Meat Processing: From Slaughter to Cutting – A Comprehensive Guide
IDENTIFICATION
Meat refers to the muscle tissue of mammals used for human consumption, including their viscera and offal. Understanding the state of the muscle is crucial for its use as meat. After death, rigor mortis sets in, causing the muscles to become rigid. This process is believed to be caused by a decrease in calcium, although the exact mechanism is not fully understood.
IMPLEMENTATION AND SACRIFICE: OPERATIONS IN THE SLAUGHTER
This section covers the pre-slaughter, during-slaughter, and post-slaughter processes involved in cattle processing.
2.1 Ante-Mortem Phase
Several factors must be considered when transporting animals to slaughter:
- Easy loading and unloading of animals.
- Separation of animals using grids.
- Adequate ventilation.
- Use of an easily washable transport vehicle.
Only animals intended for immediate slaughter should be brought to the slaughterhouse. Animals showing signs of excitement or fatigue should be rested in pens for no more than 24 hours to prevent porcine stress syndrome. Before slaughter, animals should be bathed to remove excess dirt. Stunning should be performed to minimize excitement and prevent movement, typically using an electric shock to the back of the ears.
2.2 Sacrifice
The animal is hoisted by its hind legs and a puncture is made in the carotid artery and jugular vein. Bleeding is performed, keeping in mind that approximately 50% of the blood will remain within the meat. The carcass is then showered to remove blood traces. In some countries, electrical stimulation is applied to the carcass to tenderize the meat. The ideal pH of the calf is between 5.7 and 5.8. Deviations from this range may indicate meat quality issues. Pork carcasses are typically blanched for 4 to 5 minutes in water heated to 65-75°C. After blanching, the claws are removed and the hair is removed using a scraper. Any remaining bristles are singed and the carcass is thoroughly cleaned.
2.3 Post-Mortem Phase
Skinning
The animal’s skin is removed, although this is less common in pigs.
Evisceration
An incision is made between the legs at the belly using a wide, blunt knife, taking care not to puncture the intestines. The incision is extended longitudinally to the neck, and the ribs and sternum are separated using a saw. The internal organs (heart, liver, lungs, etc.) are removed, along with the periviceral fat (lard), leaving the kidneys and head intact.
Splitting and Washing
The carcass is split in half without breaking the skin. The carcass is then washed with pressurized water and the viscera are left to dry naturally.
Post-Mortem Inspection and Sealing
Samples of the viscera and muscles are inspected. If the inspection is favorable, a seal of wholesomeness is applied. If unfavorable, the carcass is deemed unfit for consumption.
Cooling and Maturation
After slaughter, the carcass temperature is around 37°C, which is conducive to microbial growth. Therefore, rapid chilling is essential. The meat should be promptly transferred to refrigerated rooms. Pig carcasses typically require 1-3 weeks of maturation. The carcasses are suspended in pans to prevent contact with other pieces during cooling.
Freezing
Freezing can produce a tenderizing effect similar to maturation. However, thawing can result in significant water loss. Pork fat is prone to oxidation, so whole carcasses are typically frozen to prevent dehydration, rancidity, and microbial growth. The duration of frozen pork storage is 9, 10, and 12 months at -18°C, -25°C, and -30°C, respectively. Waterproof cellophane or polyethylene are commonly used for packaging.
CUTTING
Cutting is performed after cooling and maturation, or after thawing in the case of frozen meat. A boning knife is used to separate the meat from the bones, following the natural contours of the cuts. Proper boning technique involves using an appropriate knife, following the inclination of the pieces, utilizing the point of the knife effectively, and carefully separating the parts along the bone. These operations should be performed as needed to minimize oxidation and weight loss. It is crucial to avoid placing hands in the path of the knife. The muscles are grouped into categories, yielding cuts such as the shoulder, neck, back, ribs, chin, leg, head, and viscera.
Fractional Cutting
The carcass is divided into three sections: anterior, middle, and posterior thirds.
Forehand
A straight cut is made at the level of the 2nd and 3rd rib, yielding the shoulder, neck, and chest. The forehand also includes the front shank, jowl, bacon, and feet.
- Shoulder or Foreshank: Removed by slipping the knife between the ribs and separating the neck.
- Gill: Located below the neck, attached to the head.
- Neck: Located at the anterior end of the forehand.
Middle Third
Separated from the posterior third at the level of the 2nd or 3rd sacral vertebra with a straight cut. This section yields the rack or ribs, bacon, tenderloin, and belly.
- Rib or Carré: The fillet is removed from the inside, followed by the bacon and belly.
- Bacon and Belly: Separated longitudinally from the belly.
Rear Third
Yields the leg or ham, hock, and hands.
- Leg or Ham: Obtained by a perpendicular cut to the spine at the level of the last lumbar vertebra.
CUTS WITH SPECIFIC NAMES
Specific cuts of pork include:
- Head: Consumed whole or in parts (ears, brain, cheek, tongue, snout).
- Neck: Lean meat used for fillings, similar to bacon.
- Gill: Composed of meat and fat, used for sausage production.
- Carré: Yields chops, which are slices of meat with a portion of the rib. Different types of chops include:
- Center or Stick: From the center of the rib, considered the best quality.
- Needle: From the cervical part, less visually appealing, but more flavorful.
- Kidney: From the back of the loin, less visually appealing, but juicy and tender.
- Double Chop: Thicker than normal, approximately 6-8 cm.
- Coronado: Loin wrapped in a crown, with the backbone removed.
- Latigo: Boneless loin consisting of the back and loin.
- Leg: Hind leg of the pig, yields the cover, flank, hip, and shank.
- Shoulder: Foreleg of the pig, yields the ham and lean shoulder.
- Knuckle: Bottom of the shoulder to the knee joint.
- Rib: Rib bone with lean meat and jelly.
- Sirloin: Located on the first lumbar vertebrae and attached to the spine, highly prized.
- Viscera: Includes sweetbreads, heart, kidneys, hands, butter, and tail.