A method for regulating color stability of fresh beef at medium temperature

Abstract

This invention relates to the field of meat processing technology and discloses a method for controlling the color stability of medium-temperature fresh beef. Using Jingyuan yellow cattle as the processing object, this method sequentially controls the changes in post-slaughter physiological metabolism and physicochemical indicators of beef through three core processes: standardized pre-slaughter rest and management, standardized slaughter and rapid pre-cooling, and segmented monitoring-based medium-temperature aging. Through multi-process parameter linkage control, the final physicochemical indicators of medium-temperature fresh beef aging are stable and controllable, significantly inhibiting myoglobin oxidation and fading during storage, while balancing the water retention of the meat. This solves the industry problems of severe color deterioration, large juice loss, and large batch quality fluctuations in fresh beef during traditional processing methods. The process is suitable for continuous production in large-scale beef slaughtering and processing plants, requires no additional exogenous color-protecting additives, and achieves long-term color stability of meat products through physiological control throughout the entire process from pre-slaughter to aging, possessing good industrial application value.

Description

Technical Field

[0001] This invention relates to the field of meat processing technology, specifically to a method for controlling the color stability of fresh beef at medium temperatures. Background Technology

[0002] Jingyuan Yellow Cattle produces tender, flavorful fresh beef, making it a mainstream medium-temperature chilled beef raw material in the market. The medium-temperature aging process, which fully releases the beef's inherent flavor compounds and improves tenderness, is widely used in chilled beef production by large and medium-sized beef slaughterhouses in China. Currently, the industry's common processing model lacks a standardized pre-slaughter control system. Cattle are slaughtered directly after transportation, without restrictions on temperature, humidity, noise, and light in the breeding environment. Cattle are under constant stress, leading to significant glycogen depletion and a low initial pH in the muscle after slaughter, resulting in decreased stability of myoglobin molecules. Conventional slaughtering processes do not strictly control the interval between stunning and bleeding, leading to insufficient bleeding and residual blood clots in the muscle tissue. Hemoglobin in these clots is more prone to oxidation and browning. The pre-cooling process often uses natural cooling, resulting in a slow rate of temperature decrease in the carcass center, maintaining the internal muscle temperature within a range suitable for oxidation for an extended period, accelerating myoglobin denaturation. Traditional aging processes often rely on static aging with fixed temperature and humidity parameters, lacking a periodic multi-indicator monitoring mechanism. The aging endpoint is determined solely by a fixed duration, without considering muscle pH, color, and water retention. Different batches of cattle have varying physiological characteristics, and a uniform aging time can result in either over-aging or under-aging. Over-aged beef has an excessively low pH, causing myoglobin ferrous ions to lose electrons and oxidize, leading to a rapid decline in redness on the shelf and reduced product appearance. Under-aged beef has poor water retention, resulting in significant juice leakage into retail packaging and decreased consumer acceptance. Existing color-protecting methods largely rely on immersion in exogenous antioxidant color-protecting agents, but these residues can alter the original flavor of the beef, increase processing costs, and some additives face regulatory restrictions. The industry lacks a standardized process for integrated control throughout the entire process, from pre-slaughter resting to the aging endpoint. Independent parameter settings for each step prevent a synergistic color-protecting effect, resulting in poor color stability and inconsistent batch quality in mid-temperature fresh beef, thus limiting the market circulation cycle and premium potential of chilled beef products.

[0003] Based on this, this application provides a method for controlling the color stability of fresh beef at medium temperature. Summary of the Invention

[0004] Technical problems to be solved To address the shortcomings of existing medium-temperature fresh beef processing technologies, such as lack of pre-slaughter stress control, low standardization of pre-slaughter cooling processes, rigid and singular aging processes, and the inability to coordinate and control the physicochemical indicators of meat across multiple processes, which ultimately lead to rapid decline in redness, severe juice loss, and significant quality differences between batches of beef, exogenous color-protecting additives can alter the natural flavor of beef and increase production costs, this invention provides a method for controlling the color stability of medium-temperature fresh beef. This method coordinates and links parameters from three processes—pre-slaughter rest, pre-slaughter cooling, and medium-temperature aging—to regulate the post-slaughter muscle metabolism process. Without adding additional exogenous color-protecting agents, it relies on physiological regulation to stabilize the myoglobin structure and simultaneously optimize muscle water-holding capacity, achieving long-term stable color of medium-temperature fresh beef on the shelf, unifying the processing endpoint indicators of different batches of beef, and improving product quality consistency.

[0005] Technical solution To achieve the above objectives, the present invention provides the following technical solution: A method for controlling the color stability of fresh beef at medium temperature, specifically including the following steps: S1. Pre-slaughter rest and recuperation management: The Jingyuan yellow cattle awaiting slaughter will be rested before slaughter for 12-36 hours, during which they will have free access to energy supplements. S2. Slaughtering and Precooling Control: Slaughtered according to standard procedures, the pH value of the longissimus dorsi muscle was measured within 45 minutes post-slaughter; this value was recorded as pH. 45 pH required 45 ≥6.0, the carcass is pre-cooled within 2 hours after slaughter to reduce the core temperature to below 12℃, thus obtaining pre-cooled beef; S3, Acid Removal Procedure: The pre-cooled beef obtained in step S2 is transferred to an aging chamber for aging. During the aging process, the pH, meat color, and juice loss rate of the longissimus dorsi muscle are measured every 12 hours. When the measured indicators reach the preset endpoint, the aging temperature, humidity, and time at this time are recorded as standardized process parameters. The combination of parameters in the process is locked to form the standardized process for this batch.

[0006] Furthermore, in step S1, the environmental conditions for pre-slaughter incubation are: temperature 15~25℃, relative humidity 50%~70%, light intensity ≤100lx, environmental noise ≤60dB, and total airborne bacterial count ≤2500CFU / m³. 3 .

[0007] Furthermore, in step S2, the standard slaughtering process specifically involves electric stunning, with the interval between stunning and bleeding ≤30s and the bleeding time 5-8min.

[0008] Furthermore, in step S2, precooling specifically adopts forced air cooling conditions, with the cold air temperature at -5℃ to 0℃.

[0009] Furthermore, the energy supplement is an aqueous solution containing 3-7 wt% sucrose, 0.2-0.5 wt% salt and 0.3-1.0 wt% propylene glycol preparations.

[0010] Furthermore, the propylene glycol formulation is specifically food-grade 1,2-propanediol.

[0011] Furthermore, in step S3, the environmental parameters of the acid removal chamber are: temperature 4-12℃, relative humidity 80%-90%, and wind speed 0.5-1.0m / s.

[0012] Furthermore, in step S3, the specific operation method for acid removal is as follows: the carcass is suspended on the guide rail of the acid removal tank via the hind leg hooks, and a distance of 10-20cm is maintained between adjacent carcasses.

[0013] Furthermore, in step S3, the acid removal process takes 24-72 hours.

[0014] Furthermore, in step S3, the preset endpoint should simultaneously meet the following requirements: final pH value 5.5-5.8, a* value decrease rate ≤15% during the 4-day simulated shelf life, and cumulative juice loss rate within the range of 8%-10%. If these requirements are not met simultaneously within 72 hours, the parameters should be adjusted within the temperature range of 4-12℃ and the humidity range of 80%-90% until the specified requirements are met.

[0015] Beneficial technical effects 1. This invention constructs a full-process linkage control system from pre-slaughter to acid removal, in which parameters of each process work synergistically. By controlling the pre-slaughter stress level of cattle, the initial glycogen reserves and pH baseline of muscles are stabilized, reducing the probability of myoglobin oxidation from the source. This system can maintain the red color of beef for a long time without the need for exogenous antioxidant color-protecting additives, avoiding the flavor changes and food safety control costs caused by chemical additives.

[0016] 2. The pre-slaughter energy supplement uses a compound system of sucrose, salt and propylene glycol. The three components regulate the body's energy supply, cell osmotic pressure and muscle water retention structure respectively. A single component cannot simultaneously achieve stress relief and water retention optimization. The compound system can simultaneously improve the basic physicochemical conditions of the muscle after slaughter and reduce acid removal and juice separation during storage.

[0017] 3. The slaughtering and forced air-cooling pre-cooling processes are timed and cooled at specific rates to quickly block the activity of endogenous oxidases in the muscle, shorten the time the muscle is in the appropriate oxidation reaction temperature range, help delay the oxidation process of myoglobin ferrous ions, and further solidify the color stability effect in conjunction with subsequent medium-temperature acid removal.

[0018] 4. The mid-temperature aging process is equipped with a multi-indicator synchronous monitoring mechanism, abandoning the fixed-duration aging mode. The aging endpoint is determined by three indicators: muscle pH, shelf-life redness decay, and juice loss level. This can adapt to the metabolic differences of cattle carcasses in different physiological states, unify the physicochemical indicators of beef products in each batch, and reduce the quality fluctuation between product batches.

[0019] 5. The aging storage facility features a limited medium temperature range, constant high humidity, and low-speed circulating airflow. Combined with standardized hanging spacing of the carcasses, it balances the rate of endogenous protease decomposition in the muscle with the rate of moisture loss. This ensures that the tenderness of the beef is fully enhanced while releasing flavor compounds, and maintains stable water retention, thus improving the appearance of the product at the retail end.

[0020] 6. The entire process can be implemented by modifying existing general equipment in slaughtering and aging workshops without the need for new large-scale special processing equipment. The process flow is compatible with the continuous production line of beef slaughtering enterprises, and the process parameters can be quantified and recorded to form standardized production specifications, which is convenient for large-scale replication and promotion. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a process flow diagram of the technical solution of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1 A method for controlling the color stability of fresh beef at medium temperature, specifically including the following steps: S1. Pre-slaughter rest and recuperation management: The Jingyuan Yellow Cattle awaiting slaughter underwent pre-slaughter rest conditions, with the following environmental conditions: temperature 20℃, relative humidity 60%, light intensity 80lx, ambient noise 50dB, and total airborne bacterial count 2000CFU / m³. 3 The rest period is set at 24 hours, during which time participants are free to drink energy supplements. The energy supplement is an aqueous solution containing 5 wt% sucrose, 0.3 wt% salt and 0.5 wt% 1,2-propanediol.

[0025] S2. Slaughtering and Precooling Control: Slaughtering was carried out according to standard procedures, specifically using electric stunning, with a 20-second interval between stunning and bleeding, and a bleeding time of 6 minutes. The pH value of the longissimus dorsi muscle was measured within 45 minutes post-slaughter, and this value was recorded as pH. 45 pH 45 =6.3, satisfying ≥6.0; the carcass is pre-cooled within 2 hours post-slaughter to reduce the core temperature to below 12℃, resulting in pre-cooled beef; The precooling is performed under forced air cooling conditions, with a cold air temperature of -2℃ and a wind speed of 3m / s. The carcass center temperature drops to 10℃ 1.5 hours after slaughter.

[0026] S3, Acid Removal Procedure: The pre-cooled beef obtained in step S2 was transferred to an aging chamber for aging. The environmental parameters of the aging chamber were set as follows: temperature 8℃, relative humidity 85%, and wind speed 0.8m / s. The carcasses were suspended on the guide rails of the aging chamber by hooks on the hind legs, with a 15cm gap between adjacent carcasses. During the aging process, the pH, meat color, and juice loss rate of the longissimus dorsi muscle were measured every 12 hours. When the aging was completed for 48 hours, the measured indicators reached the preset endpoint. At this time, the final pH value was 5.6, the a* value decreased by 10% during the 4-day simulated shelf life, and the cumulative juice loss rate was 9%, which met the preset endpoint. The aging temperature of 8℃, humidity of 85%, and aging time of 48 hours at this time were recorded as standardized process parameters.

[0027] Example 2 A method for controlling the color stability of fresh beef at medium temperature, specifically including the following steps: S1. Pre-slaughter rest and recuperation management: The Jingyuan Yellow Cattle awaiting slaughter underwent pre-slaughter rest conditions, with the following environmental conditions: temperature 20℃, relative humidity 60%, light intensity 80lx, ambient noise 50dB, and total airborne bacterial count 2000CFU / m³. 3 The rest period is set at 12 hours, during which time participants may freely drink energy supplements. The energy supplement is an aqueous solution containing 5 wt% sucrose, 0.3 wt% salt and 0.3 wt% 1,2-propanediol.

[0028] S2. Slaughtering and Precooling Control: Slaughtering was carried out according to standard procedures, specifically using electric stunning, with a 20-second interval between stunning and bleeding, and a bleeding time of 6 minutes. The pH value of the longissimus dorsi muscle was measured within 45 minutes post-slaughter, and this value was recorded as pH. 45 pH 45=6.1, satisfying ≥6.0; the carcass is pre-cooled within 2 hours post-slaughter to reduce the core temperature to below 12℃, resulting in pre-cooled beef; The precooling was carried out under forced air cooling conditions, with a cold air temperature of -2℃ and a wind speed of 3m / s. The carcass center temperature dropped to 11℃ 1.7 hours after slaughter.

[0029] S3, Acid Removal Procedure: The pre-cooled beef obtained in step S2 was transferred to an aging chamber for aging. The environmental parameters of the aging chamber were set as follows: temperature 8℃, relative humidity 85%, and wind speed 0.8m / s. The carcasses were suspended on the guide rails of the aging chamber by hooks on the hind legs, with a 15cm gap between adjacent carcasses. During the aging process, the pH, meat color, and juice loss rate of the longissimus dorsi muscle were measured every 12 hours. When the aging was completed for 48 hours, the measured indicators reached the preset endpoint. At this time, the final pH value was 5.5, the a* value decreased by 13% during the 4-day simulated shelf life, and the cumulative juice loss rate was 8%, which met the preset endpoint. The aging temperature of 8℃, humidity of 85%, and aging time of 48 hours at this time were recorded as standardized process parameters.

[0030] Example 3 A method for controlling the color stability of fresh beef at medium temperature, specifically including the following steps: S1. Pre-slaughter rest and recuperation management: The Jingyuan Yellow Cattle awaiting slaughter underwent pre-slaughter rest conditions, with the following environmental conditions: temperature 20℃, relative humidity 60%, light intensity 80lx, ambient noise 50dB, and total airborne bacterial count 2000CFU / m³. 3 The rest period is set at 24 hours, during which time participants are free to drink energy supplements. The energy supplement is an aqueous solution containing 5 wt% sucrose, 0.3 wt% salt and 1 wt% 1,2-propanediol.

[0031] S2. Slaughtering and Precooling Control: Slaughtering was carried out according to standard procedures, specifically using electric stunning, with a 20-second interval between stunning and bleeding, and a bleeding time of 6 minutes. The pH value of the longissimus dorsi muscle was measured within 45 minutes post-slaughter, and this value was recorded as pH. 45 pH 45 =6.3, satisfying ≥6.0; the carcass is pre-cooled within 2 hours post-slaughter to reduce the core temperature to below 12℃, resulting in pre-cooled beef; The precooling is performed under forced air cooling conditions, with a cold air temperature of -2℃ and a wind speed of 3m / s. The carcass center temperature drops to 10℃ 1.5 hours after slaughter.

[0032] S3, Acid Removal Procedure: The pre-cooled beef obtained in step S2 was transferred to an aging chamber for aging. The environmental parameters of the aging chamber were set as follows: temperature 12℃, relative humidity 85%, and wind speed 0.8m / s. The carcasses were suspended on the guide rails of the aging chamber via hind leg hooks, with a 15cm spacing between adjacent carcasses. During the aging process, the pH, meat color, and juice loss rate of the longissimus dorsi muscle were measured every 12 hours. When the aging reached 36 hours, the measured indicators reached the preset endpoint. At this time, the final pH value was 5.7, the a* value decreased by 12% during the 4-day simulated shelf life, and the cumulative juice loss rate was 9.5%, which met the preset endpoint. The aging temperature of 12℃, humidity of 85%, and aging time of 36 hours at this time were recorded as standardized process parameters.

[0033] Comparative Example 1 The difference between this comparative example and Example 1 is that, in step S1, only clean water is allowed to be consumed freely during the rest period, and the water does not contain sucrose, salt, or propylene glycol.

[0034] Comparative Example 2 The difference between this comparative example and Example 1 is that in step S1, the energy supplement solution is replaced with an aqueous solution containing 5 wt% sucrose and 0.3 wt% salt, and does not contain propylene glycol.

[0035] Comparative Example 3 The difference between this comparative example and Example 1 is that in step S1, the energy replenishment solution is replaced with an aqueous solution containing only 0.5 wt% 1,2-propanediol.

[0036] Comparative Example 4 The difference between this comparative example and Example 1 is that in step S3, the temperature of the acid removal chamber is set to 2°C, the humidity to 85%, the wind speed to 0.8 m / s, the hanging spacing to 15 cm, and the test is performed every 12 hours.

[0037] Comparative Example 5 The difference between this comparative example and Example 1 is that in step S1, the rest time is shortened to 2 hours and noise (90dB) is artificially created to interfere with the rest, and the energy supplement is consumed freely.

[0038] Comparative Example 6 The difference between this comparative example and Example 1 is that in step S3, the humidity of the acid removal chamber is set to 70%, the temperature to 8°C, the wind speed to 0.8 m / s, and the hanging spacing to 15 cm.

[0039] Performance tests will now be conducted on the products of the embodiments and comparative examples. The specific test methods are as follows: After the aging process, the longissimus dorsi muscle of beef from each group was harvested, cut into 2.5cm thick steaks, and packaged in high-barrier vacuum bags (oxygen permeability <5cm). 3 / (m 2Meat samples were stored at 4°C for 4 days (24 h atm). After storage, the samples were opened, the surface liquid was absorbed with filter paper, and the weights of the meat samples before packaging (W1) and after opening (W2) were measured. The cumulative liquid loss rate was calculated using the following formula: Liquid loss rate (%) = (W1 - W2) / W1 × 100%. Simultaneously, the L, a, and b values ​​were measured using a colorimeter (D65 light source, 10° observation angle, 8 mm aperture) at day 0 (end of aging) and after 4 days of storage. Six measurements were taken at each sample, and the average value was calculated. The a* value decrease rate (%) was calculated as: (a0 - a4) / a0 × 100%. pH values ​​were measured directly at the end of aging using a penetrating pH meter on the longissimus dorsi muscle core. All tests were repeated three times, and the results are expressed as averages. Specific test results are shown in Table 1.

[0040] Table 1

[0041] Based on the results in Table 1, the data can be analyzed using a three-group comparative logic according to variable type. The first group of comparisons is between the complete process example and the examples with or without energy supplementation solution or single component. Comparative Example 1 completely eliminated the energy supplementation system. During the cattle's resting period, exogenous sugars and osmotic pressure regulating substances could not be supplemented, and the glycogen consumed by the body due to stress could not be compensated. Post-slaughter glycogen reserves in the muscle were insufficient, and the rapid accumulation of lactic acid during the acid removal process caused a low final pH. The spatial structure of myofibrillar proteins contracted, destroying the water-holding structure of muscle cells. At the same time, the low pH environment accelerated the oxidation electron transfer reaction of myoglobin, significantly increasing the rate of redness decay during shelf life, and significantly extending the period for achieving the complete process indicators. The presence of sucrose, salt, and propylene glycol is necessary to maintain the basal metabolic environment of muscle. Comparative Example 2 only retains sucrose and salt, lacking propylene glycol. Propylene glycol plays a role in regulating the rate of water migration in intercellular spaces and stabilizing the coordination structure of myoglobin. The absence of this component leads to a simultaneous decrease in the water retention and color stability of the meat. Comparative Example 3 only retains propylene glycol, lacking sucrose to provide glycogen precursors and salt to regulate cell osmotic pressure. It cannot alleviate glycogen loss caused by pre-slaughter stress, and the water-holding capacity of the muscle is still inferior to that of the complete compound system. The three comparative examples together demonstrate that there is a synergistic effect among the three components in the energy supplement solution. A single component cannot simultaneously achieve multiple effects such as stress relief, water retention optimization, and color protection. The second set of controls consisted of comparative examples where the acid removal environment parameters deviated from the range defined in this invention. Comparative example 4 lowered the acid removal temperature to outside the lower limit of the medium temperature range. The low temperature environment inhibited the activity of endogenous proteases, slowed down the muscle metabolism process, and required a longer acid removal time to approach the endpoint. At low temperatures, the stability of myoglobin binding with oxygen decreased, and the trend of oxidation and discoloration intensified. Comparative example 6 reduced the humidity of the acid removal tank environment. Insufficient relative humidity in the tank continuously removed free water from the surface of the muscle, resulting in a large loss of water between myofibrils. At the same time, the surface muscle contact with dry air accelerated myoglobin oxidation, and both the juice loss and redness reduction indicators deteriorated simultaneously. Comparing the test results corresponding to the acid removal parameters with constant temperature and humidity in the three sets of examples, it can be proved that the acid removal environment of 4 to 12°C and 80 to 90% relative humidity is the suitable range for balancing metabolic rate, water retention, and myoglobin stability.The third control group, Example 5, lacked pre-slaughter rest management. This group shortened the rest time and increased environmental noise. The continuous external stimulation triggered stress in the cattle, leading to a large amount of glycogen decomposition and consumption, a decrease in muscle pH at the endpoint, and a significant increase in juice loss due to damage to muscle cell structure. The complete energy supplement alone could not offset the basic muscle damage caused by stress. Examples 1 and 2, under standardized rest environment and sufficient rest time, could simultaneously meet all three endpoint criteria. This indicates that pre-slaughter environmental management, rest time, and compound energy supplement form a pre-treatment synergistic control system. The absence of any one link will damage the initial physicochemical basis of the muscle, and subsequent slaughter and aging processes cannot fully compensate for the early damage. All control results jointly confirm that the limiting parameters set by this invention in the entire process of pre-slaughter, slaughter, and aging work together to form a complete control link. The optimization of parameters in a single process cannot simultaneously take into account the three core indicators of pH, water retention, and shelf color. There is an inseparable synergistic effect among the various technical features of the entire process.

[0042] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0043] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0044] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments.

Claims

1. A method for controlling the color stability of medium-temperature fresh beef, characterized in that, Includes the following steps: S1. Pre-slaughter rest and recuperation management: The Jingyuan yellow cattle awaiting slaughter will be rested before slaughter for 12-36 hours, during which they will have free access to energy supplements. S2. Slaughtering and Precooling Control: Slaughtering is carried out according to standard procedures. The pH value of the longissimus dorsi muscle is measured within 45 minutes after slaughter. This value is recorded as pH45. It is required that pH45 ≥ 6.

0. The carcass is pre-cooled within 2 hours after slaughter to reduce the core temperature to below 12°C to obtain pre-cooled beef. S3, Acid Removal Procedure: The pre-cooled beef obtained in step S2 is transferred to an aging chamber for aging. During the aging process, the pH, meat color, and juice loss rate of the longissimus dorsi muscle are measured every 12 hours. When the measured indicators reach the preset endpoint, the aging temperature, humidity, and time at this time are recorded as the standardized process parameters for this batch. The combination of parameters in the process is locked to form the standardized process for this batch.

2. The method for controlling the color stability of medium-temperature fresh beef according to claim 1, characterized in that, In step S1, the pre-slaughter incubation environment conditions are: temperature 15~25℃, relative humidity 50%~70%, light intensity ≤100lx, environmental noise ≤60dB, and total airborne bacterial count ≤2500CFU / m³. 3 .

3. The method for controlling the color stability of medium-temperature fresh beef according to claim 1, characterized in that, In step S2, the standard slaughtering process specifically involves electric stunning, with the interval between stunning and bleeding ≤30s and the bleeding time 5-8min.

4. The method for controlling the color stability of medium-temperature fresh beef according to claim 1, characterized in that, In step S2, precooling specifically adopts forced air cooling conditions, with the cold air temperature at -5℃ to 0℃.

5. The method for controlling the color stability of medium-temperature fresh beef according to claim 1, characterized in that, The energy supplement is an aqueous solution containing 3-7 wt% sucrose, 0.2-0.5 wt% salt and 0.3-1.0 wt% propylene glycol preparations.

6. The method for controlling the color stability of medium-temperature fresh beef according to claim 5, characterized in that, The propylene glycol formulation specifically refers to food-grade 1,2-propanediol.

7. The method for controlling the color stability of medium-temperature fresh beef according to claim 1, characterized in that, In step S3, the environmental parameters of the acid removal chamber are: temperature 4-12℃, relative humidity 80%-90%, and wind speed 0.5-1.0m / s.

8. The method for controlling the color stability of medium-temperature fresh beef according to claim 1, characterized in that, In step S3, the specific operation method for acid removal is as follows: the carcass is suspended on the guide rail of the acid removal tank by the hind leg hooks, and a distance of 10-20cm is maintained between adjacent carcasses.

9. The method for controlling the color stability of medium-temperature fresh beef according to claim 1, characterized in that, In step S3, the acid removal process takes 24-72 hours.

10. The method for controlling the color stability of medium-temperature fresh beef according to claim 1, characterized in that, In step S3, the preset endpoint should simultaneously meet the following requirements: final pH value 5.5-5.8, a* value decrease rate ≤15% during the 4-day simulated shelf life, and cumulative juice loss rate within the range of 8%-10%. If these requirements are not met simultaneously within 72 hours, adjust the parameters within the temperature range of 4-12℃ and humidity range of 80%-90% until the specified requirements are met.

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