CA2038970A1 - Controlled atmosphere package - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A controlled atmosphere package suitable for delivery of red-ripe tomatoes to the consumer maintains the tomato in a substantially fixed position relative to the package regardless of the orientation of the package, and further maintains a substantially uniform relative humidity inside the package.

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Description

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CONTROLLED ATMOSPHE~E PACKAGE

The present invention relates to controlled atmosphere packaging, and more particularly to controlled atmosphere packaging for red-ripe fresh tomatoes.
There is considerable demand among consumers for such tomatoes, but getting truly red-ripe tomatoes to the consumer has proven exceedingly difficult due to the limited time length of the red-ripe stage and the particular susceptibility of red-ripe tomatoes to bruising, rupture, and microbial attack.
Most of the "red-ripe" tomatoes sold to the consumer are harvested in the mature green stage of ripening and subsequently exposed to ethylene gas to initiate ripening off the vine. The tomatoes are then quickly shipped in bulk to their final destination so that they will be in the red-ripe stage at the time of sale to the consumer. Problems with this method include bruising due to bulk shipping and reduced flavor in the tomatoes due to picking in the green stage rather than in the vine-ripe stage.

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Because of these problems, several attempts have been made to develop suitable controlled atmosphere packages for storing or delivering tomatoes at more advanced stages of vine-ripeness. Such a package is seen in United States Patent No. 4,079,152 to Bedrosian (Bedrosian). Bedrosian describes controlled atmosphere packages generally which employ a gas permeable film and packets of a humectant and of a carbon dioxide absorbing material. The form of the package per se is not considered to be ofjjparticular importance, and suggested forms include a bag which can be sealed or tied by any conventional means, a wrap for a tray or container which holds the produce, or as windows in an otherwise impermeable framework or container. The humectant can be any of several salts, and the positioning of the humectant and carbon dioxide absorbing packets in the package appears not to be of concern.
The types of packages described in Bedrosian are unsatisfactory in several respects, however. In one respect, these packages offer very little in the way of physical protection for the tomatoes in shipping, handling and storage; as noted earlier, red-ripe fresh tomatoes are very susceptible to physical damage. In another important respect, the packages provide no effective way to manage the humidity of the air surrounding the tomatoes so that mold can be prevented from growing.
3 The present invention overcomes these deficiencies in the known art by providing a controlled atmosphere, controlled humidity package for red-ripe 38,445-F -2-

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fresh tomatoes. The package contains at least one tomato and comprises a protective plastic enclosure which defines an opening therein. A gas permeable plastic film is situated about and in air-tight sealment with the enclosure at the opening therein. The tomato is situated within the protective enclosure in a substantially fixed position regardless of the orientation of the package, but is contacted by the package over a limited area.
A humectant material is contained within a packet having water vapor permeable, liquid water impermeable walls, with the packet in turn being positioned within the enclosure in a fixed, spaced relation to the tomato. A substantially uniform relative humidity is maintained in all regions of the enclosure by means of the selection and positioning of the humectant in the enclosure, and by reason of the limited area of contact between the tomato and package so that water vapor is not trapped and does not accumulate in any particular portion of the enclosure.
The present invention will be better understood on reviewing the detailed description which follows together with the drawings, in which:
Figure 1 is an isometric view of a controlled atmosphere, controlled humidity package for red-ripe tomatoes according to the present invention with tomatoes therein.
Figure 2, is an exploded isometric view of the package of Fig. 1.

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Figure 3 is a top view of a tomato.
Figure 4 is an isometric view partly broken away and fragmented of another embodiment of a controlled atmosphere, controlled humidity package for red-ripe tomatoes according to the present invention.
Figure 5 is an exploded isometric view of the package of Fig. 4.

A controlled atmosphere, controlled humidity package 10 is shown in Fig. 1 with red-ripe tomatoes therein. Package 10 comprises a relatively rigid protective plastic enclosure 15, a packet 22 of a humectant material, and a film 40. Enclosure 15 comprises a tray 20 and an insert 30. Package 10 is seen in an exploded view in Figure 2.
Tray 20 defines a chamber 25 which holds one or more tomatoes 12. Preferably, tray 20 is large enough to accommodate two tomatoes which weigh from 180 to 230 grams each, which have a diameter of about 3 inches (7.6 cm.), and which have a height of about 2 1/2 inches (6.4 cm.). Package 10 is preferably from 6 to 8 inches (15.2 to 20.3 cm.) in length, from 3 to 5 1/2 inches (7.6 to 14.0 cm.) in width, and from 2 1/2 to 3 1/2 inches (6.4 to 8.9 cm.) in height.
Tray 20 forms an opening 33 to chamber 25 which is bounded by a tray lip 24. Lip 24 is preferably

3 substantially flat and preferably parallel with the bottom of tray 20. Lip 24 defines outwardly-extending flange portions 27 and inner portions 26 in the form of 38,445-F -4_ 203~g7J3 localized depressions adapted to receive peripheral portions of insert 30. When such peripheral portions are received within inner portions 26, flange portions 27 and insert 30 are preferably coplanar. Tray 20 further defines bottom cradles 28 which receive and restrict the movements of tomatoes 12 in chamber 25.
A trough 23 is defined in the bottom of tray 20 for receiving the humectant packet 22, and opens toward chamber 25 and insert 30.
Package 10 includes means for holding and maintaining tomatoes 12 in a substantially fixed position with respect to the remainder of package 10 regardless of the orientation of package 10. In the particular embodiment shown, package 10 maintains tomatoes 12 in a substantially fixed position by providing various surfaces located above, below, and lateral to tomatoes 12 in the form of a tray 20, the cradles 28, and an insert 30.
Tomatoes 12, a representative specimen of which is seen in Figure 3, may rest upside down within tray 20 and package 10 with their stem scars 14 toward the bottom of package 10 and toward the packet 22. Stem scars 14 are preferably situated in proximity to the packet 22, and more preferably are situated within 1 inch (2.54 cm.) of packet 22. Since most of the water vapor transpiring from a tomato is emitted through the stem scar, proximity to a packet of humectant m~aterial allows the water vapor to be absorbed rather than accumulate to form liquid water on the surface of the tomato in the area of the stem scar. Buildup of liquid water is undesi.rable because it can accelerate mold formation.

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Insert 30 preferably performs several functions in package 10 including functioning as an internal lid for tray 20, preventing contact between tomatoes 12 and film 40, protecting tomatoes 12 from physical damage associated with stacking two or more packages 10 upon one another, and assisting in maintaining tomatoes 12 in a substantially fixed position within package 10 whereby contact between the tomatoes or between the tomatoes and the film 40 is avoided, and whereby the relationship between the packet 22 and the stem scar of the tomatoes may be effectively maintained.
Insert 30 protects tomatoes 12 from physical damage associated with stacking two or more packages 10 upon one another. Insert 30, being physically supported at its periphery by lip 24 at inner portions 26, is sufficiently rigid in this context to be capable of supporting one and preferably a stack of packages 10 in storing, shipping and display. Insert 30 may or may not be sealed to lip 24, tray 20, or any other component of package 10.
Insert 30 further assists in maintaining tomatoes 12 in a substantially fixed position within package 10, by defining depressions 32 in the surface 31 of insert 30 which contact the bottom ends of tomatoes 12. Depressions 32 work in this respect in conjunction with cradles 28 and surfaces of the tray 20 lateral to tomatoes 12. It is understood however, that film 40 may 3 be utilized in lieu of insert 30 to help hold tomatoes 12 in a substantially fixed position. Cradles 28, which receive most of the weight of tomatoes 12 when package 10 is in an upright position, are preferably configured to provide adequate structural support to tomatoes 12 with minimal surface contact therebetween to minimize 38,445-F -6-203~97~

the possibility of bruising. Further, it is preferable to minimize contact between the surfaces of tomatoes 12 and any other surfaces of package 10 for the same reason.
Insert 30 preferably also prevents contact of the film 40, described hereinafter, with tomatoes 12.
Insert 3G defines one or more openings 34. Openings 34 allow interchange and permeation of gases through film 40 between chamber 25 and the atmosphere surrounding package 10. The openings 34 are preferably positioned so that the film 40 cannot draw down and contact tomatoes 12 situated in c.hamber 25. Insert 30 and tray 20 are designed and adapted to fit together so that an opening is always defined by the combination of the two, whereby this interchange and permeation can occur.
Insert 30 is comprised of a relatively rigid thermoplastic material, and is preferably comprised of the same thermoplastic material as tray 20. Suitable thermoplastic materials include polystyrene, styrene-butadiene copolymers and blends of polystyrene with styrene-butadiene copolymers, polyvinyl chloride, polyethylene terephthalate, polyethylene terephthalate-glycol, or a cellulosic material such as celluloseacetate propionate.
Insert 30 may be formed by any conventional plastic fabrication technique such as thermoforming or injection molding. Preferably, insert 30 is thermoformed, and is 5 to 25 mils (0.127 to 0.635 mm.) thick. The lateral dimensions of insert 30 are dictated largely by the length and width of the upper portions of tray 20 and lip 24.

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Film 40 forms an airtight, water-tight seal over the top of insert 30 and tray 20. Film 40 is preferably sealed to tray 20 at lip 24, and mast preferably heat sealed thereto.
Packet 22 is held in substantially fixed, spaced relation to the tomatoes 12 in a package regardless of the orientation of the package 10.
The size of packet 22 and the amount of humectant material which should be contained therein is determined by the number and size of tomatoes 12 and their water vapor transpiration rates, as well as by the positioning of the packet 22 relative to the stem scars of the tomatoes 12. Preferably there is enough of the humectant material in the packet 22 to absorb the transpired water vapor from the tomatoes 12 for 7 to 14 days, and more preferably for 14 to 21 days.
Package 10 may further comprise an overlay 50 of a material capable of receiving printed indicia.
Overlay 50 may be comprised of a plastic or a paperlike material capable of receiving printed indicia, but is most preferably a paperlike material. Overlay 50 may have a degree of gas permeability sufficient to provide the desired gaseous composition within chamber 25, or may define one or more openings 52 therein to aid in gas permeation through film 40.
Overlay 50 is preferably heat sealed to film 40 opposite the lip 24, and preferably has lateral dimensions sufficient to cover the entirety of lip 24 of tray 20. Preferably, overlay 5a will be comprised of a material heat sealing compatible with film 40.

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g Another embodiment of the package of the present invention is illustrated in Figures 4 and 5.
Package 60 comprises a relatively rigid protective plastic enclosure 65, a packet 72 of a humectant material, and a film 90. Enclosure 65 comprises a tray 70 and an insert 80. As in package 10, tray 70, insert 80, film 90, and an overlay 100 are stacked sequentially. Package 60 defines a chamber 75 wherein tomatoes 16 can be situated. Tray 70 defines curved surfaces 78 which curve downwardly inward. Curved surfaces 78 cradle and receive tomatoes 16 when package 60 is in an upright position. A packet 72 of a humectant material is situated in a trough 73 in the bottom of tray 70. Insert 80 acts as an internal lid for package 60 and is situated about the opening at the top of the tray 70 upon flanges 76 and 77. The shape of insert 80 and its arrangement with respect to tray 70 provide openings 71 where the various gaseous components of the ambient air environment and chamber 75 can 20 interpermeate through film 90. Film 90 is heat sealed to a lip 74 of tray 70. Overlay 100 is heat sealed around its edges to film 90 opposite the lip 74.
Overlay 100 may have a degree of gas permeability 25 sufficient to provide the desired gasous composition within chamber 75, or may define one or more openings 102 therein to aid in gas permeation through the film 90. The materials for the components of package 60 can be those employed for package 10.
3o Trays for the package of the present invention commonly will be comprised of a thermoplastic resin, and can also be made utilizing any conventional plastic fabrication technique such as thermoforming or injection molding. Suitable thermoplastic resins for the tray 38,445-F -9-2~38~70 include polystyrene, styrene-butadiene copolymers and blends of polystyrene with styrene-butadiene copolymers, polyvinyl chloride, polyethylene terephthalate, or polyethylene terephthalate-glycol. Polyvinyl chloride is most preferred. The tray is preferably from lO to 25 mils (0.254 to 0.635 mm). thick, and most preferably from 15 to 20 mils (0.381 to 0.508 mm.) thick. The tray is preferably sufficiently transparent so that the consumer may inspect the tomatoes through the tray before their purchase.
Films useful in the present invention are comprised of a relatively non-rigid thermoplastic material conventionally extruded by either blown or cast film methods. The thermoplastic material comprising the film must also be heat sealable to the thermoplastic material comprising the lip of the tray. Preferred films are those that are permeable to both oxygen and carbon dioxide. Preferably the film will be 4 to 6, and more preferably 6 to 8 times more permeable to carbon dioxide than oxygen. A most preferred film has an oxygen permeance of about 1,000 to about 1,500 cc/lO0 sq. in.-day-atmosphere and a carbon dioxide permeance of 8,000 cc/100 sq. in.-day-atmosphere.
Suitable materials for the films include copolymers of styrene and butadiene, polyethylene homopolymers, copolymers of ethylene and vinyl a~etate, and coextrusions of these materials. A particularly 3 preferred film comprises a single layer of a copolymer of ethylene and vinyl acetate. The thickness of the film is dependent upon the material from which it was formed, but the film will normally be from 0.1 to 5 mils (0.0025 to 0.127 mm.) thick. The most preferred 3~,445-F -lO-203~7a --1, thickness of film 40 is from 0.5 to 2.0 mils (0.0127 to 0.0508 mm.).
Selecting a film with the desired level of carbon dioxide permeability allows the packages of the present invention to maintain the desired steady state levels of C02 within the chamber and around the tomatoes without a C02 absorber in the chamber, although such an absorber may be added to assist the film if desired.
The packages of the present invention provide a carefully controlled environment at steady state of preferably from 70 to 90, and more preferably from 70 to 78 percent relative humidity. The oxygen concentration within the chamber at steady state is preferably from 2 to 10, and more preferably from 2 to 4 percent by volume. The carbon dioxide concentration at steady state is preferably less than 5 percent, and more preferably from 2 to less than 4 volume percent. The below ambient levels of oxygen reduce the respiration rate, and thus the rate of ripening of the tomatoes.
Carbon dioxide levels in excess of about 5 volume percent may make the tomato susceptible to cellular damage, but some C02 presence is desirable to enhance the viability and longevity of the tomato. The relative humidity and gaseous concentration provided by a given package will often vary for different types of tomatoes because tomatoes differ in their respiration and/or transpiration rates. Thus, the preferred and most 3 preferred ranges for relative humidity and gaseous concentrations will vary somewhat according to the type of tomato.
The package reaches steady state oxygen and C02 concentrations after the tomatoes have been packaged for 38,445-F

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about two days. Steady state concentrations may also be achieved by gas flushing when the package is packed and sealed.
Maintenance of a lower than ambient oxygen content within the chamber prolongs the ripening process in the tomatoes, as described above. The slowing of the ripening process in turn lengthens the duration of the desirable red ripe stage. The desirable levels of oxygen and carbon dioxide can be maintained in the chamber for preferably 7 to 14 days and more preferably for 14 to 21 days, after which point the quality of tomatoes can be expected to decline. If the package is maintained at below ambient temperatures such as about 50-60 degrees F (10-15.5 deg. C), the fruit may be maintained in the red ripe stage for still longer periods because of the lower respiration rate of the tomatoes at lower temperatures.
2Q The steady state levels for oxygen and carbon dioxide within the chamber are determined by the permeability of the film for each of them. These permeabilities are determined by the characteristics of the film and by the partial pressure gradients for each of oxygen and carbon dioxide across the film. The greater the partial pressure gradient between the chamber and the ambient environment outside the package for either gas, the greater the transport through the film in one direction or the other.
3o At steady state, the rate of permeation of oxygen through the film and into the chamber will preferably about equal the projected rate of respiration of oxygen by the tomatoes, and the projected rate of permeation of carbon dioxide through the film and out of 38,445-F -12-203897~

the chamber will preferably about equal the projected rate of respiration of carbon dioxide by the tomatoes.
The humectant material contained within packet 22 preferably maintains the desired relative humidity of package 10 at a generally constant level. Packet 22 comprises a humectant material and a patch material which is water vapor permeable but substantially liquid water impermeable. Suitable patch materials include cellulose acetate and Tyvek* (trademark of E. I. DuPont de Nemours & Co.) nonwoven polyethylene fabric.
Suitable humectant materials include conventional humectant or desiccant materials such as the chloride salts, sulphate salts, silica gel, or activated alumina. Preferred humectant materials exhibit only negligible absorption of water vapor up until about 70 percent relative humidity. Preferred materials will maintain levels of 70-90 percent, and especially 70 to 78 percent relative humidity in the chamber of the package at normal room temperatures, and will further preferably maintain these levels over a temperature range of from 50 to 90F (10 C to 32.2 C).
Preferred humectant materials include sodium chloride, mannitol, and sorbitol. The most preferred material is sodium chloride due to its low cost, low toxicity, familiarity to consumers, and excellent performance.
Relative humidities of between about 70 and about 90 percent are preferred in packages of the present invention because levels below about 70 percent may result in dehydration of the tomatoes and levels in excess of about 90 percent may result in mold growth and liquid water buildup in the package and on the tomatoes.

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As indicated above. the packets of humectant material are located in proximity to and preferably within about one inch of the stem scars of the packaged tomatoes. The packet of humectant material preferably does not contact the stem scars ? however, because such contact may operate to se~l in water vapor in the area of the stem scar and to promote mold growth in the area of the stem scar. Further, the consumer's view of the stem scar may be obstructed.
Packages of the present invention preferably maintain a substantially uniform relative humidity and gaseous composition within all regions of the chamber.
A substantially uniform relative humidity means that the l~ humidity varies by no more than 20 and preferably by less than 10 percent from any given region of the chamber to another. The chamber is designed to hold the tomatoes in a substantially fixed position relative to the rest of the package 10 regardless of the package's orientation, but at the same time permits the free flow of gases from one part of the chamber to another so that localized concentrations of water vapor or condensate are kept to a negligible extent. Preferably, no region of the chamber is sealed off from other regions by contacting surfaces of the tomato or tomatoes and the package. Further preferably, no surface of the package is in direct contact with the stem scar to minimize localization of water vapor and/or condensate in this critical area. The proximity of the absorber packet to the stem scars of the tomatoes also aids in minimizing localization of water vapor and~or condensate, and thus, in maintaining a substantially uniform relative humidity throughout the package.

38,445-F _14_ 2~38~70 Inserts may be modified in other embodiments of the present invention to provide a compartment for a humectant material as the functional equivalent of a packet of humectant material, or a packet of the humectant material may simply be attached to the underside of an insert. The compartment in an insert may define a microporous or other water vapor permeable layer on the underside of the insert so that the humectant material will be in close proximity to but will not contact the stem scars of the tomatoes. With such a compartment defined within the insert or with a packet attached to the underside of the insert, the tomatoes may be situated right side or stem scar up in the package.
Packages of the present invention also define means for maintaining the separation and lack of physical contact of the tomatoes regardless of the orientation of the package. In package 60, the separation and lack of physical contact of tomatoes 16 is maintained by holding and maintaining tomatoes 16 in separate positions by various surfaces located above, below, and lateral to tomatoes 16 in the form of tray 70, curved surfaces 78 of tray 70, and insert 80.
Packages of the present invention are configured to minimize contact between the surfaces of the tomato or tomatoes and the surfaces of the package in order to minimize the possibility of bruising, in 3 addition to providing avenues for the circulation of gases in the chamber. The rigid packages are configured in this respect so that the tomato or tomatoes are held in a substantially fixed position by contact between the surfaces of the tomatoes and the package at multiple points and regions around the tomato. Preferably, less 38,445-F _15_ 2~38970 than 20 percent of the total surface area of the tomato or tomatoes is in physical contact with the package regardless of the orientation of the package. Further preferably, any given point or region of contact comprises no more than 10 percent of the total surface area of the tomato or tomatoes regardless of the orientation of the package.
It is understood that the packages of the present invention may be used with perishable fruits other than tomatoes.
A process for packaging a tomato in the manner of the present invention comprises providing a package which defines a chamber therein, placing one or more tomatoes into the chamber, maintaining the tomatoes in a substantially fixed position relative to the package regardless of the orientation of the package, maintaining a substantially uniform 70-90% relative humidity in the chamber at steady state, and maintaining a steady state gaseous composition in the chamber of from 2 to 10 volume percent of oxygen and less than 5 volume percent of carbon dioxide. It is preferable if the chamber is kept at a steady state 70 to 78 percent relative humidity for preferably 7 to 14 days, more preferably for 14 to 21 days. Preferably, the desired relative humidity levels are maintainable over a temperature range of from 50F (10 deg. C.) to 90~F (32.2 deg. C.) in the chamber. It is also preferable if the steady state gaseous composition in the chamber is kept at from 2 to 4 volume percent of oxygen and from 2 to less than 4 percent by volume of carbon dioxide for preferably 7 to 14 days, and more preferably for 14 to 21 days. In a preferred embodiment, the process further comprises maintaining a physical separation and lack of 38,445-F -t6-203897~

contact between tomatoes (if there are two or more tomatoes in the package) regardless of the orientation of the package.
The example below further illustrates the present invention.
EXAMPLE
A package of the present invention, similar to the embodiment shown in Figures 4 and 5, was tested for its performance in maintaining proper chamber environment and the saleability of red-ripe tomatoes packaged therein (Group I). The performance of a second package design (Group II) was compared to that associated with Group I. The packages of Group II
differed primarily from those of Group I in that those of Group II did not contain a packet of humectant material, and in that the film was perforated with holes of about 1 cm. in diameter in each of the four corners of the package to allow exchange of air between the chamber of the package and the environment in which the package was situated. The performance of the packages of Group I were also compared with that of a control group of conventionally boxed red-ripe tomatoes (Group III). The atmosphere in the chambers of both the packages of Group II and the boxes of Group III was largely uncontrolled.
Each package in Groups I and II contained two red-ripe tomatoes. The film in the Group I packages was like that of film 90, was formed from ELVAX 3190 (marketed by E. I. du Pont deNemours & Company) brand ethylene-vinyl acetate copolymer resin, and was 1.2 mils thick. The film used in the packages of Group II was an 38,44~-F -17-203~97~

E~A-coated polyester, and the EVA-coated polyester was 1.0 mil thick. The humectant material was 15 grams of NaCl contained within a Tyvek* (trademark of E.I. du Pont De Nemours & Co.) pouch.
The tomatoes tested as part of the various groups were harvested vine-ripe in Florida, and were subsequently washed with soapy water, rinsed with 5.0 ppm chlorinated water, and air-dried. The tomatoes were placed in the packages described above for Groups I and II, and placed in corrugated tomato boxes in Group III.
There were 96 packages of tomatoes in Group I and 72 packages in Group II, and 111 tomatoes total in Group III. Each package in Groups I and II contained tomatoes weighing a total of about 380 grams.
The packages of Groups I and II and the boxes of tomatoes of Group III were packed in corrugated cases, with 24 packages to a case in two stacked levels of twelve. The cases were shipped from Georgia to Alabama to Indiana, and examined there after 7 days from the time of initial packaging. The cases were then shipped to Michigan, and examined after 14 days from the time of initial packaging.
The tomatoes were examined at 7 days and 14 days for saleability. A tomato was deemed saleable if it had no bruises, cuts, or mold formation visible to the naked eye. The packages of Groups I and II were examined for saleability as a unit. If one of the two tomatoes in a package was deemed unsaleable, then the entire package was deemed unsaleable. The tomatoes of Group III were examined for saleability individually.

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All tomatoes tested were deemed saleable prior to their placement in the described packages and boxes.
For the packages of Group I, 96.9 percent were deemed saleable after 7 days, and 54 percent were saleable after 14 days. For the packages of Group II, 64 percent were saleable after 7 days, and 30 percent were saleable after 14 days. For the individual tomatoes of Group III, 80 percent were saleable after 7 days, and 26 percent were saleable after 14 days. Thus, the packages of Group I according to the present invention offer significantly increased shelf life over the uncontrolled atmospere packages of Group II and cell-divided boxes of Group III.
The relative humidity within the chambers of the packages of each of Groups I and II was also compared. The packages of Group I had a mean relative humidity of 72.1 percent after 9 days. The packages of Group II had a mean relative humidity of 79.5 percent after 9 days. The packages of Group I made according to the present invention offer a lower humidity level than the uncontrolled atmosphere packages of Group II while still being within preferred relative humidity ranges.
A lower relative humidity lowers the likelihood of formation of mold on the tomatoes. It should be noted that the type of tomatoes selected for the tests in this Example are known to have lower than average transpiration rates for tomatoes in general; it is 3~ accordingly expected that greater differences in the relative humidities associated with the packages of Groups I and II would be observed with most tomatoes generally.

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The oxygen and carbon dioxide concentrations within the chambers of the packages of Group I were also analyzed by gas chromatograph. The packages of Group I
which exhibited a high degree of sealing between the film and the lid of the tray of the package, as evidenced by the presence of drawdown in the package, had a mean oxygen concentration of 2.3 volume percent and a mean carbon dioxide concentration of 3.7 volume percent after 7 days. Thus, the packages of Group I
maintained the desirable, substantially below ambient levels of oxygen and desirable, controlled levels of carbon dioxide.
While specific embodiments have been shown and described herein of controlled atmosphere packages and a process for controlled atmosphere packaging, it will be appreciated that these embodiments may be modified in several respects, for example, while still being fairly within the scope of the teachings and principles herein set forth.

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Claims (15)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS
FOLLOWS:

1. A package containing a tomato and further comprising:
a) a protective plastic enclosure having an opening defined therein and including means for holding the tomato in a substantially fixed position relative to the remainder of the package regardless of the package's orientation, with the tomato being so held within the enclosure;
b) a gas-permeable plastic film sealed to the enclosure at the opening therein; and c) a packet containing a humectant material, such packet being held in the enclosure in a substantially fixed, spaced relation to the tomato regardless of the package's orientation and being in sufficient communication with all regions of the enclosure whereby a substantially uniform relative humidity is maintained within all regions of the enclosure.

2. The package according to Claim 1, wherein:
the humectant material exhibits only negligible absorption of water vapor up until 70 percent relative humidity; and 38,445-F -21-the packet of humectant material is situated within about 2.5 cm. of the stem scar.

3. The package according to Claim 2, wherein the humectant material is sodium chloride.

4. The package according to any of Claims 1-3, wherein the packet has water vapor permeable, liquid water impermeable walls.

5. The package according to any of Claims 1-4, wherein the package includes one or more additional tomatoes and means for keeping the tomatoes separate from one another regardless of the orientation of the package.

6. The package according to any of Claims 1-5, wherein less than 20 percent of the total surface area of each respective tomato is in physical contact with the package, regardless of the orientation of the package.

7. The package according to Claim 6, wherein any region of physical contact comprises no more than 10 percent of the total surface area of a tomato.

8. The package according to Claim 1, wherein the package further comprises an overlay of a material capable of receiving printed indicia which is situated about the enclosure at the opening therein and sealed to that portion of the film which is sealed to the enclosure, the overlay optionally defining an opening therein.

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9. The package according to Claim 8, wherein the enclosure comprises;
a) a tray having an opening defined therein, with the packet being situated in the tray; and b) an insert situated about the tray at the opening therein and underlying the film and printable overlay, with the periphery of the insert being in abutment with the tray at the opening therein and being supported thereby, the tray and the insert defining the opening therein of the enclosure.

10. The package according to Claim 1, wherein the film has an oxygen permeability of 1,000 to 1,500 cc/l00 sq. in.-day-atm. and a carbon dioxide permeability equal to or greater than 8000 cc/100 sq.
in.-day-atm.
ll. A process for packaging a tomato, comprising:
a) providing a package which defines a chamber therein;
b) introducing a tomato within the chamber;
c) maintaining the tomato in a substantially fixed position relative to the package regardless of the orientation of the package;
d) maintaining a substantially uniform 70 to 90 percent relative humidity in the chamber; and e) maintaining from 2 to 10 volume percent of oxygen and less than 5 volume percent of carbon dioxide in the gaseous environment of the chamber.

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12. The process according to Claim 11. wherein the chamber is maintained at a substantially uniform 70 to 78 percent relative humidity.

13. The process according to Claims 11 or 12, wherein the gaseous environment of the chamber is maintained at an oxygen content of from 2 to 4 percent by volume and a carbon dioxide content of from 2 to no more than 4 percent by volume.

14. The process according to any of Claims 11-13, wherein one or more additional tomatoes are introduced into the chamber.

15. The process according to Claim 14, further comprising keeping the tomatoes separate from one another regardless of the orientation of the package.

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