The combination of preservation techniques form a series of preservative factors. This is called as ‘hurdles’. It is a technology used to get a maximum lethality against microorganisms by a combination of two or more preservation parameters. The examples for these hurdles are, temperature,water activity, pH, preservatives and so on.

1. FOOD PRESERVATION
BY
HURDLE TECHNOLOGY
Mohamed Faiz Fathima Husna

2. Introduction
• It is a technology used to get a maximum lethality against
microorganisms by a combination of two or more preservation
parameters.
• The combination of preservation techniques form a series of
preservative factors. This is called as ‘hurdles’. The examples for these
hurdles are, temperature,water activity, pH, preservatives and so on.
• These hurdles achieve microbial stability and safety and stabilize
nutritive and economic properties of food.

3. Basics of Hurdle Technology
1. Homeostasis
• It is the key phenomenon in hurdle technology.
• It is the tendency of microorganisms internal status’ uniformity and
stability.
• If the homeostasis of microorganisms is disturbed in food temporarily
or permanently, they will not multiplied.

4. 2. Metabolic exhaustions
• It’s caused to the autosterilization of food.
• The microorganisms use their energy to overcome the food hostile
environment. Eventually after use up their complete energy,they die.
• By this, the foods become safe during the storage conditions specially in
ambient temperature.

5. 3. Stress reactions
• When microbes become stress, they produce stress shock proteins which
help to cooperate with the stress conditions.
• During food preservation, when different stresses are produced
simultaneously, the stress shock proteins require more energy.
• That causes the microorganisms to become metabolically exhausted.

6. 4. Multi-target preservation
• A small intensity of different hurdles is more effective than the large
intensity of one hurdle.
• The synergistic effect is created when different preservative characters are
gathered together.
• By this synergistic effect, different parts of microbial cells are affected. So,
the homeostasis and activation of stress shock protein become more
difficult.

7. Hurdles used for food preservation
Microbial Hurdles
• Antibiotics
• Bacteriocins
• Protective
cultures
• Miscellaneous
hurdles
• Free fatty acids
• Chitosan
• Chlorine
• Monolaurin
Physico-chemical
hurdles
• CO2
• Ethanol
• Lactic acid
• Lactoperoxidase
• Low pH
• Low Eh
• Low water activity
• Organic acids
Physical hurdles
• Aseptic packaging
• Electromagnetic
energy
• High temperature
• Low temperature
• Ultrahigh
temperature
• Ionizing radiation
• Modified
atmosphere
• Packaging films
• Ultra sonication
• Ultraviolet
radiation

8. Examples of the hurdle effect
• Fruit juice
• Acidification,
• pasteurization,
• aseptic package,
• ambient or chill storage
• Meat
• pasteurization
• vacuum package or MAP
• Pasteurized Sauces
• Acidification Hot filling or aseptic filling
• Salamis
• Drying and acidification by
fermentation
• Yoghurt
• natural starters and acidification
with chill storage
• acidification by lactic starters
following by pasteurization and
chilled storage
• Cheeses
• Reduction in water activity
• natural Acidification
• chilled storage
• Canned tomatoes
• acidification
• in-pack heating
• Tomato paste
• osmotic concentration

9. Illustration of the hurdle effect
F - High temperature
during processing (F-
value)
T – Low temperature
during storage (t value)
Aw- Low Water activity
PH- Acidity
Eh- Redox potential
Pres. – Preservatives

10. • In Figure.b water activity and preservatives are the main hurdles and others
are minors.
• In Figure.c, the microbiological stability is achieved in two hurdles due to
lower intensity of microorganisms.
• In Figure.d, the microorganisms are passing all hurdles due to high intensity
of microorganisms. This may occur due to low amount or low intensity of
hurdles or poor hygienic conditions.
• In Figure.d, due to the booster effect of vitamins and minerals, that increase
the growth of microorganisms result their initial number is increased
sharply.

11. Thank You