JPH0579299B2 - - Google Patents

Description

[Detailed description of the invention]

"Industrial Application Field" This invention relates to water-soluble dried whole blood, dried plasma, and dried plasma obtained from animal blood or its blood components.
The present invention relates to a method for sterilizing dried blood such as dried serum and dried blood cells without impairing its water solubility (solubility). "Prior Art and Problems" As is well known, blood from slaughtered cows, pigs, etc. is high in protein and low in fat, and the amino acid composition contained in the protein is nutritionally superior. However, when we look at the usage of blood from slaughtered animals, we find that only a small portion of it is manufactured using simple processing methods such as boiling and coagulation to produce low-quality blood and is used as fertilizer or feed. Currently, most of the wastewater is treated unused, creating a huge burden on wastewater treatment. Therefore, in recent years, from the viewpoint of effective use of by-products of livestock animals and modernization of slaughterhouses, blood processing methods have been developed that take advantage of the excellent nutritional value of blood components and the various physical properties of blood components for food processing. As a method, blood is separated into blood cells and plasma using a centrifuge, or fibrin is removed from the blood, and the blood is separated into blood cells and serum using a centrifuge. A method has been proposed in which whole blood without such separation is subjected to low-temperature drying such as spray drying, freeze drying, vacuum drying, etc. to obtain a dried product, blood meal (dried blood), without denaturing proteins. However, in the conventional method, sterilization by temperature cannot be considered because the concentration and drying temperature is low, and the obtained plasma or serum product contains a large number of general viable bacteria, approximately 10 ⁵ to 10 ⁷ per gram. In many cases, there was a problem with food safety. When using blood meal as a food or food processing material, the most important thing is safety as a food, and what requires particular attention is contamination by microorganisms.
To this end, it is necessary to adopt a hygienic blood collection method in the blood collection process to obtain the raw material for blood powder, and also to prevent the contamination of external microorganisms and the growth of microorganisms within the process in the subsequent separation and drying process. It is important to suppress it as much as possible. However, it is difficult to completely suppress these microorganisms during the manufacturing process. Therefore, it is important to sterilize the blood powder obtained.
Conventionally, gas sterilization using ethylene oxide, propylene oxide, etc. is known as a method for sterilizing blood meal. This sterilization method causes little protein denaturation and enables sterilization without reducing the solubility of blood powder, but the problem of residual toxicity of the gas used remains unsolved. Other sterilization methods include heat sterilization. Although this sterilization method is excellent from a sanitary standpoint, thermal denaturation of proteins occurs, resulting in a decrease in solubility and a significant decrease in the commercial value of blood meal. The present invention was made based on the above findings, and its purpose is to remove common viable bacteria from blood meal (dried blood).
It is an object of the present invention to provide a method for sterilizing blood powder, which can sterilize Escherichia coli (commercial sterilization) and causes almost no decrease in water solubility. "Means for Solving the Problems" As a result of intensive experiments to solve the above problems, the method of sterilizing water-soluble dried blood according to the present invention was developed using carbon dioxide at a specific pressure and temperature range. This method was developed based on the knowledge that it is possible to sufficiently sterilize blood powder by contacting it with water without impairing its water solubility. First, water-soluble dried blood obtained from blood or blood components is heated to an initial moisture This method is characterized by contacting carbon dioxide at a pressure of 70 to 400 atm and a temperature of 30 to 45°C in a state of 10 to 35% by weight. Second, water-soluble dried blood obtained from blood or blood components is brought into contact with a mixture of carbon dioxide and acetic acid at a pressure of 70 to 400 atm and a temperature of 30 to 45°C at an initial moisture content of 10 to 35% by weight. This method is characterized by the following. ``Effect'' According to the above method, all kinds of water-soluble dried blood, including not only dried whole blood and dried blood cells obtained by low-temperature drying, but also dried plasma and dried serum, can be processed by It becomes possible to sufficiently sterilize without impairing (solubility). Hereinafter, this invention will be explained in more detail with reference to Examples. "Example" As shown in Figure 2, blood is hygienically collected from a domestic animal 1 using a cannula-like knife, and at the same time an anticoagulant such as a sodium citrate aqueous solution in an anticoagulant tank 2 is immediately applied to the blood. Mix about 0.5% by weight of sodium citrate to prevent blood coagulation. The collected blood is passed through a strainer 3 to remove contaminants such as meat pieces, fat pieces, and hair, and then temporarily stored in a test tank 4. While the blood is stored in the inspection tank 4, the carcass is inspected for the presence of diseased animals, etc., and only the blood that is confirmed to be hygienic is passed through the next heat exchanger 5 to be cooled. . When obtaining dried blood such as plasma or blood cells, the blood is sent to a centrifuge 6. Separation is performed using this high-speed continuous centrifuge 6, and the light liquid portion is recovered as plasma liquid and the heavy liquid portion is recovered as blood cell liquid. The obtained plasma fluid and blood cell fluid are sent to the following plasma vacuum low-temperature dryer 7 and blood cell vacuum low-temperature dryer 11, respectively, where the temperature is preferably lowered to 40°C or lower when the blood concentration is low, and the concentration is lowered to 50°C.
Even when the temperature exceeds 50%, dry at a low temperature while keeping the temperature below 50°C, and be careful not to heat denature the proteins in the blood. The degree of drying in the vacuum low-temperature dryers 7 and 11 is adjusted taking into account the sterilization step of the next process, and the drying is stopped at an appropriate moisture level. The dried blood powder is usually ground to about 60 meshes using grinders 8 and 12. In addition, when obtaining dried serum instead of dried plasma, gently stir the capture element etc. in the blood to remove the fibrin in the blood, and then separate it into serum liquid and blood cell liquid using a centrifuge. Alternatively, the plasma separated by a centrifuge is stored in a storage tank for a while, the fibrin is coagulated, and the coagulated fibrin is removed using a sieve, filtration, or a strainer to obtain a serum solution. may be dried in a vacuum low temperature dryer in the same manner as above. In addition, when obtaining dried whole blood, the cooled blood may be directly dried in a low-temperature dryer without being subjected to a centrifuge. The above dried blood cells, dried plasma, dried serum, and dried whole blood correspond to the dried blood of the present invention. In order to effectively carry out the present invention, it is important to take common-sense precautions regarding the handling of foods containing protein in the blood collection step, separation step, and drying step before the next step, the sterilization step. In other words, when collecting blood, be careful to prevent microorganisms from getting into the blood, and after collecting blood, cool it thoroughly.
It is important to keep the temperature preferably below 4°C to prevent the growth of microorganisms in the blood after blood collection. Furthermore, in the separation process, the temperature of the blood increases in the centrifuge, so the storage tank (not shown) that stores the separated liquid needs to be cooled down to 4° C. or lower again. In the drying process, heating is required to evaporate water, but at this time, the product temperature should be kept below 50℃, preferably 40℃.
It is necessary to maintain the temperature below and avoid as much as possible the temperature that would cause protein denaturation. As explained above, dried blood produced with sufficient care has a solubility of 95% or more, and is an intermediate product with excellent physical properties. However, in terms of the number of microorganisms, approximately per gram of blood meal
In many cases, it contains a large amount of microorganisms on the order of 10 ⁵ to 10 ⁷ . Continuing, in the present invention, the dried blood (initial moisture content: 10 to 35% by weight, preferably 10 to 30% by weight)
For example, the materials are introduced into sterilizers 9 and 13 as shown in the schematic flow sheet of FIG. 1, and are sterilized. In FIG. 1, reference numeral 20 is a pressure vessel, which is filled with unsterilized dried blood (including whole blood). A predetermined pressure (70~
Carbon dioxide pressurized to 400 atm) enters the pressure vessel 20. The pressure vessel 20 is equipped with a temperature control device, and the introduced carbon dioxide is heated to a predetermined temperature (30 to 45 degrees Celsius, preferably 30 to 40 degrees Celsius) and brought into contact with the dried blood filled inside. death,
It extracts the water contained in dried blood and at the same time exerts a bactericidal effect on microorganisms present in dried blood. The carbon dioxide that has completed its sterilizing action is depressurized by the valve 22 and then released. Note that the released carbon dioxide can be recycled and used again after the extracted moisture and the like are separated and removed. Further, when acetic acid is further added, it is supplied by the pump 23 so that the acetic acid content is less than 6% by weight, as shown by the dotted line in FIG. In addition, the reference numeral 24 in the figure indicates carbon dioxide before extraction.
25 indicates carbon dioxide after extraction. The blood powder thus sterilized is packed into bags by a bagging machine 10, if necessary. In addition, in FIG. 2, the reference numeral 14 indicates a bagging machine for blood cell fluid. Next, an experimental example conducted to confirm the effects of the above embodiment will be explained. The water content, number of viable bacteria, and solubility shown in the following experimental examples were measured using the following methods. (Method for measuring water content) (i) Grind the dried blood well in a mortar. (ii) Take 1 to 2 g of the above pulverized sample to a weighing dish and dry it at 105°C for 2 hours. (iii) After drying, cool in a desiccator and weigh. (iv) Calculate the moisture content using the following formula. Moisture content (weight %) = Loss on drying (g) / Amount of sample collected (g) x 100 (Solubility measurement method) (i) Dry and weigh a 50 ml centrifuge tube in advance. (ii) Collect 1 g of blood powder crushed to 60 mesh or less using a precision chemical balance. (iii) Place the sample collected in (ii) into the centrifuge tube weighed in (i), add about 40 ml of distilled water, and stir well to dissolve. (iv) The solution dissolved in (iii) is centrifuged at 3000 rpm
Centrifuge for 10 minutes and pour off the supernatant. (v) Add about 40 ml of distilled water to the centrifuge tube again and stir well to dissolve undissolved substances in the precipitate. (vi) Centrifuge at 3000 rpm for 10 minutes using a centrifuge, and pour off the supernatant. (vii) Perform (v)(vi) again. (viii) Place the centrifuge tube in a dryer at 105°C, dry for 2 hours until the water at the top of the precipitate disappears, cool in a desiccator, and then weigh. (ix) Calculate solubility using the following formula. Solubility (weight %) = Collected amount (mg) - Undissolved matter (mg) / Collected amount (mg) x 100 (Viable bacteria count measurement method) (i) Collect 1 g of dried blood. (ii) Add 10 ml of sterile physiological saline (0.9% by weight NaCl) and shake well. (iii) After shaking, collect 1 ml and add sterile physiological saline9.
ml and shake well. This is the predetermined 5~
Repeat 6 times. (iv) Collect 1 ml of the solution at each dilution stage, mix it with an agar medium for viable cell count measurement (15 g, kept at 50°C) on a shear plate, and solidify. (v) Culture at 37℃ for 2 days. (vi) After culturing, count the number of colonies on the plate (N). (vii) Calculation formula: Number of viable bacteria (count/g) = N x 10 (dilution factor)/amount collected (g
) (viii) This measurement method is based on the general test method, M Bacteria Test, published by Kanehara Publishing Co., Ltd., edited by the Pharmaceutical Society of Japan, published on February 20, 1976, "Commentary on Sanitary Test Methods". This method is based on 4. "Viable Bacteria Count" in the method. Experimental Example 1 35 times dried blood (dried plasma is used, the same applies hereinafter) containing various water contents is used in the sterilizer shown in Figure 1 above.
It was sterilized with carbon dioxide at 200 kg/cm ² G at ℃. The results are shown in Table 1. The results are shown before and after treatment for comparison. Further, the processing conditions are shown in Table 2. The solubility (wt%) of dried blood after sterilization is
80% by weight or more, especially the initial moisture content of dried blood.
If the amount is 10 to 30% by weight, the modification will not be a problem. The main purpose of the present invention is to dry blood without denaturing it.
The purpose is to kill the bacteria in this dried blood. As is clear from Experiment No. 6 above, when the amount of water in dried blood is small, carbon dioxide has no sterilizing effect. However, as shown in Experiment Nos. 5 to 1, it can be seen that by increasing the amount of water, the number of bacteria (viable bacteria) existing in the blood decreases. On the contrary, the solubility of dried blood decreases as the initial water content increases, but even with a water content of 30.7% by weight, the solubility of dried blood was 91% by weight, showing almost no denaturation. In short, it has become clear that dried blood can be sterilized without changing its physical properties.

【table】

[Table] Experimental Example 2 Dried blood was treated by adding acetic acid to carbon dioxide in the proportions shown in Table 3. The results are shown in Table 3. Further, the processing conditions are shown in Table 4. As is clear from the table, the solubility in all cases was maintained at 80% by weight or higher, indicating that they were not modified. Experiment No. 7 had a solubility of 90% by weight,
This is particularly preferred. In this experimental example, acetic acid was added to reduce the moisture content and increase the bactericidal effect. If there is a large amount of water, a large amount of carbon dioxide is required to remove the water, and it also takes a long time.
As is clear from Experiment No. 7, it is recognized that the effect of carbon dioxide alone was greater than the water content of 30.7% by weight under the condition of a water content of 16.7% by weight.

【table】

[Table] "Effects of the Invention" As explained above, according to the present invention, dried blood can be sterilized efficiently without impairing water solubility.

[Brief explanation of drawings]

FIG. 1 is a schematic flow sheet of a sterilization apparatus suitable for use in the present invention, and FIG. 2 is a process diagram for manufacturing dried blood. 20...Pressure vessel, 21, 23...Pump, 2
2... Valve, 24... Carbon dioxide (before extraction),
25...Carbon dioxide (after extraction).

Claims (1)

[Scope of Claims] 1. Water-soluble dried blood obtained from blood or blood components is subjected to pressure at an initial water content of 10 to 35% by weight.
A method for sterilizing water-soluble dried blood, which comprises contacting with carbon dioxide at a temperature of 70 to 400 atm and a temperature of 30 to 45°C. 2 Pressurize water-soluble dried blood obtained from blood or blood components with an initial water content of 10 to 35% by weight.
A method for sterilizing water-soluble dried blood, which comprises bringing it into contact with a mixture of carbon dioxide and acetic acid at a temperature of 70 to 400 atm and a temperature of 30 to 45°C.