Fermented milk - fermented milk

A dairy product made by adding lactic acid bacteria to drinking milk such as cow's milk or sheep's milk or skim milk, and fermenting the lactose contained in the milk with lactic acid. Some products use yeast in addition to lactic acid bacteria, in which case a small amount of alcohol fermentation occurs. Milk is a nutritious food, but it is prone to spoilage by harmful bacteria. On the other hand, wild lactic acid bacteria and yeast are distributed in the milking environment, and if the milk is left without heat sterilization after milking, lactic acid fermentation easily occurs and lactic acid is produced. As a result, the protein in the milk coagulates into a tofu-like form (curd formation) due to the acid, and at the same time, the growth of harmful bacteria that are generally weak to acid is suppressed and the milk has good shelf life. Therefore, in ancient pastoral societies, there are many cases where milk is not drunk as it is, but is fermented into fermented milk before drinking it. Mongolian edsunsus, Indian dahi, Middle Eastern laban, Turkish and Balkan yogurt, Nordic film yolk, and products that undergo alcohol fermentation with yeast, such as Caucasian kefir and continental kumis, are all types of fermented milk. In Japan, "raku", which was introduced from China around the Nara period, is thought to be a type of dairy product, and there are records of it being used by the aristocratic class at the imperial court.

Most of the fermented milk currently on the market in Japan is made using the same manufacturing method as yogurt, and comes in a wide variety of forms, including those that are simply curdled, those that have been crushed into a paste, those that have fruit juice or other ingredients added, those that have sugar or other ingredients added, those that have been liquefied and made to be consumed as is, and those that have been frozen into ice cream. The Ministry of Health, Labour and Welfare's "Ministerial Ordinance on the Compositional Standards of Milk and Dairy Products" defines "fermented milk" as milk or a substance containing an equivalent or higher non-fat milk solids content (8.0% or more) that has been fermented with lactic acid bacteria or yeast, and that has been made into a paste, liquid, or frozen form, and that contains more than 10 million lactic acid bacteria or yeast cells per milliliter.

[Kyoji Niinuma and Akiaki Wani]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

牛乳、羊乳などの飲用乳またはその脱脂乳に乳酸菌を加え、乳中に含まれる乳糖を乳酸発酵させた乳製品。乳酸菌に酵母を併用するものもあり、その場合はわずかにアルコール発酵を伴う。乳は栄養に富む食品であって、有害細菌による腐敗がおこりやすい。一方、搾乳の環境では野生の乳酸菌や酵母が分布していて、搾乳後加熱殺菌をせずに放置しておくと、容易に乳酸発酵が行われて乳酸が生ずる。その結果、乳中のタンパク質が酸によって豆腐状に凝固（カード生成）し、同時に一般に酸に弱い有害細菌の繁殖を抑制し保存性がよくなる。したがって古来牧畜社会においては搾乳された乳をそのまま飲まずに、発酵乳の形にしてから飲用する例が多くみられる。モンゴルのエードスンスー、インドのダヒ、中近東諸国のラバン、トルコ・バルカン諸国のヨーグルト、北欧のフィルムヨルク、また酵母によってアルコール発酵を伴ったものではカフカスのケフィア、大陸内部のクミスなどはすべて発酵乳の一種である。日本では奈良朝のころから中国より伝わった「酪(らく)」がその一種と考えられ、宮廷貴族階級に用いられた記録がある。

　現在わが国で流通している発酵乳は、ほとんどヨーグルトの製造方法によっているもので、形状としては、カード生成をさせただけのものに、カードをペースト状に砕いたもの、果汁果実などを加えたもの、糖類などを加えたもの、液状にしてそのまま飲用に供する形にしたもの、凍結してアイスクリーム状にしたものなど多種類にわたる。厚生省令「乳及び乳製品の成分規格等に関する省令」では、乳またはこれと同等以上の無脂乳固形分（8.0％以上）を含むものを、乳酸菌または酵母で発酵させ、糊(のり)状、液状またはこれを凍結したもので、乳酸菌数または酵母数が1ミリリットル当り1000万個以上を含むものを、「はっ酵乳」と定義している。

［新沼杏二・和仁皓明］

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