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Yoghurt & Cheese. Milk contains bacteria Bacteria feed anaerobically on the sugar in milk (lactose) Lactose Lactic Acid This is lactic acid fermentation The acid makes the pH of the milk go down The lactic acid curdles (coagulates) the milk - makes it lumpy. Cheese Making.
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Yoghurt & Cheese • Milk contains bacteria • Bacteria feed anaerobically on the sugar in milk (lactose) • Lactose Lactic Acid • This is lactic acid fermentation • The acid makes the pH of the milk go down • The lactic acid curdles (coagulates) the milk - makes it lumpy
Cheese Making • 1) Milk is pasteurised at 73oC, then cooled • 2) Bacteria are added to curdle milk • 3) An enzyme is added to separate the solid material (curds) from the liquid material (whey) • 4) Curds are cut into blocks • 5) Salt added (to slow bacterial growth) • 6) Left to ripen and develop flavour