Meat Composition and Production Overview

Meat Composition and Production

• USDA Definition: Meat comprises muscle tissues (e.g., skeletal, tongue, diaphragm, heart, esophagus) from cattle, sheep, swine, or goats. It also includes the associated skin, sinew, nerves, and blood vessels.
• Different Regulations: Poultry, seafood, and wild game have separate USDA & FSIS definitions and regulations.
• 2021 Meat Production: Total meat production was 52 billion pounds, with poultry at 48 billion pounds. Specific meat production: beef (27.95 billion lbs), pork (27.67 billion lbs), and poultry (50.4 billion lbs).
• Top Livestock Production States (2021): Cattle: Nebraska, Kansas, Texas, Colorado, California; Hogs: Iowa, Minnesota, Illinois; Chicken: Georgia, Arkansas, Alabama; Turkey: Minnesota, North Carolina, Arkansas.
• Economic Impact: The US meat industry is a $227.9 billion industry. It employs over 532,000 people, with $257 billion in wages, contributing 5.6% to the US GDP and exporting over $30 billion in products.
• Global Impact (2017): Beef exports (1.26 million metric tons, $7.27 billion) had Japan, South Korea, Mexico, and Hong Kong as major markets. Pork exports (2.45 million metric tons, $6.49 billion) mostly went to Mexico, Japan, and South Korea. Poultry exports (3.7 million metric tons, $4.5 billion) primarily went to Mexico, China, Canada, and Taiwan.

Meat in the American Diet

• Dietary Contribution: Meat, fish, and poultry contribute 14% of calories, 39% of protein, and 24% of fat in the average American diet. Dairy products account for 10.3% of calories, 19.7% of protein, and 15% of fat.
• Protein Importance: Animal proteins are high-quality proteins, easily digestible and supplying all essential amino acids in amounts meeting human requirements. Daily protein intake is crucial, as the body can't store free amino acids to make protein every day. Recommended amounts vary by age, activity level, and gender.
• Essential Amino Acids: 9 essential amino acids for adults: Phenylalanine, Valine, Tryptophan, Threonine, Methionine, Leucine, Isoleucine, Lysine, and Histidine.
• Biological Value: Biological value measures the proportion of absorbed protein incorporated into an organism's body proteins. Animal products (meat, eggs, milk) have high biological value (95-100% digestible). Plant proteins have lower biological value (65% digestible).
• Meat Protein Composition: Meat protein primarily comes from muscle and connective tissues (Myofibrillar proteins, sarcoplasmic proteins (enzymes & myoglobin), Connective tissue proteins (collagen & elastin)).

Meat Lipids

• Lipid Importance: Meat lipids are a significant energy source and contain essential fatty acids. Fat content varies significantly depending on cattle grades and processing methods.
• Types of Lipids: Triglycerides are the largest component, with varying combinations of fatty acids (saturated or unsaturated: mono or polyunsaturated). Phospholipids are much smaller but essential for cell structures.
• Saturated Fats: High consumption can elevate LDL cholesterol, increasing cardiovascular disease risks.
• Essential Fatty Acids: Omega-3 fatty acids (DHA, EPA) are crucial for cardiovascular health and brain development. Arachidonic Acid (ARA) is also vital for brain development and cellular functions.
• CLA (Conjugated Linoleic Acid): Unique to animal products (primarily ruminants), linked to anti-obesity, anti-carcinogenic, and anti-atherogenic properties.

Meat Carbohydrates, Minerals, and Vitamins

• Carbohydrates & Fiber: Meat contains limited carbohydrates and no dietary fiber. Primarily glycogen in skeletal tissue; liver stores more. Processed meats may contain added sugar.
• Minerals: Meat is a significant source of various minerals, except calcium. It's an excellent source of iron (heme iron, readily absorbable), zinc (more bioavailable from meat than plants), copper, sodium, potassium, and magnesium.
• Vitamin B Complex: A good source of B vitamins, especially B12 (particularly significant in red meat and poultry).
• Vitamin A: Primarily found in the liver.

Meat Cooking and Variety Meats

• Cooking Impact: Cooking methods largely don't change nutritional content, though some B vitamins (e.g., thiamin) might be affected by high heat.
• Variety Meats: Vary in protein content compared to skeletal muscle. They are economical sources of protein and vitamins.
• Processed Meats: Links between excessive processed meat consumption and cancer have been established, likely due to nitrites used for preservation, which have not been definitively isolated yet.

Meat and Muscle Structure

• Muscle Tissue Composition: Skeletal muscle (35-65% carcass weight), smooth muscle (blood vessels, intestines, eyes), and cardiac muscle (heart).
• Muscle Fiber: Muscle fibers (myofibers/muscle cells) constitute 75-92% of muscle volume. They are long, multinucleated, and unbranched. Skeletal muscles are highly organized to allow contraction and relaxation.