Pork Slaughtering, Cutting, Preserving, and Cooking on the Farm

by H. Russell Cross; E. Curtis Green; William R. Jones; Anthony Kotula; R. L. West

SLAUGHTER

Stunning

The animal should be killed as quickly and humanely as possible. In most slaughter plants, hogs are immobilized either by electrical stunning or carbon dioxide gas suffocation. On the farm a hog can be stunned by striking it one sharp blow with a mechanical stunner or by shooting it in the forehead midway between and slightly above the eyes. The first attempt should be successful ([fig. 2]). Improperly placed bullets could cause the animal much pain and injure helpers or other livestock. Animals that become excited during stunning will not bleed as well as those less excited. As always the case whenever using firearms, exercise all appropriate safety precautions.

PN-5302

Figure 2.—Stunning.

Bleeding

Bleeding is a very important part of the slaughtering operation. The animal should be bled within 2 minutes after it is down because the blood pressure may increase and thus break the capillaries and cause an unattractive condition in the meat called “blood splash.” Although meat with this condition is safe for consumption, it is quite unpleasant in appearance.

After stunning the animal, place it on its back, perfectly straight with the head close to the ground. A helper can stand over the animal and hold its front legs. Locate the tip of the breastbone, along the midline ([fig. 3]). A 6-inch sticking knife sharpened on both sides of the tip is best. However, a regular boning or skinning knife can be used. Hold the knife at a 35 to 40-degree angle, thrust it under the breastbone with the point aimed toward the tail and then give an upward thrust (dip the point) to sever the carotid artery ([figs. 4] & [5]). No twisting or cross-cutting of the knife is necessary. If the hog does not bleed, insert the knife a little deeper a second time and there should be little difficulty getting a good stick. To avoid a “shoulder stick” do not insert the knife too far to either side. The bloody tissue resulting from a shoulder stick will subsequently require trimming. Care should also be taken to make certain that the hog does not kick you or the knife.

PN-5304

Figure 3.—Locating breastbone.

Figure 4.—Sticking (bleeding).

PN-5305

Figure 5.—Positions for sticking.

Hair or Skin Removal

Once the animal is bled, the hair can be removed by scalding the animal in hot water and scraping; or the skin and hair can be removed by skinning. Traditionally, hogs have been scalded and scraped, and the skin is left intact. Both procedures will be discussed because many people now find the skinning method to be easier, to require less equipment, and to result in an equally acceptable final product.

Scalding and Scraping Method:

For scalding, the most important consideration is maintaining an adequate supply of properly heated water. Approximately 50 gallons of near boiling water will be needed for each pig. This water should be ready (boiling) before the animal is stunned and bled. After the hot water is placed in the scalding barrel, it can be adjusted to the proper temperature for scalding by adding cold water.

The animal can be scalded by several methods. The easiest method is to have two barrels, one for heating the water and one for use as a scalding vat. Fifty-five gallon barrels will be large enough for most hogs. The scalding barrel can be buried in the ground at a slight angle; thus movement of the hog in and out of the barrel is easier ([fig. 6]). Be sure the angle of the barrel is not too flat or the barrel will not hold enough water to cover the carcass. Another method for scalding is to have a scalding vat or a barrel under which a fire can be built. This method requires more construction, and the temperature of the water is difficult to control.

PN-5306

Figure 6.—Scalding equipment.

Slow scald is usually best. Scalding water temperatures between 140° and 145° F are optimal. At these optimal temperatures, 3 to 6 minutes of scalding are required to loosen the hair and scurf (layer of accumulated oil, dirt, and the outer layer of cells on the skin). In the fall when the winter hair is beginning to grow, the hair of most hogs is difficult to remove. Higher water temperatures (146° to 150° F) or longer submersion times are usually required for scalding during this “hard-hair” season. About ¼ cup of rosin, lime, or some other alkaline material added to the scald water to aid in scurf removal results in a whiter skin.

On the farm, regulation of water temperature is difficult. Add boiling water to the scalding barrel, then add cool water to adjust to the proper temperature. Begin with the scalding water at 155° to 160° F because it cools rapidly. At these high temperatures, the carcass must be kept in motion and pulled from the barrel several times. This movement prevents overscalding. Overscalding causes the skin to contract around the base of the hair (“setting the hair”) and cooks the skin. If the carcass is overscalded, the hair is extremely difficult to remove.

After the proper water temperature has been attained, place the pig in the barrel, head first ([fig. 7]). Rotate the carcass in the barrel, pulling it in and out of the water occasionally. Check the hair often for ease of removal. The hair slips first over the back and sides, then in the flank regions. When the hair can be pulled easily in the flank regions behind the shoulders, remove the hog from the barrel and place the rear of the hog in the water.

PN-5307

Figure 7.—Scalding head first.

While the rear of the hog is scalding, pull the toe nails and dew claws from the front feet by inserting a hook into the top of the nail and pulling ([fig. 8]). Scrape as much of the hair on the head as possible, especially around the ears and snout ([fig. 9]). When the hair slips in the rear flanks, remove the hog from the barrel. Remove the toe nails and dew claws from the rear legs and pull the hair from the tail.

PN-5308

Figure 8.—Removing toe nails.

PN-5309

Figure 9.—Scraping head.

Grip the legs with both hands and twist to pull off the hair. Remove the hair in the difficult areas (head, feet, jowl) first, then proceed to the easier areas (back, sides). If you use the bell scraper, tilt the scraper upward on the forward edge and pull the scraper forward, applying as much pressure as possible ([fig. 10]).

PN-5310

Figure 10.—Scraping head.

Scrape the hot carcass as quickly as possible because the skin tends to “set” as it cools. If patches of hair and scurf are difficult to scrape, cover them with a burlap bag and pour hot water over them. Scraping is made easier by moving the legs or the head in order to stretch the skin, smoothing the wrinkles along the sides.

After most of the hair has been removed, pour water over the carcass and continue scraping. Place the scraper flat against the skin and move it in a rotary manner ([fig. 11]). This procedure aids in removal of scurf and dirt as well as removal of the rest of the hair. If patches of hair cannot be removed with the scraper, use a knife. Some people prefer to use a knife for the entire operation.

PN-5311

Figure 11.—Scraping middle

The carcass is now ready to be suspended. Clean the feet by cutting away the soles of the feet and cutting between and around the toes ([fig. 12]). Expose the gambrel tendons by cutting through the skin on the backs of the rear legs from dew claws to hock ([fig. 13]). Cut down each side of the tendons, being careful not to cut the tendons ([fig. 14]). Insert the spreader or gambrel under both tendons on each leg. Secure the legs to the spreader bar and suspend the carcass ([fig. 15]).

PN-5312

Figure 12.—Cleaning feet.

PN-5313

Figure 13.—Exposing gambrel tendons.

PN-5314

Figure 14.—Exposing gambrel tendons.

PN-5315

Figure 15.—Suspending the carcass.

If available, a propane torch or blowtorch can be used to singe the remaining hair and scurf ([fig. 16]). Singeing removes most of the hair and allows small, light hairs to be seen. Use caution during singeing to prevent burning the skin. Shave the remaining hair and wash the carcass thoroughly. Continue with evisceration and splitting ([pages 24–35]).

PN-5316

Figure 16.—Singeing.

Skinning Method:

The skinning procedure used for pork carcass is similar to that used for beef carcasses. Skinning requires less equipment and can be done faster than scalding and scraping. We have commonly believed that the skin was needed on hams and bacon to assure proper curing; however, this belief is not necessarily correct. A poor skinning job can lower the quality of the belly for bacon.

After stunning and bleeding the animal, move the carcass to the location of the hoisting equipment. Place the carcass on a sheet of plywood, a concrete slab, or straw. Wash the blood and dirt from the carcass. Turn the carcass on its back and hold it in place with blocks placed on each side ([fig. 17]).

PN-5317

Figure 17.—Position for skinning.

Cut the hide around the rear legs, just below the dew claws ([fig. 18]). Make a cut through only the hide, down the back of the leg, over the hocks, and to the midline at the center of the hams ([fig. 19]). Skin around each side of the leg, removing the hide to a point below the hock ([fig. 20]).

PN-5318

Figure 18.—Cutting skin around legs.

PN-5319

Figure 19.—Cutting to midline.

PN-5320

Figure 20.—Skinning legs.

Open the hide down the midline from the point where the animal was stuck, around each side of the pubis area and continue to the anus ([fig. 21]). Make this cut by inserting the point of the knife under the skin with the blade turned up. This procedure is referred to as cutting from inside out and protects against meat contamination from materials on the hide. Avoid cutting too deeply because you may puncture the intestine and contaminate the carcass.

PN-5321

Figure 21.—Cutting down midline.

Remove the hide from the insides of the hams ([fig. 22]). Be careful, it is very easy to cut through the fat into the lean. Continue skinning along the sides toward the breast. Grasp the loosened hide in the opposite hand and pull it up and out. This places tension on the hide, removes wrinkles, and allows the knife to glide smoothly. Holding the knife firmly, place it against the hide with the blade turned slightly outward ([fig. 23]). Skin as far down the sides as possible, but not around the front legs ([fig. 24]).

PN-5322

Figure 22.—Skinning hams.

PN-5323

Figure 23.—Siding.

PN-5324

Figure 24.—Siding.

Return to the rear of the carcass and remove the hide left on the rear of the hams ([fig. 25]). Do not skin the outside of the hams at this time. Remove the rear feet by sawing through the bone about 2 inches above the hock ([fig. 26]). Insert the spreader under the large tendons on the rear legs ([fig. 27]) and secure the legs to the spreader.

PN-5325

Figure 25.—Skinning rear of hams.

PN-5326

Figure 26.—Removing feet.

PN-5327

Figure 27.—Exposing tendon.

Hoist the carcass to a convenient working height (waist high) for skin removal from the outside of the hams. Skin around the outsides of the hams, leaving as much fat as possible on the carcass. Remove the hide around the anus and cut through the tail at the joint closest to the body ([fig. 28]). Pull the hide down over the hips ([fig. 29]). The hide along the hips and back can be pulled off, leaving the fat on the carcass. Occasionally, you may need to use a knife to cut between the skin and the fat if large pieces of fat are being pulled off.

PN-5328

Figure 28.—Skinning rear of hams.

PN-5329

Figure 29.—Removing hide from back.

Hoist the carcass to a fully extended position. Open the hide down the rear of the forelegs. Remove the hide on each side of the forelegs ([fig. 30]). Skin along the inside of the forelegs and neck. Skin along the outside of the shoulders and jowls to a point approximately half way to the back of the carcass ([fig. 31]).

PN-5330

Figure 30.—Skinning forelegs

PN-5331

Figure 31.—Skinning sides and back.

Slowly pull down and out on the hide ([fig. 32]), removing it along the back. If the fat begins to tear, use a knife to correct the torn area and then continue pulling the hide. Remove the hide as far down the back as possible ([fig. 33]). When it becomes difficult to pull along the top of the neck, complete removal with a knife.

PN-5332

Figure 32.—Pulling hide from back.

PN-5333

Figure 33.—Pulling hide from back.

If the head is to be saved, skin over the poll and down the face ([fig. 34]). Remove the hide at the snout. Remove the front feet by sawing just below the knee joint ([fig. 35]). Continue with evisceration and splitting.

PN-5334

Figure 34.—Skinning head.

PN-5335

Figure 35.—Removing front legs.

Evisceration

Loosen the anus by cutting around it, deep into the pelvic canal. Pull outward and cut any remaining attachments ([fig. 36]); be careful not to cut into the large intestine. When the anus is loosened, tie it with a piece of string to avoid contaminating the carcass ([fig. 37]).

PN-5336

Figure 36.—Loosening anus.

PN-5337

Figure 37.—Tying anus.

Remove the penis from a slaughtered barrow. Cut through the skin and fatty tissue along each side of the penis and around the penis opening. Lift upward and cut underneath it along the midline ([fig. 38]). Cut along the penis between the hams, pull the penis upward and remove it at its attachment at the base of the ham ([fig. 39]). Continue the cut made between the hams, at their natural separation, exposing the white connective tissue. Cut through the tissue to the pelvic (aitch) bone. Continue cutting through the cartilage between the aitch bone and separate the hams ([fig. 40]). This procedure is satisfactory in young pigs; however, a saw may be needed to split the aitch bone in older hogs.

PN-5338

Figure 38.—Removing penis.

PN-5339

Figure 39.—Removing penis.

PN-5340

Figure 40.—Splitting pelvic bone.

Make a cut through the lean and fat from the point where the pig was stuck to the upper end of the sternum or breastbone ([fig. 41]). Insert the knife at the top edge of the sternum, cut downward and slightly off center to open the chest cavity ([fig. 42]).

PN-5341

Figure 41.—Tip of sternum.

PN-5342

Figure 42.—Opening the sternum.

Open the midline, beginning at the opening made when the aitch bone was split. With the handle of the knife inserted in the opening and with the blade pointed outward to avoid cutting the intestines ([fig. 43]), open the midline to the opening made at the breast ([fig. 44]). Allow the intestines and stomach to roll outward and hang ([fig. 45]). Do not allow them to fall because the esophagus will tear and spill its contents onto the carcass.

PN-5343

Figure 43.—Opening the midline.

PN-5344

Figure 44.—Opening the midline.

PN-5345

Figure 45.—Intestines and stomach.

Pull the loosened large intestine down past the kidneys ([fig. 46]). Sever the attachments to the liver and remove it by pulling outward and cutting the connective tissue ([fig. 47]). Remove the gall bladder from the liver by cutting beneath it and pulling ([fig. 48]). Be careful not to allow its contents to spill onto the liver.

PN-5346

Figure 46.—Pulling large intestine.

PN-5347

Figure 47.—Removing liver.

PN-5348

Figure 48.—Removing gall bladder.

Pull the stomach and intestines outward and cut through the diaphragm ([fig. 49]). This is the thin sheet of muscle and white connective tissue that separates the stomach and intestines from the lungs and heart. Pull outward on the lungs and heart and cut down each side of the windpipe, severing its attachment at the head ([fig. 50]). To separate the heart from the lungs, cut across its top ([fig. 51]). The heart should be split open to allow thorough washing. Wash the heart and liver thoroughly and put them in ice or ice water.

PN-5349

Figure 49.—Cutting diaphragm.

PN-5350

Figure 50.—Removing windpipe.

PN-5351

Figure 51.—Removing heart.

Splitting and Head Removal

Wash the inside of the carcass before splitting. With the saw, begin splitting from the inside between the hams ([fig. 52]). Keep the split as near the center of the backbone as possible, and saw through the tail region to a point midway through the loin ([fig. 53]). Move around to the back and continue sawing through the shoulder and neck to the base of the head ([fig. 54]). If the split gets off center, continue sawing through to the next vertebra and then realign the saw.

PN-5352

Figure 52.—Splitting.

PN-5353

Figure 53.—Splitting.

PN-5354

Figure 54.—Splitting.

Remove the head at the atlas joint (the joint closest to the head). This joint should be exposed if the carcass is properly split ([fig. 55]). After cutting through the joint cut downward along the jaw bone, leaving the jowls attached to the carcass. If desired, remove the tongue, wash it thoroughly, and place it with the liver and heart.

PN-5355

Figure 55.—Removing head at atlas joint.

Remove the kidneys and leaf fat (figs. [56] and [57]). The leaf fat is removed by loosening it from the diaphragm muscle and lifting it upward. Wash the carcass thoroughly before chilling.

PN-5356

Figure 56.—Removing kidney.

PN-5357

Figure 57.—Removing leaf fat.

Examining the Carcass

All the internal organs and the dressed carcass ([fig. 58]) should be examined carefully for any abnormalities or conditions that might affect the fitness of the meat for food. Usually a meat inspector or graduate veterinarian is the only person qualified to do this, and one should be present to inspect the carcass; however, under farm conditions, you may need to look for the obvious signs of disease or damage yourself. If any part of the viscera or carcass is questionable, you should obtain expert advice.

Bruises, minor injuries, parasites in the organs, enclosed abscesses, and single tumors are frequently local conditions that can be easily removed. However, congestion or inflammation of the lungs, intestines, kidneys, inner surface of chest, or abdominal cavity and numerous yellowish or pearl-like growths scattered throughout the organs should be viewed seriously. Carcasses and viscera having such abnormalities should be examined by a graduate veterinarian and his opinion obtained as to the wholesomeness of the meat. You should check with a cooperating veterinarian before you slaughter the animal to be certain he will be available if you should seek his advice.

PN-5358

Figure 58.—Completed carcass.