Microbiology

2. CHEESE-started 8000 years ago
-consists of proteins and fat from milk
-made by fermentation

4. Lactococcus
lactis subsp. lactis or cremoris,
Streptococcus
salivarius subsp.thermophilus,
Lactobacillus delbruckii subsp. bulgaricus,
and Lactobacillus helveticus.

5.  Lactobacillus plantarum
 Propionibacterium freudenreichii
Yeasts and molds
e.g.Torula yeast is used in the smear for the
ripening of brick and limberger cheese.
Penicillium camemberti in camembert and
brie, Penicillium roqueforti in blue cheeses.

20.  Yogurt, a fermented
dairy product whereby
milk is inoculated with
bacteria cultures

21. A. Yogurt is the product of fermentation, a
slow decomposition process of organic
substances induced by microorganisms or
enzymesTo produce yogurt, lactose, a
compound sugar found in milk known as
lactin or milk sugar, is fermented by two
different species of bacteria: Lactobacillus
and Streptococcus.

22. B. Yogurt is commercially produced by
adding to milk a 2–4% nonfat dry milk
powder that has been inoculated with a 5%
combination of Lactobacillus bulgaricus
and Streptococcus thermophilus (1:1
ratio). The milk mixture is then incubated at
45 degrees C for 3 to 6 hours. The product
must be chilled immediately.

23. C. The fat content of yogurt varies from 0-
3.5%; most yogurt is low fat and contains
1–1.5% fat.

24. D. Lactic acid, the end product of
anaerobic metabolism of glucose, provides
the tart flavor of yogurt, as well as the
formation of a gel structure. The major
flavor components of yogurt are carbonyl
compounds; among these, acetaldehyde is
the most important and gives the yogurt its
green apple or nutty flavor. Yogurt quality
is based on color, appearance, body,
texture, and flavor.

25. E. Ropy (slime-producing) lactic acid
bacteria produce polysaccharides that are
released into the yogurt where they
increase viscosity and improve water
retention. Viscosity is the resistance of a
fluid to flow. Yogurt has a high moisture
content of 82–86%.

26. F. Milk SNF (solids-not-fat) content of
yogurt varies from 9–16%. SNF can be
increased by adding milk powder, and by
other means. Increased SNF levels are
needed to increase protein content, which
helps to increase product viscosity to
desired levels.

27. G. Frozen yogurt is manufactured by
mixing varied amounts of fermented yogurt
with ice milk containing sweeteners,
stabilizers, etc.

30. Making Butter from
Raw Milk

31.  Most Dairy Products
in the US come from
Dairy Cows with
Holsteins being the
most prominent
breed.

32.  Automatic wash
system- runs
sanitation wash
through all pipes
and milking units to
sanitize after each
milking.

34.  Pasteurize the milk
by holding at 145 F
for 30 minutes, and
cool rapidly to 40-45
F.

35.  Step 2: Milk should
be allowed to sit (at
room temperature)
over night to allow the
cream to rise to the
top. After the cream
has risen to the top,
its now time to collect
it. As shown in the
picture above, a
spoon was used to
skim the cream from
the top of the milk.

36.  Step 3: Next, pour
the cream into small
baby jars. Only fill
the jars half full, so
as to allow room for
the butter to form.
Place the cap back
on the jars after they
have been filled.

37.  Step 4: Now, it is
time to shake,
shake, shake it.
Take the baby jars
filled with cream and
begin to shake them.
This step could take
quite a while. Just
take your time and
keep shaking it.

38.  Step 5: As you
shake the cream, a
ball of butter will
begin to form slowly,
but continue
shaking until a fully
formed ball of butter
is present.

39.  Final Product- Fully
formed ball of butter

40.  Step 6: After the ball
of butter has formed
there should be liquid
that is separated from
the butter. This liquid
is known as
buttermilk. Separate
the butter from the
buttermilk by pouring
the buttermilk into a
cup. You should now
only have butter.

41.  Step 7: Wash the
butter: Pour a small
amount of very cold
water into the bowl
and work the butter.
As the water becomes
discolored, pour it out
and pour in more cold
water and continue to
work it. Continue this
process until the
water remains clear.

42.  Step 8: Place butter in a
container. Add salt:
Sprinkle in 1 teaspoon
of salt per pound of
butter and mix it in.
Then taste it. If it is too
salty for your taste, you
can put in more cold
water and work it
through the butter as
you did before. The salt
will gradually migrate
into the water.

43.  Step 9: Butter will
be soft at first, but
after flavoring the
butter if wanted,
place the butter in
the refrigerator to
allow it to stiffen.
The pictures above
demonstrate the
stiffness of the
butter.

44.  You are finished!
Now it is time to sit
back, relax, and eat
some home-made
butter! Hope you
ENJOY!