45 Practical Questions and Answers in Slaughter and Meat Processing

 1. What are the site selection requirements for the slaughterhouse?

Answer:

The slaughterhouse should be established in an area where the terrain is relatively high, dry, with sufficient water sources, convenient transportation, no harmful gases, ash, and other pollution sources, and easy to discharge sewage. The slaughterhouse shall not be built in densely populated areas, and the distance shall be at least 500 meters, and the downwind and upwind shall be avoided as far as possible in residential areas.

2. What are the ground design standards for slaughterhouses?

Answer:

2.1. The ground should be made of waterproof, non-slip, non-moisture-absorbing, washable, corrosion-resistant, and non-toxic materials; the slope should be 1% to 2% (the slaughter workshop should be above 2%).  

 2.2. No cracks on the surface, no local water accumulation, easy to clean and disinfect.

 2.3. Set up a clear trench and it should be in an isolated shape, set up a drainage outlet, and set a net cover.

3. What is the purpose of resting livestock before slaughter?

Answer:

Resting before slaughter is beneficial to bloodletting, eliminating stress response, reducing blood congestion in animals, and increasing the commodity value of meat.

4. When slaughtering livestock, what is the purpose of stunning?

Answer:

4.1. Make animals lose consciousness and reduce pain.

4.2. Avoid animals struggling when being slaughtered and consume more glycogen to ensure meat quality.

5. What is the purpose of sanitary inspection after slaughter?

Answer:

5.1. The purpose of post-mortem inspection is to find various organs and tissues that hinder human health or have lost their nutritional value, and make correct judgments and treatments.

5.2. Post-mortem inspection is the most important part of meat hygiene inspection, and it is the continuation and supplement of antemortem inspection. 

6. What are the precautions for poultry scalding?

Answer:

6.1. Strictly control the water temperature and blanching time.

6.2. Hot water should be kept clean.

6.3. Poultry carcasses that are not dead or incompletely bleeding cannot be scalded, otherwise the value of the product will be reduced.

7. What is the necessity of carcass grading?

Answer:

The grade of the carcass directly reflects the meat production performance of the meat livestock and the quality of the meat. It has a good standard and guiding effect on production and consumption, is conducive to the formation of a high-quality and high-price market law, and helps products to become high-quality The direction of development.

8. Where is the thickness of the backfat of the livestock measured on the carcass?

Answer:

Measure the thickness of the backfat perpendicular to the outer surface at 3/4 of the length of the eye muscles, starting from the side close to the spine at the ophthalmos section between the 12 to 13 thoracic ribs. 

9. What are the characteristics of bacon meat?

Answer:

It is smoked rib meat (square meat), its flavor has a palatable salty taste, a strong smoky aroma, the skin is oily golden yellow, the lean meat is brownish red, and the meat is bright after cutting.

10. What is the role of connective tissue?

Answer:

Connective tissue is the tissue that connects and fixes all parts of the animal body. It is distributed in all parts of the body, constitutes the scaffold of organs, blood vessels, and lymphatic vessels, surrounds and supports muscles, tendons, and nerve bundles, and connects the skin to the body.

11. What is the role of adipose tissue?

Answer:

The accumulation of adipose tissue in the muscle bundle can make the muscle appear marbling and improve the meat’s tender and juicy characteristics. Fat plays a role in protecting tissues and organs and providing energy to living tissue. It is the source of the main flavor substances of meat varieties. 

 12. Where is the fat deposited in the animal’s body?

Answer:

It has a great relationship with animal species, breed, age, gender, and degree of fattening. It is mainly deposited in abdominal suet, subcutaneous fat tissue, mesenteric, and omentum, and finally deposited between muscle bundles and muscle fibers. 

13. Why do the muscles of livestock become sour after slaughter (that is, the pH value drops)?

Answer:

13.1. Muscle glycogen is fermented under anaerobic conditions to produce lactic acid。

13.2. ATP breaks down to produce phosphate ions.

14. Why does meat darken during storage?

Answer:

14.1. Myoglobin is oxidized to produce metmyoglobin.

14.2. Fat is oxidized, causing adipose tissue to appear yellow.

15. What methods can be used to prevent the flesh color from darkening during storage?

Answer:

15.1. Vacuum packaging is used to isolate air and meat from contact. At the same time, it can inhibit the reproduction of microorganisms under anaerobic conditions and reduce the formation of metmyoglobin.

15.2. Inflatable packaging is used, filled with chemically inactive inert gas to adjust the air in the packaging bag to inhibit the reproduction of microorganisms and prevent the oxidation of myoglobin and fat.

15.3. Antioxidants are added to meat, and it is common to add vitamin E and vitamin C to inhibit the oxidation of meat.

16. What are the characteristics of black beef?

Answer:

The meat is dark in color, the meat has a high pH value, hard texture, high water power, and poor oxygen penetration. Mainly caused by the slaughtering of cattle and other livestock animals under stress.

17. What are the factors that affect meat tenderness?

Answer:

Factors related to antemortem factors are:

17.1. The Species, varieties, and gender

17.2. The age of the animal

17.3. The Muscle part

17.4. The Muscle temperature

17.5. The Muscle maturity

17.6. The Cooking methods

18. What is the purpose of tenderizing meat?

Answer:

For beef and mutton with high connective tissue content, because it looks old when eaten and is difficult to chew, it is especially not suitable for the elderly’s food. Therefore, it is necessary to destroy its structure and connective tissue to make the meat tender and juicy, and easy to chew.

19. How many ways are there for artificial tenderization of meat?

Answer:

19.1. Treated with tenderizing enzymes, mainly plant proteases, such as bromelain and papain, whose main function is to hydrolyze the collagen and elastin of the connective tissue, so that the meat can be tenderized.

19.2. Electrical stimulation can cause muscle fiber contraction and spasm, accelerate muscle stiffness, and shorten the maturity time.

19.3. The vinegar method, soaking the meat in an acidic solution, reduces the pH of the meat and speeds up the maturation process of the meat.

19.4. Using the pressure method, high pressure is applied to the meat to destroy muscle fibers, release Ca2+, activate proteolytic enzymes, and accelerate the maturation process of meat.

20. What is the cause of juicy meat?

Answer:

20.1. Pre-slaughter factors mainly include livestock and poultry animal species, age, pre-slaughter transportation, captivity and hunger, energy level, physical condition, etc.

20.2. The post-slaughter factors mainly include the slaughter process, carcass storage, the time of the onset of dead body stiffness, the anatomical position of the matured (maturity) muscle, the thickness of fat, the change of pH value, the activity of proteolytic enzymes, and processing conditions.

21. What are the factors that affect the water holding capacity?

Answer:

21.1. Pre-slaughter factors mainly include livestock and poultry animal species, age, pre-slaughter transportation, captivity and hunger, energy level, physical condition, etc.

21.2. The post-slaughter factors mainly include the slaughter process, carcass storage, the time of the onset of dead body stiffness, the anatomical position of the matured (maturity) muscle, the thickness of fat, the change of pH value, the activity of proteolytic enzymes, and processing conditions.

22. What is the purpose of cooling the meat?

Answer:

22.1. The purpose of meat cooling is to quickly reduce the temperature of the meat within a certain temperature range.

22.2.Minimize the growth and reproduction of microorganisms on the surface of the meat, and form a film on the surface of the meat.

22.3. Weaken enzyme activity and delay meat maturity time.

22.4. Reduce the evaporation of water in the meat and extend the preservation time of the meat. 

23. What is the difference between slow freezing and fast freezing?

Answer:

23.1. Slow freezing: The freezing time is long, the ice formation process in the meat is slow, the number of ice crystals is small, the volume of ice crystals is large, and the meat is frozen after freezing, and the meat juice is lost.

23.2. Fast freezing: The freezing process is faster, the smaller the ice crystals formed, the smaller the volume of the ice crystals, and the less gravy is lost when the meat is frozen after freezing. 

24. What is the purpose of frozen meat?

Answer:

Prevent various changes of frozen meat, in order to achieve the purpose of long-term storage of frozen meat. 

25. How to prevent meat from freezing and burning during the freezing process of fresh meat?

Answer:

25.1. Packed with polyethylene film to isolate the air and prevent oxidation and moisture sublimation.

25.2. To cross the ice coat, put the frozen carcass into the water at about 1℃ in time, so that a thin layer of ice is formed on the surface of the carcass to prevent the oxidation of the meat.

26. What are the internal factors for the loss of meat quality when meat is thawed?

Answer:

26.1. The closer the PH value of muscle is to the isoelectric point of myosin, the more serious the loss of gravy.

26.2. The greater the degree of mechanical damage of muscle tissue, the more serious the loss of meat. The mechanical damage mainly comes from the squeezing action of ice crystals.

26.3. The greater the concentration of salt ions in the tissue fluid of muscle tissue, the more severe the dehydration of the cells, which leads to protein denaturation, especially after the muscle freezes, it is prone to loss of meat juice when it is thawed.

27. What are the functions of radiation preservation in meat storage?

Answer:

27.1. Control Trichinella, the larvae of Trichinella are sensitive to radiation, and the use of gamma rays can make Trichinella lose their reproductive ability.

27.2. Extend shelf life

27.3. Sterilization preservation

28. What is the role of vacuum packaging?

Answer:

28.1. Inhibit the growth of microorganisms and avoid contamination of external microorganisms. The spoilage of food is mainly due to the growth of microorganisms, especially aerobic microorganisms. Vacuum can create an oxygen-deficient environment and inhibit the growth of many spoilage microorganisms.

28.2. Slow down the oxidation rate of fat in meat, and also have a certain inhibitory effect on enzyme activity.

28.3. Reduce product water loss and maintain product weight.

28.4. It can be used in combination with other methods, such as vacuuming and then filling with carbon dioxide and other gases. It can also be used in combination with some common antiseptic methods, such as dehydration, pickling, thermal processing, freezing and chemical preservation, etc.

28.5. Clean products, increase market effects, and better achieve market goals.

29. What are the requirements for vacuum packaging materials?

Answer:

29.1. The main purpose of gas barrier is to prevent the oxygen in the atmosphere from re-entering the vacuumized packaging bag and avoid the growth of aerobic bacteria. Ethylene and ethylene-vinyl alcohol copolymers have good gas barrier properties. If the requirements are very strict, a layer of aluminum foil can be used.

29.2. Water vapor barrier property, that is, it should be able to prevent product moisture from evaporating. The most commonly used materials are polyethylene, polystyrene, polypropylene, polyvinylidene chloride, and other films.

29.3. The scent barrier performance should be able to maintain the scent of the product itself and prevent some external bad odors from penetrating into the packaging product. Polyamide and polyethylene mixed materials can generally meet the requirements in this regard.

29.4. Shading, the light will promote the oxidation of meat and affect the color of the meat. As long as the product is not directly exposed to the sun, a transparent film without shading is usually used. In order of increasing shading efficiency, the methods used are: printing, coloring, polyvinylidene chloride coating, gold coating, adding a layer of aluminum foil, etc.

29.5. Mechanical properties, the most important mechanical properties of packaging materials are the ability to prevent tearing and sealing damage. 

30. What are the problems with vacuum packaging?

Answer:

30.1. Color, the color of meat is one of the main factors that determine the shelf life of fresh meat. Fresh meat is vacuum packaged, and the oxygen partial pressure is low. Myoglobin produces metmyoglobin, and the fresh meat is reddish-brown.

30.2. In terms of bacteriostasis, although vacuum packaging can inhibit the growth of most aerobic bacteria, even if the oxygen content drops to 0.8%, it still cannot inhibit the growth of aerobic Pseudomonas.

30.3.The problem of gravy exudation and weightlessness, vacuum packaging is easy to cause product deformation and gravy exudation, the sensory quality is reduced, and the weightlessness is obvious. 

31. What is the color mechanism of nitrate?

Answer:

Nitrate is first reduced to nitrite under the action of microorganisms, and finally N0 is formed. The latter forms a stable nitrosomyoglobin complex with myoglobin, which makes meat products appear bright red. 

Answer:

32. What is the role of using nitrate in the meat curing process?

Answer:

32.1. Inhibit the growth of microorganisms, especially the growth and reproduction of Clostridium botulinum.

32.2. Excellent color development, NO generated under the action of microorganisms binds to myoglobin to produce bright red nitrosomyoglobin.

32.3. Antioxidant effect delays the spoilage of cured meat.

32.4. It helps to produce the unique flavor of cured meat and inhibits the production of cooking flavor. 

33. What is the main function of using sugar in marinating meat?

Answer:

33.1.Seasoning effect

33.2. Auxotropism

33.3. Increase tenderness

33.4. Produce flavors

33.5. Adding sugar to the meat products that need to be fermented to mature will help the fermentation proceed.

34.What is the reason for the color change of the meat during the drying process?

Answer:

34.1. For physical reasons, as the water evaporates and the volume decreases, the concentration of the substance increases, and the color will naturally deepen

34.2. The chemical reason is browning caused by the browning of pigment-protein, Maillard reaction, and caramelization reaction during heating.

35. What is the role of salt in the curing process of meat?

Answer:

35.1. Highlight the role of umami. Meat products contain a lot of umami-flavored ingredients such as protein, fat, etc., which can only be expressed under a certain concentration of salty taste.

35.2. Antiseptic effect. Salt can inhibit the growth of microorganisms and prolong the shelf life of meat products through dehydration and osmotic pressure.

35.3. Salt promotes the deep penetration of nitrate, nitrite, and sugar into the muscles. However, using salt alone will make the cured meat darker in color, hard in texture, and only salty, which will affect the acceptability of the product. 

36. What is the purpose of using alkaline phosphate in the curing process of meat?

Answer:

It is to improve the water retention of meat, so that the meat can still maintain its moisture during the processing process, reduce the loss of nutrients, and at the same time maintain tenderness of the meat and increase the yield. 

37. What is the purpose of marinating?

Answer:

37.1. Increase the water retention of meat

37.2. Improve meat quality

37.3. Produce special flavored meat products 

38. Why phosphate improves meat water retention?

Answer:

38.1. Pyrophosphate and tripolyphosphate show an alkaline reaction to improve the pH of meat. Adding pyrophosphate and tripolyphosphate to meat can improve the pH of meat. This reaction is slow at low temperature, but it will be accelerated sharply during baking and smoking.

38.2. It has an integration effect on metal ions in meat. Polyphosphate has the effect of integrating with metal ions. After adding polyphosphate, the calcium ions bound to the structural protein of the muscle are integrated by the polyphosphate, and the carboxyl group in the muscle protein is freed. , Due to the electrostatic force between the carboxyl groups, the protein structure is relaxed and more water can be absorbed;

38.3. To increase the ionic strength of meat, polyphosphate is a compound with multivalent anions, so it can have a higher ionic strength at a lower concentration. Since the addition of polyphosphate increases the ionic strength of the muscle, it is beneficial to the dissociation of myosin, thus improving water retention.

38.4. The role of dissociating actomyosin, pyrophosphate and tripolyphosphate have the specific role of dissociating actin and myosin in muscle protein. And myosin has a strong water holding capacity, which improves the water holding capacity of meat.

39. What is the purpose of using sodium ascorbate and sodium erythorbate in meat curing?

Answer:

39.1. Ascorbate can chemically react with nitrous acid to increase the formation of NO and accelerate the color development process.

39.2. Ascorbate facilitates the reduction of metmyoglobin to fermyoglobin, thus speeding up the pickling speed.

39.3. Ascorbate can act as an antioxidant, thereby stabilizing the color and flavor of bacon.

39.4. Under certain conditions, ascorbate has the effect of reducing the formation of nitrous acid. 

40. What is the effect of crushing food raw materials?

Answer:

40.1. Improve product uniformity；

40.2. Can improve the tenderness of meat products 

41.What is the purpose of meat smoking?

Answer:

41.1. Give the product a special smoky flavor and enhance the fragrance. 

41.2. Make the appearance of the product has a unique smoky color, and promote the color development of nitrated meat products.

41.3. Dehydrate and dry, sterilize, prevent spoilage and make the meat products storage-resistant.

41.4. Smoke components penetrate into the meat to prevent fat oxidation.

42. What are the factors that affect the amount of smoke deposition？

Answer:

42.1. Moisture content of food surface

42.2. Smoke density

42.3. Air velocity and relative humidity in the smoking room

43.What is the purpose of meat drying？

Answer:

43.1. Inhibit the activity of microorganisms and enzymes, improving the preservation of meat products.

43.2. Reduce the weight of meat products, reduce the volume, and facilitate transportation.

43.3. It is to improve the flavor of meat products and adapt to consumer preferences.

44. What is the purpose of the meat in the cooking process?

Answer:

44.1. Improve the sensory properties, make the meat stick and solidify, produce physical changes such as hardness, tooth feel, and elasticity different from raw meat, fix the shape of the product, so that the product can be cut into slices.

44.2. Make the product produces a unique flavor and reach the cooked.

44.3. Kill microorganisms and parasites, improve the storage durability of products.

44.4. Stabilize the color of the meat.

45. What is the function of frying?

Answer:

45.1. Dehydrate and harden the surface of the fried raw material food, and a shell film layer appears, producing a fried flavor.

45.2. Under high temperature, the fried raw materials are quickly cured in a short time, the surface of the product forms a dry film, the evaporation of water inside the product is blocked, and the collagen is hydrolyzed, making the product appear crispy on the outside and tender on the inside.