2. NON THERMAL PRESERVATION TECHNIQUES
Zarqa Azam (Roll# 27)
Riaheen Shahbaz (Roll# 29)
B.Sc. (Hons.) Food Science and Technology
Semester 8th –Regular
FST-609. Food Quality Management
Institute of Food Science and Nutrition (IFSN)
University of Sargodha, Sargodha
2016.

3. OUTLINE: Introduction Problems Uses Cost of equipments Objectives
Types of non-thermal preservation techniques
High pressure processing
Irradiation
Ozonation
Ultrasound

4. Conti.. Oscillating magnetic field Pulsed electric field
Hurdle technologies
Pulsed light processing
Processing with E-Beam
Sanitizer washes
Natural antimicrobials
Conclusion

5. introduction Method use for processing and preservation.
Keeping the temperature of food to minimum as much as possible.
Method use without heat.
Destroy pathogens.
Keep foods safe to eat .
Retaining the sensory attributes.
Nutrient content similar to raw or fresh products.

6. Problems Problem with the thermal processing :
 Loss of volatile compounds
Nutrients
Flavour
To overcome these problems non thermal method
came into food industries:
To increase the production rate
Profit.  

7. Uses of non thermal preservation
Used for bulk quantities of foods.
Mainly used in the large scale production.
Cost of equipments:
Used in the non thermal processing is high then used in thermal processing.
After minimizing the investment costs of non thermal processing methods it can also be employed in small scale industries

8. objectives Extend shelf life Good quality
Safe food with better nutrition
Meet consumer requirements
Better financial return to industry

9. types High pressure processing Irradiation Ozonation Ultrasound
Oscillating magnetic field
Pulsed electric field
Hurdle technologies
Pulsed light processing
Processing with E-Beam
Sanitizer washes
Natural antimicrobials

10. High pressure processing
“High Hydrostatic Pressure” or “Ultra High Pressure” processing.
Method of preserving and sterilizing food
Product processed under very high pressure
High Pressures applied at short periods of time (20minutes)
The high pressure used in HPP kills most micro- organisms :
By damaging cell components such as cell membranes

11. How much pressure?
For food processing MPa pressure is required.
For inactivating milk enzymes;
Alkaline phosphates and protease about 1000 MPa is needed.
600MPa is the optimum pressure for processing commercial food products.

12. Components A pressure vessel and its closure
A pressure generation system
A temperature control device
A materials handling system

13. process Food packages are loaded onto the vessel and the top is closed
The pressure medium usually water is pumped into the vessel from the bottom.
Once the desired pressure is reached, the pumping is stopped, valves are closed, pressure can be maintained without further need for energy input

14. advantages It kills vegetative bacteria and spores
Reduced processing time.
Freshness, flavor, nutrients, color, and taste retained
Shelf life is increased  
Low energy consumption
Elimination of chemical preservatives

15. Applications:
Used in pasteurization and sterilization of fruits and fruit products
Tenderization of meat
Sterilization of heat sensitive ingredients like shellfish, flavorings, and vitamins

16. ozonation
Powerful sanitizer similar to chlorine or common bleach
Ozone can reduce contamination on food and increase storage life.
Toxic to humans at very high doses
Should not be used to treat high fat foods.
Principle
Ozone does not act as a systemic poison to microorganisms, but rather, destroys them by oxidation. Consequently, it is impossible for a microorganism to build up any resistance to oxidation

17. Advantages of ozone Instantly destroys microbes
Eliminates chemical storage
Environmentally friendly
Does not affect product taste
No harmful by-products
Can be used in air and water
It leaves no residues in food or water.

18. Irradiation
Technology that improves the safety and extends the shelf life of food by reducing or eliminating microorganisms and insects. 
Irradiation can make food safer for the consumer
Irradiation to a dose of between 1 kGy and 10 kGy is an effective method of reducing the microbial load of food.

20. advantages Extend the shelf life
Irradiation may also inactivate enzymes..
Low dose irradiation (less than 1 kGy) is also used to inhibit sprouting (e.g. onion, garlic, potato)
Used for the purpose of insect disinfestations and inactivation

21. ultrasound
Form of energy generated by sound waves of frequencies that are too high to be detected by human ear, i.e.16KHz
Ultrasound can be propagate in liquid,gasses,solids.
Effective for inactivation of microorganisms and enzymes.
Produce intracellular cavitations due to micro mechanical shocks

22. Ultrasound in industry
Major significant to industry and consumer
Better quality and healthy food
High efficiency
Saves energy and cost
Minimizing of flavor loss

23. Oscillating Magnetic Field
A magnetic field is defined as the region in which magnetic material is able to magnetize the surrounding particles.
Magnetic field may be static or oscillating
In order to inactivate microorganisms, flux density of 5 to 50 tesla (T) is required, corresponding to very high intensity magnetic fields.

24. Cont.. How High Intensity Magnetic Fields Are Generated?
Generated by an electric current passing through a coil
Capacitor is charged by high voltage DC power supply
By closing the switch
An oscillating current is produced inside the capacitor
And then an oscillating magnetic field is induced to the food placed inside the magnet coil
For high magnetic fields, superconductor coils are used
40KA current is required

25. Conti..

26. Conti.. How This Mechanism Inactivates M/O
Magnetic fields alter the growth and reproduction of microorganisms by both genetic and bio chemical phenomena
Effect may be due to magnetic field or induced electric field
Depending upon both features of magnetic field and properties of food and microbial:
The growth of microbial may be inhibited
Or unaltered by this technique

27. Conti.. Applications
Some packed liquid foods such as milk, yoghurt, orange juices etc
They may be subjected to oscillating magnetic field with a frequency between 5 and 550 kHz.
For a total exposure time between 25µs and 10ms.
Performed at atmospheric pressure and room temperature, resulting in a temperature increase not higher than 5˚C
Therefore a good retention of nutritional and sensory properties of foods is assured.

28. Pulsed Electric Field (PEF)
Another non-thermal technology that can be use to inactivate bacterial cells at ambient temperatures
More suitable for liquids and semi liquid foods which can be easily pumped
Can be used to increase the shelf life of soups, milk, whole liquid eggs and fruit juices

29. Conti.. How This Process Occurs?
Process involves placing the food material between two electrodes
And passing pulses of high electric field strength (1-50 kV/cm)
Since the pulses are applied for short durations (2µs to 1ms) the negative impact on food quality due to heat processing is highly diminished

30. Conti.. Application Of PEF Results In:
Cellular death due to generation of pores (electroporation) in the bacterial cell membrane
Without having an effect on enzymes or proteins present in foods

31. Conti.. Effectiveness
The effectiveness of this technique will strongly depend upon
Treatment time
Electric field strength
Specific energy of the pulses
Although this technique is useful, inactivation has only been achieved in the range of 3-4 logs.

32. Conti.. Advantages And Limitations
Pulse applied for shirt period so no generation of heat
Less usage of energy
Limitations:
Cannot be applied to the foods which cannot withstand high fields
And foods that form bubbles

33. Hurdle Technology Or Synergism
Hurdle approach or process of using multiple technologies is an effective approach to microbial decontamination in comparison to that of a single technology alone
Deliberate and intelligent combination of preservative treatment can help in maintaining the quality of food and delivering almost similar level of microbial destruction
At the same time it warranties to counteract the negative effect of individual technologies on food quality

34. Conti.. The choice of hurdles will strongly depends on
The type of food it is being applied to in addition to the mode of inactivation
For example:
Exposure of egg shells contaminated with S.Enteritidis with UV radiation ( µW/cm²) followed by ozone (5 lb/in² gauge for 1min) resulted in an inactivation of 4.6 logs or more in a total treatment time of 2 min

35. Pulsed Light (PL) Processing
Non thermal technology that uses short, intense pulses of white light which include ultraviolet, infrared, visible light
Treatment of foods by PL has been approved by FDA (21 CFRI79.41)
PL is like a camera flash but far more intense

36. Conti.. How It Works?
When this light is flashed on foods, it kills microorganisms but has minimal impact on foods
Short flashes of this intense light are used to prevent the temperature of the food from increasing
Within PL there is ultraviolet light that kills the pathogens by disrupting their DNA.

37. Processing With E-beam
Non-thermal technology where the high energy electrons (close to the speed of light) are aimed at solid or liquid foods
Reducing the number of or eliminating pathogens, pests or insects
Unlike Gamma radiations this technology uses no radioactive isotopes

38. Conti.. How It Works?
E-beam may work against pathogens such as viruses and bacteria
by breaking the linkages in RNA or DNA
and by disrupting other parts that are essential to organisms
Some Drawbacks include:
Limited penetration depth through food
High initial cost

39. Natural Antimicrobials
Since ancient times spices and herbs have been used for preventing food spoilage and deterioration
Also for extending shelf life and food quality
The antimicrobial effect of these components is a result of an increase in permeability of the cytoplasmic membrane which leads to the loss of cellular constituents

40. Conti.. Extracts From Vegetables, Herbs
Plants secondary metabolites such as essential oils and natural plant extracts have also been reported to have antimicrobial, antifungal and anti-insecticidal properties
Extracts from capsicum, seaweeds and green tea have been found to inhibit the growth of Salmonella spp.
Tomatoes treated with 100ppm oregano (herb) results in log reduction.

41. Using Sanitizer Washes
Sanitizers like chlorine, are used by the food industry that helps to kill pathogens in food and on equipments/utensil surfaces
FDA regulates the sanitizers to be used by food industry
Microorganisms attach to the food, can lower the effectiveness of sanitizer and to address this problem
Use of surfactants (components of detergents) is being studied to enhance the effectiveness of sanitizer

42. Conti.. How It Works Combining food grade surfactants with sanitizers
Improves the killing effectiveness
When applied to surface of food
By “Loosing” microorganisms attachment
Allowing the sanitizer to be more potent antimicrobial agent
The combination of sanitizer and surfactants has
not yet been commercialized but shows greater
potential.

43. HENCE: Non Thermal or Alternative Food Processing Methods Enhance the
MICROBIAL SAFETY
FOOD QUALITY