4. Food processing
• methods and techniques
used to transform raw ingredients into food or
to transform food into other forms for consumption by
humans or animals either in the home or by the food
processing industry.
.e.g. Takes clean, harvested crops or slaughtered and
butchered animal products and uses these to produce
attractive, marketable and often long shelf-life food
products.
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5. Food processing
Similar processes are used to produce animal feed.
Extreme examples of food processing include the
delicate preparation of deadly fungi fish or preparing
spice food for consumption under zero gravity
• it encompasses all steps that food goes through from
the time it is harvested to the time it reaches the
retailer shops or the final consumers.
e.g. Picking of vegetables or fruits from the
garden
sorting and washing before they
are sent to the market
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6. Food processing
• Some processing methods convert raw
materials into a different form or change
the nature of the product as in the
manufacture of sugar from sugar cane, oil
from sunflower and cheese from milk
• Processing may involve an extremely
complex set of techniques and ingredients
to create ready to eat convenience foods
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7. Food preservation
Processing techniques that make the food fit
for consumption. i.e. the process of
treating and handling food to stop or slow
down Food spoilage, loss of quality,
edibility or nutritional value and thus
allow for longer food storage.
includes chemical and physical changes
such as bruising and browning, infestation by
insects or other pests or growth of microorganisms such as bacteria yeast and moulds.
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8. Food preservation
Preservation usually involves preventing the
growth of bacteria, fungi (such as yeasts),
and other micro-organisms as well as
retarding the oxidation of fats which cause
rancidity.
• However some methods work by
introducing bacteria, or fungi to the food.
• can also include processes which inhibit
visual deterioration, such as the enzymatic
browning reaction which can occur
naturally during food preparation.
•
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9. Food preservation
• preserved food should retain their
colour and taste. (i.e. colour and taste of
food which is present at the time of
preservation should not change.) e.g.
preserving grapes as raisins.
• should not change texture. But this
applies to some of the foods and
processing technique/method
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10. FOOD PROCESSING METHODS
Removal of unwanted outer layers,
Chopping or slicing e.g. carrots
Mincing and macerating meat
Liquefaction, such as to produce fruit juice
Fermentation e.g. in beer breweries
Cooking,
Mixing addition of gas such as air entrainment for bread or
gasification of soft drinks
Proofing –activating until light or smooth
Spray drying
Pasteurization
Packaging
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11. History of food processing
• Prehistorically food processing involves
different activities such as slaughtering,
fermenting, sun drying, preserving with salt,
and various types of cooking (such as roasting,
smoking, steaming and oven baking).
e.g. Salt-preservation – warrior and sailors diet
• Evidence for the existence of these methods
exists in the writings of the ancient Greek,
Chaldean, Egyptian and Roman civilizations as
well as archaeological evidence from Europe,
North and South America and Asia.
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12. History of food processing
These tried and tested processing
techniques remained essentially the same
until the advent of the industrial
revolution. Examples of ready-meals also
exist from pre industrial revolution times
such as the Cornish pasty/humburger and
the Haggis/sausages
In the 19th and 20th century modern
technology was largely developed to serve
military needs.
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13. History of food processing
• In 1809 Nicolas Appert invented a vacuum
bottling technique that would supply food
for French troops, and this contributed to the
development of tinning and then canning
by Peter Durand in 1810.
• Although initially it was expensive and
somewhat hazardous due to the lead used
in cans, canned goods would later become a
useful container for food preservation around
the World.
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14. History of food processing
• In 1862, Pasteurization, was discovered by Louis
Pasteur. This was a significant advance in ensuring the
micro-biological safety of food.
• In the 20th century, World War II, the space race and
the rising consumer society in developed countries
(including the United States) contributed to the growth
of food processing with such advances as spray drying,
juice concentrates, freeze drying and the
introduction of artificial sweeteners, colouring agents,
and preservatives such as sodium benzoate.
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15. History of food processing
• In the late 20th century products such as dried instant
soups, reconstituted fruits and juices, and self cooking
meals
• In Western Europe and North America, the second half
of the 20th century witnessed a rise in the pursuit of
convenience; food processors especially marketed
their products to middle-class working wives and
mothers. Frozen foods found their success in sales of
juice concentrates and “TV dinners”
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16. History of food processing
• Processors utilized the perceived value of time to appeal
to the post war population, and the same appeal
contributes to the success of convenience foods today.
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17. Benefits of food processing and
preservation
• Mass production of food is much cheaper overall than
•
•
•
•
•
individual production of meals from raw ingredients.
Reaches areas where the food item is not grown
Easing marketing, storage and distribution tasks
Add variety to our meals
Increasing food consistency (season availability0
Toxin removal
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18. Benefits of food processing and
preservation of foods safe to eat by de makes many kinds
activating spoilage and pathogenic microorganisms.
Improves the quality of life for people with
allergies, diabetics, and other people
can also add extra nutrients such as vitamins
Processed foods are often less susceptible to early
spoilage than fresh foods
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19. Limitations/drawbacks
Can lower the nutritional value of foods, and introduce
hazards not encountered with naturally-occurring
products
Processed foods often have a higher ratio of calories to
other essential nutrients than unprocessed foods, a
phenomenon referred to as “empty calories”. Socalled junk food, produced to satisfy consumer
demand for convenience and low cost, are most often
mass produced processed food products.
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20. Limitations/drawbacks
May cause adverse health effects.-
Preservatives such as nitrites or sulphites.
Failures in hygiene standards in “lowlevel” manufacturing facilities that
produce a widely-distributed basic
ingredient can have serious consequences
for many final products
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21. processing
• Hygiene e.g. measured by number of micro•
•
•
•
organisms per ml finished product
Energy consumption, measured e.g. by “ton of steam
per ton of sugar produced”
Minimization of waste, measured e.g. by
“percentage of peeling loss during the peeling of
potatoes
Labour used, measured e.g. by “number of working
hours per ton of finished product”
Minimization of cleaning stops measured e.g. by
number of hours between cleaning stops”
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22. Trends in modern food processing
• Cost reduction
• Health
• Hygiene -application of industry and government
endorsed standards to minimize possible risk and
hazards e.g in USA- HACCP
• Efficiency:
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23. Principle of food processing and
preservation
The following principles are involved in various
methods,
Prevention or delay of microbial decomposition (control
of microorganisms)
Prevention or delay of self decomposition of the food
(control of enzymes )
Controlling insects, rodents, birds and other physical
causes of food deterioration
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24. Prevention or delay of self
decomposition of the food
Controlling enzymes by:• Inactivating endogenous enzymes
• Preventing or delaying chemical Reactions in the food
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25. Prevention or delay of microbial
decomposition
• By keeping out microorganisms (Asepsis)
• By removal of microorganisms. This is done by
removing air, water (moisture), filtration, lowering or
increasing temperature, increasing the concentration
of salt or sugar or acid in foods
• By hindering the growth and activity of
microorganisms e.g. by low temperature drying,
anaerobic conditions or chemicals
• By killing the microorganisms e.g. by heat or
radiations
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26. Growth curve of microbial cultures
Whenever microorganisms are added to a food and
conditions are favourable the organisms will begin to
multiply and will pass through a succession of phases.
When counts of organisms are made periodically and
the results are plotted with logarithms of number
organisms per millilitres as ordinates and time units as
abscissas, a growth curve is obtained as illustrated in
the following figure:
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28. Application of microbial growth
curve to food preservation
• It is especially important in food preservation to
lengthen as much as the lag phase and the phase of
positive acceleration. This can be accomplished in
different ways.
1. reducing the amount of contamination.
2. By avoiding the addition of actively growing
organisms (logarithmic phase).
3. By one or more unfavourable
environmental
conditions
4. By actual damage to organisms by processing
methods such as heating or irradiation.
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