hurdles in food preservation

1. By Kulwinder Kaur

2. Introduction
• What is Hurdle Technology?
• Combination of preservation/ process/ methods/ techniques which employ the use of two
or more hurdles or barrier to spoilage micro-organism to produce safe, shelf stable and
nutritious food.
• Also known as Barrier technology
Used for shelf stable food products and IMF
For example :
In Jam, heat, high solid content and acidification
In vegetable fermentation, salt and acidification
Leistner- Father of Hurdle Technology (1976)

3. Need of hurdle technology
• Consumer prefers fresh or minimally processed foods of high quality, more
“natural”, produced with the minimum amount of additives, microbiologically safe,
nutritious and healthy.

4. Significance of Hurdle Technology
 Improvement in product quality and microbial safety.
 Combined factors act synergistically
 Saving money, energy and several resources
 Reduce economic losses.
 Applicable in both large and small industries
 Food remain safe and stable even without refrigeration.

5. Examples of hurdles

7. Sequence of hurdle in fermented sausage
and ripened cheese.

8. Principles
of
Hurdle
Technology
Metabolic
Exhaustion
Stress reaction
Multitarget preservation
Homeostasis

9. Homeostasis
 Uniform and stable ecosystem for successful survival of
cells in the internal status of organisms.
Organisms have a strong tendency to maintain internal
environment stable, for the balanced homeostasis
conditions.
Food preservation can be achieved by deliberately
disturbing the homeostasis mechanisms through
preservative factors or hurdles.
Energy restrictions may be given by anerobic conditions like
reduced aw, pH and Eh with modified atmosphere or vacuum
packaging

10. Metabolic Exhaustion

11. Stress Reactions

12. Multi target preservation

13. POTENTIAL HURDLES IN FOOD INDUSTRY
High temperatures (blanching,
pasteurization, sterilization,
evaporation, extrusion, baking, frying),
low temperature (chilling freezing)
Electromagnetic energy (microwave,
radio frequency, pulsed magnetic
fields, high electric fields),
ultra-high pressures,
ultrasonication,
Modified atmospheres and
Packaging films (including active
packaging, edible coatings),
Physical Hurdles
Carbon dioxide,
Ethanol,
Low pH,
Low redox potential
Low water activity
Organic acids
Ozone
Salt, smoking, sodium
nitrite/nitrate, sodium or
potassium sulphite,
Spices and herbs,
Surface treatment agents
Physico-chemical hurdles Microbially derived hurdles
Antibiotics, bacteriocins,
competitive flora, protective
cultures

14. Physical Hurdles
 Heat Processing- To kill/ destroy microorganisms and/ or enzymes
 Heating in hermetic ceiling avoid recontamination
Not applicable
Temperature 60-85°C
Temperature At or above
100°C

15. Storage temperature: Mainly Chilling and freezing
during storage

16. Radiation – Process of using a radiation
frequency of 109 MHz or above

17. Electro-magnetic energy (EME)- results from high
voltage electric fields

18. Ultra high pressure process- 3000 bar and above to
inactivate enzymes and microbes
• Ultra Sonication- vibrations between 18kHz to 500 MHz

19. Packaging
 Vacuum Packaging
 Moderate vacuum packaging
 Active Packaging
 Modified atmosphere
packaging
 Controlled atmosphere
packaging
 Aseptic packaging
 Edible coating

20. Physico-chemical hurdles

22. Microbially derived hurdles
• Competitive flora: like Nisin, Bacteriocins, H2O2
• Microfiltration
• Bacteriofugation
• Ripening (aging)

23. Applications
of
Hurdle Technology

24. Fruits and Vegetables
• Shorter shelf life due to high in moisture content and water activity
• High respiration rate
• Preservation: inhibition of microbial load, reduction in respiration
rate and ethylene biosynthesis by low temperature or modified
storage, surface disinfection, thermal and non thermal treatments,
active and intelligent packaging etc.

25. Types of hurdle Example Limitations
Surface Disinfectants Chlorine/ H2O2/ Off flavour development, anthocyanin degradation
Ozone treatment Health hazards, environment pollution
Non thermal processing High voltage electric field, RF,
Ohmic heating, dielectric heating,
ultrasound processing
Not effective against microorganisms
Pressure treatment Hydrostatic pressure High cost
Active packaging MAP, CAP, CAS Fermentation and off flavour development due to
disbalance in atmosphere
Antimicrobial films Edible or bio films coating Poor mechanical and barrier properties, high cost
Storage temperature Refrigeration, freezing Chilling injuries
For example:
Multitarget preservation methods can be used to achieve desirable microbial safety and
quality of fruits and vegetables.

26. Meat Industry

27. Fish preservation
• Fish products can be preserved by applying conventional technologies
along with modern technologies.
For example:
• In IMF ; acidification along with addition of humectants
• In HMF: natural antimicrobial agents during osmotic treatment
• Heat treatment + salting+ acidification
in minced fish can increase shelf life upto 15 days at
15°C

28. Dairy industry
• Use of thermal pasteurization for
processing of milk
• Pulsed electric fields (PEF) and
microfiltration (MF) allow gentle milk
preservation at lower temperatures and
shorter treatment times for similar, or
better, microbial inactivation and shelf
stability when applied in a hurdle approach.

29. • Paneer is highly perishable with shorter life upto 3 days (at low
temperature) and one day ( at room temperature).
• Brown Peda is khoa based Indian delicacy.
• Shelf life can be extended using hurdles like surface treatment, reduction
in water activity, acidification (pH 5.0) and various packaging techniques
(vacuum or MAP).

30. Limitations of Hurdle technology

31. Limitations of Hurdle technology
Synergistic effect of combined hurdles were found to weak in
laboratory tests as to have no significance for practical food
preservation
Application of this concept is largely restricted to meat sector
Detailed understanding about how stress causing mechainsms
triggered and proceed for desired microbial safety and stability
of food products.