Packaging for Extending Life of Respiring Produce and Other Perishable Foodstuffs

Info

Publication number: 20090045095
Type: Application
Filed: Aug 12, 2008
Publication Date: Feb 19, 2009
Applicant: BAG INNOVATIONS GROUP, LLC (Chanhassen, MN)
Inventors: Tommy J. Wagner (Evanston, WY), Mark A. Ziga (Las Vegas, NV)
Application Number: 12/190,075

Abstract

A package for extending a useful life of perishable foodstuff includes at least one polymeric based layer. The at least one polymeric based layer contains an anti-microbial and anti-fungal additive in an amount effective to prevent product deterioration of the fresh produce due to microbial activity, fungal activity or both microbial and fungal activity. The at least one polymeric based layer includes an effective amount of an ethylene absorbing additive throughout a thickness of the film to absorb a sufficient amount of ethylene to delay the ripening process of the perishable foodstuff where the combination of the an ethylene absorbing additive and the anti-microbial and anti-fungal additive creates a synergistic effect that extends the useful life of the perishable foodstuff.

Description

Description

CROSS REFERENCE OF RELATED APPLICATION(S)

The present application claims the benefit and priority of U.S. Provisional Application No. 60/964,518, filed on Aug. 13, 2007, the contents of which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to packaging for extending the useful life of perishable foodstuffs. More particularly, the present invention relates to packaging that extends the shelf life of perishable foodstuffs such as fresh produce, fresh meat, fresh dairy products as well as floral products and bakery products.

BACKGROUND OF THE INVENTION

In the past, fresh produce was only available for a limited time when the produce was ripe in a particular geographic region. With the development of a global economy with limited trade restrictions, most fresh produce is now available continuously throughout the year.

To prevent spoilage and damage during transport the fresh produce is typically harvested before the produce is ripe. Because the produce is not ripe, the produce tends to incur less damage due to the fact that the unripe produce is harder than ripe produce. Ripe produce has a tendency of bruising during transport when compared to unripe produce. Also because the unripe produce can be transported for a significant distance and time, the produce tends to begin ripening while in transport.

Once the produce is transported to the desired geographic region, the produce may optionally be subjected to an atmosphere that contains an elevated amount of ethylene. Ethylene is a naturally produced plant hormone that causes such produce to ripen when emitted. By subjecting the produce to elevated concentrations of ethylene, the ripening process is accelerated such that the produce is nearly ripe or ripe when the produce is offered for sale to consumers. However, while the ethylene treatment or atmosphere accelerates the ripening process, the produce quickly begins to over-ripen and is edible for a significantly shorter time than naturally ripened produce.

Another factor that shortens the useful life of perishable foodstuffs is microbial growth. The ripening process produces sugars and nutrients that allow the naturally present or introduced microbes and fungi to flourish.

All fresh produce respires, even though it has been harvested. Utilizing polymer bags for transporting the produce from the marketplace or various distribution centers can prevent the produce from respiring and essentially suffocates the produce such that the useful life of the produce is shortened. Further, any moisture that is released from the produce pools within the bag and accelerates bacterial and fungal growth which also reduces the useful life of the produce.

Due to damage during transport, the accelerated ripening processes and improper storage of the produce, only about one half of the harvested produce is actually consumed. Packaging that slows the ripening process, inhibits bacterial and fungal growth, allows for oxygen transmission and optionally prevents the condensation of water will increase the sustainability of perishable foodstuffs while increasing food safety.

Other perishable foodstuffs such as fresh meats, fresh breads and cheeses have amounts of naturally occurring bacteria and fungus. A film or package that inhibits bacterial and fungal growth will increase the shelf life of these perishable foodstuffs.

SUMMARY OF THE INVENTION

The present invention includes a package for extending a useful life of perishable foodstuff that includes at least one polymeric based layer. At least one polymeric based layer contains an anti-microbial and anti-fungal additive in an amount effective to prevent product deterioration of the fresh produce due to microbial activity, fungal activity or both microbial and fungal activity. The at least one polymeric based layer includes an effective amount of an ethylene absorbing additive throughout a thickness of the film to absorb a sufficient amount of ethylene to delay the ripening process of the perishable foodstuff.

BRIEF SUMMARY OF THE DRAWINGS

FIG. 1 is a perspective view of a bag containing grapes.

FIG. 2 is a perspective view of a pail containing a perishable foodstuff.

FIG. 3 is a perspective view of a pallet of boxed perishable foodstuff wrapped in a polymeric film.

FIG. 4 is a graph of yeast and mold counts on parsley when stored in market provided packaging.

FIG. 5 is a graph of yeast and mold counts on parsley when stored in packaging as described herein.

FIG. 6 is a graph of yeast and mold counts on parsley when stored in packaging as described herein retained within another bag.

FIG. 7 is a graph of yeast and mold counts on lettuce when stored in market provided packaging.

FIG. 8 is a graph of yeast and mold counts on lettuce when stored in packaging as described herein.

FIG. 9 is a graph of yeast and mold counts on lettuce when stored in packaging as described herein retained within another bag.

FIG. 10 is a graph of yeast and mold counts on strawberries when stored in market provided packaging.

FIG. 11 is a graph of yeast and mold counts on strawberries when stored in packaging as described herein.

FIG. 12 is a graph of yeast and mold counts on strawberries when stored in packaging as described herein retained within another bag.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present invention relates to a flexible, semi-rigid or rigid packaging that is utilized to contain perishable foodstuffs and increase the useful life of the perishable foodstuff such as fresh produce. The packaging is also useful in packaging other perishable foodstuffs, such as fresh meats, fresh breads, other bakery products, unprocessed coffee beans, unprocessed grains and cheeses, as well as floral products.

With respect to fresh produce, the packaging slows the ripening process by absorbing respired ethylene from some foodstuffs while inhibiting bacterial and fungal growth. By fresh produce is meant to include fresh fruits, fresh vegetables and fresh greens such as lettuce and herbs. Significantly, utilizing a combination of a hydro-phobic ethylene absorbing additive in an amount that is effective to selectively absorb respired ethylene to prevent ripening and a hygroscopic anti-microbial and an anti-fungal additive in an amount effective to destroy microbes and fungus in amounts effective to prevent product deterioration of the fresh produce which can create a synergistic effect that increases the shelf life of the fresh produce up to at least three times longer than when the fresh produce was not packaged within the packaging having the additives, packaging with the hydro-phobic ethylene absorbing additive by itself or packaging with the hygroscopic anti-microbial and an anti-fungal additive by itself.

With respect to other foodstuffs that do not emit ethylene such as but not limited to meats and cheeses, the packaging extends the useful life of these perishable foodstuffs by destroying bacteria and fungus utilizing the combination of the hygroscopic anti-microbial and an anti-fungal additive and the hydro-phobic ethylene absorbing additive. While the ethylene absorbing additive will not absorb any ethylene in this application of the packaging, the synergistic effect of utilizing the hygroscopic anti-microbial and an anti-fungal additive and the hydro-phobic ethylene absorbing additive destroys bacteria and fungus on the meat and cheese to extend the useful life of the perishable foodstuff when compared to the same packaging containing only the hygroscopic anti-microbial and an anti-fungal additive or the hydro-phobic ethylene absorbing additive.

The film can also be designed to control the oxygen transmission rate (OTR) of oxygen (O₂) as well as the carbon dioxide (CO₂) concentration in an environment of the packaging by utilizing selected polymers having a known solubility rates for O₂and CO₂to extend the useful life of the foodstuff. The film is designed to allow O₂to enter the enclosed environment of the packaging which allows the foodstuff to respire while allowing CO₂, which is emitted during the respiration process, to exit the enclosed environment. By controlling the O₂and CO₂concentrations in the enclosed environment of the packaging, the useful life of a respiring foodstuff can be extended. Therefore, a desired equilibrium of O₂and CO₂can be obtained in the enclosed environment of packaging for a particular perishable foodstuff that extends the useful life of the perishable foodstuff.

The packaging can be customized to provide a specific OTR for a specific perishable foodstuff, particularly when the foodstuff has a known respiration rate, by utilizing or selecting a polymer or polymers having known OTRs. The OTR of the packaging can also be adjusted by varying the thickness of the packaging.

The packaging provides the flexibility of providing a wide range of OTRs that meet the respiration rates of a wide range of perishable foodstuffs by adjusting the polymer feedstock that is utilized to form the packaging. A micro-porous film and a micro-perforated film are also contemplated to provide the necessary OTR to meet the respiration rates of the respiring perishable foodstuff.

The packaging can be in a form such as a flexible bag as illustrated in FIG. 1 at 10 for containing the fresh produce. The packaging can also be utilized as a rigid or semi-rigid polymer container such as a clam shell container, a lid 12 for covering an opening of an impermeable container 14 or both as illustrated in FIG. 2. The packaging can also be utilized as a wrapping material 16 for retaining packaged produce on a pallet 18 or in a container for transportation as illustrated in FIG. 3. The packaging can contain indicia 20 such as labels and product information on an outer layer of the packaging as illustrated in FIGS. 1 and 2.

A typical thickness of a flexible film which is useful as a wrapping material or a bag is between about 0.005 mil and about 10.0 mil. A typical thickness of the material as a rigid or semi-rigid packaging material such as containers and lids ranges from about 10.0 mil to about 100 mil. However, any thickness of the material that is useful as a film, bag or a container is contemplated. Further, other containers that utilize the packaging material containing the selected additives as a portion of the container are also contemplated.

The packaging is typically constructed from polyethylene or polypropylene feedstock pellets. However other polymers for making the packaging are also contemplated.

The packaging is typically constructed through an extrusion process utilizing three layers to minimize the costs associated with including the additives in the packaging. However, the invention also considers utilizing a single layer for the packaging having a uniform concentration of the additives as well as any number of layers that are necessary to produce the packaging with the additives that provides the same synergistic effect.

To minimize additive costs while maintaining the effectiveness of the packaging, the anti-microbial and anti-fungal additive is typically concentrated in the inner layer of the packaging that contacts the perishable foodstuff. However, it is contemplated to include the anti-microbial and anti-fungal additive in two or more of the layers of the packaging. The anti-microbial and anti-fungal additive destroys or inhibits growth of the bacteria, including Gram negative and Gram positive species, and fungus, such as mildew and yeast, by contact. A typical anti-microbial and anti-fungal additive is a zeolite loaded with a silver ion where the silver ions are ionically bound to the zeolite at a molecular level, while the zeolite is retained within the polymeric lattice through the extrusion process where the polymer is melted and extruded.

A layer of water can develop on the inner layer and contacts the zeolite. The zeolite releases silver ions into the water layer such that a bacteria or fungus contacts the silver ions, the organism is then destroyed. The utilization of silver ions to control bacteria and fungus is referred to in the art as nanotechnology. One exemplary silver ion loaded zeolite additive is sold under the POLYBATCH ABACT trademark by A. Schulman, Inc. having an office located in Akron, Ohio.

Typically, the anti-microbial and anti-fungal additive is added in a range of between about 0.1 weight percent and about 12 weight percent of the film layer. More typically, the anti-microbial and anti-fungal additive is added to the film layer in the range of about 0.5 weight percent and 3.0 weight percent of the film layer. However, any amount that is effective to destroy microbes and fungi or prevent microbial and/or fungal growth to the extent required to extend the useful life of the fresh produce is contemplated.

A non-exclusive list of microbes that the anti-microbial and anti-fungal additive inhibits the growth of or destroys includes mold, mildew, yeast and bacteria. Each of these micro-organisms are naturally occurring on fresh produce and any of these micro-organism by itself detrimentally affects the useful life of the fresh produce.

The hydro-phobic ethylene absorbing additive is typically included throughout each of the layers of the packaging. The hydro-phobic ethylene absorbing additive is typically of a constant weight percentage throughout each layer in the film and selectively absorbs ethylene while not absorbing, or being insensitive, to water. However, it is also contemplated to have packaging containing higher concentrations of the hydro-phobic ethylene absorbing additive in the inner layers of the packaging.

A typical additive that selectively absorbs ethylene is a hydro-phobic synthetic zeolite. The synthetic zeolite is built to selectively absorb ethylene. Unlike typical zeolites which readily absorb water, the synthetic zeolite only absorbs ethylene and is impervious to water which increases the effectiveness of the packaging. An untreated zeolite will absorb both water and ethylene until the zeolite cannot absorb any more molecules. Once the untreated zeolite is fully loaded, water molecules will displace ethylene molecules from the untreated zeolite and which will release the ethylene back into the container.

The synthetic zeolite absorbs ethylene respired from the produce based on a weight percentage of the amount of synthetic zeolite added to the film. The amount of synthetic zeolite utilized to absorb ethylene can be varied by increasing the size of the film being utilized to contain the fresh produce to increase the amount of synthetic zeolite in the packaging. Alternatively, the weight percent of the zeolite can be varied by adjusting the weight percent of the synthetic zeolite in the layers of the film. Typically, the synthetic zeolite is added to the film in the range of about 2 weight percent and about 15 weight percent throughout all the layers in the film. More typically, the synthetic zeolite is added to the film in the range of about 3.0 weight percent and 12.0 weight percent and even more typically in the range of about 5.0 weight percent and 10.0 weight percent, based upon the weight of the film. However, any amount effective to control the ethylene concentration in the atmosphere within the packaging where the fresh produce is stored is contemplated such that the ripening process is delayed is contemplated. One exemplary synthetic zeolite is sold under the POLYFRESH EA trademark by A. Schulman, Inc. having an office located in Akron, Ohio.

It has also been discovered that utilizing the packaging containing both the silver ion loaded zeolite as well as the hydro-phobic ethylene absorbing zeolite produces synergistic effects that can increase the useful life of fresh produce by at least three times the useful life of the same produce that is stored in plastic or polymeric packaging that is provided by the market by both delaying the ripening process as well as controlling the growth of microbes. Further it has also been discovered that utilizing the packaging containing both the silver loaded zeolite as well as the hydro-phobic ethylene absorbing zeolite produces synergistic effects in destroying bacteria and fungi by a factor of between about 100 and 10,000 when compared films that were only loaded with the silver ion loaded zeolite.

Neither the silver ion loaded zeolite nor the hydro-phobic ethylene absorbing zeolite migrates from the package. Therefore, the packaging is safe for contact with perishable foodstuffs. Also, the packaging attracts the micro-organisms to the film surface including airborne pathogens which when in contact with the packaging destroys the airborne pathogens.

It is believed that the synergistic effect in destroying bacteria and fungi is due to the presence of both the combination of the silver loaded zeolite and the hydro-phobic ethylene absorbing synthetic zeolite in the packaging. While the synthetic zeolite selectively absorbs ethylene, it also attracts bacteria and fungi to the inner surface of the packaging due to the synthetic zeolite's strong ionic characteristics.

Once attracted to the surface of the packaging the synthetic zeolite destroys the cellular wall of the bacteria or fungi. Once the cellular wall has been destroyed, the silver ion interferes with the transport of the respiration products across the cellular wall which inhibits respiration and destroys the bacteria or fungi.

While nano-silver has been known to be effective in destroying Gram positive bacteria such as the Bacillus, listeria, staphylococcus, streptocaccus and clostridium species, nano-technologies have been less successful in destroying Gram negative bacteria such as Escherichia coli, and the Salmonella and legionella species. Surprisingly, the combination of the silver loaded zeolite and the hydro-phobic ethylene absorbing synthetic zeolite has been markedly more effective in destroying Gram negative bacteria. By way of example, the packaging containing both the combination of the silver loaded zeolite and the hydro-phobic ethylene absorbing synthetic zeolite produce an E-coli kill rate of 99.99962% which equates to a log reduction of E-coli of 6.11.

It has also been discovered that the packaging having the silver loaded zeolite and the hydro-phobic ethylene absorbing synthetic zeolite has a exponential increase in the kill rate of fungi such as Saccharomyces cerevisiae and Aspergillus niger when compared to to a similar film loaded only with a similar loading of the silver ion loaded zeolite.

The packaging optionally can include a water dispersing material such as any anti-fog additive that is generally recognized as safe (GRAS) for utilization in the food industry. The anti-fog additive typically is a migratory anti-fog additive that disperses water that condenses during the heating and cooling cycle resulting from the produce being placed into and removed from a refrigerated space. The anti-fog additive is typically included in the inner and optionally middle layers of the film in amounts effective to disperse any moisture that condenses. Typically amounts of the anti-fog additive in the inner and middle layers range from about 0.25 weight percent to about 10.0 weight percent. More typically, the anti-fog additive in at least the inner layer of the packaging ranges from 0.5 weight percent and about 3.0 weight percent of the weight of the layer of film.

The anti-fog additive disperses the water across the inner surface of the packaging which increases the wetted surface area where a larger number the silver ion is activated. However, the perishable foodstuff respires enough moisture onto the inner layer such that an adequate amount of silver ions are dispersed and activated.

The packaging can be utilized in many different markets. The packaging can be utilized as a retail product where rolls of film and a bags are sold through a retail outlet. The packaging can be utilized by institutional vendors that supply prepared foods to institutions, restaurants and delis. The packaging can also be utilized by producers to ship product to processors and wholesale entities to increase the sustainability of perishable foodstuffs to the retail market.

It has been discovered that the packaging product described herein increases the useful life of many foodstuffs above that of known packaging. The following Examples are illustrative only and are not intended to limit the present invention in any way.

EXAMPLE 1

Fresh store bought cilantro was stored in a refrigerated environment at about 40° F. in a bag constructed from a three layer film having 3 weight percent of the anti-microbial and anti-fungal additive in the inner layer and 10 weight percent of the synthetic zeolite throughout the three layers of the film. After twelve days of refrigerated storage the fresh cilantro was still fresh and edible. In contrast, when cilantro is stored in a plastic bag from the store where the cilantro was purchased, the cilantro was only edible for about four days.

EXAMPLE 2

Flat leaf parsley bundles were purchased from a local market and tested at the University of Tennessee located at Knoxville. The parsley bundles were combined and mixed together in a clean tub. Three samples of parsley were removed from the combined bundles. Prior to placing the parsley in storage containers, each of the samples were weighed at 25 gram, then each sample was placed in a container and sealed.

The first container included a bag containing five layer polyethylene film that is 2.5 mil in thickness and contains 3 weight percent of the silver loaded zeolite in the first layer and 10 weight percent of the hydro-phobic synthetic zeolite in all five layers where the weight percents are based upon the weight of each layer. The second container included the five layer polyethylene film bag utilized as the first container that was sealed inside a plastic storage bag sold under the Ziploc trademark by S. C. Johnson Home Storage, Inc. located in Racine, Wis. The third container was the bags obtained from the market which are utilized to transport in which at least one of the three bundles of parsley were transported from the market. Each of the packages were sealed or tied prior to storage to prevent contamination of the results from the outside atmosphere.

A sufficient number of samples were prepared for each of the three sets such that two samples from each set of packages could be sampled every two days for 18 days. Each of the samples was stored in at a controlled temperature of 50° F. for 18 days. Samples were collected every two days and tested for microbial growth.

For the microbiological analysis, 25 grams of parsley were placed in a stomacher bag with 100 mL of a phosphate buffer solution and blended for two minutes in a blender at a medium speed. Aerobic bacterial counts were determined by surface plating serially diluted samples onto plate count agar supplemented with cycloheximide at a solution of 10 mg/L which is a yeast and mold inhibitor and incubated on incubator plates for 24 hours at 32° C.

Yeast and mold counts were determined by surface plating serial dilutions onto dichloran rose bengal chloramphenicol agar which inhibits bacterial growth after blending per the protocol described with respect to the microbial analysis. The samples were incubated for five day at 25° C.

The results are provided in FIGS. 4-6. All of the recorded values were divided by three to reduce the range of units from 0-30 to 0-10. CFU represents in FIGS. 4-6 are colony forming units.

The results indicate that the bacteria and yeast/mold counts on the parsley in the store packaging (container three) increased steadily during the 18 day test. However while the bacteria and yeast/mold counts utilizing the film as a bag in the first set or the film utilized as a bag (container one) and contained within another bag (container two) increased during storage, the rate was substantially slower that the data obtained with respect to the store packaging (container three). The final bacteria counts on parsley in container one was about 100 fold less that the bacteria counts on parsley in container three. The final bacteria counts on parsley in container two was about between about 100 and 1,000 fold less that the bacteria counts on parsley in container three.

While the visual appearance of the parsley deteriorated more quickly in containers one and two as compared to container three, it is believed that this was the result of an inadequate OTR through containers one and two and could be easily overcome by matching the OTR of the packaging in containers one and two with the respiration rate of parsley.

EXAMPLE 3

Multiple packages of fresh cut lettuce mix were purchased from a local market and tested at the University of Tennessee located at Knoxville. The lettuce packages were combined and mixed together in a clean tub. Three samples of lettuce were removed from the combined mixture of the packages. Prior to placing the lettuce in storage containers each of the samples were weighed at 50 gram and each sample was placed in a container and sealed.

The first container included a bag containing five layer polyethylene film containing 3 weight percent of the silver loaded zeolite in the first layer and 10 weight percent of the hydro-phobic synthetic zeolite in all five layers where the weight percents are based upon the weight of each layer. The second container included the five layer polyethylene film bag utilized as the first container that was sealed inside a plastic storage bag sold under the Ziploc trademark by S. C. Johnson Home Storage, Inc. located in Racine, Wis. The third container was the bags obtained from the market which are utilized to transport in which at least one of the three bundles of lettuce were transported from the market. Each of the packages were sealed or tied prior to storage to prevent contamination of the results from the outside atmosphere.

A sufficient number of samples were prepared for each of the three sets such that two samples from each set of packages could be sampled every two days for 18 days. Each of the samples was stored in at a controlled temperature of 50° F. for 18 days. Samples were collected every two days and tested for microbial growth.

For the microbiological analysis, 50 grams of lettuce were placed in a stomacher bag with 100 mL of a phosphate buffer solution and blended for two minutes in a blender at a medium speed. Aerobic bacterial counts were determined by surface plating serially diluted samples onto plate count agar supplemented with cycloheximide at a solution of 10 mg/L which is a yeast and mold inhibitor and incubated on incubator plates for 24 hours at 32° C.

Yeast and mold counts were determined by surface plating serial dilutions onto dichloran rose bengal chloramphenicol agar which inhibits bacterial growth after blending per the protocol described with respect to the microbial analysis. The samples were incubated for five day at 25° C.

The results are provided in FIGS. 7-9. All of the recorded values were divided by three to reduce the range of units from 0-30 to 0-10. CFU represents in FIGS. 7-9 are colony forming units.

The results indicate that the bacteria and yeast/mold counts on the lettuce in the store packaging (container three) increased steadily during the 18 day test. However while the bacteria and yeast/mold counts utilizing the film as a bag in the first set or the film utilized as a bag (container one) and contained within another bag (container two) increased during storage, the rate was substantially slower that the data obtained with respect to the store packaging (container three). The final bacteria counts on lettuce in containers one and two was between about 100 and 10,000 fold less that the bacteria counts on lettuce in container three.

The visual quality of the lettuce stored in the store packaging (container three) deteriorated rapidly as compared to the lettuce stored in containers one and two. At day two of the study, there was a visual difference between the lettuce stored in containers one and two as compared to the lettuce stored in container three. At day six of the experiment, the visual appearance of the lettuce was unacceptable in container three. The lettuce in containers one and two maintained an acceptable appearance until day ten of the experiment. Therefore, the packaging extends the life of lettuce when compared to a bag supplied by the market.

EXAMPLE 4

Multiple packages of strawberries in clam shell cartons were purchased from a local market and tested at the University of Tennessee located at Knoxville. The strawberries were combined and mixed together in a clean tub. Five strawberries were then repackaged into either container one, container two or container three.

The first container included a bag containing five layer polyethylene film containing 3 weight percent of the silver loaded zeolite in the first layer and 10 weight percent of the hydro-phobic synthetic zeolite in all five layers where the weight percents are based upon the weight of each layer. The second container included the five layer polyethylene film bag utilized as the first container that was sealed inside a plastic storage bag sold under the Ziploc trademark by S. C. Johnson Home Storage, Inc. located in Racine, Wis. The third container were the clam shell containers in which the strawberries were previously stored and purchased. Each of the packages for containers one and two were sealed or tied prior to storage to prevent contamination of the results from the outside atmosphere. Container three was closed by attaching the bottom and top portions of the clam shell container together.

A sufficient number of samples were prepared for each of the three sets such that two samples from each set of packages could be sampled every two days for 18 days. Each of the samples was stored in at a controlled temperature of 50° F. for 18 days. Samples were collected every two days and tested for microbial growth.

For the microbiological analysis, three strawberries were placed in a stomacher bag with 100 mL of a phosphate buffer solution and blended for two minutes in a blender at a medium speed. Aerobic bacterial counts were determined by surface plating serially diluted samples onto plate count agar supplemented with cycloheximide at a solution of 10 mg/L which is a yeast and mold inhibitor and incubated on incubator plates for 24 hours at 32° C.

Yeast and mold counts were determined by surface plating serial dilutions onto dichloran rose bengal chloramphenicol agar which inhibits bacterial growth after blending per the protocol described with respect to the microbial analysis. The samples were incubated for five day at 25° C.

The results are provided in FIGS. 10-12. All of the recorded values were divided by three to reduce the range of units from 0-30 to 0-10. The term CFU in FIGS. 4-12 are colony forming units.

The results indicate that the bacteria and yeast/mold counts on the strawberries in the store packaging (container three) increased steadily during the 18 day test. However while the bacteria and yeast/mold counts utilizing the film as a bag in the first set or the film utilized as a bag (container one) and contained within another bag (container two) increased during storage, the rate was substantially slower that the data obtained with respect to the store packaging (container three). The final bacteria counts on the strawberries in containers one and two was between about 100 and 10,000 fold less that the bacteria counts on the strawberries in container three.

The visual quality of the strawberries stored in the store packaging (container three) deteriorated rapidly as compared to the strawberries stored in containers one and two due to the visible appearance of mold and shriveling of the strawberries. At day eight of the experiment, about one half of the strawberries in container three were covered with visible mold growth and the amount of shriveling would make the strawberries unacceptable to a consumer. The strawberries storied in containers one and two were mold free until about day 14 where about one half of the strawberries had visible mold. After fourteen days, the strawberries were unacceptable due to mold growth in containers one and two. Therefore, the packaging extends the useful life of strawberries when compared to a clam shell type packaging.

EXAMPLE 5

Tests were conducted at the National Food Laboratory, Inc. located in Dublin, Calif. to test the anti-microbial effectiveness of films. The films utilized the same microorganism and protocols. Three films were tested were designated A, B and C. Each of the films were three layer polyethylene films with a thickness of 2.5 mil. The inner layer of film A was designed to contain 3.0% by weight of the silver ion loaded zeolite and 5.0 weight percent of the hydro-phobic synthetic zeolite where the weight percent is based upon the weight of the layer. The remaining layers included no zeolite additives. The film designated B has was intended to have the same construction as film A but includes 3.0% by weight of the silver ion loaded zeolite and 5.0 weight percent of the hydro-phobic synthetic zeolite in the inner layer and also has 5.0 weight percent of the hydro-phobic synthetic zeolite in the other-two layers. The film designated C has the same construction as film 1 but was intended to include 3.0% by weight of the silver ion loaded zeolite and 10.0 weight percent of the hydro-phobic synthetic zeolite in the inner layer and also has 10.0 weight percent of the hydro-phobic synthetic zeolite in the other two layers.

The results of the testing is as follows. The initial inoculation readings on the films is provided in Table 1 for samples A and B.

TABLE 1 Initial Inoculation Counts for Films A and B Organism Initial Count Log Value E. coli O157:H7 3900000 6.59 L. mono 3800000 6.58 S. cerevisiae 19000 4.28 A. niger 100000 5.00

The initial inoculation readings on film C is provided in Table 2.

TABLE 2 Initial Inoculation Counts for Film C Organism Initial Count Log Value E. coli O157:H7 11000000 7.04 L. mono 21000000 7.32 S. cerevisiae 940000 5.97 A. niger 380000 5.58

After the 72 hour incubation period the following results were observed.

The results regarding E. coli counts are found in Table 3 below.

TABLE 3 E. coli Results Ave. Final Log Log Log % Description Count Value Reduction Red Reduction A - Inoculated 46000 4.66 1.93 1.78 98.26 A - Inoculated 100000 5.00 1.59 A - Inoculated 57000 4.76 1.83 A - Positive Control 2200000 6.34 0.25 A - Negative Control <10 1.00 5.59 B - Inoculated 240 2.38 4.21 2.67 99.94 B - Inoculated 100000 5.00 1.59 B - Inoculated 24000 4.38 2.21 B - Positive Control 2300000 6.36 0.23 B - Negative Control <10 1.00 5.59 C - Inoculated 15000 4.18 2.16 2.40 99.49 C - Inoculated 58000 4.76 1.58 C - Inoculated 96000 4.98 1.36 C - Positive Control 4800000 6.68 −0.34 C - Negative Control <10 1.00 5.34

Each of the films A, B and C reduce the E. coli count by a minimum of 98.26%.

The results regarding the L. monocytogenes counts are found in Table 4 below.

TABLE 4 L. monocytogenes Results Ave. Final Log Log Log % Description Count Value Reduction Red Reduction A - Inoculated 140000 5.15 1.43 1.23 93.16 A - Inoculated 470000 5.67 0.91 A - Inoculated 170000 5.23 1.35 A - Positive Control 3300000 6.52 0.06 A - Negative Control <10 1.00 5.58 B - Inoculated 16000 4.20 2.38 2.28 99.32 B - Inoculated 10000 4.00 2.58 B - Inoculated 51000 4.71 1.87 B - Positive Control 2200000 6.34 0.24 B - Negative Control <10 1.00 5.58 C - Inoculated 40 1.60 5.08 4.41 99.99 C - Inoculated 2300 3.36 3.32 C - Inoculated 6000 3.78 2.90 C - Positive Control 6200000 6.79 −0.11 C - Negative Control <10 1.00 5.68

The results show that up to 99.99% of all L. moncytogenes organisms can be destroyed utilizing the film of the present invention.

The results regarding Saccharomyces cerevisiae are found in Table 5 below.

TABLE 5 Saccharomyces cerevisiae Results Ave. Final Log Log Log Description Count Value Reduction Red % Reduction A - Inoculated 310 2.49 1.79 1.98 98.89 A - Inoculated 170 2.23 2.05 A - Inoculated 150 2.18 2.10 A - Positive Control 20 1.30 2.98 A - Negative Control <10 1.00 3.28 B - Inoculated 120 2.08 2.20 2.56 99.65 B - Inoculated 60 1.78 2.50 B - Inoculated 20 1.30 2.98 B - Positive Control 10 1.00 3.28 B - Negative Control <10 1.00 3.28 C - Inoculated 40 1.60 4.37 3.87 99.98 C - Inoculated 280 2.45 3.52 C - Inoculated 180 2.26 3.71 C - Positive Control 250 2.40 3.57 C - Negative Control <10 1.00 4.97

The results show that up to 99.98% of all Saccharomyces cerevisiae organisms can be destroyed utilizing the film of the present invention.

The results regarding Aspergillus niger organisms are found in Table 6 below.

TABLE 6 Aspergillus niger Results Ave. Final Log Log Log Description Count Value Reduction Red % Reduction A - Inoculated 48000 4.68 0.32 0.33 53.33 A - Inoculated 43000 4.63 0.37 A - Inoculated 49000 4.69 0.31 A - Positive Control 210000 5.32 −0.32 A - Negative Control <10 1.00 4.00 B - Inoculated 59000 4.77 0.23 0.32 51.67 B - Inoculated 40000 4.60 0.40 B - Inoculated 46000 4.66 0.34 B - Positive Control 300000 5.48 −0.48 B - Negative Control <10 1.00 4.00 C - Inoculated 9000 3.95 1.63 1.51 96.84 C - Inoculated 14000 4.16 1.42 C - Inoculated 13000 4.11 1.47 C - Positive Control 230000 5.36 0.22 C - Negative Control <10 1.00 4.58

It has been surprisingly found that utilizing the film of the present invention can destroy up to 96.84% of the A. niger organisms which was not believed to be possible utilizing a film with only the silver ion loaded zeolite or the hydro-phobic synthetic zeolite.

EXAMPLE 6

Another testing was conducted at the National Food Laboratory, Inc. located in Dublin, Calif. to test the anti-microbial effectiveness of films. Three films designated 1, 11 and 21R were tested regarding the effectiveness of destroying Escherichia coli O157:H7 obtained from NFPA #4200, 4201, 4203 and 4211, Listeria monocytogenes obtained from NFPA #7077, 7085 and 7092 , Saccharomyces cerevisiae obtained form ATCC #9733 and Apergillus niger obtained form ATCC #16404 and 16888.

The film designated 1 is a polyethylene film with a 2.5 mil thickness. The film has five layers where the inner layer contained 3.0% by weight of the silver ion loaded zeolite and 5.0 weight percent of the hydro-phobic synthetic zeolite where the weight percent is based upon the layer. The remaining layers included no zeolite additives. The film designated 11 has the same construction as film 1 but included 3.0% by weight of the silver ion loaded zeolite and 5.0 weight percent of the hydro-phobic synthetic zeolite in the inner layer and also has 5.0 weight percent of the hydro-phobic synthetic zeolite in the other four layers. The film designated 21R has the same construction as film 1 and included 3.0% by weight of the silver ion loaded zeolite and 10.0 weight percent of the hydro-phobic synthetic zeolite in the inner layer and also has 10.0 weight percent of the hydro-phobic synthetic zeolite in the other four layers. The film designated C is the same film as film C in Example 5.

The E. Coli and L. moncytogenes cultures were grown in tryptic soy broth (TSB). Cultures of the separate organism strains were separately innoculated into 40 mL of TSb and incubated at 35° C. for 18 hours. The cultures were then centrifuged, washed and strains of each type of organism were pooled. The Sacchormyces cerevisiae and Aspergillus niger cultures were grown in potato dextrose broth at 25° C. for 72 hours. The cultures were then centrifuged and washed.

Each of the film strips were cut into 3 cm by 3 cm squares and were labeled to correlate to the microorganism placed on the film. Strips of each film were placed in a tray. Strips were inoculated with the target organism and un-inoculated strips were treated as a negative control. The inoculated strips were placed in a 35° C. incubator for 24 hours. Positive control strips were placed in a 5° C. incubator for 24.

The cocktails used to for the inoculations were plated to determine the initial log values of the micro-organisms. The E. Coli and L. monocytogenes were plated onto supplemented Phenol Red Agar. The plates were incubated at 35° C. for 48 hours, and then were read and recorded. The samples of Saccarmyces cerevisiae and Aspergillus niger were plated with Potato Dextrose Agar acidified with tartaric acid. The plates were incubated at 25° C. for 5 days after which the plates were read and counted. The initial inoculation readings on the films is provided in Table 7.

TABLE 7 Initial Inoculation Readings Organism Initial Count Log Value E. Coli 1,300,000 6.1139434 L. monocytogenes 13,000 4.1139434 S. cerevisiae 380,000 5.5797836 A. niger 130,000 5.1139434

After the seventy two hour inoculation period, the following results were determined. With respect to E. coli counts the following results were determined as provided in Table 8.

TABLE 8 E. coli results Average Final Log Log Film ID Description Count Log Value Reduction Reduction 1 Inoculated 50 1.6989700 4.4149733 3.62 1 Inoculated 650 2.8129134 3.3010300 1 Inoculated 910 2.9590414 3.1549020 1 Positive Control 750000 5.8750613 0.2388821 1 Negative Control <10 6.1139434 11 Inoculated 10 1.0000000 5.1139434 3.83 11 Inoculated 1200 3.0791812 3.0347621 11 Inoculated 580 2.7634280 3.3505154 11 Positive Control 560000 5.7481880 0.3657553 11 Negative Control <10 6.1139434 21R Inoculated <10 6.1139434 6.11 21R Inoculated <10 6.1139434 21R Inoculated <10 6.1139434 21R Positive Control <10 6.1139434 21R Negative Control <10 6.1139434

The results show that a log reduction of 6.11 is achieved which correlates to count reduction of over 99%.

With respect to L. moncytogenes counts the following results were determined as provided in Table 9.

TABLE 9 L. moncytogenes results Average Final Log Log Film ID Description Count Log Value Reduction Reduction 1 Inoculated <10 4.1139434 4.11 1 Inoculated <10 4.1139434 1 Inoculated <10 4.1139434 1 Positive Control 890 2.949390 1.1645533 1 Negative Control <10 4.1139434 11 Inoculated <10 4.1139434 3.78 11 Inoculated <10 4.1139434 11 Inoculated 10 1.0000000 3.1139434 11 Positive Control 420 2.6232493 1.4906941 11 Negative Control <10 4.1139434 21R Inoculated <10 4.1139434 4.11 21R Inoculated <10 4.1139434 21R Inoculated <10 4.1139434 21R Positive Control <10 4.1139434 21R Negative Control <10 4.1139434

The results show a log reduction of up to 4.11 which substantially reduced the L. moncytogenes counts.

With respect to S. cerevisiae counts the following results were determined as provided in Table 10.

TABLE 10 S. cerevisiae results Average Film Final Log Log ID Description Count Log Value Reduction Reduction 1 Inoculated 860 2.9344985 2.64528515 2.77 1 Inoculated 420 2.6232493 2.95653431 1 Inoculated 760 2.8808136 2.69897000 1 Positive Control 290 2.4623980 3.11738560 1 Negative Control <10 5.57978360 11 Inoculated 40 1.6020600 3.97772361 3.33 11 Inoculated 130 2.1139434 3.46584024 11 Inoculated 1100 3.0413927 2.53839091 11 Positive Control 850 2.9294189 2.65036467 11 Negative Control <10 5.57978360 21R Inoculated <10 5.57978360 3.88 21R Inoculated 50 1.6989700 3.88081359 21R Inoculated <10 5.57978360 21R Positive Control 20 1.3010300 4.27875360 21R Negative Control <10 5.57978360

The results show a log reduction of up to 3.88 which substantially reduced the S. cerevisaie counts.

Another test was conducted on films designated 1, 11 and 21R as well as film C with respect to L. monocytogenes and A. niger organisms using the protocol as provided above. The initial inoculum levels for the films are provided in Table 11.

TABLE 11 Initial Inoculation Readings Organism Initial Count Log Value L. monocytogenes 320000 5.5051500 A. niger 110000 5.0423927

Utilizing the protocol provided above the following results were obtained. With respect to L. moncytogenes counts the following results were determined as provided in Table 12.

TABLE 12 L. moncytogenes Results Average Final Log Log Film ID Description Count Log Value Reduction Reduction 1 Inoculated <10 3.43 1 Inoculated 90 1.9542425 3.5509075 1 Inoculated 160 2.2041200 3.3010300 1 Positive Control 25000 4.3979400 1.1072100 1 Negative Control <10 5.5051500 11 Inoculated 120 2.0791812 3.4259687 3.18 11 Inoculated 220 2.3424227 3.1627273 11 Inoculated 350 2.5440680 2.9610819 11 Positive Control 20000 4.3010300 1.2041200 11 Negative Control <10 5.5051500 21R Inoculated 980 2.9912261 2.5139239 3.01 21R Inoculated 620 2.7923917 2.7127583 21R Inoculated 50 1.6989700 3.8061800 21R Positive Control 27000 4.4313638 1.0737862 21R Negative Control <10 5.5051500 C Inoculated 130 2.1139434 3.3912066 3.85 C Inoculated 10 1.0000000 4.5051500 C Inoculated 70 1.8450980 3.6600519 C Positive Control 25000 4.3979400 1.1072100 C Negative Control <10 5.5051500

The results provided a minimum log reduction of 3.01 of L. monocytogenes counts.

With respect to A. niger counts the following results were determined as provided in Table 13.

TABLE 13 A. niger Results Average Final Log Log Film ID Description Count Log Value Reduction Reduction 1 Inoculated 3600 3.5563025 1.4850902 1.50 1 Inoculated 3000 3.4771213 1.5642714 1 Inoculated 4000 3.6020600 1.4393327 1 Positive Control 19000 4.2787536 0.7626391 1 Negative Control <10 5.0413927 11 Inoculated 2200 3.3424227 1.6989700 1.57 11 Inoculated 3200 3.5051500 1.5362427 11 Inoculated 3800 3.5797836 1.4616091 11 Positive Control 4400 3.6434527 1.3979400 11 Negative Control <10 5.0413927 21R Inoculated 3900 3.5910646 1.4503281 1.49 21R Inoculated 3000 3.4771213 1.5642714 21R Inoculated 3700 3.5682017 1.4731910 21R Positive Control 13000 4.1139434 0.9274493 21R Negative Control 10 1.0000000 4.0413927 C Inoculated 17000 4.2304489 0.8109438 0.9 C Inoculated 13000 4.1139434 0.9274493 C Inoculated 12000 4.0791812 0.9622114 C Positive Control 5000 3.6989700 1.3424227 C Negative Control <10 5.0413927

The results of the testing indicate that all of the films destroy micro-organisms. The films resulted in an over 2 log reduction in destroying Aspergillus niger. The films saw as high as an over 6 log reduction in E. coli. Therefore, the films exhibit very good anti-fungal and anti-bacterial properties.

The test results provided inconsistencies in the results between the films designated 21R and C. As both films were designed to contain the same amount of additives, the results should have been similar.

An ash test was conducted on films B and C to determine the additive percentages in an attempt to explain the inconsistent results between films 21R and C. An ash test was not conducted on film A. After conducting the ash test it was determined that films B and C contained substantially less than the desired concentrations of the silver ion loaded zeolilte and the hydro-phobic synthetic zeolite. The ash test results indicated that the film designated B contained 1% by weight of silver ion loaded zeolite and 2% by weight of the hydro-phobic synthetic zeolite. Film C contained 2% by weight of the silver ion loaded zeolite and 7% by weight of the hydro-phobic synthetic zeolite. Therefore, the data provided in Example 5 is accurate for films contain less than the intended amounts of silver ion loaded zeolite and the hydro-phobic synthetic zeolite.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Claims

1. A package for extending a useful life of perishable foodstuff, comprising:

at least one polymeric based layer containing an anti-microbial and anti-fungal additive in an amount effective to prevent product deterioration of the fresh produce due to microbial activity, fungal activity or both microbial and fungal activity and an or fungal and an effective amount of an ethylene absorbing additive throughout a thickness of the film to delay the ripening process of the foodstuff.

2. The packaging of claim 1 and wherein the anti-microbial and anti-fungal additive comprises a silver ion loaded zeolite.

3. The packaging of claim 2 and wherein the silver ion loaded zeolite comprises between about 0.1 and about 12.0 weight percent of the at least one polymeric based layer.

4. The packaging of claim 2 and wherein the silver ion loaded zeolite comprises between about 0.5 and about 3.0 weight percent of the at least one polymeric based layer.

5. The packaging of claim 1 and wherein the ethylene absorbing additive comprises a hydro-phobic synthetic zeolite designed to selectively absorb ethylene.

6. The packaging of claim 5 and wherein the hydro-phobic synthetic zeolite comprises between about 2 and about 15 weight percent of the at least one polymeric based layer.

7. The packaging of claim 2 and wherein the hydro-phobic synthetic zeolite comprises between about 3.0 and about 5.0 weight percent of the at least one polymeric based layer.

8. The packaging of claim 1 and wherein the at least one polymeric based layer includes a selected oxygen transmission rate based upon the composition of the polymers utilized in forming the at least one polymeric based layer.

9. The packaging of claim 1 and further comprising a moisture dispersing material comprises between about 0.1 and about 5.0 weight percent of the at least on polymeric based layer.

10. The packaging of claim 9 and wherein the moisture dispersing material comprises between about 0.25 and about 3.0 weight percent of the at least on polymeric based layer.

11. The packaging of claim 1 and wherein the at least one polymeric based layer comprises at least a portion of a bag.

12. The packaging of claim 1 and wherein the at least one polymeric based layer comprises at least a portion of a clam shell package.

13. The packaging of claim 1 and wherein the at least one polymeric based layer comprises a pail, a lid or both a pail and lid.

14. The packaging of claim 1 and wherein the at least one polymeric based layer comprises a film for wrapping perishable foodstuffs.

15. The packaging of claim 1 and wherein the at least one polymeric based layer comprises three co-extruded layers.

16. The packaging of claim 1 and wherein the at least one polymeric based layer comprises polyethylene, polypropylene, or a combination of polyethylene and polypropylene.

17. A package for extending a useful life of perishable foodstuff by destroying both Gram positive and Gram negative bacteria comprising:

at least one polymeric based layer comprising a selected amount of a zeolite having ionic characteristics that attracts both Gram positive and Gram negative bacteria to a surface of the at least one polymeric based layer and wherein the zeolite destroys the cellular wall of both the Gram positive and Gram negative bacteria and a selected amount of an anti-microbial and anti-fungal additive in an amount effective to inhibit respiration of the both the Gram positive and Gram negative bacteria such that the neither the Gram positive nor the Gram negative bacteria adversely affect the useful life of the foodstuff.

18. The package of claim 17 and wherein the anti-microbial and anti-fungal additive comprises a silver ion loaded zeolite.

19. The package of claim 17 and wherein the zeolite having ionic characteristics comprises a hydro-phobic synthetic zeolite.

20. The packaging of claim 17 and wherein the at least one polymeric based layer comprising the anti-microbial and anti-fungal additive and the zeolite having ionic characteristics also destroys mold, mildew, yeast and other fungi.