Cheese/Yogurt How it’s made 楊倍昌 微生物暨免疫學研究所 1

兩題課後作業 1. 將長麴黑豆上的麴菌傳染到兩顆目 前是乾淨、乾燥的黑豆上。 ( 每位修 課同學都要做 ) 。 2. 做一罐 yogurt ，方法不拘。並說明 工法 ( 以組為單位繳交 ) 。 回答這兩道作業的前提 / 先備知識 是甚麼？ 2

%E8%B6%85%E7%B0%A1%E5%96%AE%E8%87%AA%E8%A3%BD%E5%84%AA%E6%A0%BC%26%E5%84%AA% E9%85%AA%E4%B9%B3 食材料金： NT $15 所要時間： hour 懶人指數：★★★★★ 省錢指數：★★★★★ 其實自己 DIY 做優格和優酪乳 ( 酸奶 ) 一點也不麻煩喔。 不用消毒 (???) 也不用買特製機器， 簡單又不容易失敗！ 材料： 牛乳 1 杯 原味優格 yogurt 3 湯匙 衛生紙 橡皮筋 做法： 1. 將牛奶微波約 15 秒左右，使牛奶比體溫稍高一點即可。 2. 將原味優格 3 湯匙放在杯中用湯匙輕輕弄碎。 3. 將杯口以衛生紙和橡皮筋套住，在室溫下放置一晚即可。要吃時以乾淨的湯匙取出，將優 格放在另一杯中加水即成優酪乳。原來杯中的優格不要吃完，只要繼續添牛奶進去就可以繼 續做優格囉。 %E3%80%90%E9%A3%9F%E8%AD%9C%E3%80%91%E7%B5%95%E5%B0%8D%E4%B8%8D%E5%A4%B1%E6%95%97%E7%9A %84%E8%B6%85%E7%B0%A1%E6%98%93%E8%87%AA%E8%A3%BD%E5%84%AA%E6%A0%BC 3

就這樣？ 4

有白吃的早午餐嗎？ 5 無菌技術 菌種來源 生長溫度 營養基質 100 ° C ， 5 分鐘 別人篩選的、活菌 ~30 ° C 全脂牛奶，低溫滅菌 Streptococcus thermophilusLactobacillus delbrueckii Lactobacillus acidophilus, Bifidobacterium lactis

Dynamic reaction in making Yogurt 6 Protocoorperation and antibiosis are the most important interactions in the growth of the yogurt bacteria Streptococcus thermophilus and Lactobacillus delbrueckii subsp. Bulgaricus (found in the human digestive tract, Probiotics). The associative growth of these two cultures results in a higher lactic acid production and development of flavour than what is possible from a single culture. The S. thermophilus forms acid much slower, which lacks some amino acids. Hence L. bulgaricus liberates small peptides and amino acids, mainly valine, of which serves to enhance the growth of S. thermophilus. In return the cocci enhance the growth of L. bulgaricus by the formation of formic acid from pyruvic acid under anaerobic conditions. S. thermophilus is inhibited at pH values between , while L. bulgaricus can tolerate pH values as low as to achieve a one to one ratio of these two, the incubation must be done in a controlled manner regulating growth conditions including the concentration of inoculum, time and temperature.

7 Where to find microbe? Everywhere! Cell Phone Bacteria:

Counting the viable cells Dilution ( 兩種物理特性 ) 科學的第一步在於數字化 : 定量 8

Growth and survival Lag phase: adaptation to the environment Exponential logarithmic growth: machine in full rum Stationary phase: nutrition exhausted, toxin increased Decline: cell die (steady biomass) or lysis (decrease biomass) Dormant as spore, non-viable state 9

The ideal pH range for maximum bacterial growth of most strains is 6.5 to 8.5. The ideal temperature range for maximum reproduction rate of most bacteria is between 80° F (27 o C) and 105°F (40.5 o C). 10 一般最適生長條件

in 37 o C, pH 5.1 in 45 o C, pH 6.2 In bioreactors 11

影響生長的因素 The orderly increase in the sum of all the components of an organism Affected by: Nutrients pH: neutrophils, acidophils, alkalophis Temperature: psychrophils; mesophils; themophils Aeration Pressure Ionic strength and osmotic pressure: halophils, osmophils 12

To die or not to die, that is a question Sepsis: microbes contamination Asepsis: absence of microbes contamination Sterilization: 100% killing Disinfection: loss the ability to cause disease (Pasteurization) -cide or cidal: killing of microorganism -static or stasis: inhibit growth or multiplication of microbes BC Yang 13

Types of antimicrobial agents Physical – Heat – radiation Chemical – Vapors – selectivity Scientific American284 (5):54-61 BC Yang 14

Killing is a probability Die at a constant rate (logarithmically) Depend on exposure time and microbial load Rare will reach 100% (on purpose and money consuming) BC Yang 15

As a matter of temperature Heat Boiling water Moist heat (steam under pressure, autoclave) Hot-air sterilization (Oven) Pasteurization Tyndallization Incineration Low temperature Refrigerator temp (4-7 ° C) Deep-freeze (-20 ° C to -40 ° C); liquid nitrogen (-196 ° C) Lyophilization (desiccation in low temperature) BC Yang 16

Pasteurization Suggested by L. Pasteur It is used to render mild safe (tuberculoses) and extend its storage quality Keep the flavor of milk and wine etc. 低溫： 62 o C 30 min ；高溫： 71 o C for 15 sec Disinfection BC Yang 17

1909 John Ross Robertson finances the installation of Toronto's first milk pasteurization plant in the College Street hospital, 30 years before it becomes mandatory. Pasteurization 別呆了, 不要喝尚青尚新鮮的牛奶 ! BC Yang 18

台灣人甚麼時候 開始喜歡優格？ 廣告是怎麼說的？ 19 Chao-Hung Kuo, et al. 2013, Long-Term Use of Probiotic-Containing Yogurts Is a Safe Way to Prevent Helicobacter pylori: Based on a Mongolian Gerbil's Model. Biochemistry Research International, Volume 2013 (2013), Article ID

養樂多，是一種活菌發酵乳。日本京都大學醫學部的微生物學教授代田稔於 1930 年成功培養出對人體腸道有益健康的乳酸菌，其後以其名字命名為 「代田菌」，並於 1935 年開始生產及銷售養樂多產品。 「 Yakult 」這個名 稱是取自世界語的「 Jahurto 」，意即優格。 1962 年，日本「關東養樂多株 式會社」與台灣合作籌劃「國際酵母乳業股份有限公司」，於台灣多處地方 出售養樂多，為養樂多第一個對外，也是第一個對亞洲發展的地方。 1964 年，第一家日本以外的分公司正式在台灣開幕。 20

Yogurt 工業作法 : ======================================================= 自家玩玩還可以： 用電鍋做源源不絕的優格 烹飪教學 Homemade Yogurt 自製酸 奶 : alse alse 天寬地擴 blog: %E8%87%AA%E8%A3%BD%E5%84%AA%E9%85%AA%E4%B9%B3 %E8%87%AA%E8%A3%BD%E5%84%AA%E9%85%AA%E4%B9%B3 21

幾個名詞 Fermentation Pasteurization Rennin/Rennet Acetaldehyde 22 Glycolysis: steps-by-steps-with-diagram/

硬質的起司 How It's Made Swiss Cheese: r80Tds&ebc=ANyPxKp6CDVCeZVvDZRO44E47TNW4frQ8mQWE0HudbkXLeLi- LXwMwGEqOd3o09PSb1nXQjSZnVrbU188uXNslnRbDfdzS_udA r80Tds&ebc=ANyPxKp6CDVCeZVvDZRO44E47TNW4frQ8mQWE0HudbkXLeLi- LXwMwGEqOd3o09PSb1nXQjSZnVrbU188uXNslnRbDfdzS_udA How It's Made - Blue Stilton Cheese: 4wdk6CXsMQBLuY2G9O_dZ3fqL8wEZU1w6kYMaVuSVQU_MjVMn7QaCQ 4wdk6CXsMQBLuY2G9O_dZ3fqL8wEZU1w6kYMaVuSVQU_MjVMn7QaCQ How It’s Made Parmesan Cheese: How to break open a Parmesan cheese : Channel Cheese : Traditional making of Toma Ossolana by hand in Northern Italy : SnSmzqLpv2CutlLsWCPhPffWhtQlt5aHDt_6uIIzfXjwTJ_SXDNQ SnSmzqLpv2CutlLsWCPhPffWhtQlt5aHDt_6uIIzfXjwTJ_SXDNQ 23

Ricotta cheese 不發酵，以醋及 85 °C 來凝乳 Making ricotta over an open fire in Northern Italy: pbH6XNDJOIF7gh3DCGRqDICegAZ5qSnSmzqLpv2CutlLsWCPhPffWhtQlt5aHDt_6 uIIzfXjwTJ_SXDNQ pbH6XNDJOIF7gh3DCGRqDICegAZ5qSnSmzqLpv2CutlLsWCPhPffWhtQlt5aHDt_6 uIIzfXjwTJ_SXDNQ 24 Ricotta 乳酪是一種著名的義大利乳清乳酪, ri ( 再 ) cotta ( 煮過 ), 它是因為製作 其他總類的乳酪所剩下來的乳清再度加熱, 再加上一點新鮮乳汁製成的, 含脂 量只有 20%, 嚴格說來並不算乳酪, 這種作法的 Ricotta 適合對乳蛋白不耐受的 人食用. 也可以用新鮮牛乳來製作。

新鮮、不需等待長時間發酵的乳酪起司 How It’s Made Cream Cheese: salt, lactic acid bacteria or lactic acid. AVuCja1BoCKxokXkvJVx5-hStquv4HgblynOIHEv4q15OOtMqQDx4NtQgA2oFucMNjQ AVuCja1BoCKxokXkvJVx5-hStquv4HgblynOIHEv4q15OOtMqQDx4NtQgA2oFucMNjQ ( 跟 Ricotta 乳酪很像 ) How It’s Made Goat Cheese: 0.6% salt, bacteria and rennet, around 24 h. o&ebc=ANyPxKo8kyr1PEI5FsatYC7IvPvnHwlAVuCja1BoCKxokXkvJVx5- hStquv4HgblynOIHEv4q15OOtMqQDx4NtQgA2oFucMNjQ o&ebc=ANyPxKo8kyr1PEI5FsatYC7IvPvnHwlAVuCja1BoCKxokXkvJVx5- hStquv4HgblynOIHEv4q15OOtMqQDx4NtQgA2oFucMNjQ 25

Cream cheese Cream cheese is easy to make at home, and many methods and recipes are used. Consistent, reliable, commercial manufacture is more difficult. Protein molecules in milk have a negative surface charge, which keeps milk in a liquid state; the molecules act as surfactants, forming micelles around the particles of fat and keeping them in emulsion. Lactic acid bacteria are added to pasteurized and homogenized milk. During the fermentation at around 22 °C (72 °F) the pH of the milk decreases (it becomes more acidic). Amino acids at the surface of the proteins begin losing charge and become neutral, turning the fat micelles from hydrophilic to hydrophobic state and causing the liquid to coagulate. If the bacteria are left in the milk too long, the pH lowers further, the micelles attain a positive charge and the mixture returns to liquid form. The key, then, is to kill the bacteria by heating the mixture to 52–63 °C (126–145 °F). Inaccurate timing of the heating can produce inferior or unsalable cheese due to variations in flavor and texture. Cream cheese has a higher fat content than other cheeses, and fat repels water, which tends to separate from the cheese; this can be avoided in commercial production by adding stabilizers such as guar or carob gums to prolong its shelf life 26

Protein molecules in milk have a negative surface charge, which keeps milk in a liquid state. Lactic acid bacteria are added to pasteurized and homogenized milk. During the fermentation at around 22 °C (72 °F) the pH of the milk decreases. Amino acids at the surface of the proteins begin losing charge and become neutral, turning the fat micelles from hydrophilic to hydrophobic state and causing the liquid to coagulate. Then, kill the bacteria by heating the mixture to 52–63 °C (126–145 °F). 與優格的不同在哪裡？你可以自己做 cream cheese 吧 ! 27

Funny question 被小老鼠吃掉的小孔 Why Does Swiss Cheese Have Holes? 這部片裡的答 案是亂講的： The bacterium Propionibacterium freudenreichii ( 費氏丙酸桿菌 ), which is one of several species of bacteria used in the production of Swiss or Emmentaler cheese, produces carbon dioxide from the fermentation of lactic acid while the cheese is curing. This bacterium is found in larger quantities in Swiss and Emmentaler cheeses than in other sorts of cheeses, which explains why bubbles are more evident in these cheeses than in most other cheeses. 28 Test gas and acid production:

Which cheese grows mold the fastest? Soft cheeses begin to grow mold within one week of being opened. Semi-soft cheeses, such as mozzarella, Monterey Jack and feta, last about two to three weeks without mold. Firm cheeses, such as Cheddar, Colby and Swiss, can last up to five weeks. The cheeses most resilient against mold are hard cheeses, such as Parmesan, which last up to 10 months. The key factors that influence the growth of mold are the pH level and the water activity. Some cheeses, such as blue cheese, already contain mold when they are consumed. Some mold on cheese can be toxic, so always double check before consuming cheese that contains mold. 29

發霉的乳酪能不能吃？ Basically, it's bad. There are exceptions though—for three things. Salami, which is already technically covered in the stuff, can just be scrubbed really well if uglier spores show up on its surface. Hard cheeses can still be used if mold shows up, but the moldy section has to be cut off a full inch deep into the product. The same goes for harder fruits or vegetables, if there's a spot, cut off a full inch. Anything else is tempting fate, or at least the mycotoxins. 30

Cheese DIY 為孩子自製起司， ( 其實這是 Ricotta) cheesemozzarella.html cheesemozzarella.html 31