Method and Apparatus for Killing Insects on Fresh Produce

Abstract

To kill insects on fresh produce, the fresh produce is placed into the interior of a vacuum chamber and a partial vacuum is drawn and maintained within the interior for a time interval adequate to kill the insects. In some examples the holding step is carried out with the absolute pressure maintained in a range of 4.57 to 5.0 mm Hg. In some examples a pathogen-killing sanitizing gas is injected into the vacuum chamber at the end of the time interval. In some examples the partial vacuum is continued to be drawn within the interior during the holding step while adding small quantities of an inert gas into the interior

Description

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE is a schematic top plan view illustrating one embodiment of an insect killing apparatus made according to the present invention.

Claims

1. A method for killing a target insect on fresh produce comprising: placing fresh produce into the interior of a vacuum chamber, the fresh produce possibly carrying a live insect;drawing a partial vacuum within the interior of the vacuum chamber; andholding said produce inside said chamber, while maintaining the absolute pressure in a range of 4.57 to 25.0 mm Hg, for a time interval adequate to deplete any stored oxygen in the target insect and to kill the target insect by oxygen depravation.

2. The method according to claim 1 wherein the holding step is carried out with the absolute pressure maintained in a range of 4.57 to 5.0 mm Hg.

3. The method according to claim 1 further comprising maintaining the temperature of the fresh produce during at least a portion of the time interval in the range of 32° F. to 55° F.

4. The method according to claim 1 further comprising maintaining the temperature of the fresh produce during at least a portion of the time interval in the range of 32° F. to 39° F.

5. The method according to claim 1 further comprising selecting 6 to 48 hours as the time interval.

6. The method according to claim 1 further comprising selecting 20 to 30 hours as the time interval.

7. The method according to claim 1 further comprising continuing to draw a partial vacuum within the interior of the vacuum chamber during the holding step while adding small quantities of an inert gas into the interior of the vacuum chamber to maintain the desired partial vacuum during said time interval.

8. The method according to claim 1 further comprising introducing ambient air into the chamber at the end of the time interval.

9. The method according to claim 1 further comprising introducing one or more inert gasses into the vacuum chamber at the end of the time interval.

10. The method according to claim 1 further comprising introducing a mixture of air and one or more inert gasses into the vacuum chamber at the end of the time interval.

11. The method according to claim 1 further comprising introducing vaporized hydrogen peroxide into the vacuum chamber at the end of the time interval.

12. The method according to claim 1 further comprising introducing vaporized, ionized hydrogen peroxide into the vacuum chamber at the end of the time interval.

13. The method according to claim 1 further comprising introducing atomized hydrogen peroxide into the vacuum chamber at the end of the time interval.

14. The method according to claim 1 further comprising introducing a sanitizing gas comprising ionized, vaporized hydrogen peroxide into the vacuum chamber at the end of the time interval.

15. The method according to claim 1 further comprising introducing a pathogen-killing sanitizing gas into the vacuum chamber at the end of the time interval.

16. The method according to claim 15 further comprising the step of inducing motion to the fresh produce so as to expose more surface area to the sanitizing gas.

17. The method according to claim 16 wherein the motion inducing step comprises at least one of the following: vibrating;oscillating;shaking;tumbling;rotating;turning; andflipping.

18. A method for killing a target insect on fresh produce comprising: placing fresh produce into the interior of a vacuum chamber, the fresh produce possibly carrying a live insect;drawing a partial vacuum within the interior of the vacuum chamber;holding said produce inside said chamber for a time interval sufficient to kill the target insect; andcontinuing to draw a partial vacuum within the interior of the vacuum chamber during the holding step while adding small quantities of an inert gas into the interior of the vacuum chamber to maintain the desired partial vacuum during said time interval.

19. The method according to claim 18 wherein the continuing step is carried out using nitrogen as the inert gas.

20. The method according to claim 18 wherein the holding step is carried out with the absolute pressure maintained in a range of 4.57 to 5.0 mm Hg.

21. The method according to claim 18 further comprising maintaining the temperature of the fresh produce during at least a portion of the time interval in the range of 32° F. to 39° F.

22. The method according to claim 18 further comprising introducing a pathogen-killing sanitizing gas into the vacuum chamber at the end of the time interval.

23. Apparatus for killing insects on fresh produce comprising: a series of vacuum chambers, each vacuum chamber having an interior and a produce entrance through which fresh produce can be introduced into the interior;a vacuum cooling assembly comprising: a vacuum cooling apparatus;a vacuum cooling manifold fluidly connecting each of the vacuum chambers to the vacuum cooling apparatus; andthe vacuum cooling manifold comprising a vacuum manifold valve associated with each vacuum chamber for selectively permitting and preventing fluid flow between the vacuum cooling apparatus and the associated vacuum chamber, whereby the vacuum cooling assembly can selectively create a partial vacuum within the interiors of selected ones of the vacuum chambers; anda secondary vacuum apparatus selectively fluidly connected to each said vacuum chamber to maintain for a time interval the partial vacuum within the interior of the associated vacuum chamber created by the vacuum cooling assembly.

24. The apparatus according to claim 23 wherein the vacuum cooling apparatus comprises refrigeration coils for condensing water vapor.

25. The apparatus according to claim 24 wherein at least one of the vacuum chambers comprises a water application apparatus so that water can be applied to the fresh produce within said at least one vacuum chamber.

26. The apparatus according to claim 23 further comprising means for introducing a sanitizing gas into a selected vacuum chamber after the time interval, the sanitizing gas comprising ionized hydrogen peroxide.

27. The apparatus according to claim 23 wherein the secondary venting apparatus comprises an inert gas injector adapted to inject an inert gas into the interior during the operation of the secondary venting apparatus.