Manufacturing of Cheese
By:Kyle Wanke
April 14, 2004
ITDPT 303 Manufacturing Systems
What is Cheese?
According to the National Dairy Council, "All cheese is made from milk,
but different manufacturing and aging processes are used to produce the array of cheese available today. Cheese is made
by coagulating or curdling milk, stirring and heating the curd, draining off the whey (the watery part of milk), collecting
and pressing the curd, and in some cases ripening. Cheese can be made from whole, 2%, low fat, 1 % low fat or fat-free milk,
or combinations of these milks. About one third of all milk produced each year in the United States is used to make cheese.
In 1998, 9.7 billion pounds of natural and processed cheeses were produced."
Cheese History
The process of making cheese has remained the same for hundreds and even
thousands of years. The use of milk from a goat, sheep, or cow and an enzyme resulted in a whey. Cheese making has been
dated back over five thousand years. The nomads of the Middle East were the first skillful cheese makers and cheese even
played a part in Greek mythology. Cheese was a staple part of every Romans diet but the production of cheese started to
flourish when the French monasteries were created. (frencheese.co.uk)
Process of Making Cheese
According to www.efr.hw.ac.uk the process of making cheese is the same for
many varieties of cheese but the type of milk used and the ripening maturation can greatly influence the resulting cheese.
Figure 1 below illustrates the primary stages of cheese production.
www.efr.hw.ac.uk
The National Dairy council has a similar process chart the can be fond at
(http://www.nationaldairycouncil.com)
Importance of Milk
Milk is the most important ingredient of cheese and the type of milk
determines the type of cheese that can be produced. "For example, milk containing high total solids (sheep) increases
cheese yields, and conversely, milk high in fat produces softer cheese, but improves the mouth-feel of the product. Thus,
the cheesemaking process has to be modified in relation to the type of milk used" (www.efr.hw.ac.uk). The chart below
shows the difference in milk from different mammals.
Figure 2
Animal Fat
Protein
Milk Sugar Minerals
Cow
3.8
3.0
4.8 0.75
Goat
6.0
3.3
4.6 0.84
Sheep
9.0
4.6
4.7 1.00
Buffalo
6.0
3.8
4.5 0.75
www.efr.hw.ac.uk
Making Cheese and curdled milk
"Cheesemaking capitalizes on the curdling of milk.
First, the milk is carefully selected to make sure there are no antibiotics or harmful agents that could affect
the process. The milk is then heated and held at a given temperature for a short period to destroy any harmful
bacteria (i.e. pasteurization). Special starter cultures are then added to the warm milk and change a very small
amount of the milk sugar into lactic acid. This acidifies the milk at a much faster rate and prepares it for the
next stage. Rennet (mainly chymosin) is then added to the milk and within a short time a curd is produced.
Pepsin is not normally used in Britain except for certain specialized cheeses. The resultant curd is then cut
into small cubes, and heat is applied to start a shrinking process which, with the steady production of lactic
acid from the starter cultures, will change it into small rice-sized grains. At a carefully chosen point the
curd grains are allowed to fall to the bottom of the cheese vat, the left-over liquid, which consists of water,
milk sugar and albumen (now called whey) is drained off and the curd grains allowed to mat together to form large
slabs of curd. The slabs are then milled, and salt is added to provide flavor and help preserve the cheese. Later,
it is pressed, and subsequently packed in various sized containers for maturing" (www.efr.hw.ac.uk).
Cheese Components
There are four components that are used in making cheese milk,
starter cultures, coagulants and rennet, and finally salt. The fist ingredient milk can be broken down into its
essential parts that all play a role in making cheese. Milk contains fat, protein, enzymes, vitamins, lactose,
and ash. The fat in milk helps to provide flavor even when cheese is made from skim milk which has only one
percent of fat. The protein in milk "exists in two forms in milk as a suspension/colloidal (casein) and in a
soluble form (whey proteins). As an analogy, however, consider the first type of protein as a densely woven
mesh rather like a string vest suspended freely in the aqueous phase of milk. As long as the milk remains sweet,
this structure is unaffected and the milk remains totally fluid. However, if the milk acidifies (i.e. goes sour)
without the presence of coagulating enzymes the structure changes quite suddenly at the 'iso-electric point',
and a fragile curd is formed that collapses with the slightest agitation into tiny fragments. A typical example
is the fine mass we see when milk sours naturally. By adding rennet, at just the right time before the milk would
go completely sour, the structure of the casein is changed radically to form a solid curd called para-casein. This
can then be cut with knives and saved to be collected as grains of curd for subsequent processing" (www.efr.hw.ac.uk).
The enzymes in milk come from the cow and have an effect on the quality of raw milk and the ripening of cheese.
Milk contains important vitamins that promote growth such as A, B, D, E, and K. The Lactose in milk is the main
sugar and provides the energy for the started cutlers. The ash in milk are metallic components such as sodium,
potassium, calcium, manganese, iron, and copper. The most important of these is calcium which helps with the growth of bones.
www.efr.hw.ac.uk
Starter cultures are the next important ingredient in milk.
"The acid producing bacteria can in some cases directly suppress disease-producing bacteria under normal conditions.
This is why fermented milk products are among the safest foods to take in their natural state particularly in areas
where food hygiene may be suspect" (www.efr.hw.ac.uk).
Coagulants and Rennet are used to coagulate milk. "One form of
rennet is called 'vegetable' rennet which is derived from certain strains of fungi and bacteria. Today, this type of
rennet is very popular, reflecting a move towards organic foods, and the manufacture of 'vegetarian cheese'.
Substantial amounts are now used at farmhouse and creamery level. Recently, due to world shortage of calf rennet,
recombinant or genetically engineered pure chymosin derived from different microorganisms is available on the market,
and is currently used by many cheesemakers in different countries" (www.efr.hw.ac.uk).
The last ingredient of cheese is salt. Salt is used to create
different types of cheese including hard-pressed cheese, brine-salted cheese, soft cheese salting, and blue-veined
cheese salting. Salt ads flavor and acts as a natural preservative. (www.efr.hw.ac.uk)
Making Cheese
According to the Bunker Hill Cheese company ,of 6005 Country Road
77 Millersburg, OH 44654, which makes Heinis cheese the process of making cheese starts with milk from an Amish
Farm that is cooled to 38 degrees F. The next step is to standardize and clarify the milk which removes unwanted
elements and removes cream or milk fat. Pasteurization is then preformed to kill unwanted bacteria that are found
naturally in milk. Cheese cultures are then added to the milk in order to start the process of making cheese.
Coagulant is then added to change the milk from a liquid form to a "custard like gel." The milk gel is then cut
into pieces called cheese curd. The liquid that is produced from this process is called whey. The cheese curds
are then cooked at different temperatures depending on the desired out come of the cheese type, such as Colby,
Cheddar, or Swiss. The next step involves draining the whey and cooling off the cheese curds. Salt is then added
to the curd to provide flavor and a preservative. The next step is known as hooping the curd which involved placing
the curds into stainless steel hoops. The hoops give the cheese its shape. The curds are then pressed in the hoops
for a minimum of 12 hours in order to remove the last of the whey. Finally the cheese is ready to be packaged and
consumed. (www.heinis.com)
Note on packaging cheese
Advanced subject
According to the Wisconsin Center for Dairy Research at the University
of Wisconsin-Madison it is important to prevent Calcium Lactate Crystals. "During distribution and handling of Cheddar
cheese, a white crystalline material sometimes forms on the surface of the cheese. Although this material-calcium
lactate, is harmless, consumers are going to avoid it. We investigated the development of calcium lactate crystals on
Cheddar cheese, designing our experiments to test manufacturing, packaging and storage conditions to determine what
effectively prevented crystal growth. This is what we found. The crystals originate from nonstarter bacteria, naturally
present in milk and the cheesemaking environment, and necessary for flavor development in aged Cheddar cheese. A clean
milk supply and proper pasteurization are the best defense against high numbers of these bacteria" (www.cdr.wisc.edu).
The CDR recommends proper vacuum packaging in order to combat the crystals
Conclusion
It can be concluded that after studing the manufacturing of cheese the
process has changed little over the hundreds and thousands of years that cheese has been produced but the speed and rate
that cheese can be produced has greatly increased with moderen technology.
References
www.cdr.wisc.edu, 2003.
Retrieved on March 21, 2004
http://www.cdr.wisc.edu/cdrwebpa.nsf/0/B39BA06F70317F3D86256882005852BA?opendocument
www.efr.hw.ac.uk, 2003.
Retrieved on April 2, 2004
http://www.efr.
hw.ac.uk/SDA/cheese2.htmlI
The National Dairy Council,
1997. Found on April 5, 2004
http://www.nationaldairycouncil.org/nutrition/products/figure03.pdf
www.frencheese.co.uk,
1997. Found on April 5, 2004
http://www.frencheese.co.uk/glossary/glossary.cfm/lexiconID/5
The National Dairy Council,
1997. Found on April 5, 2004
http://www.nationaldairycouncil.org/nutrition/products/product_cheese.pdf