Food preservation

1. Modern
Methods for
Food
Preservation
Presented by: Realyn D. Embalado

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Learning Outcomes:
At the end of this lesson, students must be
able to:
• Understand the importance of food
preservation; and
• Identify the modern methods for food
preservation

3. What is Food Preservation?
- Food preservation can be defined
as the process of treating and
handling food in such a way as to
stop or greatly slow down spoilage
and prevent foodborne illness while
maintaining nutritional value, texture
and flavor.

4. History of Food
Preservation

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Modern Methods for Food Preservation
6. Pascalization
7. Biopreservation
8. Hurdle Technology
9. Nonthermal plasma
10. Modified
Atmosphere
1. Pasteurization
2. Freeze Drying
3. Vacuum Packing
4. Irradiation
5. Chemical Food
Preservatives

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Modern Methods for Food Preservation
1. Pasteurization
• heat-treatment process that destroys pathogenic
microorganisms in certain foods and beverages.
• Named for the French scientist Louis Pasteur
3 methods:
1. Long temperature long time (LTLT) method
2. High temperature short time (HTST) method
3. Ultra high temperature (UHT) method

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Advantages
• The flavor and the texture of the milk
have improvised after pasteurizing it.
• The method kills the pathogens or
bacteria present in the raw milk and
makes is safe to consume without any
health risk.
• UHT method is the best to apply, as it
has less of an adverse effect on milk’s
nutritional value and taste.
• This method may prevent many diseases
such as diphtheria, tuberculosis, scarlet
fever and brucellosis by killing some of
the most harmful bacteria.
Disadvantages
• Milk pasteurized with HTST
method is believed to lose 1/3rd of
the thiamine present in the milk
and half of vitamin B12.
• The discovery of heat resistant
pathogens has increased the risk of
the presence of bacteria even after
pasteurizing the food.
• Due to loss of certain enzymes in
food during pasteurization, few
people consider raw milk a better
option to pasteurized milk.

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Modern Methods for Food Preservation
2. Freeze Drying
• Freeze drying is a water removal
process typically used to preserve
perishable materials, with the goal of
extending their shelf life and/or
preparing them for transport. Also
known as lyophilization

9. 3 Phases
1. Freezing phase - can be done in a
freezer, a chilled bath (shell freezer)
or on a shelf in the freeze dryer.
2. Primary drying (Sublimation) -
pressure is lowered and heat is
added to the material in order for the
water to sublimate.
3. Secondary drying (Absorption) - the
ironically-bound water molecules
are removed.

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Advantages
• Great snacks
• Little to no chemical changes to
food
• Little physical changes to food
• Nutritional value is almost
completely maintained – it is
healthy
• Long-term storage — 20+ years
• Lightweight food
• No refrigeration required
Disadvantages
• Water required for reconstitution
(except for simple snacks)
• Slow process — average cycle is 24+
hours
• Some dislike the dry, Styrofoam
texture
• Not all foods can be freeze dried
• Airtight containers are required for
long-term storage
• No space savings — the food’s cellular
structure is mostly retained
• Sometimes, normal dehydration is
better
• Production cost

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Modern Methods for Food Preservation
3. Vacuum Packing
• “Vacuum packing” is a method of food
packaging that removes all air from a food-
filled, plastic film package before “sealing” it.
• By keeping oxygen out, vacuum packing
preserves food by obstructing the growth of
fungus, mold and oxygen-induced (aka
“obligate’) bacteria including mesophiles,
psychrotrophic, thermophiles, and
psychrophiles.

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Advantages
• Easy to use. The vacuum packaging
can be opened easily and safely, when
eating, open the bag and eating
without heating.
• Convenient storage and transportation.
Vacuum packaging takes up less
space, saving storage and
transportation costs.
• Long preservation time, vacuum-
packed food, which does not require
refrigeration, has a long life and is
convenient for long-term use.
Disadvantages
• Everything has two sides, the same
with vacuum packaging, the main
problem is the lack of high-speed
loading equipment, bring some
influence to mass production.
• In the packaging process, inflating
and sealing problems are critical,
some foods are perishable. In the
process of production, transportation
and sales, avoid products from
mechanical or external extrusion, and
such foods are susceptible to moisture
and oxidation.

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Modern Methods for Food Preservation
4. Irradiation
• Foodstuff is exposed to ionizing
radiation either as β- particles or γ- rays.
The radiation is capable of killing
bacteria, molds and pests among others.
The irradiation is also capable of
decreasing the ripening of fruits and
stops spoilage.

14. Modern Methods for Food Preservation
5. Chemical Food Preservatives
- In processed foods, anti-microbial chemical
agents are added to preserve them. These
agents are added in smaller amount since these
are mostly toxic when consumed in larger
amount. Common preservatives are benzoic
acid and benzoates which are used in acidic
foods such as jams, salad dressing, juices,
pickles, carbonated drinks, soy sauce among
others.

15. Modern Methods for Food Preservation
6. Pascalization
• In this technique, foodstuff is pressed
inside a vessel exerting very high
pressure to the tune of 70,000 lb per
square inch. This technique is good
since foodstuffs retain their
freshness, flavour, texture and
nutrients with destruction of
microbes.

16. Modern Methods for Food Preservation
7. Biopreservation
• When natural microbes or antimicrobials
are used for preservation and increasing
the shelf life of foodstuffs, it is called
biopreservation.
• Lactic acid bacteria have been used as
biopreservatives. These bacteria produce
lactic acid, acetic acid, bacteriocins and
hydrogen peroxide among others which
act as antimicrobials.

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Modern Methods for Food Preservation
8. Hurdle Technology
• In this technology, more than one
approach are applied to inactivate any
pathogenic microbe, if present in a
food.
• an intelligent combination of hurdles
that secures the safety from microbes
and ensures no loss of nutritional
quality and economic viability of food.

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Modern Methods for Food Preservation
9. Nonthermal Plasma
• In this technology, surface of the foodstuff
is exposed to a flame of ionized gas
molecules such as nitrogen and helium. It
helps in killing the microbes if present on
the surface of the food
• is a cutting-edge technology which has
gained much attention during the last
decade in the food-processing sector as a
promising technology for food preservation
and maintenance of food safety.

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Modern Methods for Food Preservation
10. Modified Atmosphere
• is a packaging system that involves changing the
gaseous atmosphere surrounding a food product
inside a pack, and employing packaging materials
and formats with an appropriate level of gas barrier
to maintain the changed atmosphere at an
acceptable level for preservation of the food.
• Improvement in visual appeal of
packed products
• Decreased risk of food spoilage
• Prolonged the shelf life of the product

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THANK YOU!