Abstract:
A nested cooler system for temporary storage of perishable foodstuffs and more particularly to articles for convenient, temporary storage of human breast milk and infant formulas. The inner and outer coolers jointly or independently receive the perishable foodstuffs and freezable gel packs for cooling the perishable foodstuffs. The gel packs can be frozen and thawed several times and temporarily keep containers of milk within an acceptable temperature range to prevent spoilage. The gel packs fit within pockets in the coolers to maintain proper positioning of the gel packs relative to the bottles.

Description:
CROSS REFERENCE  
       [0001]    This application is a continuation of U.S. patent application Ser. No. 09/213,680, which was filed on Dec. 17, 1998, now allowed. 
     
    
     
       FIELD OF INVENTION  
         [0002]    This invention pertains to articles for temporary storage of perishable, edible foodstuffs, and more particularly to insulated articles for convenient, temporary storage of human breast milk and infant formulas.  
         BACKGROUND OF THE INVENTION  
         [0003]    Coolers are commonly used to store food and beverage items that must be kept at low temperatures to prevent spoilage. Coolers are available in various sizes and shapes from the large hard-sided insulated chests to the individual soft-sided lunch sacks. These coolers are designed for the sole purpose of keeping perishable foodstuffs cold. Coolers generally have walls defining an interior cavity into which the foodstuff is placed. The walls are usually made of or contain an insulating material such as foam or air.  
           [0004]    Specific concerns occur when transporting human breast milk or infant formula during a trip with the infant or when the nursing mother returns to work. Storing, transporting and chilling expressed human milk in the workplace creates several challenges. Discretion and safety are typical concerns when expressing milk in the workplace. Placing expressed milk in a communal refrigerator is indiscreet and provides opportunities for contamination or loss of the milk during the day. In many situations a communal refrigerator is not available, so the working woman carries a bulky ice chest to work; with the hope that the coolant packs will last long enough to drop the temperature of the expressed milk to prevent spoilage during work hours. When the parent is traveling with the baby and older siblings, storage of expressed milk or infant formula is not the only perishable food that the parent needs to think about. Other perishable foods for the older sibling must be carried along with all of the baby support supplies required. A second multi-compartment diaper bag typically fills the role of transporting additional baby support supplies. The parent ends up carrying multiple articles specialized for individual tasks.  
           [0005]    U.S. Pat. No. 5,062,557 to Mahvi, et al., describes an infant care bag for storing bottles, diapers, wet wipes and other infant care supplies comprising a primary bag section and an adjacent removable auxiliary bag section. The primary bag section has a plurality of fixed adjacent compartments. At least one of the compartments is an insulated cooler compartment with fixed smaller compartments contained within. The primary bag section can also be used as a booster chair for dining. The removable auxiliary section provides additional storage space and has a compartment for storing a changing pad. The infant care bag is constructed of a fabric-coated extruded plastic framework.  
           [0006]    U.S. Pat. No. 2,825,208 to Anderson describes a single-compartment portable refrigerated carrier, in particular a traveling bag having pockets for bottles of milk, baby food, and formula along with pockets for a refrigerant on the inner surface of the cover. Diapers, baby clothes and the like may be stored in the body of the bag.  
           [0007]    U.S. Pat. No. 4,796,758 to Hauk describes a portable case to enable the chilling, storing and transportation of expressed human milk. The portable case includes several components, a durable and rugged case, a foam insulated chest, storage bottles and chilling means. The case has upper and lower compartments, wherein the upper compartment may be used to store a breast pump or similar device. The lower compartment houses the insulated chest. Within the insulated chest are three sturdy and unbreakable storage bottles that are chilled by coolant gel packs.  
           [0008]    Ross Products Division, Abbott Laboratories Breastfeeding Support Cooler Bag is a single-compartment insulated soft-sided cooler. The insulated, zip-shut cooler bag includes two reusable 8-oz. gel packs that may be inserted into pockets located on the sides of the inner compartment.  
           [0009]    Mead Johnson® Breastfeeding Success Bag contains a single compartment cooler attached to the bottom of a diaper bag. The cooler is designed to store previously chilled or frozen bottles of expressed breast milk for up to eight hours. Bottles of refrigerated or frozen breast milk are placed directly on top of the 16-oz. frozen ice pack in the zippered cooler compartment of the diaper bag.  
           [0010]    There remains a need for a reliable, portable cooler that can be easily inserted in a larger cooler allowing the nursing mother to rely upon one system for safely storing expressed breast milk while at the workplace and easily adding the small storage cooler to a larger cooler for supplemental cold storage and convenience.  
         SUMMARY OF THE INVENTION  
         [0011]    This invention pertains to a system for temporary storage of perishable, edible foodstuffs, and more particularly to articles for convenient, temporary storage of human breast milk and infant formulas. In accordance with the invention, the system includes two containers, an inner cooler nested within the outer cooler. The inner cooler contains cooling means for cooling foodstuffs while additional cooling means are optional for the outer cooler.  
           [0012]    The inner cooler is capable of receiving items therewithin, as well as receiving cooling means that fit within the inner cooler. Preferably, the inner cooler panels are insulated to an R factor of at least about 0.29 and include at least one securing means for securing the cooling means within the cooler and closure means for selectively opening and closing the cooler to enable the removal and placement of items within the inner cooler. The first and optional second cooling means are typically capable of being repeatedly frozen and thawed.  
           [0013]    The outer cooler is capable of receiving the inner cooler therewithin, as well as receiving optional cooling means that fit within the outer cooler. Ideally, the outer cooler panels are insulated to an R factor of at least 0.29. The outer cooler generally includes at least one securing means for securing the optional cooling means within the outer cooler and closure means for selectively opening and closing the outer cooler to enable the removal and placement of the inner cooler and optional cooling means as well as other items within the outer cooler. The optional third and fourth cooling means are typically capable of being repeatedly frozen and thawed. Additional means for securing items may be provided on the outside surface of the outer cooler.  
           [0014]    The plurity of panels that define the interior space of the inner and outer cooler may further comprise a polyvinyl chloride vinyl inner- and outer-protective layer that sandwich a polyurethane foam filler intermediate layer. Typically the outer and inner PVC layers have a thickness from about 0.1 mm to about 0.5 mm and the intermediate polyurethane foam filler layer has a thickness from about 1.0 mm to about 10.0 mm.  
           [0015]    An advantage of the present invention is the convenience of the nested cooler system. The inner cooler features a lightweight design and convenient handle. The attractive inner cooler may be easily carried along with a purse or brief case, making transportation of the container and milk therein convenient for the user. Additionally, the inner cooler may be simply placed in the outer cooler for outings with the children.  
           [0016]    The present invention provides for removable cooling means. By being removable, the cooling means may be conveniently and inexpensively replaced as they wear out. In addition, an extra set of cooling means may be used so that one set is always frozen and can be placed into the cooler system when the first set of cooling means begins to lose its cooling capacity.  
           [0017]    Additionally, the present invention may provide securing means within the inner and outer cooler. Such securing means provide sure placement of the cooling means relative to the items being stored. This increases the likelihood that each item will be maintained at the correct temperature regardless of jostling the coolers during transportation. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail in this specification and illustrated in the accompanying drawings (not to scale) that form a part hereof and wherein:  
         [0019]    [0019]FIG. 1 is an exploded view of the nested cooler system  10 .  
         [0020]    [0020]FIG. 2 is a perspective view of the inner cooler  20 ;  
         [0021]    [0021]FIG. 2 a  is an enlarged cross sectional view of the preferred panel material;  
         [0022]    [0022]FIG. 3 is a cross section view of an alternate embodiment of the inner cooler  20 ;  
         [0023]    [0023]FIG. 4 is a perspective view of the outer cooler  120 ;  
         [0024]    [0024]FIG. 4 a  is an enlarged cross sectional view of the preferred panel material;  
         [0025]    [0025]FIG. 4 b  is a perspective view of an alternate embodiment of the outer cooler  120 ;  
         [0026]    [0026]FIG. 5 is a cross section of an alternate embodiment of the outer cooler  120 ;  
         [0027]    FIGS.  6 A-P illustrate graphically the results of three cooling capacity studies plotted against the criteria of Hamosh, et al., for safe storage, as described in more detail in the examples.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0028]    As used herein, R value refers to a measure of insulating power or ability to resist the flow of heat. Higher R values mean greater insulating power. The R value for a particular material is the inverse of the thermal conductivity (K) of that material. K is the thermal conductivity in British Thermal Units (BTU) per hour, square foot, and temperature gradient of 1 degree Fahrenheit per inch thickness. The lower the conductivity (K), the greater the insulating values. The sum of the R values of each material represented in a panel or packet provides a total R value for a specific panel or pocket.  
         [0029]    For the purposes of the invention, non-insulating material is one with a very low or negligable R value, such as 0.1 mm thick PVC.  
         [0030]    The terms second insulated container, larger container and outer cooler are used interchangeably and refer to the article that receives the inner cooler therewithin.  
         [0031]    Nested Cooler System  
         [0032]    Referring now to the drawings wherein the views are for purposes of illustrating a preferred embodiment of the invention only and not for purposes of limiting the same, FIG. 1 shows the nested cooler system  10  according to the invention. A frozen gel pack  12  is placed within the interior space of inner cooler  20  that is placed within the interior space of a second insulated container  120  (hereinafter outer cooler  120 ).  
         [0033]    Inner Cooler  
         [0034]    [0034]FIG. 2 shows the preferred inner cooler  20  according to the invention. The inner cooler  20  comprises a front panel  22 ; back panel  24 ; end panels  26 ,  28 ; top panel  30 ; and bottom panel  32 . The panels are connected so as to define a first interior space.  
         [0035]    One or more of the panels of the inner cooler comprise insulation material. The insulation comprises any material suitable to the application that provides an R value of at least about 0.29, preferably from about 0.29 to about 5.0, more preferably from about 0.58 to about 2.0, most preferably from about 0.72 to about 1.50. Materials that may be used to achieve the desired R value include but are not limited to closed cell foam, open cell foam, fiber insulators, air space, glass, mylar and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, durability, final desired weight and size of the article, specific structure requirements, food grade status, cost of material and appearance are characteristics addressed by the selection of the insulation material. Obviously, a material with a low R value may require great thickness to achieve the desired insulation characteristic. Consequently, materials with low R values would not be as practical for this application. However, combinations of materials with varying physical characteristics and R values may achieve the desired characteristics and with the preferred R values. Preferably a polyurethane foam filler is selected as the insulation material. Some advantages of polyurethane foam filler are the insulation capacity, softness to the touch and its light weight.  
         [0036]    The insulation capacity is important in achieving storage conditions appropriate for perishable foodstuffs and more specifically human breast milk. Human breast milk stored at various temperatures has been studied by Hamosh, et al., “Breastfeeding and the Working Mother: Effect of Time and Temperature of Short-Term Storage on Proteolysis, Lipolysis and Bacterial Growth in Milk,” PEDIATRICS, Vol. 97, Pages 492-498 (1996). Hamosh, et al., evaluated the safety of stored human milk at various temperatures by assessing the microbial growth and stability of the milk protein and lipid at intervals up to 24 hours. They chose suboptimal storage conditions (temperatures of 15° C. to 38° C.) based on typical storage temperatures found in developing countries as well as in many work situations in industrialized countries. They found that human milk can be stored safely up to 24 hours at 59° F. (15° C.) and for up to four hours at 77° F. (25° C.) but that it should not be stored at 100.4° F. (38° C.).  
         [0037]    The panels may further comprise inner and/or outer protective coverings ( 34 , 36 ) sandwiching the intermediate insulation layer  38  as shown in FIG. 2A. The inner and outer covering layers comprise any material suitable to the application, as described in more detail herein. Examples of material used as covering layers ( 34 , 36 ) include but are not limited to polyvinyl chloride (PVC), natural and man-made woven fabrics, plastic, urethane, foil, mylar and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, food grade material may be desired on the inner layer where it may become in contact with foodstuffs. Ease of cleaning, durability, final weight and shape, cost of materials, and appearance of the article are additional characteristics to be addressed in the selection of suitable inner and outer coverings. The panels preferably comprise a polyvinyl chloride vinyl inner  34  and outer layer  36 , with a polyurethane foam filler intermediate layer  38 . The outer PVC layer  36  has a thickness from about 0.1 mm to about 0.5 mm, preferably from about 0.1 mm to about 0.3 mm. The inner PVC layer  34  has a thickness from about 0.1 mm to about 0.5 mm, preferably from about 0.1 mm to about 0.3 mm. The intermediate polyurethane foam filler layer  38  has a thickness from about 1.0 mm to about 10.0 mm, preferably from about 2.0 mm to about 8.0 mm, most preferably from about 4.0 mm to about 6.0 mm. Some advantages of PVC in the form of a vinyl sheet are the ease of cleaning and durability characteristics.  
         [0038]    For the purposes of the invention, the R values represent the entire panel&#39;s insulation power. Consequently, the total insulation power of the panels of the inner cooler is the sum of the R values for the inner  34  and outer  36  PVC layers and the polyurethane foam filler intermediate layer  38 . Since the R values for the preferred PVC layers are negligible compared to the polyurethane foam filler layer, the total R value is suitably approximated by the R value for the polyurethane foam filler layer.  
         [0039]    The inner cooler  20  further comprises a closure means for selectively opening and closing the inner cooler  20 . The closure means may be any material suitable to the application including but not limited to the hook and loop system such as Velcro™, magnetic, spring hinges, channel lock system with or without a slide such as a Ziploc™, snaps, draw string, zippers and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, strength of seal, cost of material, durability and location of closure means on the article are additional characteristics to be addressed in the selection of suitable closure means. Obviously, the tighter sealing closure means promote better insulation of the interior space by decreasing the exchange of air between the interior space and external environment.  
         [0040]    In the embodiment shown in FIG. 2, the preferred closure means is a zipper  42 . The top panel  30  meets the back panel  24  to form an edge  40  that serves as a hinge. About the other three sides of the periphery of the top panel  30  is a zipper track  42   a  that cooperates with a mating zipper track  42   b  that is affixed about three sides of the periphery of the top of the front  22  and end panels  26 , 28  of the inner cooler. The zipper  42  enables the inner cooler to be selectively opened and closed so that containers of human breast milk or infant formula and cooling means may be selectively removed and replaced within the inner cooler in addition to minimizing the exchange of cooled air with the external environment.  
         [0041]    The inner cooler may comprise securing means for securing cooling means adjacent to at least one panel. The securing means may be any material suitable to the application including but not limited to the hook and loop system such as Velcro™, straps, buckles, snaps, elastic, cord, pockets and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, space available in the article, strength, location and R value are additional characteristics to be addressed in the selection of suitable securing means for securing cooling means.  
         [0042]    In the embodiment shown in FIG. 2, the securing means is a first pocket  44 . The first pocket  44  may be made of any material suitable to the application, for example mesh, natural and man-made woven fabrics, PVC vinyl, plastic sheets and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, R value, strength and shape are additional characteristics to be addressed in the selection of suitable pocket material. Preferably the securing means is a single sheet of PVC vinyl located adjacent to the inside of back panel  24 . The PVC vinyl of the pocket has a thickness from about 0.1 mm to about 0.5 mm, preferably from about 0.1 mm to about 0.3 mm. The configuration of the securing means illustrated in FIG. 2 with the securing means adjacent a back panel, is the presently preferred embodiment. However, there are other embodiments of the invention in which the securing means is located at an additional and/or a different place within the inner cooler. For example, with reference to FIG. 3, an alternate embodiment of the inner cooler includes a second pocket  46  placed inside the inner cooler adjacent to the front panel  22 .  
         [0043]    With reference to FIGS. 1, 2 and  3 , the preferred cooling means  12  is a gel pack. The preferred gel pack is available from Mid-Lands Chemical Company, Inc., Omaha, Nebraska and is sold under the trade name “Polar Pack.” Preferably the gel packs are repeatedly frozen and thawed with no appreciable decrease in performance. Other cooling means could also be used successfully, for example, rigid or flexible packs of ice substitute refrigerant, ice, and rigid or flexible chemical coolant packs. Ice substitute refrigerant is typically an inert, nontoxic polymer that forms a lattice. The lattice determines the final viscosity that determines if the end product is a partial or hard freeze gel pack. Obviously, the hard freeze gel packs remain frozen longer and therefore are the preferred gel pack for longer term storage. The cooling means is at least one gel pack from about 4 oz. to about 18 oz., preferably at least one gel pack from about 6 oz. to about 16 oz., more preferably at least one gel pack from about 6 oz. to about 8 oz. Selection of the cooling means takes into consideration the insulation power of the panels (total R value), the foodstuffs to be chilled, the size and location of the space available for the cooling means within the cooler and the securing means for the cooling means. For the inner cooler, the most preferred cooling means is one eight ounce gel pack placed in pocket  44 .  
         [0044]    In the embodiment shown in FIGS. 1 and 2, a handle  48  is depicted. One end  48   a  of handle  48  is affixed to one side of top panel  30  while other end  48   b  is affixed to the opposite side of the top panel  30 . The handle may be made of any material suitable to the application, to include but not limited to PVC, natural and man made woven fabric, plastic, wood, metal, webbing, glass and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, comfort of the handle in the hand, strength and appearance are additional characteristics to be addressed in the selection of suitable handle material. The preferred material for the handle is one inch wide polypropylene webbing.  
         [0045]    An optional identification label  50  is affixed to the inner layer of the top panel  30 . The label may be any material suitable to the application to include but not limited to PVC, natural and man made woven fabrics, paper, plastic, ink stamped onto the inner layer, embossing of the inner layer and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, appearance, durability and ability to accept ink are additional characteristics to be addressed in the selection of suitable identification label material.  
         [0046]    Optionally, the inner cooler  20  may further comprise securing means  52  on an outside surface of a panel for securing the inner cooler within the interior space of the outer cooler. Securing the inner cooler in a specific orientation permits the positioning of any non-insulated panels of the inner cooler  20  adjacent to an optional, secondary cooling means of the outer cooler to maximize cooling capacity. Those knowledgeable in the art may use any securing means suitable to the application. Optional securing means may include but are not limited to the hook and loop system such as Velcro™, straps, buckles, elastic, cord, snaps and pockets and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, strength, space and location of securing means and R value are additional characteristics to be addressed in the selection of suitable securing means for securing the inner cooler within the interior space of the outer cooler. Preferably, the inner cooler is held in such an orientation by a hook and loop system.  
         [0047]    Outer Cooler  
         [0048]    The outer cooler component  120  of the nested cooler system  10  provides for additional cooling capacity and insulation for food stuffs stored in the inner cooler as well as a second cooling compartment for foodstuffs within the outer cooler itself.  
         [0049]    Referring now to FIG. 4 that shows the preferred outer cooler  120  according to the invention. The outer cooler comprises a front panel  122 ; back panel  124 ; end panels  126 ,  128 ; and bottom panel  130  connected so as to define a second interior space of greater capacity than the first interior space. One or more of the panels of outer cooler  120  are insulated with any material suitable to the application that provides an R value of at least about 0.29, preferably from about 0.29 to about 5.0, more preferably from about 0.58 to about 2.0, most preferably from about 0.72 to about 1.50. Materials that may be used to achieve the desired R value include but are not limited to closed cell foam, open cell foam, fiber insulators, air space, mylar, glass and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, durability, final desired weight and size of the article, specific structure requirements, food grade status, cost of material and appearance are characteristics addressed by the selection of the insulation material. Obviously, a material with a low R value may require great thickness to achieve the desired insulation characteristic. Consequently, the materials with low R values would not be as practical for this application. However, combinations of materials with varying physical characteristics and R values many achieve the desired characteristics and with the preferred R values. Preferably a polyurethane foam filler is selected as the insulation material.  
         [0050]    The panels further comprise inner and outer protective coverings  132 ,  134  sandwiching the intermediate insulation layer  136  as shown in FIG. 4A. The inner and outer covering layers comprise any material suitable to the application. Examples of material used as covering layers include but are not limited to polyvinyl chloride (PVC), natural and man made woven fabrics, plastic, urethane, foil, mylar and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, food grade material may be desired on the inner layer where it may become in contact with foodstuffs. Easy of cleaning, durability and appearance of the article are additional characteristics addressed by the selection of the inner and outer coverings. As with the inner cooler, the panels preferably comprise a polyvinyl chloride vinyl inner  132  and outer layer  134 , with a polyurethane foam filler intermediate layer  136 . The outer PVC layer  134  has a thickness from about 0.1 mm to about 0.5 mm, preferably from about 0.1 mm to about 0.3 mm. The inner PVC layer  132  has a thickness from about 0.1 mm to about 0.5 mm, preferably from about 0.1 mm to about 0.3 mm. The intermediate polyurethane foam filler layer  136  has a thickness from about 1.0 mm to about 10.0 mm, preferably from about 2 mm to about 8 mm, more preferred from about 4 mm to about 6 mm. Some advantages of PVC in the form of a vinyl sheet are the ease of cleaning and durability characteristics.  
         [0051]    Additional support may be provided to the panels of the outer cooler through the inclusion of a stiffening agent such as cardboard, plastic, wood or combinations thereof. The advantage of bottom panel reinforcement is the formation of a solid bottom that supports the coolers in an upright position and provides a solid, flat surface for placement of containers within the coolers. Typically, a piece of cardboard, optionally covered in a protective sheath such as PVC, is sized to sit upon the bottom panel of the container thereby reinforcing the bottom panel.  
         [0052]    In accordance with the calculation of R values for the panels of the inner cooler, the R values for the outer cooler panels represent the entire panel&#39;s insulation power. Consequently, the total insulation power of the preferred panels of the outer cooler is the sum of the R values for the inner  132  and outer  134  PVC layers and the polyurethane foam filler intermediate layer  136 . Since the R values for the preferred PVC layers are negligible compared to the polyurethane foam filler layer, the total R value is suitably approximated by the R value for the polyurethane foam filler layer.  
         [0053]    The outer cooler  120  further comprises a closure means for selectively opening and closing the outer cooler  120 . The closure means may be any material suitable to the application including but not limited to the hook and loop system such as Velcro™, magnets, spring hinges, snaps, channel lock system with or without a slide such as ZipLoc™, draw string, zippers and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, strength of the seal, cost of material and durability and location of closure means on the article are additional characteristics to be addressed in the selection of suitable closure means. Obviously, the tighter sealing closure means promote better insulation of the interior space by decreasing the exchange of air between the interior space and external environment.  
         [0054]    In the embodiment shown in FIG. 4, the preferred closure means is a zipper  138 . Affixed to the periphery of the front panel  122  is a zipper track  140  that cooperates with a mating zipper track  142  that is affixed to the periphery of the back panel  124 . The zipper ends  138   a  and  138   b  may be left free of the end panels  126 ,  128 , both ends may be attached to the end panels  126 , 128  or one zipper end attached and one left free of the end panels  126 , 128 . The different zipper end options allow for a more or less enclosed interior space. The zipper  138  enables the outer cooler  120  to be selectively opened and closed so that the inner cooler  20 , cooling means  12  and perishable foods may be selectively removed and replaced within the outer cooler  120  in addition to minimizing the exchange of cooled air with the external environment.  
         [0055]    In a different embodiment shown in FIG. 4B, the preferred closure means, a zipper  138 , is affixed to optional top panel  158 , 160 . One edge of top panel half  158  is affixed to the top periphery of front panel  122  with the opposite edge affixed to zipper track  140 . One edge of top panel half  160  is affixed to the top periphery of back panel  124  with the opposite edge affixed to a mating zipper track  142 . The remaining top panel edges and zipper ends  138   a  and  138   b  are affixed to end panel  126  or  128  respectively. The resulting outer cooler is a fully closed, box-like system when the zipper is closed minimizing the exchange of cooled air with the external environment.  
         [0056]    Optionally, the outer cooler  120  further comprises a securing means for securing cooling means adjacent to at least one panel therewithin. The securing means may be any material suitable to the application to include but not limited to the hook and loop system such as Velcro™, straps, buckles, elastic, cord, snaps, pockets and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, space available in the article, strength, location and R value are additional characteristics to be addressed in the selection of suitable securing means for securing cooling means. In the embodiment shown in FIG. 4, the securing means is a third pocket  144  placed adjacent to back panel  124 . The third pocket  144  may be made of any material suitable to the application, for example mesh, natural and man made woven fabrics, PVC vinyl, plastic sheets and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, R value, strength and shape are additional characteristics to be addressed in the selection of suitable pocket material. Preferably the securing means is a single sheet of PVC vinyl. The PVC vinyl of the pocket has a thickness from about 0.1 mm to about 0.5 mm, preferably from about 0.1 mm to about 0.3 mm. The configuration of the securing means illustrated in FIG. 4 is one presently preferred embodiment. However, there are other embodiments of the invention in which the securing means is located at an additional and /or a different place within the outer cooler  120 . For example, with reference to FIG. 5, an alternate embodiment of the outer cooler  120  includes a fourth pocket  146  placed adjacent to the inside of the front panel  122 .  
         [0057]    With reference to FIG. 5, the optional cooling means is a gel pack  12 . The preferred gel pack is available from Mid-Lands Chemical Company, Inc., Omaha, Nebraska and is sold under the trade name “Polar Pack.” Preferably, the gel packs are repeatedly frozen and thawed with no appreciable decrease in performance. Other cooling means could also be used successfully, for example, rigid or flexible packs of ice substitute refrigerant, crushed ice, and rigid or flexible chemical coolant packs. Ice substitute refrigerant is typically an inert, nontoxic polymer that forms a lattice. The lattice determines the final viscosity that determines if the end product is a partial or hard freeze gel pack. Obviously, the hard freeze gel packs remain frozen longer and therefore are the preferred gel pack for longer term storage. The optional cooling means is at least one gel pack from about 4 oz. to about 18 oz., preferably at least one gel pack from about 6 oz. to about 16 oz., more preferably at least one gel pack from about 6 oz. to about 8 oz. For the most preferred cooler means, as illustrated in FIG. 5, one eight ounce gel pack is placed in pocket  144 .  
         [0058]    Additional securing means to secure other items may be added to the outer cooler (shown in FIG. 4) as a fifth  148  and sixth pocket  150  placed on the outside of the outer cooler  120  along front panel  122  and end panel  126 , respectively. Optionally, an additional end pocket is placed adjacent to the other end panel  128 . The end panel pocket  150  may be made of any material suitable to the application, for example mesh, natural and man made woven fabrics, PVC vinyl, plastic sheet, closed cell foam, open cell foam, fiber insulators, air space, mylar, glass and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, R value, strength, shape and appearance are additional characteristics to be addressed in the selection of suitable pocket material. Preferably the securing means  150  is a mesh pocket of polyester and polypropylene. Obviously, an increase in R value of the end panels ( 126 ,  128 ) may be achieved by adding insulation to the end panel packets  150 .  
         [0059]    The fifth pocket  148  is adjacent to the outer layer of either the front  122  or back panel  124  or both. The fifth pocket  148  may be made of any material suitable to the application, for example mesh, natural and man made woven fabrics, PVC vinyl, plastic sheet, closed cell foam, open cell foam, fiber insulators, air space, mylar, glass and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, R value, strength, shape and appearance are additional characteristics to be addressed in the selection of suitable pocket material. Preferably, as with the panels of the outer cooler, the fifth pocket  148  comprises a polyvinyl chloride vinyl inner  132  and outer layer  134 , with a polyurethane foam filler intermediate layer  136 . The outer PVC layer  134  has a thickness from about 0.1 mm to about 0.5 mm, preferably from about 0.1 mm to about 0.3 mm. The inner PVC layer  132  has a thickness from about 0.1 mm to about 0.5 mm, preferably from about 0.1 mm to about 0.3 mm. The intermediate polyurethane foam filler layer  136  has a thickness from about 1.0 mm to about 10.0 mm, preferably from about 2 mm to about 8 mm, more preferred from about 4 mm to about 6 mm. The resultant R value of the front  122  or back panel  124  would be increased with the addition of an insulated pocket.  
         [0060]    Optionally, the external pockets  148 ,  150  have closure means for selectively opening and closing the external pockets. The closure means may be any material suitable to the application to include but not limited to the hook and loop system such as Velcro™, magnets, channel lock system with or without a slide such as Ziploc™, draw string, elastic, zippers, snaps and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, strength of the seal, cost of material, durability and location of closure means on the pocket are additional characteristics to be addressed in the selection of suitable closure means. The preferred optional closure means is a hook and loop system with half of the hook and loop system affixed to the inside w of the pocket and the other half of the hook and loop system affixed to the outer layer of the panels positioned so as to contact each other.  
         [0061]    An adjustable shoulder strap  152  and handles  154  provide for ease of transport of the nested cooler system. Shoulder strap end  152   a  is affixed to end panel  126  while shoulder strap end  152   b  is affixed to end panel  128 . A set of handles  154  are attached to the front and back panels  122 , 124 . Each handle  154  and strap  152  attachment preferably withstand at least a  351   b . pull without tearing. The handle  154  and strap  152  may be made of any material suitable to the application, to include but not limited to PVC, natural and man made woven fabric, plastic, wood, metal, webbing and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, comfort of the handle or shoulder strap, strength and appearance are additional characteristics to be addressed in the selection of suitable handle or shoulder strap material. The preferred material for the handle  154  and strap  152  is one inch wide polypropylene webbing.  
         [0062]    An optional identification label  156  is affixed to the inner layer of the back panel  124 . The label may be any material suitable to the application to include but not limited to PVC, natural and man made woven fabrics, paper, plastic, ink stamped onto the inner layer, embossing of the inner layer and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, appearance, durability and ability to accept ink are additional characteristics to be addressed in the selection of suitable identification label material.  
         [0063]    Optionally, the outer cooler may further comprise securing means for securing the inner cooler within the interior space of the outer cooler. Those knowledgeable in the art may use any securing means suitable to the application. Optional securing means may include but are not limited to the hook and loop system such as Velcro™, straps, snaps, buckles, elastic, cord, and pockets and combinations thereof. Different materials may be selected depending on the desired characteristics. For example, space available in the article, strength, location and R value are additional characteristics to be addressed in the selection of suitable securing means for securing the inner cooler within the interior space of the outer cooler. Preferably, the inner cooler is held in correct orientation by a hook and loop system. One half of the hook and loop system is affixed to the outer layer  36  of an inner cooler  20  panel and the other half of the hook and loop system is affixed to the inner layer  132  of a outer cooler  120  panel. The advantage is an inner cooler positioned such that a non-insulated panel is placed adjacent to the optional cooling means in the outer cooler and the added security of ensuring that containers within the inner cooler are stored in the upright position.  
         [0064]    The inventive article provides great utility and convenience for multiple cooling tasks to the large number of mothers temporarily unavailable to a nursing infant, either due to employment commitments or other requirements of their schedule.  
         [0065]    As illustrated by the test results in Examples I-III, the nested cooler system provides excellent performance. Extensive testing has been made on the configuration of the inner and outer cooler individually and together that would yield the best results.  
       EXAMPLE I  
       [0066]    The cooling capacity of a complete Nested Cooler System made in accordance with the invention and two 8-oz. frozen gel packs inserted in the inner cooler and the Mead Johnson® Breastfeeding Success bag (hereinafter MJ bag) with the manufacturer supplied single 16-oz frozen ice pack at four different environmental temperatures with milk initially at three different temperatures is described below.  
         [0067]    Methods  
         [0068]    The tests were conducted in temperature-controlled environmental chambers by an independent testing laboratory (Insulated Shipping Containers, Inc., Pheonix Ariz.). Each Nested Cooler System contained an inner cooler with two 8 oz. frozen Polar Packs (Mid-Lands Chemical Company, Inc., Omaha, Nebr.) and three 4-fl-oz. plastic bottles filled with whole cow&#39;s milk. One frozen gel pack was placed upright in each of the two side pockets inside the inner cooler. Each MJ Bag contained a single 16-oz frozen gel pack, that was placed in the bottom compartment of the bag. Three 4-fl-oz milk storage bottles filled with whole cow&#39;s milk were also placed in the bottom compartment, in an upright position on top of the ice pack. Pasteurized whole cow&#39;s milk was used in place of human milk. Since human milk and cow&#39;s milk are similar in osmolality, the thermal properties of the cow&#39;s milk closely approximates those of human milk.  
         [0069]    Each environmental chamber was maintained at a constant temperature during the study. The ambient temperatures selected for the study were 71.6° F. (22° C.),86° F. (30° C.),95° F. (35° C.) and 104° F. (40° C.). All gel packs were stored for a minimum of 24 hours at −0.4° F. (−18° C.) and were immediately placed into the coolers at the start of each test. In addition, the Nested Cooler System and the MJ bag were stabilized at 71.6° F. (22° C.) for a minimum of 24 hours before testing. Each environmental chamber contained three nested cooler systems or three MJ bags: one containing milk initially at freezer temperature 14° F.(−110° C.), the second contained milk initially at refrigerator temperature 39.2° F. (4° C.), and the third contained milk initially at body temperature 98.6° F. (37° C.). Thus, milk at three different initial temperatures was tested in each of four ambient temperatures.  
         [0070]    The temperature of the milk in two of the three bottles in each cooler was monitored over two 8-hour periods. Temperatures were measured by inserting a 6-in. T-shape thermocouple probe (Omega Engineering, Stamford, Conn.) into the midpoint of the milk in each of these bottles. Milk temperature was recorded at the start of each 8 hour test period and every 30 minutes thereafter, generating 17 temperature readings for the milk in the bottle.  
         [0071]    Two eight-hour tests were conducted under the same conditions, and the average of these temperature readings was calculated. The coolers remained closed and were placed randomly within the environmental chambers during the study.  
         [0072]    Results  
         [0073]    The criteria used to evaluate the performance of the two cooling systems were based on studies carried out by Hamosh, et al., “Breastfeeding and the Working Mother: Effect of Time and Temperature of Short Term Storage on Proteolysis Lipolysis and Bacterial Growth in Milk”, PEDIATRICS, Vol. 97, Pages 492-498 (1996). Hamosh, et al., evaluated the safety of stored human milk at various temperatures by assessing the microbial growth and stability of the milk protein and lipid at intervals up to 24 hours. They found that human milk can be stored safely up to 24 hours at 59° F. (15° C.) and for up to four hours at 77° F. (25° C.) but that it should not be stored at 100.4° F. (38° C.). Table 1 lists the mean temperature of the milk after eight hours of storage for each chamber temperature, at each initial milk temperature for the Nested Cooler System and the MJ bag.  
                                                                         TABLE 1                           Milk mean temperature after eight hours of storage in the Nested Cooler       System and MJ bag for each chamber temperature and each milk temperature                    Initial Milk Temperature (° F.)            Environmental       14   39.2   98.6       Temperature (° F.)   Cooler System   (Freezer Temp.)   (Refrigerator Temp.)   (Body Temp.)                    71.6   Nested cooler   30.9   42.2   43.9           MJ bag   35   60.5   59.8       86   Nested cooler   30.4   47.7   54.5           MJ bag   50.9   64.1   67.3       95   Nested cooler   32.2   52.1   60.5           MJ bag   59   72.9   74.3       104   Nested cooler   38.8   61.7   80.3           MJ bag   72.3   78.8   85.8                  
 
         [0074]    The nested Cooler System with two 8-oz. gel packs in the inner cooler performed better than the single compartment MJ bag with larger cooling source (16-oz.) under every condition tested. Table 2 shows the time intervals during the eight-hour test periods in which milk in the cooling systems met the Hamosh, et al., criteria for safe storage (up to 24 hours at 59° F. and up to 4 hours at 77° F.).  
                                                                         TABLE 2                           Cooling capacity study results for the Nested Cooler System and MJ bag       compared to criteria of Hamosh, et at., for safe storage                    Initial Milk Temperature (° F.)            Environmental   Cooler   14   39.2   98.6       Temperature (° F.)   System   (Freezer Temp.)   (Refrigerator Temp.)   (Body Temp.)                    71.6   Nested   &lt;59 for entire 8 hours   &lt;59 for entire 8 hours   &lt;77 after 1 hour           coolers           &lt;59 after 1.5 hours           MJ bag   &lt;59 for entire 8 hours   &lt;59 for 6.5 hours   &lt;77 after 1.5 hour                       &lt;59 at 5.5 to 6.5 hours       86   Nested   &lt;59 for entire 8 hours   &lt;59 for entire 8 hours   &lt;77 after 1 hour           coolers           &lt;59 after 2 hours           MJ bag   &lt;59 for entire 8 hours   &lt;59 for 2.5 hours   &lt;77 after 2 hour                       Never &lt;59       95   Nested   &lt;59 for entire 8 hours   &lt;59 for entire 8 hours   &lt;77 after 1 hour           coolers           &lt;59 at 2.5 to 7 hours           MJ bag   &lt;59 for 7.5 hours   &lt;59 for 2 hours   &lt;77 after 1.5 hour                       Never &lt;59       104   Nested   &lt;59 for entire 8 hours   &lt;59 for 7 hours   &lt;77 at 1 to 7 hours           coolers           Never &lt;59           MJ bag   &lt;59 for 6 hours   &lt;59 for 1.5 hours   Never &lt;77                   &gt;77 after 7.5 hours                  
 
         [0075]    The most challenging conditions for both the Nested Cooler System and the single compartment MJ bag was the cooling of expressed milk with initial milk temperature of 98.6° F. FIG. 6A-D plot the 98.6° F. milk data against the Hamosh, et al., criteria for safe storage. The Nested Cooler System was able to decrease the milk temperature to below 59° F. at all storage temperatures with the exception of the 104° F., while the single compartment MJ bag did not achieve the 59° F. target at n storage temperatures above 86° F. In every chamber the Nested Cooler System more rapidly decreased the milk temperatures than the single compartment MJ bag.  
       EXAMPLE II  
       [0076]    The study as described in Example I was carried out on the inner cooler with one 8-oz frozen gel pack and the outer cooler with two 8-oz frozen gel packs.  
         [0077]    The mean temperature of the milk stored in the inner cooler after eight hours for all chamber temperatures and all time measurements ranged from 26.8 to 29.0° F. for milk that started out frozen (14° F.), from 47.2 to 64.8° F. for milk that started out at refrigerated temperature (39.2° F.) and from 60.9 to 94.0° F. for milk that started out at body temperature (98.6° F.). The mean temperature of the milk stored in the outer cooler after eight hours for all chamber temperatures and all time measurements ranged from 26.1 to 27.2° F. for milk that started out frozen (14° F.), from 43.3 to 58.0° F. for milk that started out at refrigerated temperature (39.2° F.) and from 50.4 to 84.1° F. for milk that started out at body temperature (98.6° F.). Table 3 and 4 shows the time intervals during the eight-hour test periods in which milk stored in the inner or outer cooler met the Hamosh, et al., criteria for safe storage.  
                                                             TABLE 3                           Cooling capacity study results for the inner cooler with one 8-oz       gel pack compared to criteria of Hamosh, et al., for safe storage                Initial Milk Temperature (° F.)            Environmental   14   39.2   98.6       Temperature (° F.)   (Freezer Temp.)   (Refrigerator Temp.)   (Body Temp.)                    71.6   &lt;59 for entire 8 hours   &lt;59 for entire 8 hours   &lt;77 after 1 hour                   never &lt;59       86   &lt;59 for entire 8 hours   &lt;59 for 5 hours   &lt;77 after 1.5 hours                   never &lt;59       95   &lt;59 for entire 8 hours   &lt;59 for 3 hours   &lt;77 after 2.0 hours                   never &lt;59       104   &lt;59 for entire 8 hours   &lt;59 for 2 hours   never &lt;77                   never &lt;59                  
 
         [0078]    The most challenging conditions for the inner cooler was the cooling of expressed milk with initial milk temperature of 98.6° F. FIG. 6E-H plot the 98.6° F. milk data for the inner and outer cooler against the Hamosh, et al., criteria for safe storage. The inner cooler with one gel pack was able to decrease the milk temperature to below 77° F. at all storage temperatures with the exception of 104° F.  
                                                             TABLE 4                           Cooling capacity study results for the outer cooler with two 8-oz       gel packs compared to criteria of Hamosh, et al., for safe storage                Initial Milk Temperature (° F.)            Environmental   14   39.2   98.6       Temperature (° F.)   (Freezer Temp.)   (Refrigerator Temp.)   (Body Temp.)                    71.6   &lt;59 for entire 8 hours   &lt;59 for entire 8 hours   &lt;77 after 1 hour                   &lt;59 after 2.5 hours       86   &lt;59 for entire 8 hours   &lt;59 for 7.5 hours   &lt;77 after 1 hour                   &lt;59 after 3.5 hours       95   &lt;59 for entire 8 hours   &lt;59 for entire 8 hours   &lt;77 after 1 hour                   &lt;59 after 4 hours       104   &lt;59 for entire 8 hours   &lt;59 for 4 hours   &lt;77 after 1 hour               &gt;77 for 0.5 hours   never 59                  
 
         [0079]    The most challenging conditions for the outer cooler was the cooling of expressed milk with initial milk temperature of 98.6° F. The outer cooler with two gel packs was able to decrease the milk temperature to below 59° F. in all chamber temperatures with the exception of the 104° F. chamber.  
         [0080]    However the outer cooler was able to decrease the milk temperature below 77° F. after one hour in the 104° F. chamber. The milk temperature remained below 77° F. until the final hour of the eight-hour test. In every chamber the inner and outer cooler were able to bring the initial milk temperature of 98.6° F. below 77° F. at about the same rates. However, the outer cooler with two 8-oz gel packs out performed the inner cooler alone with one 8-oz gel pack by decreasing the milk temperature to below 59° F. in every chamber with the exception of the 104° F. chamber.  
       EXAMPLE III  
       [0081]    The studies to evaluate the cooling capacity of the nested cooler system when using alternate gel pack sizes (4, 6, 8 oz.) and one or two gel packs followed the study design described in Example I. The variables tested included 1-6 oz. gel pack, 1-8 oz. gel pack, 2-4 oz. gel packs, 2-6 oz. gel packs, 2-8 oz. gel packs inserted in the inner cooler alone or nested within the outer cooler . Table 5 lists mean milk temperatures after eight hours of storage in the inner cooler alone with different gel packs for each chamber temperature and each milk temperature.  
                                                                         TABLE 5                           Milk mean temperature after eight hours of storage in the inner cooler       with different gel packs for each chamber temperature and each milk temperature                    Initial Milk Temperature (° F.)            Environmental       14   39.2   98.6       Temperature (° F.)   Gel Packs   (Freezer Temp.)   (Refrigerator Temp.)   (Body Temp.)                    71.6   1 - 6 oz gel pack   33.2   61.6   64.9           1 - 8 oz gel pack   31.8   59.6   63               2 - 4 oz gel packs   34   60.1   65.1               2 - 6 oz gel packs   33   52.3   57.7               2 - 8 oz gel packs   32   48.7   52.1       86   1 - 6 oz gel pack   48.4   72.7   78.9           1 - 8 oz gel pack   46.4   70.9   78.5               2 - 4 oz gel packs   37.3   72.3   77.3               2 - 6 oz gel packs   36.1   61.7   72.5               2 - 8 oz gel packs   32.6   58   64.8       95   1 - 6 oz gel pack   48.7   77.7   82.9           1 - 8 oz gel pack   47   76.3   81.1               2 - 4 oz gel packs   45.2   76   83.3               2 - 6 oz gel packs   39.9   70.5   79               2 - 8 oz gel packs   38.7   63.6   74.2       104   1 - 6 oz gel pack   70.7   96.2   99.8           1 - 8 oz gel pack   73   94.6   97.3               2 - 4 oz gel packs   65.9   93.3   98.7               2 - 6 oz gel packs   57.1   86.8   92.6               2 - 8 oz gel packs   57.9   75.4   79.9                  
 
         [0082]    [0082]FIG. 6 I-P plot the 98.6° F. milk data for the inner cooler alone and the nested cooler system against the Hamosh, et al., criteria forsafe storage. All the different gel pack combinations decreased the temperature of the 98.6° F. milk stored in the inner cooler, the largest effect on temperature was achieved with the 2-8 oz. gel packs and the least effect on temperature was achieved with 1-6 oz. gel pack. Table 6 lists mean milk temperatures after eight hours of storage in the nested cooler system with different gel packs in the inner cooler for each chamber temperature and each milk temperature.  
                                                                         TABLE 6                           Milk mean temperature after eight hours of storage in the Nested Cooler System with dif-       ferent gel packs in the inner cooler for each chamber temperature and each milk temperature                    Initial Milk Temperature (° F.)            Environmental       14   39.2   98.6       Temperature (° F.)   Gel Packs   (Freezer Temp.)   (Refrigerator Temp.)   (Body Temp.)                    71.6   1 - 6 oz gel pack   32.9   55.1   59.3           1 - 8 oz gel pack   33   53.5   56.7               2 - 4 oz gel packs   32   50.8   57.8               2 - 6 oz gel packs   31.5   44.7   47.6               2 - 8 oz gel packs   30.9   42.2   43.9       86   1 - 6 oz gel pack   38.4   64   73           1 - 8 oz gel pack   31.5   62.1   72.2               2 - 4 oz gel packs   31.6   60.9   68               2 - 6 oz gel packs   32.5   52.7   59.5               2 - 8 oz gel packs   30.4   47.7   54.5       95   1 - 6 oz gel pack   40.6   69.5   77.1           1 - 8 oz gel pack   35.3   65.9   73.8               2 - 4 oz gel packs   35.9   65.9   75.9               2 - 6 oz gel packs   36.1   61.7   65.7               2 - 8 oz gel packs   32.2   52.1   60.5       104   1 - 6 oz gel pack   52   85.6   91.7           1 - 8 oz gel pack   48.9   82   88               2 - 4 oz gel packs   46.4   82.4   89               2 - 6 oz gel packs   39.3   70.8   77.4               2 - 8 oz gel packs   38.8   61.7   80.3                  
 
         [0083]    The Nested Cooler System performed better than the inner cooler alone at every storage temperature. The data split into two groupings upon the addition of the outer cooler. The 1-6 oz. and 1-8 oz. gel pack sample results were similar. While the 2-6.oz. and 2-8 oz. gel pack sample results were similar. The 2-4 oz. gel pack sample results fell between the other two data groupings. Interestingly, the 2-4 oz. gel pack data would start out similar to the two gel pack data and as time passed the data was more similar to the one gel pack data. The additional insulation of the outer cooler diminishes the differences observed between the two single gel pack variables and also between the two double gel pack variables. Consequently, the selection of gel pack size for a desired result is less critical in the nested cooler system.  
         [0084]    As illustrated by the results of the cooling capacity tests in Examples I-III, the inner cooler alone and nested cooler system provide excellent performance by satisfying the Hamosh, et al., criteria for safe storage of breast milk under a broad range of temperatures. The nested cooler system can help health care professionals promote breast feeding by addressing mothers, who are expressing breast milk, concerns about a convenient, safe and reliable storage of the milk. The added convenience of being able to insert the inner cooler in the outer cooler for transport of additional perishable foodstuffs and baby support items makes the nested cooler system suitable for multitasks.  
         [0085]    The invention has been described with reference to a preferred embodiment, obviously, modifications and alternations will occur to others upon a reading and understanding of the this specification. It is intended to include all such modifications and alterations in so far as they come within the scope of the appended claims or the equivalents thereof.