.

[Percents original material.]
Names of Cuts and Parts.	Water.		Fat.	Nitrogenous Substances.				Leci- thin.[6]		Ash.		Total.
				Pro- teids, insol- uble in hot water.	Gelati- noids.	Flesh bases.	Total.
Meat:
American backs,	32.27		57.69	7.00	0.50	0.91	8.41	0.15		0.51		99.03
American bellies,	37.27		51.93	7.00	0.56	1.22	8.78	0.14		0.55		98.67
Short-cut hams,	60.29	[7]	22.19	14.00	0.69	1.15	15.84	0.65		0.96		99.93
New York shoulders,	54.97	[7]	29.01	11.25	0.81	1.56	13.62	0.15		0.89		98.64
Four feet,	61.28		16.83	12.19	4.69	2.34	19.22	0.61		0.82		98.76
Spareribs,	52.54		29.10	13.44	1.13	1.19	15.76	0.35		1.00		98.75
Tenderloins,	68.06		8.78	18.56	0.50	1.06	20.12	0.49		1.17		98.62
Neck bones,	55.70		27.92	12.44	0.75	1.06	14.25	0.68		0.81		99.36
Backbones,	52.83		27.22	14.38	0.87	1.44	16.69	0.26		1.24		98.24
Trimmings,	29.68	[7]	62.00	5.19	0.69	1.03	6.91	0.11		0.41		99.11
Tail,	24.02		68.23	5.75	0.56	0.50	6.81	0.17		0.39		99.62
Bones,	38.94		11.67	17.50	0.38	1.25	19.13	0.44		26.12		96.30
Marrow,	14.36		81.51	2.00	0.19	0.06	2.25	0.46	[8]	..		98.58
Skin,	50.24		17.11	25.25	6.69	1.37	33.31	0.41		0.63		101.70
Spinal cord,	65.70		26.76	3.88	0.69	0.16	4.73	1.47	[9]	0.40	[10]	97.19
Tendons,	58.43		13.40	22.44	4.44	0.62	27.50	0.45		1.18		100.96
Hoofs,	41.09		0.86	..	..	..	58.00	..		0.93		100.88

[ [6] Lecithin in extracted sample only, unless otherwise noted.

[ [7] Result of direct determination on original material. Other numbers in this column represent the sum of the percent of water removed in the preparation of sample and the percent of water remaining in the air-dry sample.

[ [8] In fat extract.

[ [9] In fat extract, calculated from averages for like cuts.

[10] Calculated from averages of like cuts.

TABLE F.—DATA FOR THE ENTIRE DRESSED ANIMAL; THE HEAD, LEAF LARD, AND KIDNEYS HAVING BEEN REMOVED.
PIG NO. 1.—BERKSHIRE.

Names of Parts.	Weight of Parts—		Of Entire Pig.	Weight of Each Constituent.
	From each cut.	Total.		Water.	Fat.	Nitrogenous substances.				Leci- thin.		Ash.
						Pro- teids, insol- uble in hot water.	Gelati- noids.	Flesh bases.	Total.
Meat (fat and lean):	Grams.	Grams.	Percent.	Grams.	Grams.	Grams.	Grams.	Grams.	Grams.	Grams.		Grams.
Backs,	14,767.9	..	..	4,765.6	8,519.6	1,033.8	73.8	134.4	1,242.0	22.15		75.3
Bellies,	8,230.6	..	..	3,067.5	4,274.2	576.1	46.1	100.4	722.6	11.52		45.3
Hams,	9,407.9	..	..	5,672.9	2,087.6	1,317.2	64.9	108.2	1,490.3	61.15		90.3
Shoulders,	8,448.2	..	..	4,644.2	2,450.6	950.4	68.4	131.8	1,150.6	12.67		75.2
Feet,	325.3	..	..	199.3	54.7	39.6	15.3	7.6	62.5	1.98		2.7
Spareribs,	1,683.8	..	..	884.7	490.0	226.4	19.0	20.0	265.4	5.89		16.8
Tenderloins,	470.8	..	..	320.4	41.3	87.4	2.3	5.0	94.7	2.31		5.5
Neck bones,	493.2	..	..	274.7	137.7	61.4	3.7	5.2	70.3	3.35		4.0
Backbones,	704.0	..	..	371.9	191.7	101.3	6.1	10.1	117.5	1.83		8.7
Trimmings,	7,021.5	..	..	2,084.0	4,353.1	364.4	48.4	72.3	485.1	7.72		28.8
Tail,	291.7	..	..	70.1	199.1	16.8	1.6	1.5	19.9	0.50		1.1
Total for meats,	..	51,844.9	88.19	22,354.4	22,799.6	4,774.8	349.6	596.5	5,720.9	131.07		353.7
Bones (less marrow),	..	4,374.7	7.44	1,703.6	510.6	765.6	16.6	54.7	836.9	19.25		1,142.6
Marrow,	..	69.7	0.12	10.0	56.8	1.4	0.2	0.1	1.7	0.32	[11]	..
Skin,	..	2,232.5	3.80	1,121.6	381.9	563.7	149.4	30.6	743.7	9.15		14.1
Spinal cord,	..	55.7	0.09	36.6	14.9	2.2	0.4	0.1	2.7	0.82	[12]	0.2	[13]
Tendons,	..	159.5	0.27	93.2	21.4	35.8	7.1	1.0	43.9	0.72		1.9
Hoofs,	..	52.6	0.09	21.6	0.4	..	..	..	30.5	..		0.5
Total weights,	..	58,789.6	..	25,341.0	23,785.6	6,143.5	523.3	683.0	7,654.9	161.33		151.3
Total percents of original material,	..	..	..	43.10	40.46	10.45	0.89	1.16	13.02	0.27		2.57

[11] In fat extract.

[12] In residue and fat extract, calculated from averages of like cuts.

[13] Calculated from average of like cuts.

The data for the entire dressed animal after the removal of the head, hoofs, lard, and kidneys are shown in [Table F].

General Conclusions.

—The composition of the flesh of pigs has been given in detail for two reasons. First, because the data relative to this point are much more complete than those of any other flesh product and were obtained in a more systematic way. In the second place, pork is one of the chief meat products of the United States,—the industry being one of great magnitude, and pork being a common article of diet among all classes of people. Further than this, the data indicate the general character of fresh meat, and illustrate as well as that of any of the typical animals the nutritive value and properties of flesh. The study of pork, therefore, may be regarded as a typical study of meat products. It is quite as important that all people should be informed respecting the nature of the wholesome meat which they consume and its value as a diet as it is that they should be certain these meats be procured from healthy animals and in a sanitary way. These two classes of knowledge together give a complete scheme of information which the consumers in this and other countries are entitled to have.

Pork, by many hygienists, is regarded as the least desirable of meat products, and it is not the purpose here to combat that idea. Granting, however, for the sake of argument, that pork is a less desirable meat food than those derived from cattle or sheep, that is all the more reason for knowing particularly everything connected with it. Modern investigations have appeared to establish the fact that swine are less subject to those forms of disease, with the exception of trichinosis, which tend to infect the meat and make it unfit for consumption than cattle or sheep. The diseases to which swine are usually subject act quickly, as a rule, and are speedily fatal, as in the case of hog cholera, whereas the diseases most to be feared in cattle and sheep are those of slow activity and those of a nature which is often not revealed until slaughter, namely, tubercular diseases. In so far, therefore, as infection from disease is concerned, previous to slaughter, it appears that the flesh of swine is less objectionable and less open to suspicion than that of cattle or sheep. One of the chief objections to the use of pork in any form, whether fresh or cured, has been based upon the unsanitary habits of the animals themselves. With the modern methods of cleanliness and care, however, the conditions under which the pigs grow and fatten are, or should be, quite as sanitary as those surrounding cattle and sheep. The consumer, of course, has the right to insist upon such sanitary conditions and these, under present laws or those which are to be enacted, will doubtless be supplied. It is believed that in this country sanitary environments and a sanitary method of feeding will develop types of animals superior to those grown in other countries, where the population is denser and where the facilities for the proper growth and fattening of the animal are less abundant. It is hoped that the general diffusion of knowledge respecting all food products among our people will aid greatly in securing these very desirable results.