WO2019119167A1 - Device for monitoring the cold chain in frozen or refrigerated products - Google Patents

Abstract

The invention corresponds to a device with internal chambers, in which each chamber contains brine at various concentrations, each concentration being pigmented with a different colour and frozen. The device of the present invention is used for monitoring the cold chain in frozen or refrigerated products.

Description

 DEVICE FOR COLD CHAIN MONITORING IN PRODUCTS

 FROZEN OR REFRIGERATED

Field of the invention.

The present invention is part of the field of conservation of temperature sensitive products, preferably products that require maintenance at low temperatures, and more specifically, the present invention allows to verify, for example, if the cold chain, in the transport of sensitive products at temperature, it has remained.

Background.

The present invention consists of an indicator device to control faults in the cold chain in frozen and refrigerated products. The invention is based on the use of brine at different concentrations, pigmented and frozen, where the different melting points at each concentration correspond to a series of different predetermined temperatures, which allows knowing if the cold chain has been lost in frozen or refrigerated products, through an irreversible change in the hydrophilic substance when dyed by the specific indicator pigment. The invention also comprises a corresponding method of monitoring the maintenance of the cold chain in frozen or refrigerated substances. In order to better illustrate the invention, the present document describes the present invention considering some cases in which it can be applied, however these examples should not be considered as limiting the invention.

In the market there are various substances or products that during their storage, transport and marketing phase require to be kept frozen or refrigerated at low temperatures in order to prevent deterioration and maintain the quality desired by buyers. For the adequate conservation of this type of products, "cold chain" systems are used, which during the entire process of conservation, handling, transport and distribution of the products, maintain the appropriate light and temperature conditions, in accordance with the requirements of each substance or product. Only the correct functioning and the strict compliance of said system allow to assure that a substance is in optimal conditions at the moment of being used or consumed. Cold chain systems are widely used in the food and pharmaceutical industry, where perishable substances are used, such as frozen foods, vaccines, biological products (nucleic acids, commercial enzymes, cell lines, etc.) and medicines, among others. For example, foods such as beef or fish can be Keep one year or six months, respectively, if they are kept frozen at temperatures of about -18 ° C, while, if they are kept frozen between 0 ° C and 8 ° C, their preservation does not go beyond 2-3 days. For example, the Sanitary Code of Chile and the Sanitary Food Regulation define a frozen food as that which has been brought to a temperature of -18 ° C in its thermal center and establishes that the temperature may rise for brief periods to -15 ° C during interurban transport and never rise from -12 ° C during local transport and distribution to retailers and offer to the public. Therefore, it is very useful to have systems that detect if, at a certain point, the cold chain has been broken, and even know how long the product has been standing outside the freezer, exposed to room temperature.

Several useful systems have been described as temperature indicators for the control of faults in the cold chain, most of which base their operation on physical or chemical processes that cause an irreversible color to appear, indicating visually and directly that the critical temperature It has been exceeded. To evaluate the merits of the invention described in this document, a brief summary of the most relevant documents present in the art is presented. Among the most relevant documents include CN104501994A, W02010109023A1 and CN205738798U. In all three cases, the technology is based on the phase change (fusion) of a component at a certain temperature and an irreversible change of an indicator. In CN104501994A a device is described which comprises, among others, a material that changes phase with temperature, and due to that change an alteration occurs in another part of the device corresponding to an indicator. In the case of document CN205738798U a box is described which has several internal chambers filled with pastes that react to the temperature. The change in temperature generates an alteration in the pastes which works as an indicator. Other related documents are CN204330175U, WO2013132121 A1, EP24131 18A1, EP0606033A1, FR2678373A1 and EP0501880A1 which also use the phase change of a component as a basis for monitoring faults in cold chain systems.

Brief description of the Figure

Figure 1 shows images of the described experiment illustrating the appearance of the sensors 6 minutes (panel on the left), 25 minutes (center panel) and 40 minutes (panel on the right) after having removed the product from the freezer. At the bottom of the panels are two electronic devices that indicate the time, the external temperature and the ambient humidity (device on the left), and the internal temperature and humidity of the corn pack (device on the right). In the upper part of the panels you can see the bag with frozen corn and the prototype device inside them with the active faces upwards from the temperature sensor. After 6 minutes of breaking of the chain of trio (panel of the left) both sensors are fundamentally white. After twenty-five minutes, when the central temperature of the corn is -12 ° C, the most sensitive chamber (the circle on the left) shows a substantial fraction of its colored surface, approximately half, while the least sensitive of the Right is beginning to color. After 40 minutes, when the indoor temperature has risen to -9.4 ° C, both chambers are almost completely stained.

BRIEF DESCRIPTION OF THE INVENTION

The invention corresponds to a device with internal chambers in which each chamber contains brine in different concentrations, each concentration pigmented with a different color and frozen. Each brine concentration has a different melting temperature and it is thawed at a certain temperature, the lower the salt concentration. If the device is exposed to room temperature the brine crystals will defrost at different speeds. The brines with more concentration will become liquid faster than those with less concentration. Each brine chamber, totally or partially fused, will allow the marking of the hydrophilic substance with its specific pigment. A moderate exposure of the product at room temperature will activate the most sensitive chambers and an extensive one will activate, in addition, progressively, the brine crystals that are more resistant to temperature. The embodiment of the invention has several possibilities.

The control device of the present invention is based on the irreversible transformation of the appearance of the hydrophilic substance when colored by the specific pigments of the brines as they reach their determined melting temperature. The dyeing of the hydrophilic substance indicates visually and directly that the substance, or product, has been exposed for a considerable time at temperatures higher than those required for its optimal preservation. The invention also comprises a corresponding method of monitoring the maintenance of the cold chain in frozen or refrigerated substances, according to the progressive dyeing of the different chambers of the device.

Detailed description of the invention

The present invention relates to a monitoring device to verify if the temperature in a container has been maintained within pre-established ranges. In particular, the monitoring device is focused on detecting failures in cold chains, particularly during transport or storage of frozen or refrigerated products. In a more specific embodiment, the frozen or refrigerated products they can be food, medicines, or any other product that requires maintaining a controlled freezing or cooling temperature. The device further comprises a hydrophilic material, and a support frame that holds all internal chambers together in the same device, and where each internal chamber is hermetically separated from the other chambers.

In a first aspect, the invention corresponds to a monitoring device to verify if the temperature in a container has been maintained within pre-established ranges.

In a specific embodiment, the device contains at least one internal chamber. In a preferred embodiment, the device is subdivided into at least two internal chambers, and in an even more preferred embodiment, the device is subdivided into at least three internal chambers. In a more general embodiment, the device can be subdivided into as many internal chambers as desired, where the number of cameras allows a more sensitive indicator regarding the ranges of temperature and / or time that the monitored container has been exposed.

In a specific embodiment of an internal chamber of the device, it is considered that a brine solution is present at a certain concentration, pigmented with different colors according to the concentration, and frozen.

In another embodiment, in the event that the device of the invention has more than 1 internal chamber, each of the chambers may contain a brine solution at a brine concentration which may be different from the other internal chambers. In a specific embodiment, more than one chamber could contain an identical brine and pigment, so that both chambers can act as control.

In yet another embodiment, when the device comprises more than 1 internal chamber, the concentrations of brine and pigments in each may be different, preferably, in increasing concentrations of brine, where each pigment associated with each concentration of brine allows the user to quickly identify if the monitored container has been subjected to a cut in the cold chain that could have affected the quality of the frozen or refrigerated product.

In a specific embodiment, the brine concentrations present in each internal chamber of the device have certain melting temperatures (solid to liquid phase change) determined. In a specific embodiment, the melting temperature of the pigmented brine inside the inner chamber can be tuned at will making the brine crystals more or less resistant to exposure at room temperature.

In another embodiment of the invention, the device has a face of transparent material that allows observing the state of each of the internal chambers present in the device.

In another embodiment, a hydrophilic substance that functions as an irreversible indicator of exposure to heat, is located between the interior of the internal chamber and the face of transparent material, so that when the contents of an internal chamber are fused, the pigment is adsorbed on the hydrophilic substance, allowing the observation of said change from the outside, thanks to the face of transparent material.

In a particular embodiment, if the device of the invention is exposed to temperatures higher than those of the cold chain for a prolonged time, the different brine ices will reach their specific critical temperatures (their melting points) and begin to thaw. The appearance of the colored liquid phases in each chamber of the device will produce the dyeing of the hydrophilic substances with their specific pigment. Brittle brine crystals will liquefy faster and faster, and their respective hydrophilic sensors will be marked more quickly than those of the most heat-resistant crystals in the environment. If the product is frozen again, the strongest sensors will be unmarked, but the most sensitive ones will be irreversibly colored, even if all the brines are frozen again.

In a preferred embodiment this device is used to monitor the cold chain system of frozen or refrigerated products.

In a preferred embodiment, the monitored products correspond to food, pharmaceutical products and biological material, among others.

In a preferred embodiment, the products to be monitored are frozen and / or chilled foods such as different types of meat, fruits, vegetables and dairy products, among others.

In another preferred embodiment, the products to be monitored are pharmaceutical products such as vaccines.

In another preferred embodiment, the products to be monitored are biological material such as commercial enzymes, nucleic acids, living cells or tissues, among others. In a particular embodiment, the device is packaged together with each product that must remain in cold chain.

In another particular embodiment, the device remains inside the final or commercial package of the product until its arrival to the final consumer.

EXAMPLES

In order to illustrate the device of the present invention, a specific example is described, which should not be considered as limiting the scope of the invention.

The device developed as an example of embodiment corresponds to a rectangular tray of light plastic having two cylindrical chambers of approximately 3 cm in diameter and 0.3 cm in depth, providing a volume of approximately 2.1 cm ³ each. One of the chambers contains brine dyed yellow and frozen. The other chamber contains distilled water dyed red and frozen. Tinctures were used edible dyes commonly used in baking. The ice is exposed by one of the circular faces of the cylinder and on these faces the hydrophilic material rests. In the case of this example, said hydrophilic material consisted of layers of tissue paper. The hydrophilic material was kept in close contact with the ice by resting on it a frame of the same light plastic of the tray with circular holes of approximately 3 cm in diameter, located solidly on each of the two cylindrical chambers mentioned above. All this set was introduced in a small transparent plastic bag closed with metal pressure clamps. This device was inserted inside a bag of frozen corn kernels, of habitual presence in supermarkets, in such a way that the hydrophilic material was visible through the plastic, and the bag of corn with the device was left in a freezer. family use for several hours, allowing you to reach an equilibrium temperature. The bag of corn was equipped with a digital thermometer to control the temperature in its center.

The example performed consisted in removing the bag of corn with the sensor device and leaving it at room temperature while monitoring the changes in the appearance of the hydrophilic substance and the internal temperature. In various embodiments of the experiment some parameters were varied. In the device itself, 3, 4 or 5 layers of tissue paper were used, and concentrations of 1, 5 and 2.8 g of NaCl in 100 cc of distilled water were used in the brine crystal. The initial equilibrium temperature for the product inside the freezer was also allowed to vary between -26 and -17 ° C and the ambient temperature between 21 and 24 ° C. The chosen colors are intended to make an analogy with the lights of a traffic light: That the Yellow sensor that is totally or partially colored indicates a moderate exposure to environments outside the cold chain, possibly within the limits allowed by the regulation (temperature lower than -12 ° C). The yellow sensor is completely colored and the partially colored red indicates that this limit has probably been violated. Finally, the fact that the red sensor is completely colored indicates that the exposure to ambient temperature outside the cold chain was greater than that allowed by regulation and that the temperature in the center of the package probably rose above -12 ^o C. T abla 1 describes the variation of the colored surface of the sensors for an experiment made with concentrated yellow brine at 1.5 g of NaCl in 100 cc of H ₂ 0, hydrophilic substance consisting of 5 layers of tissue paper, initial temperature of equilibrium of -17.4 ° C, external temperature of 21 ° C, approximately. The table indicates the percentage of colored area in each of the sensors as the time elapses when the product is outside the cold chain and exposed to the ambient temperature, and the temperature in the center of the corn package. The image includes photos of the experiment at three different times (see description of the figure).

The variation of the results shown in Table 1 as a function of changes in the available adjustment parameters is intuitively easy to understand. By increasing the salt concentration, the crystal becomes more sensitive to temperature and the sensor is colored faster. Increasing the volume of hydrophilic substance increases the thermal insulation between the external medium and the sensor, so the fusion occurs more slowly. It also takes more volume of liquid to dye the same fraction of surface, so both effects contribute to make a sensor more resistant to exposure. Increasing the external temperature increases the heat transfer to the interior of the sensor and the colored surface grows faster. And by increasing the initial equilibrium temperature of the product inside the freezer the brine crystals will start with less capacity to incorporate heat before starting to melt, so the sensors are more sensitive and will color faster. In any case, for the variations of initial parameters controlled in this experiment, exposures of between 10 and 20 minutes resulted in a coloration between partial and total of the yellow sensor and an interior temperature close to the upper limit of -12 ° C, while exposures between 20 and 40 minutes resulted in a coloration between partial and total of the red sensor and indoor temperatures two or three degrees above the -12 ° C limit.

The food industry provides a wide variety of products in different types of packages. Each of these will have different thermal inertias so it is necessary to adapt the sensors to each presentation. But this can be done very easily by varying the salt concentration, the area of the exposed sensor, the thickness of the layers of hydrophilic substance, or the shape of the brine crystal itself.

Claims

1. Monitoring device to verify if the temperature in a container has been maintained within pre-established ranges, in particular to detect failures in cold chains, particularly during transport or storage of frozen or refrigerated products, CHARACTERIZED because the device contains at least one internal chamber, wherein said internal chamber contains a solution of brine at a certain concentration, pigmented with different colors according to the concentration, and frozen; a hydrophilic material; and a support frame that holds all internal cameras together in the same device, and where each internal chamber is hermetically separated from the other cameras. Device according to claim 1, characterized in that the device is subdivided into at least two internal chambers, and in an even more preferred embodiment, the device is subdivided into at least three internal chambers.  3. Device according to claim 1, CHARACTERIZED because the device can be subdivided into as many internal cameras as desired, where the number of cameras allows a more sensitive indicator with respect to the temperature and / or time ranges that the monitored container has been exposed. 4. Device according to claim 1, characterized in that in the case that the device of the invention has more than 1 internal chamber, each of the chambers can contain a brine solution at a concentration of brine that can be different. of the other internal cameras.  Device according to claim 4, CHARACTERIZED because more than one chamber could contain identical brine and pigment, so that both chambers can act as control.  Device according to claim 1, characterized in that when the device comprises more than 1 internal chamber, the concentrations of brine and pigments in each may be different, preferably, in increasing concentrations of brine, where each pigment associated with each concentration brine allows the user to quickly identify if the monitored container has been subjected to a cut in the cold chain that could have affected the quality of the frozen or refrigerated product. Device according to claim 1, characterized in that the brine concentrations present in each internal chamber of the device have certain melting temperatures (change of solid phase to liquid). Device according to claim 1, characterized in that the device has a transparent material face that allows observing the status of each of the internal cameras present in the device.  9. Use of a device as described in the preceding claims, CHARACTERIZED because it is to monitor the cold chain system of frozen or refrigerated products.  10. Use according to claim 9, CHARACTERIZED because the monitored products correspond to food, pharmaceutical products and biological material.