Multiple-stage energy-efficient produce processing system

• US 6,537,600 B1
• Filed: 09/14/2000
• Issued: 03/25/2003
• Est. Priority Date: 09/14/1999
• Status: Expired due to Fees

• Current Assignee: Charles R. Meldrum
• Original Assignee: Charles R. Meldrum
• Inventors: Meldrum, Charles R.
• Primary Examiner(s): Hendricks, Keith
• Assistant Examiner(s): BECKER, DREW E
• Application Number:
  US09/661,493
• Time in Patent Office: 922 Days
• Field of Search: 426/102, 426/238, 426/244, 426/248, 426/286, 426/615, 426/385, 426/506, 426/520, 426/524, 426/242, 426/521, 134/1, 134/19, 134/25.3, 134/34, 134/37, 134/42, 15/31
• US Class Current: 426/102
• CPC Class Codes: A23B 7/005 Preserving by heating
• CPC Class Codes: A23B 7/0053 by direct or indirect contact with heating gases or liquids
• CPC Class Codes: A23B 7/01 by irradiation or electric treatment
• CPC Class Codes: A23B 7/015 Preserving by irradiation or electric treatment without heating effect
• CPC Class Codes: A23B 7/02 Dehydrating; Subsequent reconstitution dried cooked potatoes A23L19/12
• CPC Class Codes: A23B 7/0205 by contact of the material with fluids, e.g. drying gas or extracting liquids
• CPC Class Codes: A23B 7/16 Coating with a protective layer; Compositions or apparatus therefor A23B7/08 takes precedence
• CPC Class Codes: A23L 3/00 Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs preserving foods or foodstuffs in association with packaging B65B55/00
• CPC Class Codes: A23L 3/005 by heating using irradiation or electric treatment drying or kilning A23L3/40
• CPC Class Codes: A23L 3/26 by irradiation without heating
• CPC Class Codes: A23L 3/30 by treatment with ultrasonic waves
• CPC Class Codes: A23L 3/32 by treatment with electric currents without heating effect
• CPC Class Codes: A23L 3/40 by drying or kilning; Subsequent reconstitution
• CPC Class Codes: A23L 3/42 with addition of chemicals before or during drying
• CPC Class Codes: A23L 3/54 using irradiation or electrical treatment, e.g. ultrasonic waves
• CPC Class Codes: A23L 5/30 Physical treatment, e.g. electrical or magnetic means, wave energy or irradiation cooking A23L5/10
• CPC Class Codes: A23L 5/32 using phonon wave energy, e.g. sound or ultrasonic waves
• CPC Class Codes: F26B 17/045 the material on the belt being agitated, dispersed or turned over by mechanical means, e.g. by vibrating the belt, by fixed, rotating or oscillating elements
• CPC Class Codes: F26B 21/06 Controlling, e.g. regulating, parameters of gas supply F26B21/14 takes precedence; control in general G05
• CPC Class Codes: F26B 3/283 in combination with convection
• CPC Class Codes: F26B 3/343 : in combination with convection
• CPC Class Codes: Y02P 60/85 : Food storage or conservation, e.g. cooling or drying

Abstract

Mobile systems for cleaning and drying produce in order to extend shelf life, are described. Produce cleaning systems (20) are provided that employ plural forms of energy in an ionic liquid-based washing system (22, 24, 26) containing solvents and solutes which promote the conduction of electrical energy. The electrical energy can be applied to the produce in the wash bath (24) in various waveforms, such as a modulating wave superimposed on a carrier wave. Additionally, ultrasonic energy is employed to provide high-frequency mechanical pressure waves against the produce. The electrical energy and the mechanical energy combine to produce energy in the applicable resonant frequency range that acts to destroy or transform pathogens, dirt and synthetic molecules that may exist on the item of produce (190). Systems for drying the item of produce (190), after it has been immersed in a natural soluteladen slurry maintained at a temperature below the freezing point of water, are also provided. The drying process is rapidly and effectively accelerated in order to fully crystallize a layer of solute-laden slurry that has been applied on the external surface of an item of produce (190).

Claims

1. A method of extending the shelf life of produce, by reducing pathogen populations on the surface of the produce through the use of an applied electric waveform, and by sealing at least a portion of the surface of the produce by applying a slurry layer to at least a portion of the produce and drying the produce in an accelerated manner, without significantly reducing the moisture content inside of the produce, in order to form a film including crystalline structures on the produce, that helps protect the produce against deterioration, the method comprising:

immersing at least a portion of the produce in a liquid energizing bath;

subjecting the portion of the produce immersed in the liquid energizing bath to an electrical waveform for a predetermined period of time in a liquid energizing bath, said waveform removing at least some portions of the pathogens from the surface of the produce;

immersing at least a portion of the produce in a rinse bath to assist in removing pathogens from the immersed surface of the produce;

applying a solute-laden slurry layer to at least a portion of the surface of the produce from which at least some of the pathogens have been removed;

subjecting the produce to a first accelerated drying procedure, wherein at least a portion of the moisture in the solute-laden slurry layer is removed to form a moisture-reduced slurry layer on the produce;

subjecting the produce to a second accelerated drying procedure including the application of at least a first form of energy other than moving air, wherein at least a portion of the moisture in the moisture-reduced slurry layer is removed to form a protective stratum on the produce; and

subjecting the produce to a third accelerated drying procedure different from the second accelerated drying procedure, wherein at least a portion of the moisture in the protective stratum is removed to form a film including crystalline structures on the produce.

2. The method according to claim 1, wherein the step of subjecting the produce to the electrical waveform includes subjecting the produce to an alternating electrical waveform that includes a fundamental carrier wave and a higher frequency wave imposed on the carrier wave.

3. The method according to claim 2, wherein the step of subjecting the produce to the electrical waveform includes generating the carrier wave at a current sufficient enough to establish an electric current in the energizing bath and generating the higher frequency wave at a frequency sufficient to provide microelectrification of at least some of the pathogens on the surface of the produce.

4. The method according to claim 1, wherein the step of subjecting the produce to the electrical waveform includes sweeping the electrical waveform from a first predetermined frequency to a second predetermined frequency at least twice the first predetermined frequency.

5. The method according to claim 4, wherein the step of sweeping the electric waveform from the first predetermined frequency to the second predetermined frequency includes ramping up the frequency of the electrical waveform in a step like manner through a first series of at least four successive steps where each step in the first series is at a higher frequency than a previous step in the first series and wherein the frequency of the waveform is maintained at each such step for a predetermined period of time.

6. The method according to claim 2, wherein the carrier wave has a frequency in the range of 10 Hz to 100 kHz and an electrical current in the range of 1 milliamp per square centimeter to 1,000 milliamps per square centimeter in the bath.

7. The method according to claim 1, further comprising the step of subjecting the produce to an ultrasonic waveform to vibrate the produce for a predetermined period of time in the energizing bath.

8. The method according to claim 7, wherein the step of subjecting the produce to an ultrasonic waveform includes sweeping the ultrasonic waveform between a first predetermined ultrasonic frequency and a second predetermined ultrasonic frequency at least twice the first predetermined frequency.

9. The method according to claim 8, wherein the step of sweeping the ultrasonic waveform between the first frequency to the second frequency includes ramping up the ultrasonic waveform in a step like manner through a first series of at least four successive steps where each step in the first series is at a higher frequency than a previous step in the first series and is maintained at each such step for a predetermined period of time.

10. The method according to claim 1, wherein the step of immersing the produce in an energizing bath includes immersing the produce in a heated energizing bath.

11. The method according to claim 10, wherein the step of immersing the produce in an energizing bath includes immersing the produce in an energizing bath heated to about 95°

F.

12. The method according to claim 1, wherein the step of immersing the produce in an energizing bath includes immersing the produce in a water based ionizing bath.

13. The method according to claim 12, wherein the step of immersing the produce in the ionizing bath includes immersing the produce in a bath including dissolved salts.

14. The method according to claim 1, wherein the step of immersing the produce in an energizing bath includes immersing the produce in an acid bath having a pH less than 7.

15. The method according to claim 1, wherein the step of immersing the produce in an energizing bath includes immersing the produce in an alkaline bath having a pH greater than 7.

16. The method according to claim 1, wherein the first drying procedure includes applying a stream of air to the produce.

17. The method according to claim 16, wherein the stream of air has a temperature in the range of about room temperature to about 500°

F.

18. The method according to claim 1, wherein the first accelerated drying procedure includes applying a vibratory force to the produce.

19. The method according to claim 1, wherein the second accelerated drying procedure includes applying light energy to the produce.

20. The method according to claim 1, wherein the second accelerated drying procedure includes applying heat energy to the produce.

21. The method according to claim 1, wherein the third accelerated drying procedure includes applying light energy to the produce.

22. The method according to claim 1, wherein the third accelerated drying procedure includes applying heat energy to the produce.

23. A method of extending the shelf life of produce, by reducing pathogen populations on the surface of the produce through the use of applied electric and ultrasonic waveforms, and by thereafter sealing at least a portion of the surface of the produce by applying a slurry layer to at least a portion of the produce and drying the produce in an accelerated manner, without significantly reducing the moisture content inside of the produce, in order to form a film including crystalline structures on the produce, that helps protect the produce against deterioration, the method comprising:

immersing the produce in a liquid energizing bath;

subjecting the produce to an alternating electrical waveform for a predetermined period of time in the liquid energizing bath;

subjecting the produce to an ultrasonic waveform to vibrate the produce for a predetermined period of time in the energizing bath, wherein the combination of the ultrasonic waveform and the electrical waveform applies sufficient energy to decouple and neutralize pathogens and other contaminants existing on the produce;

applying a solute-laden slurry layer to at least a portion of the external surface of the produce;

subjecting the produce to a first accelerated drying procedure, wherein at least a portion of the moisture in the solute-laden slurry layer is removed to form a moisture reduced slurry layer on the produce;

subjecting the produce to a second accelerated drying procedure including at least a first form of energy other than mechanically-applied energy, wherein at least a portion of the moisture in the moisture-reduced slurry layer is removed to form a protective stratum on the produce; and

subjecting the produce to a third accelerated drying procedure different from the second accelerated drying procedure and including a second form of energy other than mechanically-applied energy, wherein at least a portion of the moisture in the protective stratum is removed to form a film including microcrystalline structures on the produce.

24. The method according to claim 23, wherein the step of subjecting the produce to the electrical waveform includes subjecting the produce to an alternating electrical waveform that includes a fundamental carrier wave and a higher frequency wave imposed on the carrier wave.

25. The method according to claim 24, wherein the step of subjecting the produce to the electrical waveform includes generating the carrier wave at a current sufficient enough to establish an electric current in the energizing bath and generating a higher frequency wave that has a frequency sufficient to provide microelectrification of bacteria and other pathogens on the surface of the produce.

26. The method according to claim 23, wherein the step of subjecting the produce to the electrical waveform includes sweeping the electrical waveform from a first predetermined frequency to a second predetermined frequency at least twice as high as the first predetermined frequency.

27. The method according to claim 26, wherein the step of sweeping the electric waveforms from the first predetermined frequency to the second predetermined frequency includes ramping the electrical waveform in a step like manner through a first series of at least four steps where each successive step in the first series is at a higher frequency than the previous step in the first series and is maintained at each such step for a predetermined period of time.

28. The method according to claim 24, wherein the carrier wave has a frequency in the range of 10 Hz to 100 kHz and an electrical current in the range of 1 milliamp per square centimeter to 1,000 milliamps per square centimeter in the bath.

29. The method according to claim 23, wherein the step of subjecting the produce to an ultrasonic waveform includes sweeping the ultrasonic waveform between a first ultrasonic frequency and a second ultrasonic frequency at least twice the first predetermined frequency.

30. The method according to claim 29, wherein the step of sweeping the ultrasonic waveform from the first ultrasonic frequency to the second ultrasonic frequency includes ramping up the ultrasonic waveform in a step like manner through a first series of at least four successive steps where each successive step in the first series is at a higher frequency than a previous step in the first series and is maintained at each such step for a predetermined period of time.

31. The method according to claim 23, wherein the step of immersing the produce in an energizing bath includes immersing the produce in a heated energizing bath.

32. The method according to claim 23, wherein in the step of immersing the produce in an energizing bath includes immersing the produce in an energizing bath heated to about 95°

F.

33. The method according to claim 23, wherein the step of immersing the produce in an energizing bath includes immersing the produce in a water based ionizing bath.

34. The method according to claim 33, wherein the step of immersing the produce in the ionizing bath includes immersing the produce in a bath including dissolved salts.

35. The method according to claim 33, wherein the step of immersing the produce in an energizing bath includes immersing the produce in an acid bath having a pH less than 7.

36. The method according to claim 33, wherein the step of immersing the produce in an energizing bath includes immersing the produce in an alkaline bath having a pH greater than 7.

37. The method according to claim 33, wherein the first drying procedure includes applying a stream of air to the produce.

38. The method according to claim 37, wherein the stream of air has a temperature in the range of about room temperature to about 500°

F.

39. The method according to claim 33, wherein the first accelerated drying procedure includes applying a vibratory force to the produce.

40. The method according to claim 33, wherein the first accelerated drying procedure includes applying a stream of air and a vibratory force to the produce.

41. The method according to claim 33, wherein the second accelerated drying procedure includes applying light energy to the produce.

42. The method according to claim 33, wherein the second accelerated drying procedure includes applying heat energy to the produce.

43. The method according to claim 33, wherein the third accelerated drying procedure includes applying light energy to the produce.

44. The method according to claim 33, wherein the third accelerated drying procedure includes applying heat energy to the produce.

45. A method of extending the shelf life of produce, by reducing pathogen populations on the surface of the produce through the use of an applied ultrasonic waveform, and by sealing at least a portion of the surface of the produce by applying a slurry layer to at least a portion of the produce and drying the produce in an accelerated manner, without significantly reducing the moisture content inside of the produce, in order to form a film including crystalline structures on the produce, that helps protect the produce against deterioration, comprising:

subjecting the produce to an ultrasonic waveform to vibrate, for a predetermined period of time in the bath, various pathogens and contaminants having different sizes that may exist on the produce;

sweeping the ultrasonic waveform between the first ultrasonic frequency and a second ultrasonic frequency that is at least twice the first ultrasonic frequency so as to decouple and disintegrate a range of the various pathogens and contaminants having different sizes that may exist on the produce in order to clean the produce;

applying a solute-laden slurry layer to at least a portion of the external surface of the produce cleaned by use of the ultrasonic waveform;

subjecting the produce to a first accelerated drying procedure, wherein at least a portion of the moisture in the solute-laden slurry layer is removed to form a moisture-reduced slurry layer on the produce;

subjecting the produce to a second accelerated drying procedure including the application of at least a first form of energy other than moving air, wherein at least a portion of the moisture in the moisture-reduced slurry layer is removed to form a protective stratum on the produce; and

subjecting the produce to a third accelerated drying procedure different from the second accelerated drying procedure, wherein at least a portion of the moisture in the protective stratum is removed to form a crystalline structure on the produce.

46. The method according to claim 45, wherein the step of sweeping the ultrasonic waveform from the first frequency to the second frequency includes ramping up the ultrasonic waveform in a step like manner in a first series of at least four steps where each step in the first series is at a higher frequency than a previous step in the first series and is maintained at each such step for a predetermined period of time.

47. The method according to claim 45, wherein the step of immersing the produce in an energizing bath includes immersing the produce in a heated energizing bath.

48. The method according to claim 47, wherein in the step of immersing the produce in an energizing bath includes immersing the produce in an energizing bath heated to about 95°

F.

49. The method according to claim 45, wherein the step of immersing the produce in an energizing bath includes immersing the produce in a water based ionizing bath.

50. The method according to claim 49, wherein the step of immersing the produce in the ionizing bath includes immersing the produce in a bath including dissolved salts.

51. The method according to claim 45, wherein the step of immersing the produce in an energizing bath includes immersing the produce in an acid bath having a pH less than 7.

52. The method according to claim 45, wherein the step of immersing the produce in an energizing bath includes immersing the produce in an alkaline bath having a pH greater than 7.

53. The method according to claim 45, wherein the first drying procedure includes applying a stream of air to the produce.

54. The method according to claim 53, wherein the stream of air has a temperature in the range of about room temperature to about 500°

F.

55. The method according to claim 45, wherein the first drying procedure includes applying a vibratory force to the produce.

56. The method according to claim 45, wherein the first drying procedure includes applying a stream of air and a vibratory force to the produce.

57. The method according to claim 45, wherein the energy of the second drying procedure is selected from the group consisting of light, heat, and combinations thereof.

58. The method according to claim 45, wherein the energy of the third drying procedure is selected from the group consisting of light, heat, and combinations thereof.