Transcript Dairy farming Case study – part 2 © BRITISH NUTRITION FOUNDATION 2014

Dairy farming
Case study – part 2
© BRITISH NUTRITION FOUNDATION 2014
Learning objectives
• To recall the key stages in
milk processing .
• To learn about Cheddar
cheese production.
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Case study
For three generations a family
have farmed dairy cows and
produced Cheddar Cheese in
the West country.
On this farm, each cow
produces about 7,000 litres of
milk per year, which in total
supplies the cheese dairy with
just over 7 million litres of fresh
milk to be made into traditional
farmhouse cheese. This volume
of milk equates to an annual
cheese production of 6,000
tonnes.
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Milk processing
After the milk has been delivery from
the dairy, it is pasteurised.
Pasteurisation is a process used to kill
harmful microorganisms, such as
certain pathogenic bacteria, yeasts
and moulds, which may be present in
the milk after initial collection. This
process extends the shelf life of milk.
The basic process for whole milk
involves heating the milk to a
temperature of no less than 71.7ºC for
25 seconds. This process is known as
High Temperature Short Time (HTST).
The milk is then cooled for packing,
storage and transportation.
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Homogenisation
Homogenisation of milk involves
the milk being pumped at very
high pressures through narrow
tubes, breaking up the fat globules
in order for these to disperse
through the liquid.
This process produces milk of a
uniform composition and
palatability, without removing or
adding any constituents.
Most milk available for purchase is
homogenised.
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Packing
The milk is then packaged into
bottles and labelled.
The packaging helps to
increase the shelf-life of the
milk.
The milk is then distributed to
supermarkets and shops for
sale.
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Find out more about milk
To find out more about milk, access
the From grass to glass – the journey
of milk poster.
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Click here to download the poster
Cheese production
In this cheese factory, up to
25,000 litres of milk can be
delivered from dairy farms at
any one time.
The milk is unloaded and
literage is checked before the
milk is transferred into silos.
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Pasteurisation
The first process the milk goes
through is pasteurisation.
Pasteurisation reduces the
number of spoilage
microorganisms and provides a
good environment for the
starter cultures to grow.
Milk is cooled in a vat after
pasteurisation to 32 °C, an
ideal temperature for the
starter culture to grow.
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Curdling
A starter culture, similar to freeze
dried natural yogurt, is then added
to the pasteurised milk. This begins
to acidify the milk.
The curlding step allows the
bacteria to grow and begin
fermentation. Rennet, an enzyme
that acts on the milk protein caesin,
is added and the milk coagulates,
forming lumps.
The milk is mixed and then left to
settle, while the junket forms, where
the milk curdles and separates into
curds and whey.
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Cooling tables and draining whey
The curds and whey run from the
cheese vat onto the cooling tables.
The cooling tables are used to:
1) cool the curds and whey;
2) separate the curds from the whey.
The whey is drained off for further
processing where cream is removed
from the whey by centrifuge and
made into butter. Protein is also
extracted from the whey for different
ingredients. In addition, lactose is
removed from the water and then
used for animal feed.
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Cheddaring
The mixture is moved around
on the cooling tables allowing
the whey to drain out through
a central perforated channel.
As the liquid is drained off a
solid mass is created, called
curd mats.
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Cheddaring
The curd mats are cut into sections and piled
on top of each other and turned
periodically. This step is called ‘cheddaring’.
The protected name is West Country
Farmhouse Cheddar and the conditions are:
• The cheddar is made using milk from local
herds reared and milked in the four
Counties (Cornwall, Devon, Somerset,
Dorset);
• The cheddar contains no colouring,
flavouring or preservatives.
• The cheddar is made in these four
counties to traditional methods, e.g.
cheddaring.
• The cheddar is made and matured on the
farm and aged for at least 9 months.
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Salting
Around 1,900 kg of cheese can be
made on the cooling table within an
hour.
The curd pieces are fed into a mill and
sliced into pieces about half the size of
a thumb. This ensures the salt can be
uniformly mixed throughout the curd.
Salt is added to act as a preservative
and prevent the cheese from going
rancid during the maturing process. It
also adds flavour to the cheese.
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Cheese blocks
The mixture is then taken into a six
metres high tower to form rectangular
shaped cheese blocks, weighing 20
kilograms each. After confirming the
weight, these blocks are individually
identified, ensuring traceability.
Following this, the blocks are vacuum
packaged and encased in six or seven
wooden boards. They are then taken
to the cool room and are chilled to a
temperature of 10-12°C.
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Cheese ripening
In the cool room, acidification of
cheese continues at a much
slower rate during this period
known as ripening.
When it is time to select the
cheese, the grader decides
which cheeses are the best
eaten young and which should
be left to ripen (for up to 18
months) developing the special
features and flavours associated
with West Country Farmhouse
Cheese.
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Cheese packaging
The final stage in cheese
production is slicing and
packaging.
The cheese blocks are then cut
into specific sizes, packaged and
labelled. These products are sold
via retailers large and small
throughout the UK, as well as in
the farm shop.
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By-products from the farm
In addition to the cheese, there
are other products produced on
the farm. The male calves are
kept to form a herd of beef
animals supplying quality meat to
the farm shop.
Arable crops, including wheat,
barley, oats, oilseed rape and
maize is grown. Some of the grain
is used to feed the stock, such as
dairy cows and pigs, while the
rest is sold.
Pigs are fed on whey from the
cheese production and cereals
grown on the farm.
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Slurry lagoon
The farm has a slurry lagoon
which stores the slurry, a mixture
of dairy cow manure and the
water used to wash out the cow
barn.
This is used as fertiliser and spread
over the fields at certain times of
the year. The fields are used for
grazing or growing crops such as
wheat and barley.
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Quiz
Take the quiz.
Take the quiz
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End
Question 1
True or false? Pasteurisation is a process
used to kill harmful microorganisms, such
as certain pathogenic bacteria, yeasts
and moulds, which may be found in the
milk after initial collection.
A. True
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B. False
Question 1
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Question 1
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Question 2
What is homogenisation?
A. Milk is heated and cooled
very quickly to pasteurise the
milk.
B. Milk is pumped at high
pressure to disperse the fat
through the milk.
C. Milk is sorted into different
types according to fat
content.
D. The dairy cows are
grouped according to milk
yield.
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Question 2
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Question 2
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Question 3
Which enzyme is added to the milk and
acts on the milk protein caesin, causing it
to coagulate, forming lumps.
A. Curdle
B. Junket
C. Amylase
D. Rennet
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Question 3
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Question 3
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Question 4
Which of the following is removed and
drained away when making Cheddar
cheese?
A. Curds
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B. Whey
Question 4
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Question 4
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Question 5
What is added to act as a preservative
and prevent the cheese from going
rancid during the maturing process?
A. Fat
B. Sugar
C. Salt
D. Whey
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Question 5
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End
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End
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