Freezing and thawing method of fresh meat, and meat product

Abstract

To provide a freezing and thawing method of fresh meat capable of making the fresh meat hard to be tissue-destroyed even when being frozen and capable of killing bacteria to a level at which food poisoning is not caused, and a meat product.SOLUTION: In a freezing and thawing method, packed fresh meat is rapidly frozen to generate frozen meat. The generated frozen meat is immersed in boiling water being heated, heating is stopped immediately after immersing or three minutes later from the immersing, and the frozen meat is settled for 40 minutes.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for freezing and thawing fresh meat, and to a meat product. [Background technology]

[0002] In order to operate a business that handles food, a business license based on the Food Sanitation Act is required. This includes the handling of meat products, and in order to prevent food poisoning, businesses must meet strict licensing standards according to their type of business.

[0003] Meanwhile, with the recent development of food preservation technology, various cooling and thawing techniques have been developed to keep food as fresh as possible (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-209512 A Summary of the Invention [Problem to be solved by the invention]

[0005] By the way, roast beef, one of the most well-known beef dishes, is generally cooked to the extent that the cut surface is reddish, but if the cooking method is incorrect, there is a risk that some of the meat may be eaten raw. In that case, if a block of meat for eating raw is used as the ingredient, there is no particular problem, but if a block of meat for cooking is used, there is a risk of food poisoning due to insufficient heating. If the ingredients are heated thoroughly, the bacteria that cause food poisoning will be killed, but the meat will become tough overall and the texture will be lost.

[0006] In particular, when thawing and cooking a block of frozen meat, if the meat tissue is destroyed and the umami components leak out as drips, it will directly affect the taste and texture, making cooking even more difficult.

[0007] The above problems are also common to meats other than beef, such as fresh meats that are widely consumed by the general public, such as pork and chicken.

[0008] In view of the above-mentioned problems, the present invention aims to provide a method for cold-thawing fresh meat that is less likely to cause tissue destruction even when frozen and that can kill bacteria to a level that does not cause food poisoning, and a meat product. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the method for cold-thawing fresh meat of the present invention is characterized by comprising a freezing step of rapidly freezing packaged fresh meat to produce frozen meat, and a residual heat thawing step of immersing the frozen meat in heated boiling water, stopping the heating immediately after immersion, and leaving the meat to stand for 40 minutes.

[0010] Alternatively, the method is characterized by including a freezing step in which packaged fresh meat is quickly frozen to produce frozen meat, and a residual heat thawing step in which the frozen meat is immersed in boiling water while being heated, the heating is stopped after 3 minutes, and the meat is left to stand for 40 minutes.

[0011] The meat product according to the present invention is characterized in that it is produced by a method for cold-thawing fresh meat comprising the steps described above. Effect of the Invention

[0012] According to the present invention, tissue destruction is unlikely to occur even when frozen and it is possible to kill bacteria to a level that does not cause food poisoning. [Brief description of the drawings]

[0013] [Figure 1] 1 is a graph showing temperature changes due to heating of chicken meat in Example 1. [Diagram 2] 2 is a graph showing temperature changes due to heating of pork in Example 1. [Diagram 3] 1 is a graph showing temperature changes due to heating of beef in Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, the embodiment of the method for cold-thawing fresh meat and meat products according to the present invention will be described. In the following description, "fresh meat" is a general term for fresh, raw edible meat, and is a term that comprehensively includes edible meat consumed by general consumers, such as beef, pork, and chicken.

[0015] First Embodiment The method for cold-thawing fresh meat according to the first embodiment (hereinafter referred to as the "first method") includes a freezing step and a residual heat thawing step.

[0016] [Freezing process] The freezing process is a process for freezing the target fresh meat. In this example, first, the meat block cut into blocks is vacuum-packed. Then, the meat block is quickly frozen in the vacuum-packed state using a quick freezer. The quick freezer used may be a commercially available one, but when the meat block is quickly frozen, liquid alcohol is cooled to -35°C or lower to make it into a sherbet-like state. Then, the meat block is immersed in the sherbet-like alcohol. By making the alcohol into which the meat block is immersed into a sherbet-like state in this way, the thermal conductivity of the alcohol increases. As a result, the meat block can be quickly frozen by passing through the maximum ice crystal formation zone in a short time, so that the tissue damage of the meat block can be prevented as much as possible. The immersion time depends on the shape of the meat block, but as a guideline, it is about 15 to 20 minutes for a meat block with a thickness of about 5 cm and a weight of 250 g. This freezing process produces frozen meat that is quickly frozen in a vacuum-packed state.

[0017] [Residual heat thawing process] The residual heat thawing process is a process for heating and thawing the frozen meat produced by the above-mentioned freezing process. In this example, the frozen meat is heated under the following conditions. First, a required amount of water is heated to prepare boiling water. Next, the frozen meat is immersed in the boiling water while it is being heated, and the heating is stopped immediately after immersion. The frozen meat is then left to stand for 40 minutes, and the residual heat is used to thaw the frozen meat.

[0018] The meat product according to this embodiment is produced by carrying out the first method including the above-mentioned freezing step and residual heat thawing step. This meat product has the following characteristics. First, all bacteria that may cause food poisoning (Enterobacteriaceae group, such as coliform bacteria, Staphylococcus aureus, and Salmonella) are negative. In other words, bacteria in this meat product have been killed to a level that does not cause food poisoning.

[0019] Secondly, although the surface has changed color due to heating, the meat tissue is hardly destroyed and the umami components hardly leak out as drips, so it is in the same state as fresh meat that has been cooked at low temperature until it is half-raw. Therefore, even though it has been frozen once, the original umami flavor and texture of the meat are hardly lost.

[0020] <Second embodiment> The method for cold thawing fresh meat according to the second embodiment (hereinafter referred to as the "second method") differs from the first method in the heating conditions in the residual heat thawing step, but is otherwise basically the same as the first method. Therefore, the second method will be described mainly with reference to the configurations (steps) that are different from the first method, and a description of the configurations (steps) that are substantially the same will be omitted.

[0021] In the residual heat thawing step of the second method, the frozen meat is immersed in boiling water that has been prepared and heated, and heated continuously for 3 minutes. After 3 minutes, the heating is stopped and the meat is left to stand for 40 minutes to thaw using the residual heat.

[0022] The meat product produced by carrying out this second method has substantially the same characteristics as the meat product produced by the above-mentioned first method: even though it has been frozen once, the original flavor and texture of the meat is almost intact, and bacteria have been killed to a level that does not cause food poisoning. EXAMPLES

[0023] The present invention will be described in more detail below with reference to several examples and evaluation methods.

[0024] Example 1 [Freezing process] Using the freezing process described in the first embodiment, (a) 250 g of frozen chicken meat chunks and (b) 250 g of frozen pork meat chunks were prepared, which were quickly frozen in a vacuum-packaged state.

[0025] [Residual heat thawing process] The (A) frozen chicken block and (B) frozen pork block prepared were thawed by the residual heat thawing process described in the first embodiment above. The specific procedure is as follows. First, 2 liters of water was heated using a commercially available portable stove and a pot to prepare boiling water. The (A) frozen chicken block was immersed in this boiling water, and the heat was turned off immediately after immersion and the block was left to stand for 40 minutes. The (B) frozen pork block was also immersed in boiling water in the same manner, and the heat was turned off immediately after immersion and the block was left to stand for 40 minutes.

[0026] [Evaluation method] In the residual heat thawing process described above, the temperatures of (a) the frozen chicken block and (b) the frozen pork block were measured at two different positions about 1 cm deep from the surface of the meat. A temperature measurement unit (model NR-TH08, manufactured by Keyence Corporation) was used to measure the temperatures. Table 1 and Figure 1 show the temperature change due to heating the chicken. Table 2 and Figure 2 show the temperature change due to heating the pork.

[0027] [Table 1]

[0028] [Table 2]

[0029] Example 2 Using the freezing process described in the first embodiment, 250 g of frozen beef chunk (c) was prepared, which was quickly frozen in a vacuum-packed state.

[0030] [Residual heat thawing process] The prepared (c) frozen beef block was thawed by the residual heat thawing process described in the second embodiment above. The specific procedure is as follows. First, as in Example 1, 2 liters of water was heated using a commercially available portable stove and a pot to prepare boiling water. The (c) frozen beef block was immersed in this boiling water, and after immersion for 3 minutes, the heat was turned off and the block was left to stand for 40 minutes.

[0031] [Evaluation method] In the residual heat thawing process described above, (c) the temperature of the frozen beef block was measured at two different positions about 1 cm deep from the surface of the meat. The temperature was measured using a temperature measuring unit (model NR-TH08, manufactured by Keyence Corporation) in the same manner as in Example 1. The temperature change due to heating of the beef is shown in Table 3 and Figure 3.

[0032] [Table 3]

[0033] [Measurement of viable cell count after thawing] Microbial testing was carried out using a test method in accordance with the "Food Sanitation Inspection Guideline" for the (a) chicken, (b) pork, and (c) beef thawed in Examples 1 and 2. The results are shown in Table 4.

[0034] [Table 4]

[0035] [Consideration] As shown in Table 4, it was confirmed that bacteria were killed to a level that would not cause food poisoning in both Example 1 and Example 2. What is noteworthy here is that the measured temperature in both Example 1 and Example 2 never exceeded 63 degrees. For heated meat products, legal heating conditions are set out as "sterilization must be performed by heating the product to a temperature of 63 degrees for 30 minutes at the center, or by a method with an equivalent or greater effect... (omitted)...." In light of this, technically, neither Example 1 nor Example 2 meets the legal heating conditions, but they are sterilized. In other words, it can be said that Example 1 and Example 2 are "sterilized by a method with an equivalent or greater effect" under the legal heating conditions.

[0036] Moreover, since the meat products thawed according to Examples 1 and 2 are sterilized even if they are semi-raw when thawed, there is an extremely low risk of food poisoning even if they are eaten as is. Therefore, for example, even ordinary households that do not own a low-temperature cooker can safely enjoy low-temperature cooking.

[0037] In this way, the method of cold thawing fresh meat of the present invention is a highly useful technology that makes it possible to simultaneously thaw and sterilize frozen meat, and it is thought that not only could it become one of the standards for statutory heating conditions, but it may even lead to the relaxation of standards for business licenses under the Food Sanitation Act.

[0038] The method for cold-thawing fresh meat and meat products according to the present invention have been described above based on the embodiments and examples. However, the present invention is not limited to the above-described forms, and may be embodied in the following forms, for example.

[0039] <Modification> (1) In the above embodiment and modified examples, vacuum-packaged fresh meat is flash-frozen. However, the meat may be packaged in any manner other than vacuum-packaging.

[0040] (2) In the above embodiment and modified examples, the meat chunks are immersed in the liquid alcohol that has been cooled to below -35°C and turned into a sherbet-like alcohol. However, the meat chunks may be immersed in the liquid that is not yet in a sherbet-like state and that is in a temperature range of about -30°C.

[0041] Furthermore, the freezing process exemplified above is based on the premise that so-called "liquid quick freezing" is carried out, in which the meat block is immersed in liquid and quickly frozen. However, as long as a method defined as quick freezing is adopted, that is, a method in which "the food product temperature passes through the maximum ice crystal formation zone (-5 to -1°C) within 30 minutes," it is presumed that the same effects as those of the above embodiments and examples will be obtained.

[0042] The present invention can be implemented in various forms that include improvements, modifications, or variations based on the knowledge of a person skilled in the art without departing from the spirit of the present invention. In addition, the present invention can be implemented in a form in which any of the invention-specific features are replaced with other technologies within the scope of the same action or effect.

Claims

1. a freezing step for rapidly freezing the packaged fresh meat to produce frozen meat; A residual heat thawing process in which the frozen meat is immersed in boiling water during heating, the heating is stopped immediately after immersion, and the meat is left to stand for 40 minutes; A method for cold thawing fresh meat, including:

2. a freezing step for rapidly freezing the packaged fresh meat to produce frozen meat; A residual heat thawing process in which the frozen meat is immersed in boiling water during heating, heating is stopped after 3 minutes, and the meat is left to stand for 40 minutes; A method for cold thawing fresh meat, including:

3. A meat product produced by the method of cold-thawing fresh meat according to claim 1 or 2.

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