The present invention relates to a tray for use as an underlay for food. More particu- larly, it relates to a preparation or serving tray for food, where the food may be in di- rect contact with a surface of the preparation or serving tray. In what follows, for the sake of simplicity, the description will be directed towards a tray for use when preparing food, a so-called cutting board or chopping board. How- ever, it will be understood that the tray according to the present invention will also include a serving tray or a tray for use in food preparation with no use of cutting uten- sils. A tray that is used for preparing so-called stewing beef, for example, is an exam- pie of a preparation tray that is not exposed to cutting utensils. Another example is a tray on which food is prepared by using the hands, without using utensils, that is.

A tray like that represents a source of bacteria transfer from the tray to the food that is brought into contact with a surface of the tray. So-called cross-contamination be- tween different food products such as meat, fish and vegetables is particularly chal- lenging when the food products undergo no or little heat treatment after preparation.

In some kitchens, to avoid such cross-contamination, dedicated trays are used for different types of food. The trays may be marked with standard colour codes used in the trade, such as red for raw meat, blue for raw fish, green for salad and

fruit/greens, etc. Alternatively, or in addition to colour codes, the tray may be formed with text, symbols or have a design that indicates the intended use.

Independently of said cross-contamination, the tray must be cleaned regularly to dis- infect the tray to prevent the tray from having a bacterial flora that may represent a hazard to consumers of the food that has been prepared on the tray. Particularly un- desirable bacteria are for example Staphylococcus aureus, Salmonella Enteritidis, Escherichia coli 0157 : H7 and Campylobacter which may cause disease in a consumer.

In professional kitchen, such disinfection is typically performed by means of heat

BE treatment in a so-called industrial dishwasher. Such a dishwasher is also called a "steam machine".

However, it may sometimes be difficult to decide whether the heat treatment has been adequate with respect to time and temperature; that is to say, whether the tray has been exposed to a sufficiently high temperature over a given time, or whether the tray has been the object of any cleaning at all.

There is therefore a need for a tray that may provide information on whether a suffi cient heat treatment has been carried out.

From the publication CN 205602313 U, a pallet for storing and transporting goods is known. The pallet is provided with a weighing device to be able to measure the weight of the goods placed on the pallet, and a temperature sensor to be able to measure the temperature of the goods. The temperature sensor and the weighing device are con- nected to a microcontroller, a display and an alarm that is set off if the weight or tem- perature reading exceeds a predetermined value. From the publication EP 2081013 Al, a method of inspecting food by means of NIR irradiation to detect any foreign bodies or to determine the quality of the food is known.

From the publication CN 203519486 U, a hand-held NIR spectrometer for measuring the quality of oranges is known. From the publication CN 106333618 A, a two-layer chopping board made of wood is known, the board having an integrated weight sensor and a display for displaying the weight reading.

The invention has for its object to remedy or to reduce at least one of the drawbacks of the prior art or at least provide a useful alternative to the prior art. The object is achieved through the features that are specified in the description below and in the claims that follow.

The invention is defined by the independent claim. The dependent claims define ad- vantageous embodiments of the invention.

According to a first aspect of the invention, a tray for use in food preparation is pro- vided, the tray being provided with at least a temperature sensor which is arranged to communicate with a reading unit to give information at least on whether the tray has

BE undergone a heat-treatment process that is sufficient to disinfect the tray. By the term "preparation", the serving of food is to be understood as well, as some dishes may be served on the tray on which they have been prepared.

A heat-treatment process is dependent on both time and temperature. In one embod- iment, the temperature sensor may be arranged to register only the temperature and communicate it to the reading unit at given intervals. A reading unit like that is ar- ranged to log the time of receipt of every temperature registered and thus be able to record the heat-treatment process.

The reading unit may be in communication with a condition indicator, such as a dis- play screen and/or a sound-generating unit, which is arranged in association with, for example, a dishwasher for disinfecting the tray. A user may thereby get information on whether the heat-treatment process is sufficient, even while the tray is in the dish- washer. Alternatively, the reading unit may be in communication with a computer, a tablet or a mobile phone provided with suitable software so that the condition of the tray is communicated from the reading unit to a screen that is independent of the dishwasher. In addition, or alternatively to said screen in the dishwasher or said PC, tablet or mobile phone, the reading unit may be in communication with a condition indicator connected to the tray in the same way as the temperature sensor. The read- ing unit may be an integrated part of the temperature sensor; that is to say, the tem- perature sensor and the reading unit are one single part.

Independently of the location of the reading unit, this may be arranged to output a signal as to whether the desired or required heat treatment has been achieved. The signal from the reading unit is preferably transmitted wirelessly to the condition indi cator. The condition indicator may be one of or a combination of a sound indicator and a visual indicator. A visual signal may be based on light, a symbol or written infor- mation that is presented on said screen.

The temperature sensor may be releasably attached to the tray. This has the effect of allowing one temperature sensor to be used for several trays, simply by placing the sensor on the desired tray. In one embodiment, the sensor may also be used for monitoring the temperature in a portion of the food product after it has been fully prepared and until serving takes place.

When such a detachable temperature sensor is used, it is an advantage if the tray is further provided with an identification means such as an RFID (radio-frequency identi-

BE fication) tag which can be read by a reading unit in order to log which tray the tem- perature sensor is being used in.

There are commercially available sensors today that are suitable for use in the present invention. The temperature sensor may be provided with a timer so that the tempera- ture sensor is a temperature logger. An example of such a sensor is a temperature logger which is sold under the trade name Signatrol SL50 by the company Signatrol Ltd in Great Britain.

Alternatively, the reading unit may be provided with a timer.

The temperature sensor may, independently of whether it is arranged to register the temperature or to log the temperature, that is to say both the time and the tempera- ture, be integrated in the tray, for example in a recess in a portion of the tray.

It is an advantage if the temperature sensor or temperature logger is arranged to communicate wirelessly with the reading unit, so that there is no need for cables.

Such wireless communication may be provided, for example, by means of a radio- transmission protocol, like Bluetooth™.

Disease transmitted from a food product to a consumer represents a considerable health burden all over the world. If the freshness of food is monitored before it is served, said disease problems may be reduced. There is therefore a need for a simple system that can be used to accurately assess the freshness of the food. So far, the most common way of assessing the quality of the food product has been based on a visual inspection or a smell test. However, such a visual inspection and/or smell test may be subjective and may lack accuracy and precision. For example, a smell test may be influenced by the user's sense of smell and ambient smells. A visual inspection will only reveal visible portions of the food product. A person skilled in the art will be aware that a bacterial flora develops fastest at tem- peratures between 4,5° and 60 °C. This temperature range is often called the "Danger Zone". In favourable conditions, the number of bacteria doubles every 20 minutes.

To be able to provide an objective analysis of the food product, the tray according to the invention may further be provided with a sensor for detecting characteristics of a food product that is placed on the tray. Characteristics of the food product may, for example, be related to how fresh the food is, the bacteria content, and at least some of the constituents of the food product. In addition, said sensor may be arranged to register a bacterial flora on at least a work side of the tray. It is thus an advantage if

BE the tray is further provided with a sensor for registering at least one of bacterial floras on at least a work side of the tray. In one embodiment, said sensor is further arranged to register characteristics of a food product that is placed on the tray.

A sensor like that, for registering bacterial floras on the tray and/or characteristics of a food product placed on the tray, is based on a spectroscopic analysis of characteristic spectra in the NIR region (NIR = Near Infrared) and will, in what follows, also be re- ferred to as an NIR spectrometer. Measurements taken by means of the NIR spec- trometer are analysed against a database, as will be well known to a person skilled in the art. The database may be integrated in the NIR spectrometer, or the database may be remote from the NIR spectrometer. By such an external database, the NIR spectrometer is arranged to communicate with the database, for example via Blue- tooth™ or the Internet.

The NIR spectra measured by means of the NIR spectrometer will be classifiable with great accuracy according to the day of aging of the food, and by the level of chemical and microbial indicators such as the thiobarbituric acid (TBA - a measurement of ran- cidness of meat), volatile basic nitrogen levels and bacteria levels. Thus, NIR spectros- copy may be used to determine the freshness of meat, fish, vegetables and fruits that are placed on the tray according to the invention.

Said characteristics of a food product may further include traces of antibiotics and other undesired chemical agents that have possibly been added to feeds for animal food products, or crop-spraying agents that have possibly been used in the production of vegetable food products. The characteristics may further include mould fungi and allergens such as nuts.

A person skilled in the art will be aware that an NIR spectrometer may also provide information on the nutritional content and energy content of the food product.

The NIR spectrometer may be detachably attached to the tray, or it may be integrat- edly arranged in a recess in a work side of the tray. By a work side is meant herein the surface on which the food product is placed. An integrated NIR spectrometer is activated by means of an integrated activation device, such as an activation switch. A detachable spectrometer which is suitable for use in the present invention is sold under the trade name NeoSpectra produced and sold by Si-Ware Systems.

The result from measurement performed by means of an NIR spectrometer may, for example, be presented visually on a screen of a PC, a tablet or a mobile phone with

BE software. In a prototype of the invention, the result from such an analysis was pre- sented on a screen of a mobile phone with an application programmed for communica- tion with the NIR spectrometer.

In an embodiment in which the tray according to the invention is provided with both a temperature sensor or temperature logger and an NIR spectrometer, the tray is thus arranged to give the user information on whether the tray has been sufficiently cleaned for further use and information about the food that is placed on the tray.

The above-mentioned temperature sensor and sensor for registering at least one of bacterial floras on at least a functional side of the tray, and possibly characteristics of a food product that is placed on the tray, require electrical energy. Such energy may typically be provided from an energy source such as a battery. The inventors have surprisingly found that the energy may be provided by means of temperature differ ences to which the tray is subjected as it is put into a dishwasher. For this, a so-called thermoelectric generator (TEG), also called a Seebeck generator which is commercially available in the market, may be used. A person skilled in the art will be aware that a TEG is a solid-state unit which converts an amount of heat (temperature differences) directly into electrical energy through a phenomenon called the Seebeck effect (a form of thermoelectric effect). Thermoelectric generators function like heat engines but are less voluminous and have no moving parts. In one embodiment, at least the temperature sensor may be connected to an energy source in the form of a thermoelectric generator. Further, an energy source of the sensor for registering at least one of bacterial floras on at least a functional side of the tray, and characteristics of a food product that is placed on the tray, may be provided with a rechargeable battery which is charged by means of a thermoelectric generator. In one embodiment of the tray according to the invention, it may further be provided with an integrated sensor for weighing the food that is placed on the tray. Thus, the tray according to the invention may be a combination of scales and a chopping board. The sensor may typically be a load cell. Together with the NIR spectrometer, the load cell may give information about the weights of the different constituents of the food. The tray according to the invention may be made from any suitable material, such as a wood-, plastic- or mineral-based material. A tray made of wood, such as wattle wood, teak, bamboo, beech, oak and other kinds of hard wood, is preferred by many because of its functional characteristics. The functional characteristics are related to the inherent "disinfecting" character of the wood and good friction against the product

BE being prepared, which is advantageous in terms of safety. When the food product is being chopped by means of a cutting or chopping tool, a wooden board shows far less "bouncing" of the tool hitting the board than a board made of plastic. Such bouncing is not very desirable. Compared with a plastic board or a mineral-based board, a board made of wood will be gentler to the cutting tool and thus require less frequent sharp- ening of the cutting tool.

In spite of the above-mentioned advantageous characteristics, the use of chopping boards made of wood has decreased over the last 20-30 years, especially in commer- cial kitchens. The cause for the decreasing use is primarily due to the fact that an un- treated wooden chopping board that is repeatedly exposed to moisture and high tem- perature will quickly be ruined or at least deformed so that it is not suitable as a chopping board.

Chopping boards made from a plastic material, for example, are far more resistant to repeated influence by moisture and high temperatures. Such chopping boards are also inexpensive to produce and have therefore been almost supreme in professional, but also in private kitchens in recent years.

However, plastic boards like that have some considerable drawbacks in relation to chopping boards made of wood.

A plastic board that is exposed to a sharp utensil will get permanent pits or scratches inflicted on its surface. It is well known that biological material may penetrate into such pits and that such material may be difficult to remove in a washing operation and may thereby create good conditions for bacterial growth. Biological material may also penetrate into scratches or pits in a wooden board, but enzymes in the wood help to reduce bacterial growth. Even though there will be less bacterial growth in the surface of a chopping board made of wood compared with a chopping board made of plastic, such a wooden board requires regular and thorough cleaning.

Because a chopping board or serving tray made of wood cannot stand repeated clean- ing in a dishwasher, such trays must be scrubbed and washed manually to satisfy hy- giene regulations. A cleaning process like that is time-consuming and resource- demanding. To make wood more resistant to water absorption, two in principle differ ent treatment methods are known. The first method is applying an impregnating agent to the wood, such as oil which is absorbed by the wood. The second method is apply- ing a surface-treatment agent, for example by means of a wax or a varnish. The sur-

BE face-treatment agents that, to the applicant's knowledge, have been used for wood are all diffusion-open.

Wood that is impregnated with oil, for example, may reduce the absorption of liquid to which the wood is exposed during use and during cleaning. However, such an oil will, to a great degree, be leached from the wood when this is exposed to liquid at a high temperature and any fat-soluble detergents. In addition, the wood will be subjected to great temperature fluctuations which turn out to cause cracks in the wood. An im- pregnating agent of the kind mentioned above may, in addition, give flavour to the products that are being made while, at the same time, the friction may be reduced. An impregnating agent that might be used for a chopping board must also be approved for use in contact with an article of food.

Wood that has been treated with a surface agent of the wax or varnish type is not very suitable as a chopping board. This is, among other things, because the surface agent would quickly become perforated by, for example, a knife which is moved against the board, so that liquid may penetrate into the wood.

In one embodiment, the tray according to the present invention is made of wood that has gone through a so-called acetylation process. Since the late 1920s, acetylated wood has been used in wooden structures in the building industry. Chopping boards made of acetylated wood are as suited for repeated machine cleaning as chopping boards made of plastic but are not encumbered with the disadvantages that the plastic trays represent. Radiata pine is particularly suitable for acetylation.

In what follows, examples of preferred embodiments are described, which are visual- ized in the accompanying drawings, in which :

Figure 1 shows a perspective view of a tray according to the present invention, the tray being provided with an integrated temperature sensor and a reading unit placed in a chamber in the tray, and also an NIR spectrom- eter; and

Figure 2 shows a side view of the tray of figure 1 shown partially transparently.

In the figures, the reference numeral 1 indicates a tray according to the present in- vention. The tray is provided with a temperature sensor 3 which is in wireless commu- nication with a reading unit 5. In the embodiment shown, the temperature sensor 3 and the reading unit 5 are integrated in a chamber or a recess 6 in the tray 1.

BE The temperature sensor 3 may be configured with a timer or a time meter so that the temperature sensor 3 is a temperature logger. Alternatively, a time meter may be arranged in the reading unit 5, possibly in an external condition indicator which is shown as a mobile phone M in figure 1. The recess 6 is provided with a removable cover 6a, for example made of rubber which is attached to the periphery of the recess 6 by means of an interference fit.

In figure 1, the reading unit 5 is in communication with a condition indicator 7 which is integrated in the tray 1, shown here in the form of three light sources 7a, 7b, 7c which are arranged to emit light of different colours. For example, the light source 7a may emit red light to indicate that sufficient heat treatment has not been achieved, the light source 7b a yellow light to indicate that sufficient heat treatment is being ap- proached and the light source 7c a green light to indicate that sufficient heat treat- ment has been achieved, that the tray 1 is ready for use, that is.

In the embodiment shown, the reading unit 5 is additionally in wireless communication with an external unit, shown here as a so-called "smart" mobile phone M. The wireless communication is shown as broken lines Ml. The condition or heat-treatment status of the tray 1 is thus shown both in the tray 1 itself and on the screen of the mobile phone M. In an alternative embodiment (not shown), the reading unit 5 may be in communication with, for example, a computer or a tablet on which a status of the heat treatment is presented on a screen which will then be said condition indicator 7. When an external screen is used, the condition may be presented as text, symbols or light, alternatively as a sound signal by means of a loudspeaker connected to the screen. In the embodiment shown, the screen of the mobile phone M indicates that "Status heat treatment" is "OK". In another alternative embodiment (not shown), the reading unit 5 may communicate the result to a condition indicator arranged in association with, for example, a dish- washer for washing the tray. In an embodiment like that, the dishwasher may be pro- vided with a screen and/or a sound-emitting unit to give a user information on wheth- er the heat-treatment process is sufficient, as described above. In embodiments in which the reading unit 5 is in communication with an external con- dition indicator as explained above, the integrated condition indicator 7 of the tray 1 may possibly be omitted; that is to say, the tray 1 may be made without the condition indicator 7.

In the exemplary embodiment shown in figure 1, the tray 1 is further provided with an

BE identification means 10 in the form of an RFID tag that can be read by the reading unit. The purpose of the RFID tag 10 is to enable logging of which tray the tempera- ture sensor 3 is used in.

In the embodiment shown, the tray 1 is further provided with a sensor in the form of an NIR spectrometer 12 for registering at least one of bacterial floras on a work sur- face of the tray 1, and characteristics of any food product (not shown) placed on the tray.

In the embodiment shown, the NIR spectrometer 12 is releasably attached near the periphery of the tray 1 by means of a fastening device 14. The NIR spectrometer is arranged to analyse both a portion of the work surface B of the tray 1 and any food product (not shown) placed on the tray, as indicated by broken "lines of sight" LI and L2, respectively, in figure 2. The NIR spectrometer 12 is provided with a switch 13 for activation of the NIR spectrometer 12.

In an alternative embodiment (not shown), the NIR spectrometer 12 may be tiltably attached to the tray 1 by means of a tilt-mount. In such an embodiment, the NIR spectrometer 12 may be formed with just one "spectrometer eye" instead of the two shown in figure 1. In such an embodiment, the NIR spectrometer 12 is tilted in such a way that the eye is directed towards the work surface B of the tray, or towards a de- sired portion of a food product desirably to be checked. The tilt-mount may be config- ured for tilting the spectrometer 12 around a single tilt axis, or it may be arranged to be tiltable around several axes, for example by means of a so-called ball-head mount.

In one embodiment (not shown), the NIR spectrometer may be partially integrated in the tray 1.

In figure 1, the NIR spectrometer 12 is in wireless communication with the mobile phone M which is also in communication with the reading unit 5. The wireless commu- nication between the NIR spectrometer 12 and the mobile phone M is shown as broken lines M2. Data from the NIR spectrometer 12, for example bacterial floras on the work surface B of the tray 1 and/or characteristics of a food product on the tray 1, are thus displayed on the screen of the mobile phone M. In figure 1, only the display for the heat-treatment status is shown.

The tray 1 is further provided with an integrated sensor for weighing food that is placed on the tray. The sensor is shown here as a load cell 18 of a kind known per se. The load cell 18 is arranged to communicate with the NIR spectrometer 12. In figure 2, the load cell 18 is shown connected to the NIR spectrometer 12 by means of a cable

BE 19, but communication may alternatively be wireless, for example by means of Blue- tooth™.

As the NIR spectrometer measures the percentages of the different constituents of the food, such as fat and proteins, the load cell 18 together with the NIR spectrometer 12 may indicate the weight of the different constituents of the food that is placed on the tray 1.

By the very fact of the NIR spectrometer 12 being releasably attached to the tray 1, it may be removed before the tray 1 is put into a dishwasher, and possibly in a usage situation in which there would be no need for the NIR spectrometer 12. A thermoelectric generator 16 (shown best in figure 1) is arranged in the tray 1 to generate power for the temperature sensor 3.

From the above description, it will thus be understood that the tray 1 according to one embodiment of the invention will give a user very useful information related to the condition of the tray 1 with respect to whether it has been sufficiently cleaned, the bacterial flora before, during and after use, any allergens on the tray, and also infor- mation about the food that is on the tray.

It should be noted that all the above-mentioned embodiments illustrate the invention, but do not limit it, and persons skilled in the art may construct many alternative em- bodiments without departing from the scope of the attached claims. In the claims, reference numbers in brackets are not to be regarded as restrictive.

The use of the verb "to comprise" and its different forms does not exclude the pres- ence of elements or steps that are not mentioned in the claims. The indefinite article "a" or "an" before an element does not exclude the presence of several such elements.

BE