Title: Gaseous blend of CO2 and Ox and its use for biological burden reduction
Abstract: A gaseous blend of CO2 and Ox and a method for applying a continuous stream of a gaseous blend of CO2 and Ox to a material are disclosed. The gaseous blend and the method significantly reduce the biological load on consumer products, such as food products, botanicals and cosmetic ingredients; in building structures; on transportation containers; and in soil.
Patent Number: 6,955,786 Issued on 10/18/2005 to Carman, et al.
| Inventors:
|
Carman; Gary B. (Reno, NV);
Wirtz; Steven K. (Sparks, NV)
|
| Assignee:
|
Cosmed Group, Inc. (Jamestown, RI)
|
| Appl. No.:
|
098929 |
| Filed:
|
March 15, 2002 |
| Current U.S. Class: |
422/33; 422/22; 422/23; 422/28; 422/32; 422/186.07 |
| Intern'l Class: |
A61L 009/00 |
| Field of Search: |
422/33,22,23,28,29,30,186.07,292,32
|
References Cited [Referenced By]
U.S. Patent Documents
| 4182663 | Jan., 1980 | Vaseen.
| |
| 4200656 | Apr., 1980 | Cohen et al.
| |
| 4549477 | Oct., 1985 | McCabe, Jr.
| |
| 4640782 | Feb., 1987 | Burleson.
| |
| 4889708 | Dec., 1989 | Latif et al.
| |
| 4988484 | Jan., 1991 | Karlson.
| |
| 4989363 | Feb., 1991 | Doernemann.
| |
| 4998377 | Mar., 1991 | Tsutsumi et al.
| |
| 5011699 | Apr., 1991 | Mitsuda et al.
| |
| 5069880 | Dec., 1991 | Karlson.
| |
| 5120512 | Jun., 1992 | Masuda.
| |
| 5135721 | Aug., 1992 | Richard.
| |
| 5178896 | Jan., 1993 | Langner.
| |
| 5200158 | Apr., 1993 | Jacob.
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| 5241803 | Sep., 1993 | Griffin.
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| 5403597 | Apr., 1995 | Mueller.
| |
| 5413758 | May., 1995 | Caputo et al.
| |
| 5464457 | Nov., 1995 | Winston et al.
| |
| 5518698 | May., 1996 | Karlson et al.
| |
| 5566627 | Oct., 1996 | Pryor.
| |
| 5624635 | Apr., 1997 | Pryor.
| |
| 5678352 | Oct., 1997 | Leitner et al.
| |
| 5897841 | Apr., 1999 | Shroff.
| |
| 6027667 | Feb., 2000 | Horn Feja et al.
| |
| 6066348 | May., 2000 | Yuan et al.
| |
| 6197081 | Mar., 2001 | Schmidt.
| |
| 6284193 | Sep., 2001 | Carman et al.
| |
| 6793884 | Sep., 2004 | Carman et al.
| |
| Foreign Patent Documents |
| 34 15 301 | Oct., 1985 | DE.
| |
| 39 17 250 | May., 1989 | DE.
| |
| 02076562 | Mar., 1990 | JP.
| |
Other References
European Patent Office, European Office Action dated May 26, 2003 in European
Application No. 98 964 716.9-2113.
M. Margaret Barth et al, Ozone Storage Effects on Anthocyanin Content and Fungal
Growth in Blackberries, Journal of Food Science, vol. 60, No. 6, pp. 1286-1288, (1995).
J. Kuprianoff, The Use of Ozone for the Cold Storage of Fruit Z. Kaltentechnik,
10:1-4 (1953) (in German with English Translation of major points) (Abstract).
Jae-Kun Chun, Yung-Jin Lee, Kyung-Man Kim, Hong-Won Lee, and Eu-Yung Jang, College
of Agriculture & Life Science, Seoul National University, Korea), Sterilizing and
Deodorizing Effect of UV-Ray Air Cleaner for Refrigerator; Korean J. Food Sci.
Technol. 25(2): 174-177 (1993) (in Korean, English ABSTRACT).
|
Primary Examiner: Jastrzab; Krisanne
Attorney, Agent or Firm: Patton Boggs LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application continuation-in-part to U.S. application Ser. No. 09/903,685,
filed Jul. 13, 2001now U.S. Pat. No. 6,793,884, which is a continuation of application
Ser. No. 09/217,581, filed Dec. 22, 1998 (now U.S. Pat. No. 6,284,193), which claims
priority to provisional application Ser. No. 60/068,668, filed Dec. 23, 1997; and
to provisional application Ser. No. 60/276,041, filed Mar. 16, 2001.
Claims
1. A method for fumigating an enclosed structure to reduce biological burden
in said structure, comprising:
releasing a gaseous blend of O
x and CO
2 to said enclosed
structure, said gaseous blend comprising about 1-10% O
x and about 90-99%
CO
2; and
maintaining said gaseous blend of O
x and CO
2 in said enclosed
structure for an amount of time sufficient to reduce said biological burden in
said structure.
2. The method of claim 1, wherein said gaseous blend comprises about 1-2% O
x
and about 98-99% CO
2.
3. A method for fumigating a material contained within an enclosed space to reduce
biological burden, comprising;
releasing a gaseous blend of O
x and CO
2 into said enclosed
space, said gaseous blend comprising about 1-10% O
x and about 90-99%
CO
2 and
maintaining said gaseous blend of O
x and CO
2 in said enclosed
space for an amount of time sufficient to reduce said biological burden on said
material.
4. The method of claim 3, wherein said gaseous blend comprises about 1-2% O
x
and about 98-99% CO
2.
5. A method for fumigating soil in a field to reduce biological burden, comprising:
placing a gas impermeable membrane over said soil to provide an enclosed space
above said soil; releasing a gaseous blend of O
x and CO
2 into
said enclosed space, said gaseous blend comprising about 1-10% O
x and
about 90-99% CO
2 and
maintaining said gaseous blend of O
x and CO
2 in said enclosed
space for an amount of time sufficient to reduce said biological burden in said
soil.
6. The method of claim 5, wherein said gaseous blend comprises about 1-2% O
x
and about 98-99% CO
2.
7. A fumigant system comprising a gaseous blend of O
x and CO
2,
said gaseous blend comprising about 1-10% O
x and about 90-99% CO
2.
8. The system of claim 7, wherein said gaseous blend comprises about 1-2% O
x
and about 98-99% CO
2.
9. A method for fumigating a material, comprising:
placing said material in an enclosed space; and
applying a continuous stream of O
x and CO
2 through said
enclosed space, wherein said O
x includes oxygen and its radicals and
wherein x is an integer from 1 to 3.
10. The method of claim 9, wherein a temperature within said enclosed space is
maintained at about 45° F. to about 140° F.
11. The method of claim 10, wherein a temperature within said enclosed space
is maintained at about 85° F. to about 115° F.
12. The method of claim 9, wherein said O
x is generated within an
O
x generation cell and wherein said CO
2 is introduced into
said O
x generation cell prior to said O
x generation.
13. The method of claim 9, wherein said O
x is generated within an
O
x generation cell and wherein said CO
2 is introduced after
generation of said O
x.
14. The method of claim 12, wherein said CO
2 and said O
x are
withdrawn from said O
x generation cell into said enclosed space; and
wherein said CO
2 and said O
x are withdrawn from said enclosed space.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a gaseous blend of CO
2
and O
X and a method for applying the gaseous blend that can be utilized
to significantly reduce the biological load on consumer products such as food products,
botanicals and cosmetic ingredients, which have traditionally been treated with
commercial sterilants or fumigants such as ethylene oxide, propylene oxide, methyl
bromide, hydrogen phosphide, phosphine, steam (heat), irradiation, and the like.
The gaseous blend of CO
2 and O
x and method for applying the
gaseous blend can also be used to reduce biological load in enclosed structures
and on transportation containers (e.g., wooden pallets and crates), which are often
used to store food products, as well as to reduce biological load on other commodities,
and, in particular, on soil.
2. Background of the Technology
Damage to food products, building structures and other commodities by insects
and other pests accounts for billions of dollars of losses in the United States
annually. Traditionally, a number of fumigants have been utilized to control these
pests by their application under air tight tarpaulins, in sealed rooms and in steel
chambers. The most widely used fumigants are methyl bromide, hydrogen phosphide
and hydrogen cyanide. As disclosed in U.S. Pat. Nos. 6,284,193 and 6,334,979, many
of these compounds pose hazardous conditions for application personnel and can
form deleterious residues on the foodstuffs, building structures, transportation
containers and commodities that are treated. Furthermore, some of the traditional
fumigants have been identified with the formation of carcinogens and mutagens,
thereby limiting the products that can be treated. All three of the primary employed
gaseous fumigants; i.e., methyl bromide, hydrogen phosphide and hydrogen cyanide,
have faced major regulatory restrictions and/or total phase out agreements. With
these limitations in mind, the search for effective alternatives has led to the
use of materials such as methyl iodide and sulfonyl fluoride. Unfortunately, these
alternatives have limitations because of factors such as worker exposure, halogen
content and damage to certain commodities.
Ozone (O
3) and its primary active component, atomic oxygen, have
been used in water and commodity sterilization for about 100 years. Carbon dioxide
(CO
2) has been used in conjunction with various pesticides to enhance
their effectiveness by increasing the target organism's rate of respiration. As
discussed in more detail below, however, prior treatment methods using O
3
or CO
2 have proven ineffective for many applications.
U.S. Pat. Nos. 5,624,635 and 5,566,627 disclose a method and apparatus for use
of O
3 to treat soil.
U.S. Pat. Nos. 4,889,708; 5,403,597; 5,897,841 and 6,027,667 disclose the use
of CO
2 as a carrier gas for phosphine fumigant.
U.S. Pat. No. 4,200,656 discloses the use of CO
2 as a carrier for
methyl bromide in fumigation.
U.S. Pat. No. 4,998,377 discloses the use of CO
2 as a carrier for
methyl bromide and hydrogen phosphide in fumigation.
U.S. Pat. No. 5,678,352 discloses the use of CO
2 as a carrier for
toxic agents such as methyl bromide during fumigation.
U.S. Pat. No. 5,464,457 discloses the use of an ammonium carbonate ingredient
that decomposes to ammonia and CO
2 in order to fumigate a plot of soil.
U.S. Pat. No. 4,989,363 discloses application of CO
2 in pesticidal
quantities for fumigation. The process disclosed in U.S. Pat. No. 4,989,363 requires
administration of CO
2 for a period of time of at least about 5 days.
U.S. Pat. No. 5,011,699 discloses the use of O
3 and CO
2 in
specified ratios, i.e., from 1:2 to 2:1, to sterilize foodstuffs at reduced temperatures.
U.S. Pat. No. 6,066,348 discloses the use of O
3 and CO
2 at
reduced temperature to disinfect a foodstuff.
Japanese Patent Publication No. 02076562A (Abstract) discloses the use of
O
3, CO
2 and N gas to sterilize foodstuffs.
U.S. Pat. Nos. 6,283,193 and 6,334,979 disclose methods that use a gaseous mixture
of oxygen-containing gases, i.e., O
3, O
2 and O
1,
hereinafter referred to as O
x, in a vacuum chamber to reduce biological
loads on foodstuffs and other commodities. Although such use of O
x has
proven successful in controlling insects and microbiological concerns for selected
fruits, vegetables and other botanicals, because of phyto-toxic issues and the
fact that O
3 readily converts to oxygen when exposed to an oxygen-rich
atmosphere, there remains a need to treat foodstuffs and other commodities that
cannot withstand treatment under vacuum.
The present inventors have surprisingly discovered that regardless of whether
a vacuum is employed, for a number of commodities, a gaseous blend of CO
2
and O
x having a specified ratio, i.e., about 90-99% CO
2 and
about 1-10% O
x, preferably about 98-99% CO
2 and about 1-2%
O
x, is highly effective in biological burden reduction. This surprising
discovery permits the application of gaseous O
x to products in many environments.
SUMMARY OF THE INVENTION
It is desirable to treat a wide variety of materials in a cost effective manner.
The gaseous blend of CO
2 and O
x and the method for applying
the gaseous blend of the present invention permit fumigation (hereinafter referred
to as "biological burden reduction") of a commodity on-site where the commodity
is normally stored, thereby eliminating the need to transfer the commodity to another
location for treatment.
The method of the present invention utilizes the gaseous blend of CO
2
and O
x in a technologically advanced treatment system that overcomes
limitations formerly encountered with CO
2 and/or O
3 treatment
on biological burden. Most importantly, the method of the present invention eliminates
the need for complex systems often employed in prior art methods. The method may
be employed on-site, thereby eliminating the need to transfer material to a special
processing location.
Accordingly, it is an object of the present invention to provide a gaseous
blend of CO
2 and O
x and a method for applying the gaseous
blend of CO
2 and O
x to reduce biological burden from food
products and other commodities, building structures, transportation containers
and soil.
It is another object of the present invention to provide a gaseous blend of CO
2
and O
x and method for applying the gaseous blend of CO
2 and
O
x to reduce biological burden from food products and other commodities,
building structures, transportation containers and soil in a safe manner.
It is, therefore, an object of the present invention to eliminate the health
risks
that are associated with the reduction of biological burden from food products
and other commodities, building structures, transportation containers and soil.
It is a further object of the present invention to provide a simple, efficient
and economical gaseous blend of CO
2 and O
x and a method for
applying the gaseous blend of CO
2 and O
x for reducing biological
burden from food products and other commodities, building structures, transportation
containers and soil that can be used on-site.
In accordance with the above and other objects, the inventive gaseous blend consists
of about 90-99%, preferably about 98-99%, CO
2 and about 1-10%, preferably
about 1-2%, O
x. The inventive method for applying the gaseous blend
comprises applying a continuous stream of CO
2 and O
x gas
to a material. Preferably, the gaseous blend is applied at an elevated temperature,
e.g., approximately 45° F. to 140° F., and more preferably at about 85°
F. to 115° F.
The continuous stream of CO
2 and O
x, gas can be prepared
by any means. For example, the continuous stream of O
x gas may be prepared
in an O
x generation cell that contains a means for generating the O
x
gas at a pressure less than about 20 lbs/in
2 such as, for example,
one or mote of the following: corona discharge, electrical discharge, ultraviolet
light, x-ray, radioactive isotope and electron beam. CO
2 and smaller
concentrations of CO can be added to the O
x generation cell prior to
production of O
x, or CO
2 can be mixed into the O
x gas
flow immediately after its formation.
After application of the gaseous blend of CO
2 and O
x to
the material, the gaseous blend may then be passed through a commercially available
catalytic destruct unit to eliminate any residual CO, O
3 and O
1
before the gas stream is discharged to the atmosphere.
The present invention is also directed to treated food products and other commodities,
building structures, transportation containers and/or soil that result from use
of the inventive gaseous blend of CO
2 and O
x and method.
Additional objects and attendant advantages of the present invention will
be set forth in the description and examples that follow, or may be learned from
using the gaseous blend or practicing the method of the present invention. These
and other objects and advantages may be realized and attained by means of the features,
instrumentalities and/or combinations particularly described herein. It is also
to be understood that the foregoing general description and the following detailed
description are only exemplary and explanatory and are not to be viewed as limiting
or restricting the invention as claimed.
The invention itself, together with further objects and attendant advantages,
will best be understood by reference to the following detailed description, taken
in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic showing an embodiment of a method for using a continuous
flow of CO
2 and O
x to reduce biological burden in accordance
with the method of the present invention.
FIG. 2 is a schematic showing another embodiment of a method for using a continuous
flow of CO
2 and O
x to reduce biological burden in accordance
with the method of the present invention.
In the following description, like parts are designated by like reference numerals
throughout the figures.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
All patents, patent applications and literatures that may be cited herein are
incorporated herein by reference.
The antibacterial potential of O
3 has been recognized for many years.
O
3 is widely used as a disinfectant for sewage treatment and for purification
of drinking water. It has, however, failed to gain acceptance as a biological burden
reduction treatment. The primary reason for this failure is that the O
3 molecule
is highly unstable and quickly reverts to O
2 if it does not encounter
a susceptible substrate with which to react. O
3 also has the capacity
to react with a broad array of substrates and would be expected to react with packaging
materials surrounding the items being treated. This further reduces the number
of O
3 molecules available to react with and inactivate microbial contaminants.
U.S. Pat. Nos. 5,011,699 and 6,066,348 disclose previous attempts to use O
3
as a biological burden reduction treatment that include the reliance upon filling
a chamber with O
3 and exposing the materials to be treated in static
fashion for various periods of time without replenishment of O
3. Under
these conditions, the concentration of O
3 within the chamber would be
expected to rapidly decrease to a level below that required for effective biological
burden reduction because of the short half life of O
3, which is typically
less than 20 minutes. A further disadvantage of the static exposure technology
is the reliance on simple diffusion to promote permeation of the O
3 molecules
through packaging materials and into the voids and interstices of the materials
being treated. Such methods, therefore, do not achieve adequate permeation of the
O
3 molecules into the material being treated.
The method of the invention offers significant advances over the prior static
biological burden reduction technology in that it provides a continuous flow of
CO
2 and a continuous flow of O
x throughout the treatment
cycle and promotes rapid permeation of O
x through packaging materials
and into the voids and interstices of the materials undergoing treatment. The flow
of CO
2 is between about 90% and 99%, preferably between about 98% and
99%, and the flow of O
x is between about 1% and 10%, preferably between
about 1% and 2%. Continuously supplying newly generated O
x molecules
to replace those molecules that have spontaneously degraded to inactive O
2
and those that have reacted during the process ensures that the concentration
of O
x remains essentially the same throughout the process.
The method of the invention also provides significant cost advantages over existing
biological burden reduction technology. The most significant savings derive from
the fact that the gaseous blend of CO
2 and O
x may be generated
and applied on site.
Because O
x is not flammable or explosive, facilities need not
include damage-limiting construction or explosion-proof equipment. Another advantage
of the method of the invention is that scrubbing will be easily accomplished using
existing technology. Moreover, O
3 is classified by the U.S. Food and
Drug Administration as a generally recognized as safe "GRAS" substance.
The gaseous blend of CO
2 and O
x and method of the invention
has proven successful in the treatment of a wide variety of materials, including
food products and other commodities, building structures, transportation containers
and soil.
The method of the present invention avoids many of the limitations of previous
practices by avoiding the need for water sprays and/or water immersion of the substrate
to be treated. Many products such as spices, flour-based products, sugar-based
products, cosmetic bases, herbs, and botanicals, all of which are sensitive to
high levels of moisture, can be treated using the method of the present invention.
The method of the present invention also avoids the need to open conventional commercial
packing before treatment, thereby avoiding unnecessary product degradation and
loss. The product may be treated in situ utilizing conventional processing. Previous
methods have required the product to be agitated, blended, bubbled or re-packaged
during or immediately upon completion of the treatment. The extended half life
of the O
x radicals allows the active portions of the treatment gas to
fully penetrate the substrate and act upon offending organisms. In combination
with CO
2, the stabilized O
x gas mixture is further enhanced
by the increased respiration rates of the offending organism(s) while in the presence
of the permeated O
x gases.
According to an embodiment, a gaseous mixture comprised primarily of CO
2,
as well as smaller concentrations of O
3, O
2 and carbon monoxide
(CO), is used. The gaseous mixture is preferably fed through an ozone generator
such as that described above where a gaseous blend is formed consisting of CO
2,
O
3, O
2 and CO. This gaseous blend assists in the stabilization
of the O
3 molecules by dampening the molecular collision of the O
3
molecules, which would degrade this triatomic form of oxygen back to its
diatomic form, atmospheric oxygen. Several benefits have been observed by generating
this gaseous blend. The first benefit is to "tame" the O
3 so it has
a chance to penetrate into the interstitial spaces of the material being treated.
In addition, the CO
2 acts as a non-polar solvent to assist in the penetration
of the gaseous blend into the material. By reducing the residual oxygen levels
equal to or below normal atmospheric levels, oxidative damage to the material is
highly reduced. The presence of high levels of CO
2 has been shown to
enhance the effects of fumigants by promoting increased respiration in insects,
thereby allowing the infusion of the fumigant into the insect spiracles and coming
into direct contact with the insects' bodily fluids.
As an alternative, the CO
2 can be mixed into an O
3-rich
gas flow immediately after the ozone generator to assist in the formation of the
gaseous blend. According to this technique, no CO is formed because no CO
2
molecules are cleaved. A disadvantage of this system is the increased amount
of oxygen required to produce the O
3 in the generator, which subsequently
allows the O
3 to degrade at an accelerated rate.
This gaseous blend is allowed to flow into, through and out of an impervious
tarpaulin or sealed room as a continuous stream for a given period of time. Fans
may be utilized to distribute the gaseous blend throughout the enclosed area to
effect penetration into the commodity being treated. An outlet for excess gas allows
for a constant release of gas through a catalytic bed consisting of, e.g., oxides
of manganese, copper and aluminum to destruct any residual O
3, O
1
and CO. This process has been demonstrated to operate at temperatures between 45°
F. and 140° F. Heating units can be incorporated into the fans to assist in
bringing the temperature of the material to a desired temperature. The ideal temperature
is 85° F. to 115° F.
Produce and the like generally require 1 to 24 hours treatment where other
commodities such as grains may require treatment in excess of 48 hours. The concentration
as measured directly from the O
x generator can be adjusted to fall within
the range of about 10 ppm to about 3,500 ppm, and more preferably about 10 ppm
and 1,800 ppm, for food products, and up to about 20,000 ppm for building structures,
transportation containers and soil, by using a starting gas mixture of about 90%
to 100% CO
2, preferably about 98% to 99%, and about 0% to 10%, preferably
about 1% to 2% oxygen or air. Although the gas stream flowing through the ozone
generator must be extremely dry, no additional moisture is required to humidify
the material to be treated.
Agricultural soil may be treated in accordance with the method of the
invention, wherein the gaseous blend of CO
2 and O
x is continuously
fed under a gas impermeable membrane, e.g., a polyethylene film or a fumigation
tarpaulin that has proven to be O
3 resistant. This process would be
typical of a methyl bromide soil fumigation that is routinely performed to control
various insects, weed seeds, nematodes and fungal infections. After application,
the gaseous blend of CO
2 and O
x would be destructed at an
exit port.
Infested structures may also be treated in accordance with the method of
the invention, wherein the structure is first covered with a gas impermeable membrane
and sealed for leaks, and wherein the gaseous blend of CO
2 and O
x
is then fed continuously and allowed to diffuse into the structure. The gaseous
blend is evenly distributed using fans, which could also be used to supply any
required additional heat. After application, the gaseous blend of CO
2 and
O
x would exit a vent and be destructed using a destruct unit.
Referring to FIGS. 1 and 2, the apparatus that may be used to practice
the method if the invention includes, e.g., a shipping container 1 (FIG.
1) or storage containers 1′ (FIG. 2) that is covered with an O
3-resistant
tarpaulin 2. The shipping container 1, or storage containers 1′,
contains material 3 to be treated. The shipping container 1, or storage
containers 1′, is connected via piping and appropriate control valves
to a O
x generator 4 at one end and to a destruct unit 5
at another. A first fan 6 is employed to draw gas from the O
x generator
4 into the shipping container 1 or storage containers 1′.
A second fan 6′ is employed to draw gas from the shipping container
1 or storage containers 1′ to the destruct unit 5.
Either the first fan 6 or the second fan 6′ may contain a
heating means (not shown) to bring the shipping container 1 or the storage
containers 1′ to a desired temperature. A gas analyzer 7 is
employed to determine the concentration of O
3 in the shipping container
1 or storage containers 1′.
Referring to FIGS. 1 and 2, according to one embodiment of the invention,
material 3 for which biological burden is to be reduced is placed within
the shipping container 1 or storage containers 1′. A desired
temperature is maintained via heating means (not shown). The process is then initiated
by activating the O
x generator 4. A stream of CO
2 gas,
which may be added to the O
x generator 4 or may be added after
generation of O
x, and CO
2 and O
x gas is then drawn
into, through and out of the shipping container 1 or storage containers
1′ via the first fan 6 and the second fan 6′.
The O
x generator 4 operates continuously during the process.
Exposure to the CO
2 and O
x gas mixture may be varied
in time from several minutes to several hours, depending on the material being
treated. Once the biological burden reduction phase is complete, the O
x generator
4 is inactivated and fresh air is allowed to enter the shipping container
1 or storage containers 1′. All gases may then be passed through
destruct unit 5, which eliminates any residual CO, O
3 and O
1
before the gas stream is discharged to the atmosphere. The treated material
3 is then ready for use following appropriate tests to confirm biological
burden reduction.
According to the invention, the material can be treated by applying a continuous
stream of O
x and CO
2 under atmospheric conditions. This permits
the treatment of the material under, e.g., a tarpaulin or in a sealed room, thereby
removing the need for a vacuum chamber.
EXAMPLES
The present invention will be further illustrated by the following non-limiting Examples.
Example 1
The gaseous blend of CO
2 and O
x and the method of the present
invention were used to treat alfalfa pellets for animal feed. The alfalfa pellets
were heavily infested with saw-toothed grain beetle adults, grubs and eggs. The
alfalfa pellets were placed in a breathable paper sack (sewn) and placed in a treatment
room that was equipped with two circulation fans and a heater system. The gaseous
blend described below was allowed to flow through the room. The following parameters
were used:
| |
| |
Gas Mixture: |
99.5% CO2 and 0.5% O2 |
| |
|
(mixed prior to O3 generation) |
| |
Temperature of Room: |
95° F. |
| |
Relative Humidity: |
maintained at less than 20% |
| |
Final O3 Concentration: |
650 ppm |
| |
Total time of gas exposure: |
16 hours |
| |
O3 Generation Technique: |
corona discharge |
| |
Results
The alfalfa pellets were observed for sixty days after treatment. No secondary
infestation nor any damage to the product was observed.
Example
The gaseous blend of CO
2 and O
x and the method of the present
invention were used to treat papaya fruits artificially laced with Drosophila fruit
flies (adults only). The fruit was placed in normal shipping crates of cardboard
construction. The fruit flies were placed in small glass tubes plugged with tissue
and located in various locations within the shipping crates. The following parameters
were used:
| |
| |
Gas Mixture: |
98% CO2 and 2% O2 |
| |
|
(mixed prior to O3 generation) |
| |
Chamber Temperature: |
85° F. |
| |
Relative Humidity: |
maintained at less than 20% |
| |
Final O3 Concentration: |
1,100 ppm |
| |
Time of gas exposure: |
60 minutes |
| |
O3 Generation Technique: |
corona discharge |
| |
Results
All flies were killed in the process. No damage to the fruit was observed.
Example
The gaseous blend of CO
2 and O
x and the method of the present
invention were used to treat fresh strawberries. The strawberries were dipped into
a buffered water solution containing a starting titre of 100,000
E. coli bacteria.
The strawberries were allowed to air dry and placed into the treatment chamber
along with several tubes containing live aphids. The glass tubes were plugged with
tissue to retain the insects. A control set of plated strawberries was retained
at room temperature for later enumeration. The following parameters were used:
| |
| |
Gas Mixture: |
98% CO2, and 2% O2 |
| |
|
(mixed prior to O3 generation) |
| |
Chamber Temperature: |
112° F. |
| |
Relative Humidity: |
maintained below 20% |
| |
Final O3 Concentration: |
1,600 ppm |
| |
Time of Gas Exposure: |
60 minutes |
| |
O3 Generation Technique: |
corona discharge |
| |
Results
All insects were killed during the process. The control set of strawberries tested
positive for
E. coli at the concentration of 6,846 cfu/sq. inch. The treated
strawberries tested negative for
E. coli and were devoid of any damage to
the fruit and the carpels.
The gaseous blend of CO
2 and O
x and the method for applying
the gaseous blend of CO
2 and O
x of the invention are an excellent
substitute for commercial sterilants and fumigants in all of their current uses.
The gaseous blend and method of the present invention and are also useful for the
treatment of many food ingredients on which use of commercial sterilants and fumigants
is not permitted, including cocoa beans, grains, and edible gums. Examples of commodities
to be treated using the gaseous blend of CO
2 and O
x and method
of the invention include:
- fresh and dried fruits and vegetables,
- herbs and botanicals,
- dry pet foods,
- cotton and other fibers,
- wood and wood products,
- grains,
- livestock feed,
- transport vehicles,
- nursery rootstocks, and
- ornamentals and cut flowers.
Although the invention has been described with some particularity with respect
to preferred embodiments thereof, many changes could be made and many alternative
embodiments could be derived without departing from the scope of the invention.
*
