WO2017097684A1

WO2017097684A1 - A system and method for determining the freshness of a food item, and a configuration method

Info

Publication number: WO2017097684A1
Application number: PCT/EP2016/079693
Authority: WO
Inventors: Weihua LU; Ya Fang JIN; Weimin Xiao
Original assignee: Koninklijke Philips N.V.
Priority date: 2015-12-11
Filing date: 2016-12-05
Publication date: 2017-06-15

Abstract

A system for determining the freshness of a food item comprises an input for receiving a sensed pH level of the food item and a controller for comparing the sensed pH level with reference information which comprises at least a lowest pH level for the food item or expected for the type of food for which the food item is a sample, thereby to determine a level of freshness of the food item. This system enables the freshness of a food item to be determined based on a pH measurement. It is based on the realization that certain food items experience an increase in pH level during the decay process, which starts from a lowest level. The system can be used in the trade, for example to prevent spoiled food reaching the customer, or by consumers. In particular, it does not need complex measurement or analysis.

Description

A system and method for determining the freshness of a food item, and a configuration method

FIELD OF THE INVENTION

This invention relates to a system and method for determining the freshness of a food item, and a configuration method.

BACKGROUND OF THE INVENTION

It is well known that it can be dangerous to eat food which is no longer fresh. For some food items, it is easy to tell visually when the food item has perished, or tasting a small sample can give a reliable indication. However, for other food items, the safety of consuming a food item is not easy to determine either visually or from tasting a sample.

There is therefore a need for a system which can sense food freshness, but there is no existing practical solution. There is thus an unmet customer need for a freshness sensing system.

Investigations show that meat, fish and dairy products have the greatest need for freshness sensing. Two possible problems arise from not knowing if food is still fresh enough to be eaten.

One problem is that many people become sick due to the consumption of spoiled food. The other is that a lot of food that is still edible is simply wasted just because it exceeds a specified expiration date or else the consumer is simply not sure about its freshness level.

If food freshness could be evaluated in a simple way, it could provide significant benefit for both health and for the reduction of food waste.

Total volatile basic nitrogen (TVB-N) and total viable bacteria concentration (TVC) are known direct indicators of meat or fish freshness. However, the measurement of these parameters is destructive and can only be measured by a professional operator in a laboratory, and it requires a relatively long time. These measures are thus not suitable for onsite test or consumer use.

The measurement of TVOC (total volatile organic compounds) can be made but the traditional method for TVOC which is performed in an open space would not meet a sufficient LOD (limit of detection). There is also no known suitable correlation between TVOC and food freshness.

Thus, there remains a need for a suitable testing method to objectively determine food freshness quickly that can be used by consumers and by the trade.

SUMMARY OF THE INVENTION

The invention is defined by the claims.

According to examples in accordance with an aspect of the invention, there is provided a system for determining the freshness of a food item, comprising:

an input for receiving a sensed pH level of the food item; and a controller for comparing the sensed pH level with reference information which comprises at least a lowest pH level for the food item or expected for the type of food for which the food item is a sample, thereby to determine a level of freshness of the food item.

This system enables the freshness of a food item to be determined based on a pH measurement to obtain a sensed pH level. It is based on the realization that certain food items experience an increase in pH level during the decay process, which starts from a lowest level. The system can be used in the trade, for example to prevent spoiled food reaching the customer, or by consumers. In particular, it does not need complex measurement or analysis, since it makes use of reference information (the lowest pH level) which enables eventual determination of the freshness to be carried out in a simple manner. The lowest pH level may be determined for each food item. This may be based on an average value expected from the particular type of food. Alternatively, it may be based on a measured value for an actual food item, for example measured in the slaughterhouse in the case of a meat food item. The value may then be stored on packaging associated with the food item, such as in a barcode or in an RFID tag.

The system may further comprise a database which stores the pH difference threshold or the sensed pH level threshold in respect of different types of food item and /or a lowest pH level for the type of food for which the food item is a sample. The pH difference threshold or the sensed pH level threshold is used to enable a mapping between the sensed pH level and a freshness indication, and there are different thresholds for different types of food. By storing or taking account of expected lowest pH values, this avoids the need to obtain a measured lowest pH value for each individual food item - instead comparison with the database is used based on the food item type (e.g. what kind of animal, what particular meat cut, what slaughter method etc.).

In one method, the controller is adapted to determine a difference between the lowest pH level for the food item or expected for the type of food and the sensed pH level, and determine a level of freshness based on the determined difference. The difference in the sensed pH to the lowest pH level may thus be used as the measure of freshness, by comparing the difference with the pH difference thresholds. This method thus involves calculating a difference between the sensed pH level and the lowest pH, and then comparing it with one or more thresholds.

In another method, the controller is adapted to compare the sensed pH level with a pH threshold based on the lowest pH level for the food item or expected for the type of food for which the food item is a sample and a pH difference threshold in respect of different types of food item. This method is essentially the same - but instead of calculating a difference pH level, the sensed pH level is simply compared with a threshold which itself takes account of the lowest pH level and the threshold for the pH difference.

These are two slightly different methods for implementing the same method - one involves comparing a difference value with a pH difference threshold, and the other involves comparing a sensed value with a pH level threshold (and the threshold itself takes account of the difference to the lowest pH level).

The controller may be adapted to apply at least two thresholds to the pH difference or to the sensed pH level, thereby to determine a fresh status, a semi- fresh status and a spoiled status.

By applying different thresholds, different freshness indications may be made, so that a user can make the best judgement about the nature of the food item.

Each type of food may comprise a particular flesh portion for a particular species of animal.

The flesh portions may comprise different muscles, or different organs of the animal. The animals may be mammals or fish, for example beef, pork, horse and different fish species.

Each particular food item may also take into account the slaughter method.

The slaughter method may for example be stored as data associated with the food item, for example as information stored in a barcode on the packaging. The information may for example include the name of the manufacturer (the slaughter house), the slaughter method, the lowest pH level when this has been measured as part of the slaughter and preparation process, and the food type. In this way, the system may obtain information about the food item in an automated way.

The system preferably further comprises a pH sensor for sensing the pH level of the food item. In this case, the overall system includes the data analysis and processing part as well as the pH sensing part. However, the two parts may be manufactured and sold separately.

Thus, different parts of the system may be implemented in different units. For example, a database may be a remote database, to which data is sent by the pH sensor. The controller may be implemented at the remote database or at the device which includes the sensor. The remote database may for example be a portable device such as a smartphone or tablet on which an app is loaded, or it may be a remote central server. Alternatively, the whole system may be implemented as a single device.

The system may comprise a hand held device in which the pH sensor comprises a probe, and the device comprises:

an input interface to enable input of the type of food being tested and optionally also the lowest pH level as measured for the particular food item; and

an output interface for providing a freshness indication to a user.

This provides a simple way to use hand held probe device. The output interface may be a display such as a screen or a sound system, but it may equally be a wireless transmitter for sending a signal to another device, such as a smart phone or tablet of the user. The input to the device may be manually input by the user, or it may be

automatically input for example by reading a barcode.

The invention also provides a hand held device for determining the freshness of a food item, comprising:

a pH sensor for sensing the pH level of the food item;

a transmission module adapted to transmit the sensed pH level to the system as defined above (when it does not have an integrated pH sensor).

This aspect relates to a probe system which sends sensed pH information to a system which then interprets the pH information to determine the freshness of the food item.

Examples in accordance with another aspect of the invention provide a method for determining the freshness of a food item, comprising:

sensing a pH level of the food item; and comparing the sensed pH level with reference information which comprises at least a lowest pH level for the food item or expected for the type of food of which the food item is a sample, thereby to determine a level of freshness of the food item.

The method may comprise:

determining a difference between the sensed pH level and the measured or expected lowest pH level, and for example applying at least two thresholds to the determined difference, thereby to determine a fresh status, a semi- fresh status and a spoiled status; or comparing the sensed pH level with a pH threshold based on the lowest pH level for the food item or expected for the type of food for which the food item is a sample and a pH difference threshold in respect of different types of food item.

The reference information for example comprises pH difference thresholds and optionally also the lowest pH level expected, for a plurality of types of food, wherein the types of food include particular flesh portions for a particular species of animal. Different cuts of meat may degrade differently, and they can thus be analysed using different data.

The method for example comprises:

a user providing an input to a hand held device to identify the type of food for which the food item to be tested is a sample; and

the user applying a pH sensor probe of the hand held device to the food item to be tested; and

the hand held device providing an output which provides a freshness indication.

This defines the way the user operates the device. The data processing to determine the freshness indication may be performed in the device or remotely. The user input to the device may be manual using an input interface (such as a touch screen or keypad) or it may be by scanning a barcode or RFID tag in the packaging of the food item.

Examples in accordance with another aspect of the invention provide a method of configuring a system for determining the freshness of a food item, the method comprising:

sensing a pH level of a food item which is a sample of a particular type of food, wherein the particular type of food is a particular flesh portion for a particular species of animal, wherein the sensing is conducted at a plurality of times after the slaughter of the animal;

measuring a total volatile basic nitrogen level or a total viable bacteria concentration for the food item at the plurality of times; determining a lowest pH level expected for the particular type of food for which the food item is a sample;

calculating a difference pH level which is the difference between the pH value of the food item and its lowest pH value;

determining a correlation between the volatile basic nitrogen level over time or the total viable bacteria concentration over time and the difference pH level over time; and from the determined correlation, deriving at least one threshold for the pH difference level or for the pH level, wherein the threshold is for use in determining a level of freshness of other food items which are samples of the same particular type of food.

This method for example enables a database to be created, which then enables a simple conversion from a sensed pH level of a food item to a determination of the level of freshness. Determining a correlation may for example comprising fitting a line or polynomial curve of best fit to the measured TVB-N or TVC and the pH difference levels. The thresholds may then comprise the conversion from particular TVB-N or TVC levels to the corresponding pH difference levels as determined by the line or curve of best fit.

The method is for example conducted for a plurality of different particular types of food, and for each particular type of food a plurality of samples are analysed.

The method may comprise deriving at least two thresholds of the pH difference level, for use in determining a fresh status, a semi-fresh status and a spoiled status.

The data processing used by the system and method may be implemented by a computer program.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the invention will now be described in detail with reference to the accompanying drawings, in which:

Fig. 1 is used to explain how meat changes after slaughter;

Fig. 2 shows how a pH level varies after slaughter;

Fig. 3 shows how the pH changes vary for different animals and different meat cuts;

Fig. 4 shows a calibration method and a freshness sensing method;

Fig. 5 show the pH difference that is used;

Fig. 6 shows the correlation between the pH difference level and freshness for a first experiment;

Fig. 7 shows the results of the first experiment applied to other samples; Fig. 8 shows the correlation between pH difference level and freshness for a second experiment;

Fig. 9 shows the results of the second experiment applied to other samples;

Fig. 10 shows a hand held system for freshness sensing; and

Fig. 11 shows generally the architecture of a computer for implementing the control aspects of the system.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The invention provides a system for determining the freshness of a food item, comprising an input for receiving a sensed pH level of the food item and a controller for comparing the sensed pH level with reference information which comprises at least a lowest pH level as measured for the food item or as expected for the type of food for which the food item is a sample, thereby to determine a level of freshness of the food item.

This system enables the freshness of a food item to be determined based on a pH measurement. It is based on the realization that certain food items experience an increase in pH level during the decay process, which starts from a lowest level. The system can be used in the trade, for example to prevent spoiled food reaching the customer, or by consumers. In particular, it does not need complex measurement or analysis.

To understand how a pH measurement enables food (and in particular meat/fish) freshness to be determined, an understanding of the process of processing meat (or fish) is required. The muscle-to-meat conversion takes roughly 24 hours, in which three stages can be distinguished:

Exsanguinations (blood removal);

Rigor mortis (decline in muscle pH);

Autolysis (self-digestion of the muscle cells) and protein degradation.

After slaughter, the blood is removed from the body and circulation stops. As a consequence, different processes start.

The conditions inside the muscle switch from aerobic (sufficient oxygen) to anaerobic (no oxygen). In life, the oxygen is used in the reaction:

glycogen + 02→ C02 + H20 + ATP (energy)

In death:

glycogen→ lactic acid.

Due to lactic acid formation the pH will drop and reach a limit value. This glycogeno lysis period occurs in slaughterhouse and the time needed depends on the type of meat. The pH value will then be stable in the maturing stage. In this period, the meat may be still in the slaughterhouse, in the transport chains or it may have been sold in the market.

White blood cells are no longer are present and bacteria accumulate. The nervous system fails and the temperature falls. The supply of vitamins and anti-oxidants ceases, enabling chemical decay reactions.

Meat decay is a continuous enzymatic process that starts after slaughter and includes a 'ripening' stage. The various decay and spoilage mechanisms include:

Meat spoilage by bacteria, yeasts, and molds (microbial attack);

Oxidative rancidity (oxidation of fats);

Discoloration (due to photo degradation);

Dehydration and absorption of off- flavours.

These decomposition reactions are based on the proteolytic enzymes decomposing the proteins into amino acids, and the proteases catalysing the hydrolysation of peptide bonds. The enzymes involved have natural occurrence in the body, e.g. in the digestive tract. Biogenic amines (BA) are organic bases that are produced by microbial or thermal decarboxylation of amino acids. Due to BA formation the pH will increase. This takes place during the meat storage process, and is the so-called spoilage period.

The slaughter process and post mortem changes to the meat are shown in Fig.

1.

The steps comprise catching the animal in step 10, slaughter in step 12 giving rise to death of the animal in step 14. Anaerobic glycolysis takes place in step 16 giving rise to pH chnages in step 18. There is activity of the ATPase in step 20 and degradation of ATP in step 22. The animal then undergoes rigor mortis in step 24, autolysis in step 26 after which spoilage takes place in step 28. The ATP decomposition process is shown as step 30 which leads to the formation of uric acid.

The pH of meat is about 7 when the animal is just dead. The pH will then decrease as the glycogen turns to lactic acid. After all the glycogen is consumed, the pH reaches an ultimate lowest value, which is below 6. This lowest level is affected by many factors. After that, as the biogenic amine and other basic materials such as TVB-N are formed, the pH will increase. Thus, the pH change is closely related to the meat freshness.

The lowest pH is affected by factors such as the species, breed, muscle type, and individual differences. Meanwhile the animal condition before slaughter (stress, exhaustion, hunger) will also affect the lowest pH level that will be reached. Furthermore, the rigor mortis after slaughter will also change the lowest pH values. Fig. 2 shows the measurement of pH of a meat sample over time. Period 32 is the glycogeno lysis period during which the pH drops until it reaches an ultimate lowest value at 33. Period 34 is the maturing stage and period 36 is the spoilage stage.

The lowest pH of the meat is affected by species and muscle type as well as slaughter process. The top plot of Fig. 3 shows the change over time of the pH of the same muscle meat (longissimus muscle) in different animal species (plot 40 is beef, plot 41 is horse and plot 42 is pork).

The bottom plot of Fig. 3 shows the change over time of the pH of the different meat portions (plot 43 is horse diaphragm, plot 44 is beef semitendinosus, plot 45 is beef longissimus muscle, plot 46 is beef psoas and plot 47 is horse myocardial).

For every type of meat (i.e. the species and muscle type, such as pork tender loin or chicken breast), the pH change profile after slaughter is similar.

The invention provides a system for determining the freshness of a food item. The invention is based on establishing a link between food freshness and the pH difference from a lowest pH level, and then using pH measurements to enable the meat freshness to be determined.

The complete method is shown in Fig. 4. The initial steps 50 relate to the setting up of a database and the final steps 52 relate to the freshness evaluation using pH measurement.

The setting up of the database involves measuring the pH value in step 54 of a food item which is a sample of a particular type of food, wherein the particular type of food is a particular flesh portion for a particular species of animal. This pH sensing takes place at a plurality of times after the slaughter of the animal to obtain a function of pH level over time. Step 54 also involves measuring a total volatile basic nitrogen (TVB-N) level for the food item at the plurality of times. Instead or as well the total viable bacteria concentration (TVC) may be used.

This may be a destructive process performed on samples of the meat portion. The TVB-N or TVC value is used as an indicator of the actual freshness. In this way, a function over time of the food freshness is also obtained.

A correlation is then determined between the sensed pH level and the food freshness. This correlation in particular makes use of the lowest pH level (reference 33 in Fig. 2) and involves calculating in step 55 a difference pH level which is the difference between the sensed pH value of the food item and its lowest pH value. In step 56, a correlation between the volatile basic nitrogen level (or TVC value) over time and the difference pH level over time is derived.

In step 57, from the determined correlation, at least one threshold is obtained for the difference pH level, wherein the threshold is for use in determining a level of freshness of other food items which are samples of the same particular type of food.

These steps enable a database to be created, which then enables a simple conversion from a sensed pH level of a food item to a determination of the level of freshness. Determining a correlation may for example comprise fitting a line or polynomial curve of best fit to the measured TVB-N or TVC and pH difference levels. The thresholds may then comprise the conversion from particular TVB-N or TVC levels to the corresponding pH difference levels as determined by the line or curve of best fit.

The method is for example conducted for a plurality of different particular types of food (again this means particular flesh portions), and for each particular type of food a plurality of samples are analysed. There may be two thresholds of the difference pH level (i.e. the pH level relative to the lowest pH level), for use in determining a fresh status, a semi- fresh status and a spoiled status.

The database is set up in an initial configuration stage which is conducted only once.

Fig. 4 also shows how the database is subsequently used.

In step 58, the lowest pH level of the food item is measured at the

slaughterhouse and recorded on packaging used for the food item, either as text, or as a coded message such as a barcode or RFID tag. The code may include may other types of information, such as the slaughterhouse, the animal providence, the type of cut (i.e. the type of flesh portion), the species of animal etc.

Note that instead of measuring the lowest pH level, this may be obtained from the database based on all of the other information. For example this may be appropriate if the meat is not held in the slaughterhouse long enough for the lowest pH level to be reached (which may for example be between one and two days as shown in Fig. 2).

The final steps 52 are carried out by a user or by the trade to assess the meat freshness.

In step 59, the pH value of the food item is sensed. In step 60, the packaging is read to obtain the lowest pH value. As mentioned above, this lowest pH value may instead be estimated based on all of the other information about the food item. In step 61, the sensed pH level is compared with the lowest pH level for the food item (i.e. as previously measured) or expected for the type of food for which the food item is a sample (i.e. as predicted).

The difference value is compared with two thresholds to give three possible ranges. A lowest pH difference is detected in step 62 when the pH level is below the lower threshold. An output is given in step 63 indicating the food item is fresh. A middle pH difference is detected in step 64 when the pH level is between the two thresholds. An output is given in step 65 indicating the food item is semi-fresh. A largest pH difference is detected in step 66 when the pH level is above the higher threshold. An output is given in step 67 indicating the food item is spoiled.

This system enables the freshness of a food item to be determined based on a simple pH measurement. It is based on the realization that certain food items experience an increase in pH level during the decay process, which starts from a lowest level. The system can be used to prevent spoiled food reaching the customer, or it can be used by consumers. As explained above, the lowest pH level may be determined for each food item. This may be based on an average stored value expected from the particular type of food or it may be based on a measured value for that actual food item.

The accuracy of this method depends on the size of the database. When measuring the lowest pH level, it can for example be assumed that different meat portions from the same position of the carcass of the same animal are the same.

The thresholds are chosen so that the pH difference values correlate with the freshness indicator, such as the TVB-N values which are known to relate to freshness levels. For example, spoilage corresponds to TVB-N > 15. For example, if the lowest pH of a pork tenderloin is 5.6, and the measured pH is found to be 6.1 when the TVB-N level is 15, this means the pH difference, denoted as ΔρΗ, of 0.5 sets the (upper) threshold for determining if the pork is spoiled. This is shown in Fig. 5.

To illustrate the effectiveness of the method experiments have been conducted, and the results of two such experiments are presented below.

In a first experiment, pork tenderloin samples were stored at 15 °C for up to 5 days. Both pH and TVB-N were measured over time. TVB-N is used as the freshness indicator. In particular, the pork is deemed to be fresh when the TVB-N value is smaller than 12 mg/lOOg, semi- fresh when the TVB-N value is between 12 and 15 mg/lOOg and spoiled when the TVB-N value is larger than 15 mg/lOOg. The correlation between the pH difference value and TVB-N value can be seen in Fig. 6 which plots the TVB-N value versus the pH difference value. A quadratic line of best is expressed as y = 25.819x² - 18.018x + 9.6535. Of course, the correlation for different parts of the pork will be different.

The calculated ΔρΗ value was 0.81 when TVB-N reached 12 mg/lOOg and

0.93 when TVB-N reached 15 mg/lOOg. The lowest (ultimate) pH value was found to be 5.58 which was used as the lowest value from which the difference values are obtained. Thus, the sample is deemed to be fresh when the difference pH, ΔρΗ < 0.81, semi- fresh when ΔρΗ is between 0.81 and 0.93, spoiled when ΔρΗ > 0.93.

Another batch of pork tenderloin was used to verify the difference threshold values, and the results are shown in Fig. 7 which plots the pH difference value ΔρΗ for 11 samples. It shows the threshold values 70, 71 which define the fresh (left) zone, the semi- fresh (middle) zone and spoiled (right) zone. The pH and TVB-N of these samples were measured, and the freshness prediction based on the pH difference value was compared with the TVB-N value. One fresh sample was mistaken for a semi- fresh one (this sample is shown circled).

In a second experiment, chicken breast portions were stored at 15 °C for up to 5 days. Both pH and TVB-N value were measured. As in the first experiment, TVB-N values are used as freshness indicators. Again, the chicken is deemed to be fresh when the TVB-N value is smaller than 12 mg/lOOg, semi- fresh when the TVB-N value is between 12 and 15 mg/lOOg and spoiled when the TVB-N value is larger than 15 mg/lOOg.

The correlation between pH difference value and TVB-N value can be seen in Fig. 8 which plots the TVB-N value versus the pH difference value. A linear line of best fit is expressed as y = 48.61x +4.5491. The correlation for different parts of the poultry may be different.

The calculated ΔρΗ was 0.15 when the TVB-N level was 12 mg/lOOg and 0.22 when the TVB-N level was 15 mg/lOOg. The lowest (ultimate) pH value was measured to be 5.90. The sample was thus deemed to be fresh when ΔρΗ < 0.15, semi-fresh when ΔρΗ was between 0.15 and 0.22, and spoiled when ΔρΗ > 0.22.

Another batch of chicken breast was used to verify the threshold values, and the results are shown in Fig. 9 which plots the pH difference value ΔρΗ for 11 samples. Again, it shows the threshold values 90, 91 which define the fresh (left) zone, the semi- fresh (middle) zone and spoiled (right) zone. The pH and TVB-N of these samples were measured, and the freshness prediction based on the pH difference value was compared with the TVB-N value. The freshness of all samples was predicted correctly.

Fig. 10 shows a system 100 for determining the freshness of a food item. It comprises a pH sensor 102 for sensing the pH level of the food item and a controller 104. The controller 104 has an input for receiving the sensed pH level of the food item. In the example shown, the controller is part of the sensor probe. However, it may instead be remote from the pH sensor and they may then communicate wirelessly. Thus, the input to the controller 104 may be a wireless signal and it may be remote.

The controller 104 compares the sensed pH level with at least a lowest pH level for the actual food item or else expected for the type of food for which the food item is a sample, thereby to determine a level of freshness of the food item (as explained above, by first obtaining pH difference information).

The sensor probe 102 has a probe electrode 106, a control panel 108 to enable user input and a display 110.

The control panel is shown as a key pad, for entering a sample code (which encodes the required information about the sample) or for entering a lowest pH value and a type of food item. The control panel may use buttons (as shown) or a touchscreen. The pH sensor probe contacts the meat sample directly and measures the pH value (to obtain the

"sensed pH value" discussed above).

The device may have a barcode reader instead or as well as a keypad or touchscreen input.

The algorithm to give a freshness reading may be implemented in many different ways. Two examples are given above, both in which a pH difference is obtained and compared with one or more thresholds. In another example of different ways, a sensed pH level is compared with one or more thresholds (which thresholds then take account of the lowest pH level and the difference to that level). These are equivalent ways of determining freshness based on the difference between the lowest pH level and a sensed pH level. The invention is related generally to the broader concept of using this difference information, no matter how an algorithm is formulated.

As described above, the system makes use of a controller for implementing the conversion from measured pH value to a freshness determination. A controller is also used to process the data obtained during the calibration process. Fig. 11 illustrates an example of a computer 110 which may be used to implement the controller in the examples above. Various operations discussed above may utilize the capabilities of the computer 110.

The computer 110 includes, but is not limited to, PCs, workstations, laptops, PDAs, palm devices, servers, storages, and the like. Generally, in terms of hardware architecture, the computer 110 may include one or more processors 111, memory 112, and one or more I/O devices 117 that are communicatively coupled via a local interface (not shown). The local interface can be, for example but not limited to, one or more buses or other wired or wireless connections, as is known in the art. The local interface may have additional elements, such as controllers, buffers (caches), drivers, repeaters, and receivers, to enable communications. Further, the local interface may include address, control, and/or data connections to enable appropriate communications among the aforementioned components.

The processor 111 is a hardware device for executing software that can be stored in the memory 112. The processor 111 can be virtually any custom made or commercially available processor, a central processing unit (CPU), a digital signal processor (DSP), or an auxiliary processor among several processors associated with the computer 110, and the processor 111 may be a semiconductor based microprocessor (in the form of a microchip) or a microprocessor.

The memory 112 can include any one or combination of volatile memory elements (e.g., random access memory (RAM), such as dynamic random access memory (DRAM), static random access memory (SRAM), etc.) and non-volatile memory elements (e.g., ROM, erasable programmable read only memory (EPROM), electronically erasable programmable read only memory (EEPROM), programmable read only memory (PROM), tape, compact disc read only memory (CD-ROM), disk, diskette, cartridge, cassette or the like, etc.). Moreover, the memory 112 may incorporate electronic, magnetic, optical, and/or other types of storage media. Note that the memory 112 can have a distributed architecture, where various components are situated remote from one another, but can be accessed by the processor 111.

The software in the memory 112 may include one or more separate programs, each of which comprises an ordered listing of executable instructions for implementing logical functions. The software in the memory 112 includes a suitable operating system (O/S) 115, compiler 114, source code 113, and one or more applications 116 in accordance with exemplary embodiments. As illustrated, the application 116 comprises numerous functional components for implementing the features and operations of the exemplary embodiments. The application 116 of the computer 110 may represent various applications, computational units, logic, functional units, processes, operations, virtual entities, and/or modules in accordance with exemplary embodiments, but the application 116 is not meant to be a limitation.

The operating system 115 controls the execution of other computer programs, and provides scheduling, input-output control, file and data management, memory management, and communication control and related services. It is contemplated that the application 116 for implementing exemplary embodiments may be applicable on all commercially available operating systems.

Application 116 may be a source program, executable program (object code), script, or any other entity comprising a set of instructions to be performed. When a source program, then the program is usually translated via a compiler (such as the compiler 114), assembler, interpreter, or the like, which may or may not be included within the memory 112, so as to operate properly in connection with the O/S 115. Furthermore, the application 116 can be written as an object oriented programming language, which has classes of data and methods, or a procedure programming language, which has routines, subroutines, and/or functions, for example but not limited to, C, C++, C#, Pascal, BASIC, API calls, HTML, XHTML, XML, ASP scripts, JavaScript, FORTRAN, COBOL, Perl, Java, ADA, .NET, and the like.

The I/O devices 117 may include input devices such as, for example but not limited to, a mouse, keyboard, scanner, microphone, camera, etc. They are for receiving control commands from the user or input data, such as the food type or weight, or indeed any other information from a barcode or RFID tag or other data source associated with the food item.

Furthermore, the I/O devices 117 may also include output devices. Finally, the I/O devices 117 may further include devices that communicate both inputs and outputs, for instance but not limited to, a network interface controller (NIC) or

modulator/demodulator (for accessing remote devices, other files, devices, systems, or a network), a radio frequency (RF) or other transceiver, a telephonic interface, a bridge, a router, etc. The I/O devices 117 also include components for communicating over various networks, such as the Internet or intranet.

If the computer 110 is a PC, workstation, intelligent device or the like, the software in the memory 112 may further include a basic input output system (BIOS) (omitted for simplicity). The BIOS is a set of essential software routines that initialize and test hardware at startup, start the 0/S 115, and support the transfer of data among the hardware devices. The BIOS is stored in some type of read-only-memory, such as ROM, PROM, EPROM, EEPROM or the like, so that the BIOS can be executed when the computer 110 is activated.

When the computer 110 is in operation, the processor 111 is configured to execute software stored within the memory 112, to communicate data to and from the memory 112, and to generally control operations of the computer 110 pursuant to the software. The application 116 and the O/S 115 are read, in whole or in part, by the processor 111, perhaps buffered within the processor 111, and then executed.

When the application 116 is implemented in software it should be noted that the application 116 can be stored on virtually any computer readable medium for use by or in connection with any computer related system or method. In the context of this document, a computer readable medium may be an electronic, magnetic, optical, or other physical device or means that can contain or store a computer program for use by or in connection with a computer related system or method.

The application 116 can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a "computer-readable medium" can be any means that can store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The computer readable medium can be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS:

1. A system for determining the freshness of a food item, comprising:

an input (104) for receiving a sensed pH level of the food item; and a controller (104) for comparing the sensed pH level with reference information which comprises at least a lowest pH level for the food item or expected for the type of food for which the food item is a sample, thereby to determine a level of freshness of the food item.

2. A system as claimed in claim 1, wherein the controller is adapted to compare the sensed pH level with the reference information by:

determining a pH difference level between the sensed pH level and the lowest pH level for the food item or expected for the type of food for which the food item is a sample, and comparing the pH difference level with a pH difference threshold in respect of different types of food item; or

comparing the sensed pH level with a pH threshold based on the lowest pH level for the food item or expected for the type of food for which the food item is a sample and a pH difference threshold in respect of different types of food item.

3. A system as claimed in claim 2, wherein the controller is adapted to apply at least two thresholds to the pH difference threshold or to the sensed pH level, thereby to determine a fresh status, a semi-fresh status and a spoiled status.

4. A system as claimed in claim 1, 2 or 3, further comprising a database which stores the pH difference threshold or the sensed pH level threshold and / or the lowest expected pH level.

5. A system as claimed in claim 1, 2 or 3, wherein each type of food comprises a particular flesh portion for a particular species of animal.

6. A system as claimed in claim 1, wherein each food item also takes into account the slaughter method.

7. A system as claimed in claim 1, further comprising:

a pH sensor for sensing the pH level of the food item.

8. A system as claimed in claim 7, comprising a hand held device in which the pH sensor comprises a probe, and the device comprises:

an output interface for providing a freshness indication to a user.

9. A hand held device for determining the freshness of a food item, comprising:

a pH sensor for sensing the pH level of the food item;

a transmission module adapted to transmit the sensed pH level to the system according to one of claims 1 to 6.

10. A method for determining the freshness of a food item, comprising:

sensing a pH level of the food item; and

comparing the sensed pH level with reference information which comprises at least a lowest pH level for the food item or expected for the type of food of which the food item is a sample, thereby to determine a level of freshness of the food item.

11. A method as claimed in claim 10, wherein the method comprises

12. A method as claimed in claim 10, wherein the reference information comprises information for plurality of types of food, wherein the types of food include particular flesh portions for a particular species of animal.

13. A method as claimed in claim 10, comprising:

the hand held device providing an output which provides a freshness indication.

14. A computer program comprising code means which is adapted, when the computer program is run on a computer, to implement the method of any one of claims 10 to 12.