Most meat products have to go through the curing process during processing to promote the maturation of meat products, enhance their flavor, and stabilize their sensory state. Due to different curing methods and times, as well as the influence of production processes and packaging, various products with unique flavors have been formed during the processing of meat products. From a technological perspective, the quality of curing can affect the next process and determine the final product structure, flavor, color, and a series of other results. With the development of food processing science and technology, people have a new understanding of meat curing and have conducted in-depth research. Meat curing has been widely used as an important processing method in production. This article provides an overview of some basic issues related to curing.
1. Meat composition and characteristics
The main components of meat include protein, fat, water, ash and other substances. The content of these components varies due to factors such as the type of animal, age, nutrition and part. In meat processing, not only the physical properties and chemical composition of different raw meat should be considered, but also the differences in water-holding capacity and meat color, as well as pH value. The moisture content of raw meat is generally between 70% and 80%, and the crude protein is between 17% and 22%. The crude fat varies more depending on the breed and part. The ash content is about 1%.
Meat temperature is a very important link in the processing. From the moment of slaughter, the meat begins to be contaminated by bacteria, which is an inevitable process. Therefore, temperature control of the meat is a necessary condition for each link. So factors such as room temperature, processing machines and water temperature are all crucial for the meat. The duration of time is also a necessary condition affecting the process. The temperature for curing is limited to between 3 and 5 degrees Celsius, and the curing time depends on the size of the meat and the method. The termination temperature for chopping and mixing should be below 12 degrees Celsius. Smoking and drying should avoid the temperature range of 20 to 40 degrees Celsius, which is suitable for microbial growth.
2. The purpose of meat curing and curing materials
The purpose of curing
The purposes of curing include the following aspects: preventing the spoilage of meat and extending its shelf life; giving the meat a good color due to the effect of nitrite; improving the water-holding capacity and binding force of the meat; and enhancing the flavor structure and taste of the meat through curing.
Curing materials and their functions
1) Salt
The main component of salt is NaCl, with a content of over 85%. Besides, it also contains impurities such as Mg and Ca. After the hydrolysis of salt, water molecules gather around sodium ions and chloride ions to form hydrated ions. An increase in the number of hydrated ions leads to a reduction in free water, which to a certain extent lowers the water activity. When the water activity is less than 0.75, most bacteria and yeasts cannot grow. When the salt concentration is 1%, its osmotic pressure will damage the cell membranes of microorganisms, causing them to lose water and thus inhibiting their growth.
In addition, the enzymes secreted by microorganisms will denature in a low-concentration salt solution, as the salt will bind with the peptides in the enzyme proteins, altering their original form and structure and destroying their ability to break down meat proteins. These conditions are not conducive to the growth of microorganisms.
2) Water-holding capacity of meat products
It refers to the ability of meat and the water added to it to retain water. The water content of most animal muscles is around 75%. Whether this water can be retained in its original state in the largest amount after heating or whether the water added from the outside can be well retained under the influence of external conditions is an important factor in determining the quality of the product.
Through experiments, it has been found that the water-holding capacity is the highest when the ionic strength of sodium chloride is between 0.8 and 1.0. Beyond this range, the water-holding capacity decreases. In the curing process, the water-holding capacity is mainly affected by the salt content. The main substances responsible for the water-holding capacity and binding force of meat are the proteins in the muscle. Under normal curing conditions, the ionic strength of sodium chloride is around 0.6, and the treatment time is 24 to 48 hours. Due to the effect of ionic strength, a large amount of myosin proteins in the muscle are extracted, causing non-soluble proteins to transform into soluble ones or gel-like proteins to transform into sol-like ones. This transformation is the fundamental reason for the increase in the water-holding capacity of the meat. Gel-like myosin can also absorb a certain amount of water and swell due to solvation, but this water-holding capacity without sufficient ionic strength is very limited. During heating, due to protein denaturation, the non-polar groups originally hidden in the secondary structure of the protein are exposed, and the hydrophobicity of these non-polar groups greatly reduces the water-holding capacity of the meat. Un-cured meat loses water during heating for this reason. After curing, the gel-like myosin in the meat is transformed into a sol-like state with a certain concentration, and its swelling capacity is greatly enhanced, achieving a highly solvated state. Under a certain ionic strength, the solvation process is most complete, and the water-holding capacity reaches its maximum. During processing, the sol-like myosin is released from the cells and acts as a binder. During heating, this sol-like protein forms large aggregates, enclosing the water and fat within the network structure of the aggregates.
Of course, in actual processing, a certain amount of pyrophosphate or polyphosphate is often added to increase the extraction of proteins, strengthen the binding force between tissues, and improve the water-holding capacity of the product.
The mechanism of color development during curing
To make cured meat have a bright red color, inhibit the growth of microorganisms, and generate a special flavor, nitrate or nitrite is often added to the meat curing agent. Nitrate is reduced to nitrite by reductive bacteria in the meat, which is usually the case for products that are cured for a long time.
We all know that the red substance in meat is mainly myoglobin and hemoglobin. Hemoglobin is lost due to the slaughter of the animal. In the presence of nitrite ions, myoglobin reacts with oxygen to form the reddish-brown metmyoglobin. Nitrite is reduced to nitric oxide by bacteria in the meat, and nitric oxide reacts with metmyoglobin to form nitric oxide myoglobin. After heating, it generates the bright red nitroso-myoglobin chromogen. In actual curing processes, sodium L-ascorbate is often added as a color-developing aid to accelerate the reduction of metmyoglobin and prevent the oxidation of myoglobin, thereby stabilizing the color of meat products.
1) Residual nitrite content
Nitrite is a chemically active substance that acts as an oxidizing agent, releasing O2 and turning into NO; conversely, it can also be oxidized to nitric acid. During the reaction, nitrite is consumed in the meat, but the consumption is not straightforward. Therefore, the residual nitrite and nitrate content does not have a fixed relationship with the curing time. To ensure consumer health, different countries have regulations on the residual nitrite content.
2) Other curing agents
In the curing process of meat products, main curing agents such as salt and nitrite are used. In addition, depending on the product, polyphosphates, glucose, Vc, spices, etc. are added during the curing process to create different flavors. Phosphates, mainly sodium tripolyphosphate, sodium hexametaphosphate, and sodium pyrophosphate, are used as water retention agents. The addition of phosphates during curing increases the pH value, improving the water-holding capacity of the meat, enhancing tenderness, and increasing adhesiveness. The combined use of these phosphates is more effective than the single use. Commonly, a mixture of 20% sodium hexametaphosphate, 40% sodium tripolyphosphate, and 40% sodium pyrophosphate is used, typically at a rate of 0.2% to 0.5% of the meat weight. The addition of spices can enhance the special flavor of the product and eliminate off-flavors. Sometimes, preservatives and antioxidants are added during curing, but this is based on product design needs and is somewhat distant from the true purpose of curing.
3) Maltol
In meat product processing, instead of using nitrite, maltol can be used in combination with iron salts during the processing to achieve the same color as that obtained with nitrite. Maltol has the important chemical property of turning purple-red when it encounters iron ions. Recommended iron salts include ferric gluconate and ferric citrate, which not only achieve the desired color but also increase the content of trace elements. Maltol should be used at 0.7% of the meat weight, but the formation of microorganisms during the curing process must be controlled. Red rice pigment is a natural pigment extracted from red rice, which is very stable and has good dyeing properties for proteins. However, the formation of microorganisms should also be considered.
3. Methods of Curing Meat
The correct choice of curing method plays an important role in the subsequent processing of the product and the quality, shape, etc. of the final product.
1) Dry curing method
The dry curing method refers to the curing method where the curing agent is directly mixed with the meat or applied to the surface of the meat, or the large meat blocks or meat particles are stirred evenly to facilitate the absorption of the curing agent. This method has the advantages of simple operation, less nutrient loss, and high salt and color-fixing agent concentration around the meat blocks, which inhibits the reproduction of bacteria and makes it easy to preserve for a long time. The disadvantage is that the fat is prone to oxidation. The dry curing method is suitable for Chinese hams, Chinese cured meats, dry sausages, air-dried poultry, etc. The dry curing method has a long cycle, which has a significant impact on the batch and scale of the product.
2) Wet curing method
The wet curing method is a curing method where a certain concentration of curing agent solution is prepared in a container in advance, and the curing agent is allowed to penetrate into the interior of the meat through diffusion and water transfer to achieve a relatively uniform distribution until its concentration is the same as that of the salt solution. The wet curing method can better promote the maturation of the meat, especially for ground meat, when cured at 0-4℃ for 24-48 hours, the water-holding capacity and binding capacity are greatly increased, resulting in good color, flavor, and texture. The disadvantage is that the long curing time allows the reproduction of microorganisms, which can lead to product spoilage, fermentation, etc. The wet curing method is not commonly used now, mainly due to the introduction of injection and tumbling processes, but some Chinese braised and stewed meat products and Western-style hams without injection still use this method, resulting in products with unique flavor characteristics.
3) Semi-dry and semi-wet curing method
The semi-dry and semi-wet curing method is a curing method where the curing agent is dissolved in a small amount of water and then mixed and stirred evenly with the meat. This method combines the advantages of dry curing and wet curing methods and is often used in fresh sausages, meat paste hams, etc.
4) Injection curing method
The injection curing method is a more advanced curing method than the previous two methods. It is a new curing method that emerged with the development of food machinery. It involves preparing the curing brine in advance and injecting it into the meat using an injector, followed by static placement or tumbling. The injection curing method combines the advantages of wet curing and dry curing methods, featuring rapid distribution of the curing solution, short curing cycle, good effect, and high efficiency, and is widely used in meat product processing. This method is usually combined with tumbling processing and is an important means of modern meat product processing. The injection curing method is suitable for Western-style hams, bone-in poultry, Chinese soft-packaged block meat products, exposed meat block sausages, and some Western-style roasted meats, etc.
4. Other Factors Affecting the Pickling Effect
1) Temperature and Time
High temperature can accelerate the curing process of meat, shortening the curing time. Conversely, low temperature will prolong the curing time. However, excessively high temperatures can lead to increased microbial growth and spoilage of the meat. Measures: Select appropriate temperature and time. Generally, during meat curing, the ambient temperature should be between 0-4℃, and the meat temperature should not exceed 7℃. Curing for 18-24 hours at this temperature can achieve good curing quality.
2) Air (Oxidation)
When meat is cured and exposed to air, the surface turns brown due to the action of oxygen. Measures: Cover the upper layer of the cured meat with clean cloth (plastic paper), etc.
3) Complex Phosphates
Excessive use of phosphates can affect the coloration of meat, as it raises the pH value too high. The best pH value is 6.0. Measures: Add according to food additive usage standards. Generally, the addition of complex phosphates should be ≤0.5%.
4) Nitrate or Nitrite
The addition of nitrate or nitrite is essential for good coloration of meat. However, excessive use can lead to high nitrite residues, affecting human health, and excessive HNO2 in the meat can cause the formation of green substances. Insufficient use can also affect the coloration effect due to insufficient nitrite. Measures: Add according to additive usage standards, i.e., 0.15g/Kg of meat. Use color enhancers such as sodium ascorbate in combination with nitrite, but add them after the nitrite.
5) Low Nitrite Curing System
Currently, there is no complete substitute for nitrite in meat curing. Therefore, a small amount of nitrite still needs to be added to the curing system, but other substitutes are also required. These substitutes mainly play roles in color enhancement, inhibition of bacteria, anti-toxin, and blocking the formation of nitrosamines.
Research has found that a mixture of 550mg/kg of ascorbate and 550mg/kg of tocopherol is very effective in inhibiting the formation of nitrosamines. The addition of nitrite can be reduced to 120mg/kg, but further toxicity and mutagenicity tests are needed.
Adding lactic acid-producing bacteria to meat products requires an increase in the addition of sucrose, and the addition of nitrite can be reduced to 40mg/kg. The sensory and taste are the same as when using nitrite alone. Lactic acid-producing bacteria such as Streptococcus lactis, Lactobacillus bulgaricus, and Lactobacillus acidophilus can be selected. The concentration of added lactic acid bacteria should be 0.2% to 1%, with an addition of 10mL/kg, which can inhibit the growth of other bacteria and reduce the nitrite content. Experiments have shown that the addition of nitrite is only 0.01% to 0.06% of the original amount.
Currently, there are potassium sorbate, lactic acid, tannic acid, gallic acid, fumaric acid, ethylenediaminetetraacetic acid, and hypophosphite salts, etc.
5. Conclusion
Curing meat products is an important method in meat processing. Curing meat can improve the flavor and quality of meat products and enhance their anti-corrosion and antibacterial effects. However, when curing meat, it is essential to pay attention to the following: choose the curing method correctly based on the nature of the product, use curing agents reasonably, and pay attention to and strengthen the prevention of influencing factors. Only in this way can the curing quality of meat be guaranteed and high-quality meat products be made.
1. Meat composition and characteristics
The main components of meat include protein, fat, water, ash and other substances. The content of these components varies due to factors such as the type of animal, age, nutrition and part. In meat processing, not only the physical properties and chemical composition of different raw meat should be considered, but also the differences in water-holding capacity and meat color, as well as pH value. The moisture content of raw meat is generally between 70% and 80%, and the crude protein is between 17% and 22%. The crude fat varies more depending on the breed and part. The ash content is about 1%.
Meat temperature is a very important link in the processing. From the moment of slaughter, the meat begins to be contaminated by bacteria, which is an inevitable process. Therefore, temperature control of the meat is a necessary condition for each link. So factors such as room temperature, processing machines and water temperature are all crucial for the meat. The duration of time is also a necessary condition affecting the process. The temperature for curing is limited to between 3 and 5 degrees Celsius, and the curing time depends on the size of the meat and the method. The termination temperature for chopping and mixing should be below 12 degrees Celsius. Smoking and drying should avoid the temperature range of 20 to 40 degrees Celsius, which is suitable for microbial growth.
2. The purpose of meat curing and curing materials
The purpose of curing
The purposes of curing include the following aspects: preventing the spoilage of meat and extending its shelf life; giving the meat a good color due to the effect of nitrite; improving the water-holding capacity and binding force of the meat; and enhancing the flavor structure and taste of the meat through curing.
Curing materials and their functions
1) Salt
The main component of salt is NaCl, with a content of over 85%. Besides, it also contains impurities such as Mg and Ca. After the hydrolysis of salt, water molecules gather around sodium ions and chloride ions to form hydrated ions. An increase in the number of hydrated ions leads to a reduction in free water, which to a certain extent lowers the water activity. When the water activity is less than 0.75, most bacteria and yeasts cannot grow. When the salt concentration is 1%, its osmotic pressure will damage the cell membranes of microorganisms, causing them to lose water and thus inhibiting their growth.
In addition, the enzymes secreted by microorganisms will denature in a low-concentration salt solution, as the salt will bind with the peptides in the enzyme proteins, altering their original form and structure and destroying their ability to break down meat proteins. These conditions are not conducive to the growth of microorganisms.
2) Water-holding capacity of meat products
It refers to the ability of meat and the water added to it to retain water. The water content of most animal muscles is around 75%. Whether this water can be retained in its original state in the largest amount after heating or whether the water added from the outside can be well retained under the influence of external conditions is an important factor in determining the quality of the product.
Through experiments, it has been found that the water-holding capacity is the highest when the ionic strength of sodium chloride is between 0.8 and 1.0. Beyond this range, the water-holding capacity decreases. In the curing process, the water-holding capacity is mainly affected by the salt content. The main substances responsible for the water-holding capacity and binding force of meat are the proteins in the muscle. Under normal curing conditions, the ionic strength of sodium chloride is around 0.6, and the treatment time is 24 to 48 hours. Due to the effect of ionic strength, a large amount of myosin proteins in the muscle are extracted, causing non-soluble proteins to transform into soluble ones or gel-like proteins to transform into sol-like ones. This transformation is the fundamental reason for the increase in the water-holding capacity of the meat. Gel-like myosin can also absorb a certain amount of water and swell due to solvation, but this water-holding capacity without sufficient ionic strength is very limited. During heating, due to protein denaturation, the non-polar groups originally hidden in the secondary structure of the protein are exposed, and the hydrophobicity of these non-polar groups greatly reduces the water-holding capacity of the meat. Un-cured meat loses water during heating for this reason. After curing, the gel-like myosin in the meat is transformed into a sol-like state with a certain concentration, and its swelling capacity is greatly enhanced, achieving a highly solvated state. Under a certain ionic strength, the solvation process is most complete, and the water-holding capacity reaches its maximum. During processing, the sol-like myosin is released from the cells and acts as a binder. During heating, this sol-like protein forms large aggregates, enclosing the water and fat within the network structure of the aggregates.
Of course, in actual processing, a certain amount of pyrophosphate or polyphosphate is often added to increase the extraction of proteins, strengthen the binding force between tissues, and improve the water-holding capacity of the product.
The mechanism of color development during curing
To make cured meat have a bright red color, inhibit the growth of microorganisms, and generate a special flavor, nitrate or nitrite is often added to the meat curing agent. Nitrate is reduced to nitrite by reductive bacteria in the meat, which is usually the case for products that are cured for a long time.
We all know that the red substance in meat is mainly myoglobin and hemoglobin. Hemoglobin is lost due to the slaughter of the animal. In the presence of nitrite ions, myoglobin reacts with oxygen to form the reddish-brown metmyoglobin. Nitrite is reduced to nitric oxide by bacteria in the meat, and nitric oxide reacts with metmyoglobin to form nitric oxide myoglobin. After heating, it generates the bright red nitroso-myoglobin chromogen. In actual curing processes, sodium L-ascorbate is often added as a color-developing aid to accelerate the reduction of metmyoglobin and prevent the oxidation of myoglobin, thereby stabilizing the color of meat products.
1) Residual nitrite content
Nitrite is a chemically active substance that acts as an oxidizing agent, releasing O2 and turning into NO; conversely, it can also be oxidized to nitric acid. During the reaction, nitrite is consumed in the meat, but the consumption is not straightforward. Therefore, the residual nitrite and nitrate content does not have a fixed relationship with the curing time. To ensure consumer health, different countries have regulations on the residual nitrite content.
2) Other curing agents
In the curing process of meat products, main curing agents such as salt and nitrite are used. In addition, depending on the product, polyphosphates, glucose, Vc, spices, etc. are added during the curing process to create different flavors. Phosphates, mainly sodium tripolyphosphate, sodium hexametaphosphate, and sodium pyrophosphate, are used as water retention agents. The addition of phosphates during curing increases the pH value, improving the water-holding capacity of the meat, enhancing tenderness, and increasing adhesiveness. The combined use of these phosphates is more effective than the single use. Commonly, a mixture of 20% sodium hexametaphosphate, 40% sodium tripolyphosphate, and 40% sodium pyrophosphate is used, typically at a rate of 0.2% to 0.5% of the meat weight. The addition of spices can enhance the special flavor of the product and eliminate off-flavors. Sometimes, preservatives and antioxidants are added during curing, but this is based on product design needs and is somewhat distant from the true purpose of curing.
3) Maltol
In meat product processing, instead of using nitrite, maltol can be used in combination with iron salts during the processing to achieve the same color as that obtained with nitrite. Maltol has the important chemical property of turning purple-red when it encounters iron ions. Recommended iron salts include ferric gluconate and ferric citrate, which not only achieve the desired color but also increase the content of trace elements. Maltol should be used at 0.7% of the meat weight, but the formation of microorganisms during the curing process must be controlled. Red rice pigment is a natural pigment extracted from red rice, which is very stable and has good dyeing properties for proteins. However, the formation of microorganisms should also be considered.
3. Methods of Curing Meat
The correct choice of curing method plays an important role in the subsequent processing of the product and the quality, shape, etc. of the final product.
1) Dry curing method
The dry curing method refers to the curing method where the curing agent is directly mixed with the meat or applied to the surface of the meat, or the large meat blocks or meat particles are stirred evenly to facilitate the absorption of the curing agent. This method has the advantages of simple operation, less nutrient loss, and high salt and color-fixing agent concentration around the meat blocks, which inhibits the reproduction of bacteria and makes it easy to preserve for a long time. The disadvantage is that the fat is prone to oxidation. The dry curing method is suitable for Chinese hams, Chinese cured meats, dry sausages, air-dried poultry, etc. The dry curing method has a long cycle, which has a significant impact on the batch and scale of the product.
2) Wet curing method
The wet curing method is a curing method where a certain concentration of curing agent solution is prepared in a container in advance, and the curing agent is allowed to penetrate into the interior of the meat through diffusion and water transfer to achieve a relatively uniform distribution until its concentration is the same as that of the salt solution. The wet curing method can better promote the maturation of the meat, especially for ground meat, when cured at 0-4℃ for 24-48 hours, the water-holding capacity and binding capacity are greatly increased, resulting in good color, flavor, and texture. The disadvantage is that the long curing time allows the reproduction of microorganisms, which can lead to product spoilage, fermentation, etc. The wet curing method is not commonly used now, mainly due to the introduction of injection and tumbling processes, but some Chinese braised and stewed meat products and Western-style hams without injection still use this method, resulting in products with unique flavor characteristics.
3) Semi-dry and semi-wet curing method
The semi-dry and semi-wet curing method is a curing method where the curing agent is dissolved in a small amount of water and then mixed and stirred evenly with the meat. This method combines the advantages of dry curing and wet curing methods and is often used in fresh sausages, meat paste hams, etc.
4) Injection curing method
The injection curing method is a more advanced curing method than the previous two methods. It is a new curing method that emerged with the development of food machinery. It involves preparing the curing brine in advance and injecting it into the meat using an injector, followed by static placement or tumbling. The injection curing method combines the advantages of wet curing and dry curing methods, featuring rapid distribution of the curing solution, short curing cycle, good effect, and high efficiency, and is widely used in meat product processing. This method is usually combined with tumbling processing and is an important means of modern meat product processing. The injection curing method is suitable for Western-style hams, bone-in poultry, Chinese soft-packaged block meat products, exposed meat block sausages, and some Western-style roasted meats, etc.
4. Other Factors Affecting the Pickling Effect
1) Temperature and Time
High temperature can accelerate the curing process of meat, shortening the curing time. Conversely, low temperature will prolong the curing time. However, excessively high temperatures can lead to increased microbial growth and spoilage of the meat. Measures: Select appropriate temperature and time. Generally, during meat curing, the ambient temperature should be between 0-4℃, and the meat temperature should not exceed 7℃. Curing for 18-24 hours at this temperature can achieve good curing quality.
2) Air (Oxidation)
When meat is cured and exposed to air, the surface turns brown due to the action of oxygen. Measures: Cover the upper layer of the cured meat with clean cloth (plastic paper), etc.
3) Complex Phosphates
Excessive use of phosphates can affect the coloration of meat, as it raises the pH value too high. The best pH value is 6.0. Measures: Add according to food additive usage standards. Generally, the addition of complex phosphates should be ≤0.5%.
4) Nitrate or Nitrite
The addition of nitrate or nitrite is essential for good coloration of meat. However, excessive use can lead to high nitrite residues, affecting human health, and excessive HNO2 in the meat can cause the formation of green substances. Insufficient use can also affect the coloration effect due to insufficient nitrite. Measures: Add according to additive usage standards, i.e., 0.15g/Kg of meat. Use color enhancers such as sodium ascorbate in combination with nitrite, but add them after the nitrite.
5) Low Nitrite Curing System
Currently, there is no complete substitute for nitrite in meat curing. Therefore, a small amount of nitrite still needs to be added to the curing system, but other substitutes are also required. These substitutes mainly play roles in color enhancement, inhibition of bacteria, anti-toxin, and blocking the formation of nitrosamines.
Research has found that a mixture of 550mg/kg of ascorbate and 550mg/kg of tocopherol is very effective in inhibiting the formation of nitrosamines. The addition of nitrite can be reduced to 120mg/kg, but further toxicity and mutagenicity tests are needed.
Adding lactic acid-producing bacteria to meat products requires an increase in the addition of sucrose, and the addition of nitrite can be reduced to 40mg/kg. The sensory and taste are the same as when using nitrite alone. Lactic acid-producing bacteria such as Streptococcus lactis, Lactobacillus bulgaricus, and Lactobacillus acidophilus can be selected. The concentration of added lactic acid bacteria should be 0.2% to 1%, with an addition of 10mL/kg, which can inhibit the growth of other bacteria and reduce the nitrite content. Experiments have shown that the addition of nitrite is only 0.01% to 0.06% of the original amount.
Currently, there are potassium sorbate, lactic acid, tannic acid, gallic acid, fumaric acid, ethylenediaminetetraacetic acid, and hypophosphite salts, etc.
5. Conclusion
Curing meat products is an important method in meat processing. Curing meat can improve the flavor and quality of meat products and enhance their anti-corrosion and antibacterial effects. However, when curing meat, it is essential to pay attention to the following: choose the curing method correctly based on the nature of the product, use curing agents reasonably, and pay attention to and strengthen the prevention of influencing factors. Only in this way can the curing quality of meat be guaranteed and high-quality meat products be made.
