Meat Science test 1

meat

animal tissues suitable for food, including processed or manufactured products

meat science

the study of animal tissues and all aspects of the meat industry, from production to consumption

Humane Methods of Slaughter Act (HMSA)

U.S. federal law requiring humane handling, stunning, and slaughter of livestock (excluding poultry)

humane handling

managing animals to minimize fear, pain, and stress to improve welfare and meat quality

slaughter

the process of killing animals for food, usually by blood loss (exsanguination)

stunning

rendering an animal unconscious before slaughter to prevent pain

effective stunning

keeping an animal unconscious throughout shackling, sticking, and bleeding

exsanguination

removal of blood from the animal during slaughter

dressing

removing all non-carcass parts (drop items) to leave the hot carcass

drop (by-products)

everything removed from the animal except the carcass (hide, head, organs, blood, feet)

variety meats

edible by-products such as liver, heart, and tongue

drift

(shrink) weight loss during animal transportation due to dehydration and feed loss

pencil shrink

typical 4% live weight loss in cattle during transport

dressing loss

weight lost due to removal of drop items

chill loss

weight loss from moisture evaporation during carcass chilling

breaking loss

loss from sawing, bone dust, moisture loss, and tissue left on equipment

cutting loss

loss from trimming fat, bone, and lean meat during fabrication

retail loss

loss from theft, discounts, spoilage, or reworked meat

cooking loss

weight loss during cooking due to moisture evaporation and trimming

plate waste

uneaten meat discarded by consumers

hot carcass weight (HCW)

weight of the carcass immediately after slaughter and dressing

pay weight

live animal weight used by packers to pay producers

dressing percentage (DP)

percentage of pay weight that becomes carcass weight

why is humane handling important

it improves animal welfare and meat quality

which animals are not protected by HMSA

poultry

Why are animals fasted before slaughter

to ease evisceration and reduce bacterial contamination

What is the purpose of stunning

to render animals unconscious and maintain it until death by bleeding

How many approved stunning methods are there

Chemical, mechanical, gunshot, electrical

what part of the brain must NOT be destroyed during effective stunning

medulla oblongata

What does “comatize, not kill” mean

Stunning should cause unconsciousness without stopping the heart or breathing

What are signs of a properly stunned animal?

No righting reflex, limp body, no rhythmic breathing, no response to nose pinch, pinprick on nose, or nose contact with hot water, and no vocalization

How does exsanguination work

bleeding the animal by severing major blood vessels

Why is vertical bleeding preferred for cattle

Improves blood removal efficiency

What causes transportation shrink

dehydration, feed loss, stress, and time in transit

Why do hogs shrink faster than cattle

They are monogastric and lose water more quickly

What causes chill loss

moisture evaporation during carcass chilling

Why is spray chilling better than blast chilling

It reduces moisture loss

What is breaking loss mostly caused by

Bone dust, tissue loss, and moisture evaporation

What meat item is most often shoplifted

ribeye steak

What causes cooking loss at home

overcooking, trimming, and unused portions

What is the dressing percentage formula

DP = (HCW ÷ Pay weight) x 100

dressing percentage; hot carcass weight

Why do packers want a higher DP

More carcass weight means more meat to sell

Does higher DP always mean higher animal value

No, fat and fill can inflate DP without increasing saleable meat

How does fatness affect DP

Increased fatness increased DP

How does gut fill affect DP

More fill lowers DP

Why do hogs have higher DP than cattle

they have less gut fill and smaller hides relative to body weight

Typical dressing percentages by species

sheep ~50%, cattle ~60-62%, swine ~70%

Why must the heart continue beating after stunning

to allow efficient blood removal during exsanguination

What happens if stunning is ineffective

Animals may regain consciousness, causing pain, stress, and meat quality defects

Which animals are most commonly stunned using captive bolt

cattle, sheep, and pigs

How does captive bolt stunning work

a bolt penetrates the skull, causing concussion and brain trauma to induce unconsciousness

What is the key difference between penetrating and non-penetrating captive bolt

penetrating enters the brain; non-penetrating causes concussion without penetration

What stunning method is most common for cattle

Mechanical stunning using a penetrating captive bolt

What are signs of proper captive bolt stunning in cattle

no blinking, blank stare, limp head and tongue, no righting reflex, no rhythmic breathing

What is a major risk if captive bolt placement is incorrect

Incomplete unconsciousness or immediate recovery

Why is gunshot stunning rarely used in commercial plants

Safety concerns and lack of precision in processing environments

Which species are most commonly electrically stunned

Swine and sheep

What are the three electrical stunning configurations

head-only, heat-to-back, and head-to-rib

How does electrical stunning induce unconsciousness

Electric current causes a generalized epileptic seizure in the brain

Why is the stun-to-stick interval critical for electrical stunning?

Animals can regain consciousness quickly if bleeding is delayed

What is the recommended stun-to-stick interval for electrically stunned animals

less than 60 seconds

What amperage is recommended for electrical stunning

approximately 1.25 amps

How long should electrical current be applied when stunning

less than 3 seconds

Why must animals be wetted before electrical stunning

Water improves electrical conductivity

Why are hot wands not allowed in electrical stunning

they cause burns and poor current flow

Why is double stunning prohibited

It increases stress, injury, and meat defects

What meat quality defect is commonly associated with electrical stunning

Ecchymosis (blood splash)

What physical damage can electrical stunning cause

Bone breakage due to intense muscle contractions

Which animals are commonly stunned using CO₂

Pigs

What chemical is the only approved gas for stunning

Carbon dioxide

How does CO2 stunning cause unconsciousness

High CO2 levels cause respiratory acidosis and loss of consciousness

Why is stun-to-stick interval less critical with CO2 stunning

Animals remain unconscious longer after exposure

How is the duration of unconsciousness in CO2 stunning controlled

by adjusting the length of time animals are exposed to CO2

What is the major advantage of CO2 stunning

No broken bones and minimal physical damage

What is a major welfare concern with CO2 stunning

Initial respiratory distress before unconsciousness

What form of stunning is commonly used for sheep

electrical; It’s effective and compatible with their size and anatomy

Which federal agency enforces stunning regulations in the U.S.

USDA Food Safety and Inspection Service (FSIS)

What CFR part governs humane stunning methods

9 CFR Part 313

On a diagram of a cow’s head, where should the captive bolt be places for proper stunning

At the intersection of two imaginary lines from the base of each horn to the opposite eye

What is the correct angle of the captive bolt in cattle

Perpendicular 90° to the skull

What is the correct captive bolt placement on a pigs head

Slightly above eye level, on the midline of the forehead

Why is pig captive bolt placement higher than cattle placement

Pigs have a thicker frontal bone and different brain orientation

On a sheep’s head, where should electrical stunning electrodes be placed

on either side of the head, between the eyes and ears

On a pig, where are the electrodes placed for head-only electrical stunning

On both sides of the head, behind the ears

On a pig, where are the electrodes placed for head-to-back electrical stunning

One electrode on the head and one on the back or shoulder

What is the purpose of head-to-back stunning

to induce unconsciousness and cardiac arrest

What voltage limit is required for electrical prods under HMSA?

Less than 50 volts, subject to inspector approval

When is dragging animals prohibited?

At all times unless they are stunned

When must animals have access to feed

If held longer than 24 hours

When must animals have access to water?

At all times before slaughter

Which blood vessels are severed during exsanguination?

Carotid arteries and jugular veins

Why is horizontal bleeding not recommended for swine?

It increases bruising, PSE risk, and lengthens stun-to-stick interval

Why do sheep have a lower dressing percentage than cattle?

Large GI tract, heavy fleece, and higher proportion of non-carcass components

Why do hogs have a higher dressing percentage than cattle?

Smaller GI tract, thinner hide, and no rumen