Abstract:
Food safety can be enhanced by applying a temperature indicating element to packaging for a food product. The element can be applied before or after the food product has been inserted into the packaging. The color of the element indicates if the temperature of the packaged food product has rise to an unsafe level, and/or, has stayed at or above that level for a predetermined time interval.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention pertains to food safety devices and methods. More particularly the invention pertains to temperature responsive indicators affixable to food products.  
       BACKGROUND OF THE INVENTION  
       [0002]     Food products such as frozen foods, dairy products, various types of juices and the like generally must be stored at a temperature below a predetermined value to maintain product freshness and safety. In this regard, it is undesirable to have food products of the type noted above exposed for any significant period of time to temperatures above their safe storage temperature.  
         [0003]     While food product packages including the containers for fluids such as milk or juice, frozen food containers or the like usually contain or carry a date after which the product is preferably not to be sold, such packaging does not usually carry any indicators as to temperatures that the food product might have been subjected to in transit or while at the respective retail outlet.  
         [0004]     From the point of view of consumers, as well as the food product merchandisers, there are benefits to being able to recognize, ahead of time, where one or more food products might have deteriorated due to temperature. For example, if a case of frozen food product was left out of the freezer for an extended period of time, more likely than not the vendor would want to remove those food products from inventory to avoid inadvertent sales or other distribution to retail customers.  
         [0005]     There continues to be a need for food product packaging which would not only carry a “sell by” date but also would carry an indicator of any excessive temperature to which the respective food product had been subjected to subsequent to manufacture and before final sale. Preferably such indicators would be irreversible such that if the food product warmed to a temperature above the storage temperature and then was cooled again, the indicator would not revert to its initial color. It would also be preferable if such indicators could be incorporated into food product packaging with minimal additional cost.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1A  is a side elevational view of an exemplary product in accordance with the invention;  
         [0007]      FIG. 1B  is a top plan view of a different type of product in accordance with the invention;  
         [0008]      FIG. 2A  is a top plan view of a roll of temperature responsive material usable on the product packaging of  FIG. 1A  or  FIG. 1B ; and  
         [0009]      FIG. 2B  is a side elevational view of the roll of material of  FIG. 2A . 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0010]     While this invention is susceptible of embodiment in many different forms, there are shown in the drawing and will be described herein in detail specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated.  
         [0011]     A material which embodies the present invention makes a one-time change between two readily distinguishable colors when the material experiences a temperature drop below a set point and subsequently the temperature of the material rises back above set point. A coating of the material can be placed directly on product packaging. Alternately, material in accordance with the invention can be deposited on a layer which could also carry a layer of adhesive or directly on a layer of adhesive material.  
         [0012]     In one aspect of the invention, a multilayer product can include a layer of temperature responsive material, deposited onto an inert elongated body layer which also carries a layer of adhesive. This embodiment of the invention can exhibit an elongated tape-like shape which can be wound onto a core forming a dispensing roll.  
         [0013]      FIG. 1A , a side elevational view of a container of a liquid food product  10 , for example milk, juice or the like, carries a dispensing or pouring region of a conventional type  12 . The container  12  also carries product and brand information of a conventional type  14 .  
         [0014]     In accordance with the invention, the container  12  also carries a temperature sensitive material  20 . The material  20  can be deposited directly onto the container  10 . Alternately, the material  20  can be applied to an inert underlying base layer which carries an adhesive layer. The base layer and material  20  can be attached to the container  10 .  
         [0015]     While the material  20  is illustrated with a rectangular shape, neither shape nor position are limitations of the invention. For example, as an alternative, an arbitrarily shaped deposit  20 ′, shown integral with the product and brand information, could be used.  
         [0016]     The material  20  exhibits first and second readily discernible colors. Preferably, material  20  exhibits a first color at room, or processing temperature and retains that color, from normal room or processing temperature, to a lower temperature of a value compatible with the food product carried by the container  10 . For example, the material  20  could exhibit a first color, assuming the food product was milk or juice, throughout the entire time that the container of milk or juice  10  was filled, sealed and was kept at or below a safe storage temperature. Similarly, the material  20  could be applied to other types of non-frozen food products which need to be kept at a relatively low temperature.  
         [0017]     The material  20  irreversibly changes to a second, different color in response to rising above a safe storage temperature for the respective food product, milk or juice in this example. The second color provides an indication to consumers that the product  10  has risen to a temperature above the safe storage temperature. The irreversible nature of the color change continues to inform the consumer even when the temperature of the product  10  has been subsequently reduced to the safe storage region.  
         [0018]      FIG. 1B  is a top plan view of another food product package  30 , which, for example could contain a frozen food product such as frozen juice, a frozen dinner, a frozen dessert or the like. The product  30  includes an appropriate form of container  32  which contains the food product as well as product and brand information  34 .  
         [0019]     The container  32  also carries a circular temperature responsive region  40  which exhibits a first color when initially produced and throughout the entire time that the product in package  30  remain at a safe storage temperature, preferably below freezing. If the packaging  30  increases in temperature above a safe storage temperature, for example freezing, the material  40  will permanently change color and exhibit its second color indicative of the product  30  having been exposed to temperatures above the safe storage temperature.  
         [0020]     It will be understood that, as an alternate, the temperature responsive material can be provided in any arbitrary shape or location on container  32 . For example, material  40  can be integrated with product/brand information  34  in a shape compatible therewith.  
         [0021]     Relative to both the products  10  and  30 , the consumer can readily ascertain whether the product has been continuously maintained at or below its safe storage temperature by viewing the respective material  20 ,  20 ′ or  40 ,  40 ′. Since the material  20 ,  20 ′ or  40 ,  40 ′ exhibits a one-time color change in response to rising above its predetermined safe storage temperature, the consumer can immediately ascertain which packages of product can be expected to be safe for consumption.  
         [0022]      FIG. 2A  is a top plan view of a roll  50  of a representative form of a temperature sensitive material, such as the material  20 .  FIG. 2B  is a side elevational view of the roll  50  of  FIG. 2A .  
         [0023]     The roll  50  is formed with an inert elongated base layer  52 . The layer  52  can be formed of any material, such as paper or resin, acceptable for use in connection with food products. It will be understood that the exact characteristics of the layer  52  are not a limitation of the present invention.  
         [0024]     The layer  52  carries an adhesive layer  54  for attachment to a food product container such as containers  12  or  32 . The layer  54  also carries temperature sensitive material  56  which, as described above, exhibits a first color when manufactured and when exposed to an acceptable food storage temperature, dependent upon the type of food product associated with the material  56 . That material exhibits a second and permanent color in response to the temperature thereof rising above the safe storage temperature of the respective food product.  
         [0025]     Those of skill in the art will also understand that the adhesive  54  and material  56  could be mixed and deposited directly on the container  12  in an alternate embodiment, in a circular shape, corresponding to the shape  40  on the container  32 , or in any other shape. If desired, the material  56  could be applied, whether carried on a layer  52  or directly as described above, in a decorative shape to blend into and be compatible with the product and brand information  14  or  34 .  
         [0026]     The shapes  20 ,  40  could be formed spaced apart on a release layer. It will be understood that all such configurations come within the spirit and scope of the present invention.  
         [0027]     In summary, the temperature sensitive material  56 , which could be placed on product packaging in exemplary form  20 ,  20 ′ in  FIG. 1A  or could be placed on product packaging in exemplary form  40 ,  40 ′ presents to the consumer a readily ascertainable indicator that the respective food product has been consistently stored at or below its safe storage temperature. Once the temperature sensitive material experiences a temperature in excess of the safe storage temperature of the respective food product it exhibits a permanent color change thereby informing the consumer that the respective package should not be purchased.  
         [0028]     In an alternate embodiment, the temperature sensitive material can be configured to spell out a warning, such as “spoiled”, or “do not use”. In yet another embodiment, the temperature sensitive material can surround letters of a warning word or phrase. In this embodiment, if the temperature sensitive material changes color, the warning word or phrase will appear in the initial color surrounded by the second, temperature responsive color.  
         [0029]     From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.