Introduction to Meat Science

Course Information

  • Course: Meat Science 1: Introduction to Meat Science

  • Institution: College of Agricultural & Environmental Sciences, University of Georgia

  • Course Code: ADSC 2010L

  • Week Number: Unknown

American Meat Industry

  • Key Characteristics:

    • Seasonal production

    • Primary processing occurs in the fall

    • Preservation techniques include salting, pickling, and smoking.

  • Geographic Centers:

    • Major cities:

    • Boston, MA

    • Cincinnati, OH

    • Chicago, IL

  • Dependence on Resources:

    • Dependence on water supply.

  • Historical Context:

    • Introduction of pigs to North America by Hernando DeSoto in 1593.

    • Introduction of cattle by Ponce DeLeon in 1513.

History of Meat

  • Early Human Lifestyle:

    • Hunter/gatherers and scavengers consumed small mammals and birds.

    • Larger mammals were also hunted.

  • Cognitive Development Hypothesis:

    • It is hypothesized that meat consumption contributed to higher cognitive development in humans.

  • Domestication of Animals:

    • Occurred during the Neolithic Period (New Stone Age).

    • Agricultural revolution took place approximately 10,000-15,000 years ago.

    • Animals began to be utilized for both work and food.

Technological Advancements in Meat Processing

  • Transportation:

    • Development of railroads facilitated cattle drives; limited numbers of cattle could be transported by train.

    • Packing plants relocated farther south due to transportation needs.

  • Refrigeration:

    • First load of refrigerated beef shipped in 1867.

Uncle Sam and Meat Packing History

  • Uncle Sam:

    • Reference to Samuel Wilson, a meat packer in Troy, NY around 1812.

    • Meat was packaged in oak barrels stamped with "U S" for U.S. government stores.

    • Soldiers joked that "U S" meant Uncle Sam.

    • Troops during the War of 1812 referred to their rations as Uncle Sam's meat.

Definitions

  • Meat:

    • The carcass portion of the animal remaining after the head, covering, internal organs, and feet have been removed.

    • Edible parts of the animal include:

    • Muscle

    • Fat

    • Organs

    • Skin

    • Connective tissue

Classifications of Meat

  • Red Meat:

    • High in myoglobin content (type: oxymyoglobin).

    • Examples of species:

    • Cattle: beef (> 1 year), veal (< 1 year)

    • Sheep: lamb (young), mutton (old)

    • Swine: pork

    • Goat: chevon (old), cabrito (young)

  • Poultry:

    • Lower myoglobin content compared to red meat.

    • Types include:

    • Chicken

    • Turkey

    • Geese

    • Duck

    • Ratites (ostrich & emu)

    • All poultry specified as domestically raised.

U.S. Per Capita Meat Availability and Consumption

  • Graph Analysis (1910-2021):

    • Data represents per capita availability in pounds for beef, pork, chicken, and fish/shellfish.

    • Weight calculations based on raw and edible boneless, trimmed weight.

    • Excludes edible offals, bones, viscera, game, and commercially prepared pet food from chicken.

    • Fish and shellfish data available only through 2019.

Composition of Meat

  • Nutritional Breakdown:

    • Protein: 18-20%

    • Fat: 2-12%

    • Minerals: 1%

    • Carbohydrates: < 1%

    • Water: 65-75%

Importance of Meat Consumption

  • Reasons for Consumption:

    • High quality of protein available in meat.

    • High digestibility rates (96-99%).

    • High biological availability, typically meets essential amino acid (EAA) requirements.

    • Contains essential vitamins such as B12, Niacin, Riboflavin, vitamins A, D, E, K.

    • Rich in minerals, including iron, zinc, selenium, and phosphorous in digestible forms.

    • Favorable taste profile.

What is Meat Science?

  • Definition:

    • The study of meat, including its production, preparation, and preservation.

Locations of Slaughterers and Meat Packers (as of May 2021)

  • Location Quotient by State:

    • Data visualizes the concentration of slaughterhouses and meat packers across different U.S. states.

  • Scale of Measurement:

    • Ranges indicate low to high concentrations in relation to the national average.

Harvest Process

  • Key Locations:

    • Slaughterhouse: Main location for animal processing.

    • Packing Plant: Where meat is packaged post-processing.

    • Abattoir: Another term for slaughterhouse.

  • Steps Involved in the Process:

    • Lairage (holding area).

    • Stunning and bleeding (to prepare the animal).

    • Scalding and dehairing/feather removal/skinning.

    • Evisceration (removal of internal organs).

    • Carcass chilling.

    • Fabrication (cutting into smaller, market-ready pieces).

Inspection and Grading of Meat

  • Inspection:

    • Ensures safety and wholesomeness of meat products.

    • Regulated by FSIS (Food Safety and Inspection Service).

    • Mandatory for commerce, funded by federal taxes.

    • Conducted by government-employed inspectors.

  • Grading:

    • Aims to predict the eating quality (palatability) and yield (quantity) of meat.

    • Regulated by AMS (Agricultural Marketing Service).

    • Not mandatory, paid for by the meat packers.

    • Governed by government employees; many companies implement their own quality designations.

Meat Inspection Act of 1906

  • Background Information:

    • Public awareness heightened by Upton Sinclair's "The Jungle."

    • Enforced both antemortem and postmortem inspections to ensure animal health and carcass quality.

    • Addressed the 4Ds (downed, diseased, disabled, dead).

    • Applicable to interstate commerce and imports only.

    • Set precedent making meat one of the most regulated food products in the U.S.

Wholesome Meat and Poultry Act (1967-1968)

  • Significance:

    • Required states to implement inspection guidelines at the intrastate level.

    • If a state could not comply, federal intervention was permitted.

    • Consolidated all previous inspection laws, including those for poultry.

    • Mandated safety standards for all meat available to consumers.

Humane Methods of Slaughter Act (1978)

  • Requirements:

    • Animals must be treated humanely prior to slaughter and during the process.

    • Must be rendered insensible to pain before exsanguination.

    • Methods include:

    • Captive bolt (cattle, sheep, goats).

    • CO2 or electrical stunning (hogs, poultry).

Pathogen Reduction Act (1996)

  • Overview:

    • Shifted industry focus to preventative measures rather than reactive.

    • Established HACCP (Hazard Analysis Critical Control Points).

    • Plants must develop plans to manage contamination incidents and other issues.

    • Aim: Prevent tainted products from reaching consumers and causing illness.

HACCP Steps/Principles

  • Overview of HACCP Principles:

    1. Conduct hazard analysis.

    2. Determine critical control points (CCPs).

    3. Establish critical limits for each CCP.

    4. Establish monitoring procedures for each CCP.

    5. Establish corrective actions when monitoring indicates a potential hazard.

    6. Establish verification procedures to confirm that the system is working effectively.

    7. Establish record-keeping and documentation procedures to maintain accountability.

Steps in the Slaughter Process

  • Procedural Overview:

    • Antemortem Inspection:

    • First step to assess animal health.

    • Immobilization/Stunning:

    • Make the animal insensible to pain using:

      • Electric shock for swine and poultry.

      • Captive bolt for beef, sheep, goats.

      • CO2 stunning for swine and poultry.

    • Exsanguination:

    • Rapid loss of blood via severing the jugular vein or carotid artery (kills the animal).

    • Removal of Skeletal Parts:

    • Removal of feet (a primary contamination source) and tail head.

    • Dressing Process:

    • Pork: Scalding and dehairing.

    • Poultry: Scalding and defeathering.

    • Beef: Hide removal.

    • Evisceration:

    • Removal of internal organs to prevent spoilage.

    • **Carcass Splitting, Trimming, and Washing

    • Cooling:

    • Prepares the meat for storage to limit microbial growth.

    • Postmortem Metabolism:

    • Results in rigor mortis; aging improves tenderness through enzymatic breakdown of muscle and minimizes moisture loss.

Dressing Percentage

  • Definition:

    • Dressing percentage is calculated as:
      ext{Dressing percentage} = rac{ ext{Carcass weight}}{ ext{Live weight}} imes 100

  • Factors Influencing Dressing Percentage by Species:

    • Poultry: 75-80%

    • Swine: 70-75%

    • Ruminants (e.g., beef, sheep): 60-65%

Inspection vs. Grading

  • Differences Between Inspection and Grading:

    • Inspection:

    • Ensures meat safety and wholesomeness.

    • Mandated, funded by taxpayers.

    • Conducted by government employees.

    • Grading:

    • Attempts to predict eating quality or product quantity.

    • Not mandatory, paid for by packers.

    • Often involves voluntary designations by companies.

Beef Grading

  • Types of Beef Grading:

    • Quality Grade:

    • Predicts overall eating experience (palatability, tenderness, juiciness, flavor).

    • Evaluated primarily by marbling and maturity.

    • Yield Grade:

    • Predicts the percentage of the carcass that yields boneless, closely trimmed retail cuts from specific primals (round, loin, rib, chuck).

Yield Grade Calculation

  • Formula for Yield Grade:

    • ext{YG} = 2.5 + (2.5 imes ext{adjusted 12th rib fat thickness, in}) + (0.20 imes ext{%KPH}) - (0.32 imes ext{ribeye area, sq. in}) + (0.0038 imes ext{hot carcass weight, lbs.})

  • Key Variables:

    • 12th rib fat thickness is a crucial factor in yield grade assessment.

Pork Quality Standards

  • Evaluation Criteria:

    • Quality of fresh pork differs significantly.

    • Variations affect consumer perception, taste, and processing.

  • Quality Evaluation:

    • Visual appraisal and scientific tests determine quality levels.

    • Important quality attributes include color, texture, and marbling.

Pork Quality Category Standards:

  • Color and Texture Standards:

    • PSE (Pale Soft Exudative):

    • Pale pinkish gray with undesirable softness; excessive shrink.

    • RFN (Reddish Firm Non-exudative):

    • Desirable characteristics; ideal quality.

    • DFD (Dark Firm Dry):

    • Firm, sticky surface exhibiting high water-holding capacity.

  • Marbling Standards:

    • Color and marbling scores correspond to intramuscular fat content.

Lamb Classification

  • Classification by Class:

    • Ewe, Wether, Ram

    • Maturity Stages:

    • Lamb (<14 months)

    • Yearling (12-25 months)

    • Mutton (>24 months)

    • Joint Types:

      • Spool joint: cartilage turns to bone.

      • Break joint: cartilage is a growth plate, indicates age.

Lamb Grading

  • Yield Grade Formula:

    • Yield is calculated as follows:
      ext{Yield} = 0.4 + (10 imes ext{12th rib fat thickness})

  • USDA Grade Scale:

    • Ranging from 1 to 5.

  • Quality Indicators:

    • Conformation and maturity indicators considered.

Grading of Poultry

  • Grading Standards:

    • Grade A:

    • No missing parts, no broken bones.

    • Grade B:

    • Some exposed flesh or minor defects.

    • Grade C:

    • Significant defects (e.g., broken bones).

  • No Grade:

    • Some poultry deemed unfit for consumption.

Beef Primals

  • Cuts Included:

    • Round

    • Loin

    • Rib

    • Chuck

Pork Primals

  • Cuts Included:

    • Loin

    • Boston Butt

    • Ham

    • Side/Belly

    • Picnic Shoulder

Lamb Primals

  • Cuts Included:

    • Shoulder

    • Rack

    • Loin

    • Leg