Test 2 Continued

Question 1

Do the functions of muscle stop at death?

Answer 1

No

Question 2

What can still occur postmortem?

Answer 2

Metabolism and contraction.

Question 3

During and after slaughter, the body is attempting to maintain what?

Answer 3

Homeostasis

Question 4

Homeostasis is maintained by these, which do not exist in a postmortem system.

Answer 4

Nervous and endocrine systems.

Question 5

Conversion time for chickens, pigs and cattle?

Answer 5

Chickens: 30 mins

Pigs: 6 hours

Cattle: 12-24 hours

Question 6

What are the steps of conversion?

Answer 6

Immobilization, exsanguination, and shift in metabolism.

Question 7

What is it when an animal is unconscious and it’s nervous system is disrupted?

Answer 7

Immobilization

Question 8

What are the three types of stunning?

Answer 8

Electric bolt, chemical (CO2), and mechanical.

Question 9

What is the removal of blood, which severely compromises homeostasis and decreases blood pressure?

Answer 9

Exsanguination

Question 10

Metabolism shifts from aerobic to…

Answer 10

Anaerobic

Question 11

Loss of circulation causes loss of what?

Answer 11

Temperature control.

Question 12

What is the peak temperature in carcasses after slaughter?

Answer 12

107-109 F

Question 13

At high temperature proteins become what?

Answer 13

Denatured

Question 14

Stiffness of death is what?

Answer 14

Rigor mortis.

Question 15

Rigor mortis causes the formation of what?

Answer 15

Permanent actin and myosin bonds.

Question 16

What are the steps of rigor mortis?

Answer 16

Delay, onset, completion, and resolution.

Question 17

What is delay?

Answer 17

Muscle at original length and flexibility; calcium can be held within the SR.

Question 18

What is onset?

Answer 18

Muscle starts to lose flexibility; sarcomere starts to shorten and tension increases, which causes toughness; contraction occurs due to presence of ATP and leakage of calcium from SR.

Question 19

What is completion?

Answer 19

Muscle is at max tension, actin/myosin cross bridges are fully formed, no ATP or capacity for protection of ATP exist within the muscle.

Question 20

What is resolution?

Answer 20

Slight decrease in tension caused by protein degradation.

Question 21

Shift in metabolism from aerobic to anaerobic causes an increase in production of what?

Answer 21

Lactic acid

Question 22

What is the normal pH of muscle?

Answer 22

7.2

Question 23

What is the normal pH of meat?

Answer 23

5.3-5.8

Question 24

What directly influences meat quality and what do they entail?

Answer 24

Rate: how fast pH drops.

Extent: how low pH gets.

Question 25

What influences rigor?

Answer 25

Depletion of ATP.

Question 26

What is pH decline?

Answer 26

Glycogen to glucose to lactic acid and ATP.

Question 27

What is PSE?

Answer 27

Rapid decline of pH postmortem due to acute stress antemortem, which causes a buildup of lactic acid prior to death.

Question 28

In PSE the acidic conditions coupled with increased temperature causes protein denaturation, which leads to what?

Answer 28

Loss of WHC.

Question 29

What is the pale appearance caused by?

Answer 29

Free water being purged from the muscle and myoglobin being lost.

Question 30

What makes meat soft?

Answer 30

Lack of water.

Question 31

What causes the meat to be excavated?

Answer 31

Free water of surface of product and leaks/drips water.

Question 32

What has a very slow ph decline and high ultimate ph?

Answer 32

Dark, firm, dry.

Question 33

What is the ultimate pH in DFD?

Answer 33

6.2-6.4

Question 34

What causes DFD?

Answer 34

Chronic antemortem stress.

Question 35

Chronic stress leads to a lack of this in postmortem muscle, meaning very little atp and lactic acid generation.

Answer 35

Glycogen

Question 36

What causes the dark appearance in meat?

Answer 36

Retained water due to high pH and retained myoglobin.

Question 37

What causes firmness in meat?

Answer 37

Retained water.

Question 38

What causes dryness in meat?

Answer 38

No free water leaves so no water appears on the surface.

Question 39

What happens 24 hours postmortem?

Answer 39

There is no ATP, completion of rigor, pH decline has stopped, and temperature decline should be complete.

Question 40

What is electrical stunning?