Meats exam 1 and quizzes

colonial animal husbandry

meat came from families hunting, fresh meat was eaten immediately, smoked over open fires or salted - needing to find a way to expand the shelf life of meat

how to expand meat shelf life

packing meats in salt barrels

William Pynchon

started as a fur trader and turned into a salted pork importer

what time of the year was meat packing done

winter to prevent meat from spoiling - needed to be chilled as soon as possible

meat industry growth due to

westward expansion and population growth

intercontinental railroad

meat packing and sales were able to reach the east coast where the cities grew while the animal industry grew to the west

animals were harvested near the railroad due to

quick packaging and shipping to the east

invention of what in the 1850-70s meant that animals could be harvested all year round

refrigerated railcars and buildings

packing plants were built near population centers due to

their need of lots of people in them

how many stockyards existed in the 1920s

around 70 major stockyards

major improvement in centralized harvest facilities were

the assembly line - making it possible for the workers not having to bend over - getting to stand which allowed for more efficiency

most accredited harvest and packing plants were

armour and swift

consumer protection became a concern in the late 1800s due to

food and drug misbranding and cutting

Upton Sinclair wrote the Jungle with the intention to highlight the poor working conditions and improve worker welfare instead the public took it as

a public outcry over the unclean environment where meat was processed (would not separate the dead mice from the meat)

Harvey Wiley is an advocate for food purity laws leading to congress

passing numerous protection laws and the FDA was created to protect

closing of stock yards and industry decentralization was due to

cities continuing to expand after WW2 and the justification of stockyards over housing became more difficult

housing over industry

people couldn’t stand the smell of stockyards which ultimately made Swift and Armour to leave Chicago in the 1950s

feedlots

final stage in beef cattle production cycle where animals are the heaviest

feedlots are concentrated more in

smaller midwestern facilities which allowed for less cattle movement

modern packing facilities are massive

8,000 head per day

3 main reasons why the meat industry evolved from homesteading to modern grocery stores

1.Refrigeration

2. efficient industrial processing

3. decentralization of the packing facilities

increase in carcass weight in the domestic market due to

making the animals as large as they can be over time

slaughter of beef trend

decreasing. more than 2 million decrease since 2022 to 2024

cattle industry is highest in

Texas, Nebraska, Kansas, California, Oklahoma

beef market issues

supply and demand issues since covid are still rippling through the system

on the farm everything is more expensive

large packers are consolidating processing plants and closing older facilities

unknown if this trend will continue or not

flatline in meat packing industry

packer and farmer will push the weight of the animal

Brazil has rapidly modernized beef cattle production and is competing with

US market for top global beef producer

pork production trend

increasing weight and feed efficiency

remaining stable after covid and Iowa leads US pork production

poultry production trend

increasing

regulation of US meat production is separated by

livestock species and alternative species (rabbit, bison, water buffalo, venison, elk)

Pure food and drug act 1906

prohibited the sale of misbranded or adulterated food and drugs in interstate commerce

Federal meat inspection act 1906

mandated inspection of cattle, hogs, sheep, and goats before slaughter, after, and during the process

prohibited the sale of adulterated or misbranded livestock and livestock derived food products and ensured sanitary slaughter and processing

poultry production inspection act 1957

poultry industry was not big enough in the early 1900s to need a law

similar inspection system as Federal Meat Inspection Act

Humane Slaughter Act 1958

mandated humane treatment of livestock animals inside the slaughter plant and was amended in the 1970s to allow FSIS to stop slaughter is humane methods are not used

Wholesome Meat Act 1967

Amendments to Federal Meat Inspection Act

required state level inspection services to be held to the same inspection standard as federal law

Processed products inspection improvement Act 1986

relaxed inspection for facilities that do not slaughter. Continuous inspection is still required for slaughter facilities

allowed condemned meat to be reused for non-human consumption

Pathogen Reduction: hazard analysis and critical control points 1996

in response to jack in the box E coli outbreaks

new regulations requiring standardized sanitation procedures and implementation of HACCP systems

Federal inspection

inspection by USDA FSIS that allows inspected products to be sold across state lines and exported

state inspection

inspection by local state agency where inspected products cannot be sold across state lines

some states have increased inspection scrutiny and are granted sales outside state borders

retail exempt

carve out that allows for retail shops to forgo federal or state inspection requirements if they sell products that have already been inspected

custom exempt

allows for non inspected slaughter of livestock for exclusive use of the animal owner (own livestock and cannot sell)

new plants must

conduct a hazard analysis and develop a written HACCP plan

follow good manufacturing practices (GMP)

develop sanitation standard operating procedures (SSOPs)

Posses a “suitable facility” that meets regulatory requirements for sanitation and pest control

plants already in operation can have Grant of Inspection revoked for

failure to meet regulatory operational requirements

skeletal muscle is

the only type of muscle that contracts voluntarily

smooth muscle is

the primary muscle in the digestive tract

cardiac muscle is

only in the heart

composition of Mammalian skeletal muscle water:

65 to 80%

composition of Mammalian skeletal muscle protein

16 to 22%

composition of Mammalian skeletal muscle nucleotides and other nitrogen containing non protein substances

1.5%

composition of Mammalian skeletal muscle carbohydrates

1%

composition of Mammalian skeletal muscle inorganic ions

1%

how does calcium influence the muscle

regulator of muscle contraction

water acts as

a medium, biochemical solvent and coolant, regulates heat in the muscle

glycogen

primary source of muscle carbohydrate used for energy, large polymer of glucose, 2-8% in the liver, 1% in muscle and used for primary energy source for contraction

animal fats are triglycerides or phospholipids

triglycerides are the most important for meat processing and phospholipids can cause lipid oxidation in meat

flavor differences in meat come from

different fatty acids chains

muscle protein functions

metabolism

contraction

strength and structure

Proteins for energy metabolism

sarcoplasmic proteins

proteins for muscle contraction

myofibril proteins

proteins for strength and structure

stromal proteins

myoglobin

most common sarcoplasmic protein that is water soluble, globular, and binds oxygen and transports it inside muscle cells (responsible for meat color)

why is animal protein better to get iron in the diet

iron molecule to bind and stabilize O2

contraction proteins that exist in the myofibril

myosin, actin, troponin and tropomyosin

myofibril

contractile organelle of the muscle cell

stromal proteins

collagen and elastin

connective tissue transfers force

generated by muscle contraction to bones for movement

how can collagen be broken down

with moist heat

elastin is resistant to

heat

important muscle cell organelles

sarcoplasm, sarcolemma, myofibril, transverse tubules, sarcoplasmic reticulum, nuclei, mitochondria

sarcolemma

cell membrane of the muscle fiber

how does sarcolemma work

entire structure is very elastic and contracts with the muscle

transports nerve impulses

periodically invaded by transverse tubules or T tubules

sarcoplasm

cytoplasm of the muscle cell

how does the sarcoplasm work

provides contraction lubrication

myofibril

contraction organelle made of repeating sarcomeres

how does a myofibril work

unique to muscle fibers and muscle fibers have at least 1000 and as many as 2000 myofibrils

Transverse Tubules

tubular channels of the sarcolemma that are responsible for transmitting nerve signal from the membrane surface to the interior

sarcoplasmic reticulum

a network of tubes that forms a meshed network around the myofibrils and closely associated with the T tubules of the sarcolemma to form a Triad

how does the sarcoplasmic reticulum work

regulates calcium ion concentration in the sarcoplasm

releases calcium into sarcoplasm during contraction

pumps calcium internally using the SERCA (sarcoplasmic endoplasmic reticulum Ca+2 ATPase) pump and stores it for relaxation

Nuclei

located near the sarcolemma around where nerve endings contact muscle cells (neuro muscular junction)

how many nuclei are in skeletal muscle fibers

multi nucleated and each cell may contain 100-200 nuclei

what does the neuromuscular junction look like

tiny trees

mitochondria

oblong organelles located in the sarcoplasm and located on the edge of the muscle fiber, usually near the neuromuscular junction and Z disk

how does the mitochondria work

powerhouse of the cell and contains enzymes for oxidative metabolism (energy production using oxygen) and stays metabolically active after rigor mortis

skeletal muscle structure (biggest to smallest)

muscle

muscle bundle (fascicle)

muscle fiber

myofibril

sarcomere

connective tissue structure

epimysium (wraps muscle)

perimysium (wraps muscle bundles)

endomysium (wraps muscle fiber)

muscle fiber (one cell)

roughly 75 to 93% of the volume of skeletal muscle and remaining volume is connective tissue

skeletal muscle fibers are not branched and require connective tissue to translate contraction to movement

muscle fiber contraction for one cell

can contract around 50% of resting length

what are the ends of muscle fiber like?

taper at the ends and are bound to each other by connective tissue

myofibril structure

composed of at least 10 different proteins

made of REPEATING SACROMERES that are made up of thick and thin myofilaments

sarcomere

REPEATING unit of the myofibril and is the smallest unit where muscle contraction and relaxation occurs

ONE sarcomere is Z line to Z line

structure of the sarcomere

thick filament

thin filament

A band

I band

Z line

H zone

M line

thick filament

myosin complex

thin filament

actin, troponin, tropomyosin complex

A band

thick filament zone (A = anisotropic)

I band

Zone where thin filament does not overlap with thick

spans two sarcomeres (I=isotropic)

Z line

anchor of thin filaments

H zone

zone where thick filament does not overlap with thin filament

M line

Center line

isotropic (meat science def)

light passes through

myosin

most abundant myofibrillar protein

looks like tentacles

ATP enzyme for muscle contraction

located in think filaments (that dissolves with salt to individual myosin molecules)