NON THERMAL PRESERVATION TECHNIQUES

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 200-800MPa 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 • Advantages: • 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 (1500-2500 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 2.78 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