【０００１】
【発明の属する技術分野】
本発明は、牛や鶏等の家畜内臓肉を安全な生食用や焼食用として無菌化するための処理方法に関する。
【０００２】
【従来技術とその課題】
現在、牛や鶏の内臓肉は、近年の病原性大腸菌Ｏ−１５７による食中毒事件の多発等により、生食が制限され、且つ敬遠されている。これは、赤身肉よりも内臓肉の方がＯ−１５７等に汚染される可能性が高いことによるが、何らかの方法で食感や旨さを損なうことなく無菌化して汚染を確実に排除できれば、内臓肉の生食需要も復活・拡大する筈である。
【０００３】
しかるに、食品の殺菌方法としては加熱殺菌が一般的に汎用されているが、生食品としての肉や魚介類には当然に加熱は適用できない。無論、殺菌剤等の使用は食品衛生法上で認められない上、薬剤を加えれば変質して本来の食感や旨さが損なわれてしまうことになる。そこで、近年では、肉や魚介類の如き生鮮食品に対する超高圧による殺菌方法についての様々な研究が進められつつあるが、超高圧による食肉の殺菌に関する発表データはまだ少なく、特に牛や鶏の内臓肉に至っては研究そのものが皆無に近い現状である。また、病原性大腸菌Ｏ−１５７についても、深刻な社会問題になっているにもかかわらず、有意な殺菌データは提示されていない。
【０００４】
本発明らは、上述の事情に鑑みて、牛や鶏等の内臓肉について、生食用や焼食用として安全で美味しいものを提供するために様々な観点より検討を重ねると共に、綿密な実験研究を行った結果、これら内臓肉を特定条件下で処理することにより、本来の食感や旨さを損なうことなく無菌化し得ることを見出し、本発明をなすに至った。
【０００５】
【課題を解決するための手段】
すなわち、本発明の請求項１に係る内臓肉の処理方法は、家畜内臓肉を真空パックし、この内臓肉に対して真空パックごと２０００〜４５００気圧の超高圧を加えることを特徴とする構成を採用したものである。また、このような請求項１の内臓肉の処理方法における好適態様として、請求項２の発明は、３０００〜４５００気圧での５〜１５分間の超高圧印加と加圧解除とを５回以上繰り返すことを特徴としている。
【０００６】
【発明の実施の形態】
本発明に係る内臓肉の処理方法は、既述のように、家畜内臓肉を真空パックし、この内臓肉に対して真空パックごと２０００〜４５００気圧の超高圧を加えるものであり、これによって内臓肉を無菌化し得る上、生食用や焼食用としての内臓肉の食感や旨さが損なわれないという優れた特徴がある。
【０００７】
図１は、上記の超高圧処理に用いる加圧装置の一例を示す縦断面図である。図において、１は中央に上下に透通する円筒状の処理室１０を備えた高圧容器、２は該高圧容器１の下方に配置した低圧シリンダ、３は低圧シリンダ２のピストン２１を作動させる油圧装置、４は高圧容器１の外周に設けた恒温水循環ジャケット１１に恒温水を循環供給する恒温水循環装置である。しかして、高圧容器１の処理室１０の上端開口部には、オーバーフロープラグ５１及び温度センサー５２を付設した着脱可能な上蓋５が液密に嵌着されると共に、該処理室１０の下端開口部には、低圧シリンダ２から突出したピストン２１の加圧ピストン部２１ａが液密に嵌入している。また、ピストン２１は、処理室１０に嵌入した加圧ピストン部２１ａの受圧上端面２ａの面積に対し、低圧シリンダ２内の受圧下端面２ｂの面積が小さく設定されている。
【０００８】
このような加圧装置による超高圧処理は、真空パックした内臓肉Ｍと純水Ｗ（蒸留水又はイオン交換水）とを高圧容器１の処理室１０内に上方から入れ、上蓋５を嵌着固定し、オーバーフロープラグ５１からのオーバーフロー水によって処理室１０の満水を確認すると共に、恒温水循環装置４によって処理室１０内の温度を一定（一般的に常温）にし、油圧装置３の駆動によって設定した所要の油圧でピストン２１を上昇側へ作動させればよい。これにより、パスカルの原理に基づき、処理室１０内にはピストン２１の受圧下端面２ａと受圧上端面２ｂとの面積比に対応する増圧比で静水圧が発生し、真空パックした内臓肉Ｍに対して全方向から超高圧が印加されることになる。
【０００９】
しかして、印加圧力は２０００〜４５００気圧の範囲とすべきであり、この圧力が２０００気圧未満の場合は殺菌不完全で食中毒菌が生き残る可能性を排除できず、逆に４５００気圧を越える場合は内臓肉Ｍが硬く且つ不味くなったり、色合いも悪く見た目に劣ることになって生食用や焼食用として適さないことが判明している。
【００１０】
また、この超高圧処理による内臓肉Ｍの食感（柔かさ）と味を未処理と変わらぬ程度に保つ上では、比較的長い時間で一回だけの処理を行うよりも、比較的短い時間の超高圧印加と加圧解除とを反復する方がよく、特に３０００〜４５００気圧での５〜１５分間の超高圧印加と加圧解除とを５回以上繰り返す方法が推奨される。
【００１１】
処理対象の家畜内臓肉としては、特に制約はないが、例えば牛レバー、センマイ、ミノ、シマ腸の如き牛の内臓肉と、鶏レバー、砂ずりの如き鶏の内臓肉が好適である。
【００１２】
【実施例】
以下、本発明の処理方法を実施例によって具体的に説明する。なお、以下の実施例における超高圧処理には、図１に示す構成において、処理室１０の有効寸法が６０ｍｍ径×２００ｍｍ高さ（容積約６００ｍｌ）、増圧比１０、最高使用圧力６８６ＭＰａ、昇圧時間８４秒、減圧時間１〜２秒の加圧装置（三菱食品加圧試験装置Ｆｒｅｓｃａｌ／ＭＰＦ−７０００）を用い、装置付属のタイマーにて加圧保持時間を設定した。
【００１３】
実施例１
内臓肉サンプルとして牛レバー、センマイ、ミノ、シマ腸、鶏レバー、砂ずりの各１０ｇにカットしたものを用い、それぞれに常在する大腸菌、サルモネラ菌、黄色ブドウ球菌の菌数を測定した上で、これらサンプルを真空パックし、それぞれ加圧装置の処理室１０に蒸留水と共に封入し、常温下（２３℃で昇圧直後のみ３０℃まで上昇するが、１０分位で戻る）、３０００気圧にて３０分間の超高圧処理を施したのち、各サンプルの内臓肉を取り出して再び上記菌数を測定した。その結果を表１に示す。なお、牛レバー、センマイ、ミノ、シマ腸におけるサルモネラ菌と、牛レバー、ミノ、シマ腸における黄色ブドウ球菌については、未処理の段階でも菌は測定されなかったので、表１では空欄としている。
【００１４】
【表１】
【００１５】
表１に示すように、内臓肉サンプルに存在していた大腸菌、サルモネラ菌、黄色ブドウ球菌は、１０１ 〜１０２ 個のオーダーであるが、３０００気圧，３０分間の超高圧処理によって死滅している。従って、本発明における２０００気圧以上の超高圧処理が非加熱殺菌として極めて有効であることが判る。
【００１６】
実施例２
実施例１と同様の７種の内臓肉サンプル（各１０ｇ）の多数を用意し、これらに大腸菌、サルモネラ菌、黄色ブドウ球菌、病原性大腸菌Ｏ−１５７のいずれかを後記表２Ａ及び２Ｂに記載の菌数で植菌して真空パックし、各々を両表記載の圧力及び時間条件で超高圧処理したのち、各サンプルの内臓肉を取り出して再び上記菌数を測定したところ、両表記載の結果が得られた。
【００１７】
【表２Ａ】
【００１８】
【表２Ｂ】
【００１９】
表２Ａ及び２Ｂに示すように、大腸菌、サルモネラ菌、黄色ブドウ球菌、病原性大腸菌Ｏ−１５７のいずれの菌種においても、植菌数１０１ 〜１０３ のオーダーでは、内臓肉の種類に関係なく３０００気圧で３０分間の超高圧処理で完全に死滅している。また、高度汚染を想定した植菌数１０５ 〜１０６ のオーダーでも、サルモネラ菌では３０００気圧で５分×６回、大腸菌及び病原性大腸菌Ｏ−１５７では３０００気圧で１０分×６回、黄色ブドウ球菌では４０００気圧で１０分×６回、のそれぞれ超高圧処理によって死滅している。従って、高度汚染を想定しても、４５００気圧以下の超高圧処理で充分に内臓肉の安全性を確保できること、特に３０００〜４５００気圧で５〜１５分間の超高圧印加と加圧解除を５回以上繰り返す処理が好適であることが示唆される。
【００２０】
実施例３
牛レバー、センマイ、ミノ、シマ腸、鶏レバー、砂ずりの７種の新鮮な内臓肉の各々について、未処理品と、実施例１，２同様の超高圧処理として４０００気圧で１０分×６回の処理を行ったもの、同５０００気圧で１５分の処理を行ったもの、のそれぞれ３品を用意した。そして、これらを、１０人（男６、女４）のモニターにより、牛レバー、センマイ、鶏レバー、砂ずりは生食と焼食で、ミノ及びシマ腸は焼食のみで、それぞれ食べてもらった上で、色（生食のみ）、柔かさ、美味しさについて次の５段階で評価を受け、１０人の平均点を求めた。その結果を、生食は表３に、焼食は表４にそれぞれ示す。
【００２１】
〔 評 価 〕 〔 点 数 〕
良い ・・・・・ ５点
やや良い ・・・・・ ４点
普通 ・・・・・ ３点
やや悪い ・・・・・ ２点
悪い ・・・・・ １点
【００２２】
【表３】
【００２３】
【表４】
【００２４】
表３の結果から、生食では、４０００気圧で１０分×６回の処理を行ったものは、未処理品に比較し、色が白くなる傾向があるが、柔かさと味は殆ど変わらず、美味しく食べられることが判る。これに対し、５０００気圧で１５分の処理を行ったものは硬くなったり、ぱさぱさした舌触りとなり、食感が悪い上に味も極端に落ちることが明らかである。従って、食感と味の点でも４５００気圧以下での処理が望ましいと言える。
【００２５】
【発明の効果】
請求項１の発明に係る処理方法によれば、牛や鶏等の家畜内臓肉を特定の超高圧条件で非加熱の処理を施すことから、本来の食感や旨さを損なうことなく無菌化することができ、もって生食用や焼食用として安全で美味しい家畜内臓肉を提供できる。
【００２６】
請求項２の発明によれば、前記の家畜内臓肉の処理方法において、家畜内臓肉を特定圧力で短時間の超高圧印加と加圧解除とを繰り返すことから、確実な殺菌に加え、食感と味をより未処理に近いものにできるという利点がある。
【図面の簡単な説明】
【図１】本発明に係る家畜内臓肉の処理方法に用いる加圧装置の一例を示す縦断面図である。
【符号の説明】
１ 加圧容器
１０ 処理室
１１ 恒温水循環ジャケッット
２ 低圧シリンダ
２１ ピストン
２１ａ 加圧ピストン部
３ 油圧装置
４ 恒温水循環装置
５ 蓋板[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a treatment method for sterilizing livestock offal meat such as cows and chickens for safe raw food and grilled food.
[0002]
[Prior art and its problems]
At present, the raw meat of beef and chicken offal is restricted and shunned due to the recent outbreak of food poisoning caused by pathogenic Escherichia coli O-157. This is because the offal meat is more likely to be contaminated with O-157 and the like than red meat, but if it can be aseptically sterilized without impairing the texture and taste by any method, The demand for raw meat for offal should be revived and expanded.
[0003]
However, heat sterilization is generally used as a food sterilization method, but heating cannot naturally be applied to meat and seafood as raw foods. Needless to say, the use of a bactericide or the like is not allowed under the Food Sanitation Law, and if a drug is added, the disinfectant deteriorates the original texture and taste. Therefore, in recent years, various researches have been conducted on the sterilization method of ultra-high pressure for fresh foods such as meat and seafood, but there are still few published data on sterilization of meat by ultra-high pressure, especially the internal organs of cows and chickens. At present, there is almost no research on meat. In addition, no significant bactericidal data has been presented for pathogenic Escherichia coli O-157 even though it is a serious social problem.
[0004]
In view of the above-mentioned circumstances, the present invention has been repeatedly studied from various viewpoints to provide safe and delicious meats for roast and edible meats of beef and chicken, etc. As a result, it has been found that by treating these organ meats under specific conditions, the meat can be sterilized without impairing the original texture and taste, and the present invention has been accomplished.
[0005]
[Means for Solving the Problems]
That is, the method for treating offal meat according to claim 1 of the present invention is characterized in that a livestock offal meat is vacuum-packed, and an ultra-high pressure of 2000 to 4500 atm is applied to this offal meat together with the vacuum pack. It has been adopted. Further, as a preferred embodiment of the method for treating offal meat according to the first aspect, the invention according to the second aspect repeats application of an ultrahigh pressure at 3000 to 4500 atm for 5 to 15 minutes and release of pressure at least 5 times. It is characterized by:
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
As described above, the method for treating visceral meat according to the present invention is to vacuum-pack livestock visceral meat and apply an ultra-high pressure of 2000 to 4500 atm to the visceral meat together with the vacuum pack. In addition to being able to sterilize the meat, it has the excellent characteristics that the texture and taste of the offal meat for raw and grilled foods are not impaired.
[0007]
FIG. 1 is a vertical cross-sectional view showing an example of a pressurizing device used for the above-mentioned ultra-high pressure processing. In the drawing, reference numeral 1 denotes a high-pressure vessel having a cylindrical processing chamber 10 which is vertically penetrated in the center, 2 denotes a low-pressure cylinder disposed below the high-pressure vessel 1, and 3 denotes a hydraulic pressure for operating a piston 21 of the low-pressure cylinder 2. The device 4 is a constant temperature water circulating device that circulates constant temperature water to a constant temperature water circulation jacket 11 provided on the outer periphery of the high-pressure vessel 1. Thus, a detachable upper lid 5 provided with an overflow plug 51 and a temperature sensor 52 is liquid-tightly fitted to an upper end opening of the processing chamber 10 of the high-pressure vessel 1, and a lower end opening of the processing chamber 10. , A pressurizing piston portion 21a of a piston 21 protruding from the low-pressure cylinder 2 is fitted in a liquid-tight manner. In the piston 21, the area of the pressure receiving lower end surface 2b in the low-pressure cylinder 2 is set smaller than the area of the pressure receiving upper end surface 2a of the pressurizing piston portion 21a fitted into the processing chamber 10.
[0008]
In the ultra-high pressure treatment using such a pressurizing device, the vacuum-packed meat M and pure water W (distilled water or ion-exchanged water) are put into the treatment chamber 10 of the high-pressure vessel 1 from above, and the upper lid 5 is fitted. It was fixed, the fullness of the processing chamber 10 was confirmed by the overflow water from the overflow plug 51, and the temperature in the processing chamber 10 was made constant (generally normal temperature) by the constant temperature water circulation device 4, and set by driving the hydraulic device 3. What is necessary is just to operate the piston 21 to an ascending side by required hydraulic pressure. Thus, based on the principle of Pascal, hydrostatic pressure is generated in the processing chamber 10 at a pressure increase ratio corresponding to the area ratio between the pressure receiving lower end surface 2a and the pressure receiving upper end surface 2b of the piston 21. On the other hand, an extremely high voltage is applied from all directions.
[0009]
Thus, the applied pressure should be in the range of 2000 to 4500 atm. If this pressure is less than 2000 atm, sterilization is incomplete and the possibility of food poisoning bacteria surviving cannot be excluded. It has been found that the visceral meat M is hard and unpalatable, has a poor color, and is inferior in appearance, and is not suitable for raw or grilled food.
[0010]
In addition, in order to keep the texture (softness) and taste of the offal meat M by the ultra-high pressure treatment to the same level as that of the untreated meat M, it takes a relatively short time to perform the treatment only once in a relatively long time. It is preferable to repeat the application of the ultra-high pressure and the release of the pressure, and it is particularly recommended to repeat the application of the ultra-high pressure and the release of the pressure at 3000 to 4500 atm for 5 to 15 minutes or more.
[0011]
There are no particular restrictions on the livestock offal meat to be treated. For example, beef offal meat such as beef liver, omasum, mino and sima intestine, and offal meat of chicken such as chicken liver and sand sand are suitable.
[0012]
【Example】
Hereinafter, the processing method of the present invention will be specifically described with reference to examples. In the configuration shown in FIG. 1, the effective size of the processing chamber 10 is 60 mm diameter × 200 mm height (volume about 600 ml), the pressure increase ratio is 10, the maximum working pressure is 686 MPa, and the pressure rise time is as follows. Using a pressurizing device (Mitsubishi Food Pressurizing Test Device Frescal / MPF-7000) for 84 seconds and a decompression time of 1 to 2 seconds, a pressurizing holding time was set by a timer attached to the device.
[0013]
Example 1
Escherichia coli, Salmonella, Staphylococcus aureus, which were resident in each, were measured using beef liver, spring mai, mino, striped intestine, chicken liver, and sandbags that were cut into 10 g each. These samples are vacuum-packed, respectively, sealed in distilled water in the processing chamber 10 of the pressurizing device, and at room temperature (the temperature rises to 30 ° C. only immediately after the pressure rise at 23 ° C., but returns in about 10 minutes). After subjecting the sample to ultra-high pressure treatment for 5 minutes, the visceral meat of each sample was taken out, and the number of bacteria was measured again. Table 1 shows the results. In addition, as for Salmonella in cattle liver, Senmai, Mino, and shima intestine, and Staphylococcus aureus in cattle liver, Mino, and shima intestine, no bacteria were measured even in an untreated stage.
[0014]
[Table 1]
[0015]
As shown in Table 1, Escherichia coli, Salmonella, and Staphylococcus aureus, which were present in the internal organ meat sample, were on the order of 10 1 to 10 2 , but were killed by the ultra-high pressure treatment at 3000 atm for 30 minutes. . Therefore, it is understood that the ultrahigh-pressure treatment of 2000 atm or more in the present invention is extremely effective as non-heat sterilization.
[0016]
Example 2
A large number of 7 kinds of offal meat samples (10 g each) similar to those in Example 1 were prepared, and any of Escherichia coli, Salmonella, Staphylococcus aureus, and pathogenic Escherichia coli O-157 were described in Tables 2A and 2B below. The cells were inoculated with the number of bacteria, vacuum-packed, and each was subjected to ultra-high pressure treatment under the pressure and time conditions shown in both tables. Then, the offal meat of each sample was taken out and the number of bacteria was measured again. was gotten.
[0017]
[Table 2A]
[0018]
[Table 2B]
[0019]
As shown in Tables 2A and 2B, in any of Escherichia coli, Salmonella, Staphylococcus aureus, and pathogenic Escherichia coli O-157, in the order of inoculation number of 10 1 to 10 3 , regardless of the type of organ meat, It has been completely killed by ultra-high pressure treatment at 3000 atm for 30 minutes. In addition, even in the order of 10 5 to 10 6 inoculations assuming high contamination, Salmonella bacteria at 3000 atmospheres for 5 minutes × 6 times, Escherichia coli and pathogenic Escherichia coli O-157 at 3000 atmospheres for 10 minutes × 6 times, yellow grape Streptococci are killed by ultra-high pressure treatment at 4000 atmospheres for 10 minutes x 6 times. Therefore, even if a high level of contamination is assumed, the safety of the internal organs meat can be sufficiently ensured by the ultra-high pressure treatment of 4500 atm or less, and in particular, the super-high pressure application and the pressure release at 3000 to 4500 atm for 5 to 15 minutes are performed 5 times. It is suggested that the above-described repeated processing is preferable.
[0020]
Example 3
For each of the seven types of fresh offal meat, beef liver, spring, mino, shima intestine, chicken liver, and sand sand, untreated products and ultra-high pressure treatment as in Examples 1 and 2 at 4000 atmospheres for 10 minutes x 6 Three samples were prepared, each of which had been subjected to the above-mentioned treatments, and which had been subjected to the same treatment at 5,000 atm for 15 minutes. These were monitored by 10 people (6 males and 4 females), and the beef liver, the spring Mai, the chicken liver, and the sand pork were eaten raw and burned, and the mino and shima intestines were burned only. Above, the color (raw food only), the softness, and the taste were evaluated in the following five stages, and the average score of ten persons was obtained. The results are shown in Table 3 for raw food and Table 4 for grilled food.
[0021]
[Evaluation] [Points]
Good ... 5 points slightly good ... 4 points normal ... 3 points somewhat bad ... 2 points bad ... 1 point [0022]
[Table 3]
[0023]
[Table 4]
[0024]
From the results in Table 3, in the case of raw foods, those processed at 4000 atmospheres for 10 minutes x 6 times tend to be whiter than the untreated products, but the softness and taste hardly changed. It turns out that it can be eaten deliciously. On the other hand, those treated at 5,000 atm for 15 minutes harden or have a crisp texture, and it is clear that the taste is bad and the taste is extremely reduced. Therefore, it can be said that processing at 4500 atm or less is desirable also in terms of texture and taste.
[0025]
【The invention's effect】
According to the processing method according to the first aspect of the present invention, since livestock offal meat such as cows and chickens is subjected to non-heating treatment under specific ultra-high pressure conditions, sterilization can be performed without impairing the original texture and taste. Therefore, it is possible to provide safe and delicious livestock offal meat for raw or grilled food.
[0026]
According to the invention of claim 2, in the method for treating livestock offal meat, the application of livestock offal meat at a specific pressure for a short period of time by applying an ultra-high pressure and depressurization are repeated. This has the advantage that the taste can be made closer to untreated.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an example of a pressurizing device used in a method of treating livestock offal meat according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pressurized container 10 Processing chamber 11 Constant temperature water circulation jacket 2 Low pressure cylinder 21 Piston 21a Pressurizing piston part 3 Hydraulic device 4 Constant temperature water circulation device 5 Cover plate
