TECHNICAL FIELD
[0001] The present subject matter relates in general to detection of adulterants in milk samples, and in particular, to devices and methods for detection of adulterants in milk samples.
BACKGROUND
[0002] Milk may be adulterated with water, table sugar, starch, acids, soap, formalin, urea, and the like. Adulteration of milk reduces the quality of milk and can even make it hazardous. Hence, quality control tests are used to assure adulterant free milk is available for consumption. However, most of the quality control tests have to be performed in laboratories and are hence ineffective in checking adulteration at point of sale. Recently, milk testing kits have been developed to facilitate testing of milk outside of laboratories. Typical milk testing kits are specific to a type of adulterant being detected. For example, a lactometer may be used to detect dilution of milk with water. Further, general milk testing kits are expensive and procedure for testing for adulterants is time-consuming.
BRIEF DESCRIPTION OF DRAWINGS
[0003] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.
[0004] Fig. 1 depicts a block diagram of a device for detecting presence of adulterants in milk, in accordance with an implementation of the present subject matter. [0005] Fig. 2 depicts an electrochemical sensor of a device for detecting presence of adulterants in milk, in accordance with an implementation of the present subject matter.

[0006] Fig. 3 depicts a sensor holder associated with an electrochemical sensor of a
device for detecting presence of adulterants in milk, in accordance with an
implementation of the present subject matter.
[0007] Fig. 4 depicts an external view of a housing of an adulteration detection unit, in
accordance with an implementation of the present subject matter.
[0008] Fig. 5 illustrates a device used for testing adulteration of milk, in accordance
with an implementation of the present subject matter.
[0009] Fig. 6 depicts a method for detection of adulterants in milk, in accordance with
an implementation of the present subject matter.
[00010] Fig. 7 depicts a graph illustrating variation of impedance of milk with dilution,
in accordance with an implementation of the present subject matter.
DETAILED DESCRIPTION
[00011] The present subject matter provides devices and methods for detecting presence of adulterants in milk. The devices and the methods can detect adulteration of milk with synthetic milk and other chemical reagents.
[00012] Principal constituents of natural milk are water, fat, proteins, lactose, and minerals. Natural milk also contains trace amounts of other substances, such as pigments, enzymes, vitamins, phospholipids, and gases. While these are constituents of natural milk, the milk that is available in the market may include adulterants, such as water, table sugar, starch, acids, soap, formalin, urea, common inorganic salts, and the like. Adulteration reduces the quality of milk, standard of nutrition provided by milk, and can even make it unsafe for consumption.
[00013] In particular, when adulterated with synthetic milk, the adulterated milk is rendered unfit for consumption. Synthetic milk is an artificial imitation of natural milk that may be used to increase the volume of milk or make the dilution of milk with water undetectable by a lactometer. Main components of synthetic milk are water, pulverized

detergent or soap, sodium hydroxide, vegetable oil, salt, and urea. Most of these components, such as urea, neutralizers, and detergents are harmful to human health. [00014] Conventionally available milk testing methods are specific to a type of adulterant being detected. For example, a lactometer may be used to detect dilution of milk with water; adulteration with table sugar can be detected by using resorcinol; adulteration with starch can be detected using iodine; adulteration with soap can be detected by adding phenolphthalein indicator to the adulterated milk, and the like. Therefore, conventionally available milk testing methods are laboratory-oriented, require skilled personnel, and are expensive and time consuming. Further, conventionally available milk testing methods and commercially available kits are generally unable to detect adulteration by synthetic milk. This is because synthetic milk is made by mixing organic and inorganic components in a particular ratio so as to provide fat and solid-not-fat (SNF) percentage similar to that of natural milk. [00015] The present subject matter provides devices and methods for detection of adulterants in milk. In one example, a device comprises an electrochemical sensor to be introduced into a milk sample. The electrochemical sensor can comprise two parallel electrodes. The device further comprises an adulteration detection unit to be electrically coupled to the electrochemical sensor. The adulteration detection unit can include a function generator to provide Alternating Current (AC) voltage to the electrochemical sensor, for example, at a frequency in a range of 10 - 30 kHz. A current measurement corresponding to current flowing between the two parallel electrodes placed in the milk sample on application of the AC voltage can be received. Based on the measured current, impedance provided by the milk sample can be computed and the computed impedance can be compared with a reference impedance of natural milk to detect a presence of adulterants in the milk sample. As will be understood, natural milk is milk obtained from source and does not comprise any adulterant.
[00016] The reference impedance of natural milk, measured at a particular frequency, can vary in a range, i.e., the reference impedance of natural milk corresponds to a range

having a first threshold and a second threshold. A lower limit of the range is hereinafter referred to as the first threshold and an upper limit of the range is hereinafter referred to as the second threshold. If the impedance of milk sample is less than first threshold, the device can detect the presence of a chemical reagent and if the impedance of the milk sample is more than a second threshold the device can detect the presence of synthetic milk.
[00017] In accordance with various embodiments, the device of the present subject matter can be a hand-held device and can, therefore, be used portably at milk collection centers. In one example, the device may be used for primary level screening of milk for adulteration while exact adulterants of milk may be identified by standard physicochemical analysis after the primary level screening. The device can be used to detect the presence of certain adulterants added to natural milk obtained from different sources, such as cow, goat, and the like. Further, the device has high accuracy and can detect presence of greater than 5% of synthetic milk and as less as 0.5% of several other chemical reagents. As mentioned above, synthetic milk is made by mixing organic and inorganic components in a particular ratio so as to provide fat and solid-not-fat (SNF) percentage similar to that of natural milk. Hence, addition of synthetic milk in quantities above 5% leads to an observable increase in impedance of the adulterated milk. Whereas, when one or more individual chemical reagents are used as adulterants without being formulated as synthetic milk, the chemical reagents lead to an observable decrease in impedance of the adulterated milk due to the higher conductivity of the chemical reagents in solution.
[00018] The above and other features, aspects, and advantages of the subject matter will be better explained with regard to the following description and accompanying figures. It should be noted that the description and figures merely illustrate the principles of the present subject matter along with examples described herein and, should not be construed as a limitation to the present subject matter. It is thus understood that various arrangements may be devised that, although not explicitly

described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and examples thereof, are intended to encompass equivalents thereof. Further, for the sake of simplicity, and without limitation, the same numbers are used throughout the drawings to reference like features and components.
[00019] Fig. 1 depicts a block diagram of a device 100 for detection of presence of adulterants in milk, in accordance with an implementation of the present subject matter. The device 100 can include an electrochemical sensor 102. The electrochemical sensor 102 can be introduced into a milk sample which is to be tested for adulteration. The electrochemical sensor 102 can comprise two parallel electrodes as will be explained later with reference to Fig. 2.
[00020] The electrochemical sensor 102 can be electrically coupled to an adulteration detection unit 104. In one example, the adulteration detection unit 104 and the electrochemical sensor 102 may be detachably coupled. For example, the adulteration detection unit 104 may be provided in a housing with a port to detachably connect the electrochemical sensor 102 to the adulteration detection unit 104. [00021] The adulteration detection unit 104 can comprise a function generator 106. The function generator 106 can provide Alternating Current (AC) voltage to the electrochemical sensor 102. In one example, the function generator 106 can provide a low-frequency and low-amplitude AC characterized as a sine or a square wave to the electrochemical sensor 102. In one example, the frequency provided by the function generator 106 is in a range of 10 - 30 kHz. An amplitude of AC voltage supplied may be in a range of lOmV - 50mV. By using low-frequency and low-amplitude AC, amount of power required to detect presence of adulterants is reduced. [00022] It is to be understood that the function generator 106 can be electrically coupled to the electrochemical sensor 102 through other electrical components, such as buffer amplifies, operational amplifiers, absolute value circuits, and the like, to

ensure safety and accuracy of the device 100. These are not shown in the figures or described as they will be understood by a person skilled in the art. [00023] The adulteration detection unit 104 can further comprise a processor 108. The processor(s) 108 may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions. Among other capabilities, the processor(s) 108 fetches and executes computer-readable instructions stored in a memory 109. While memory 109 has been shown internal to the adulteration detection unit 104, it may be communicatively coupled external to the device 100 as well. The functions of the various elements shown in the figure, including any functional blocks labeled as processor, may be provided through the use of dedicated hardware as well as hardware capable of executing computer readable instructions.
[00024] The processor 108 can receive a current measurement corresponding to current flowing between the parallel electrodes of the electrochemical sensor 102 when placed in the milk sample on application of the AC voltage. In an example, the device 100 can comprise a current sensor 112 to measure the current between the two parallel electrodes on application of the AC voltage. The current sensor 112 can provide the current measurement to the processor. In this example, the processor 108 can receive the measured current from the current sensor 112. As will be understood, the current sensor 112 can include components, such as analog-to-digital converter to convert analog signals corresponding to current flowing in the milk sample to digital signals. In an example, the current sensor 112 is an operational amplifier (op-amp) based current sensor.
[00025] Based on the current measurement and instructions obtained from the memory 109, the processor 108 can compute impedance of the milk sample being tested for adulteration. The processor 108 can, based on the instructions obtained from the memory 109, compare the computed impedance with a reference impedance of natural

milk to detect a presence of adulterants in the milk sample. In one example, the adulterant may be one of: chemical reagent and synthetic milk. [00026] When one or more individual chemical reagents are used as adulterants without being formulated as synthetic milk, the chemical reagents lead to an observable decrease in impedance of the adulterated milk due to the higher conductivity of the chemical reagents in solution. In one example, the chemical reagent is an inorganic chemical compound. Synthetic milk can be made by mixing organic and inorganic components in a particular ratio so as to provide fat and solid-not-fat (SNF) percentage similar to that of natural milk. In an example, the synthetic milk comprises at least one organic components.
[00027] The reference impedance of natural milk for a type of dairy animal, hereinafter also referred to as source of milk, measured at a particular frequency, can vary in a range. The reference impedance of natural milk, therefore, can correspond to the range. The range can have a first threshold and a second threshold. For example, the reference impedance of natural milk obtained from cows can vary between a range of xi and X2, where xi is the lowest value and X2 is the highest value of impedance measured from natural milk obtained from a set of cows, for example 20 cows. A lower limit of the range, i.e., xi, is referred to as the first threshold of impedance of natural milk and an upper limit of the range, i.e., X2, is referred to as the second threshold of impedance of natural milk. If the impedance of milk sample is less than the first threshold, it is indicative of the presence of a chemical reagent and if the impedance of the milk sample is more than a second threshold it is indicative of the presence of synthetic milk. Accordingly, the processor 108 can detect the presence of chemical reagent or synthetic milk based on the comparison of the impedance of the milk sample with the reference impedance.
[00028] As previously explained, milk comprises constituents, such as casein proteins, phospholipids, minerals, such as, calcium, magnesium, chloride, phosphate, and the like. The impedance of milk is based on the constituents present in the milk sample and

differs from sample to sample based on source and origin of the milk. For example, cow's milk has a lower fat content compared to buffalo's milk. Further, in buffalo's milk, size of fat globules is bigger than in cow's milk. Therefore, as impedance is based on current path in the milk sample, which further depends on constituents of the milk sample, impedance varies based on source.
[00029] Impedance of milk further depends on the frequency of AC voltage at which impedance is measured. However, in the range of 10 - 30 kHz it was found that the impedance of natural milk remains almost a constant with the frequency of AC voltage, forming a plateau region in a plot of impedance as a function of the frequency of AC voltage. The plateau region is, therefore, a unique region of the impedance plot and is, thereby, used as a basis for the selected frequency range. Thus, AC voltage of any frequency within the frequency range of 10 - 30 kHz can be used for the detection of presence of adulterants. In one example, the frequency of AC voltage provided by the function generator 106 may be pre-set or set manually within the range of 10-30 kHz. [00030] The first threshold and the second threshold for natural milk can vary based on origin of the milk. The device 100 can also include a database 110 to store the reference impedance of natural milk, i.e., the first threshold and the second threshold, to be used for each source of milk, such as, cow's milk, goat's milk, and the like. The database 110 may serve as a repository for storing data that may be fetched, processed, received, or created by device 100 or received from the processor 108. While the database 110 is shown as being internal to the adulteration detection unit 104, it will be understood that the database 110 may be external as well and can be accessed by the adulteration detection unit 104 using various communication means. Further, in some implementations, the database 110 may be stored in the memory 109. The processor 108 can retrieve the first threshold and the second threshold value from the database 110 based on the source of milk sample for comparison of the computed impedance with the reference impedance of natural milk for detection of adulterants.

[00031] In one example, the device 100 can comprise an input-output (I/O) unit 115 to receive an input corresponding to the source of natural milk. In this example, the processor 108 can receive the input corresponding to the source of natural milk. Based on the input, the reference impedance can be obtained by the processor 108 from the database 110. Further, the I/O unit 115 may also include network interfaces for communicating with external devices, for example, for receiving updates to the instructions stored in the memory 109 and the data stored in the database 110. [00032] As will be understood, the adulteration detection unit 104 may include various interfaces, memories, other data, and the like, which are not shown for brevity. The interfaces may include a variety of computer-readable instructions-based interfaces and hardware interfaces that allow interaction with other communication, storage, and computing devices, such as network entities, web servers, databases, and external repositories, and peripheral devices. The memories may include any non-transitory computer-readable medium including, for example, volatile memory (e.g., RAM), and/or non-volatile memory (e.g., EPROM, flash memory, etc.). The memories may include an external memory unit, such as a flash drive, a compact disk drive, an external hard disk drive, or the like. The other modules may include modules for operation of the adulteration detection unit 104, such as operating system, and other applications that may be executed on the adulteration detection unit 104. Other data may include data used, retrieved, stored, or in any way manipulated by the adulteration detection unit 104.
[00033] The adulteration detection unit 104 can further comprise a display module 114 to display a digital output corresponding to the presence of adulterants in the milk. On detection of presence of adulterant, the processor 108 can provide the digital output to the display module 114. In one example, the digital output may be the impedance measured and presence or absence of the adulterants. In one example, the display module 114 may be a Light Emitting Diode (LED) display unit. In another example, the display module 114 can include a color-based LED.

[00034] In operation, the electrochemical sensor 102 maybe electrically coupled to the adulteration detection unit 104. The electrochemical sensor 102 can then be dipped in the milk sample to be tested for adulteration and by using the I/O unit 115 the input corresponding to the source of natural milk can be provided. When switched ON, the function generator 106 provides AC voltage to the electrochemical sensor 102. Current flowing between the two parallel electrodes of the electrochemical sensor 102 can be measured by the current sensor 112 and the current measurement corresponding to the measured current can be provided to the processor 108.
[00035] The processor 108 can receive the current measurement from the current sensor 112 and the input corresponding to the source of natural milk from the I/O unit 115. Based on instructions fetched from the memory 109, the processor 108 can compute the impedance of the milk sample based on the current measurement. Further, based on the source of natural milk, the processor 108 can retrieve the first threshold and second threshold of reference impedance of natural milk from the database 110 and compare the computed impedance with the first threshold and the second threshold to detect presence of adulterants in the milk sample. The processor 108 can provide an output corresponding to the presence of adulterants in the milk sample to the display module 114. The display module may display the output, for example, as text, light indicator, etc.
[00036] In an example, the device 100 may be calibrated prior to testing the milk sample for presence of adulterants. The device 100 may be calibrated by dipping the electrochemical sensor 102 in a buffer solution, for example, phosphate buffer. Calibration of the device 100 may be performed once a day, for example, before a first test of the day. After each test, the electrochemical sensor 102 can be washed before introducing into a subsequent milk sample.
[00037] Fig. 2 depicts the electrochemical sensor 102 of the device 100 in greater detail, in accordance with an implementation of the present subject matter. The electrochemical sensor 102 can comprise two parallel electrodes 202a and 202b. Each

of the two parallel electrodes 202a, 202b can be fabricated from epoxy strips coated with metal selected from the group consisting of nickel and stainless steel. In one example, dimension of each of the two parallel electrodes 202a, 202b may be 20 mm X 5 mm.
[00038] Each of the two parallel electrodes 202a, 202b may be electrically coupled to the adulteration detection unit 104. The two parallel electrodes 202a, 202b may be electrically coupled to the adulteration detection unit 104, for example, through electric leads 204a, 204b, respectively. However, it is to be understood that other means of electrically coupling the two parallel electrodes 202a, 202b may be used. [00039] The two parallel electrodes 202a, 202b can be separated by a spacer 206. The spacer 206 may be fabricated from an insulator. In an example, the spacer 206 is fabricated from a material selected from the group consisting of Teflon, ceramic, porcelain, and the like. In an example, a dimension of the spacer 206 is 5 mm in width. The spacer 206 may be fastened between the two parallel electrodes 202a, 202b by using fasteners as shown in Fig. 3.
[00040] Fig. 3 depicts the two parallel electrodes 202a, 202b with the spacer 206 provided therebetween, in accordance with an implementation of the present subject matter. The spacer 206 may be coupled between the two parallel electrodes 202a, 202b by using fastener 302 (shown as 302a and 302b). In the example as shown in Fig. 2(b), the fastener 302 shown is a nut 302a and a bolt 302b. However, it is to be understood that other fasteners, such as clamps may also be used to couple the spacer 206 between the two parallel electrodes 202a, 202b.
[00041] Further, as shown in Fig. 3, the two parallel electrodes 202a, 202b may be coupled to a sensor holder 306 via connector 304. The connector 304 can include a male component and a female component. The male component may be coupled to the two parallel electrodes 202a, 202b, for example, at the spacer 206 while the female component may be coupled to the sensor holder 306. In another example, for ease of handling, the electrochemical sensor 102 comprising the two parallel electrodes 202a,

202b, may be coupled to a sensor holder 306 which may then be coupled to the adulteration detection unit 104. In said example, the female component may be provided in the sensor holder 306 and may be electrically coupled to the adulteration detection unit 104, in addition to the electrical leads 204a, 204b, when the sensor holder 306 is coupled to the adulteration detection unit 104.
[00042] Fig. 4 depicts an external view of a housing 400 of the adulteration detection unit 104 to which the sensor holder 306 can be coupled, in accordance with an implementation of the present subject matter. Fig. 4 depicts the housing 400 in which electrical components of the adulteration detection unit 104 can be housed. In an example, the housing 400 may be fabricated from liquid resistant material. [00043] As can be seen from a bottom-view 401 of the housing 400, the adulteration detection unit 104 can have a connecting port 402 for coupling with the sensor holder 306 (not shown). The connecting port 402 can be used to electrically couple the sensor holder 306 and the connecting port 402. The connecting port 402 may be coupled to a port on the sensor holder 306 using the electrical leads (not shown in Fig. 4). [00044] Front-view 404 depicts the display module 114. As previously explained, the display module 114 may be an LED display unit. However, it is to be understood that other mechanisms for display, such as Liquid Crystal Display (LCDs) may also be used. While not shown in front-view 404, the adulteration detection unit 104 can also comprise input-output (I/O) unit 115, to receive inputs from a user, for example, personnel at the milk collection center. The input may be source of the milk sample. As will be understood, the I/O unit 115 may include a keypad, a touch-screen, and the like.
[00045] The adulteration detection unit 104 can also include a power button 406 as shown in a side-view 408. The power button 406 can be used to switch off or switch on the adulteration detection unit 104, where on switching on the adulteration detection unit 104, the function generator (not shown in Fig. 4) provides AC voltage to the two parallel electrodes 202a, 202b. In one example, on switching on the power button 406,

power may be received by the I/O unit 115 and processor 108 to receive input of parameters, such a frequency of AC voltage to be supplied and the like. Further, in one example, the adulteration detection unit 104 can include a switch button to switch on the function generator 106 based on the parameters. In another example, the processor may trigger the function generator 106 on receiving the input of parameters. [00046] In one example, the adulteration detection unit 104 may include a power source to supply power for the functioning of the various components. In one example, the power may be supplied by using a battery as a power source. The adulteration detection unit 104, as shown in back-view 410, can include a battery holder 412 to hold the battery. By using the battery, the adulteration detection unit 104 and, thereby, the device 100 becomes portable. It is to be understood that other methods of supplying power to the adulteration detection unit 104 may be used. For example, the power source may be an adapter that can be plugged into a power supply socket. In one example, the device 100, in addition to the adulteration detection unit 104 and the electrochemical sensor 102, can also include a sample cell as shown in Fig. 5 to hold the milk sample for adulteration detection.
[00047] Fig. 5 depicts a sample cell 500, in accordance with an implementation of the present subject matter. The sample cell 500 can be used to hold the milk sample to be tested for measurement. The sample cell 500 may be detachably coupled to the sensor holder 306. In another example, the sample cell 500 may be a separate component, such as a cup, a bowl, and the like, in which the two parallel electrodes 202a, 202b of the electrochemical sensor 102 maybe dipped.
[00048] Fig. 6 depicts a method 600 for detecting presence of adulterants in a milk sample, in accordance with an implementation of the present subject matter. The order in which the method 600 is described is not intended to be construed as a limitation, and any number of the described method blocks can be combined in any order to implement method 600 or an alternative method. Additionally, individual blocks may be deleted from the method 600 without departing from the spirit and scope of the

subject matter described herein. Furthermore, the method 600 may be implemented in any suitable hardware, computer readable instructions, firmware, or combination thereof. For discussion, the method 600 is described with reference to the implementations illustrated in Fig(s). 1-5.
[00049] A person skilled in the art will readily recognize that steps of the method 600 can be performed by programmed computers. Herein, some examples are also intended to cover program storage devices and non-transitory computer readable medium, for example, digital data storage media, which are computer readable and encode computer-executable instructions, where said instructions perform some or all of the steps of the described method 600. The program storage devices may be, for example, digital memories, magnetic storage media, such as, magnetic disks and magnetic tapes, hard drives, or optically readable digital data storage media.
[00050] With reference to Fig. 6, at block 602, a function generator can be operated to provide Alternating Current (AC) voltage to an electrochemical sensor at a frequency in a range of 10 - 30 kHz. In an example, the function generator 106 of the adulteration detection unit 104 may be operated by the processor 108. The function generator 106 may be operated based on parameters, such as source of the milk sample. In one example, the electrochemical sensor 102 can be dipped in the milk sample prior to application of AC voltage by the function generator and the parameters may be provided by a user and received by the processor 108, for example, using the I/O unit 115. In one example, the electrochemical sensor 102 may be calibrated with a buffer solution prior to detecting presence of adulterants in the milk sample. [00051] At block 604, a current measurement corresponding to current flowing between two parallel electrodes of the electrochemical sensor can be received on application of the AC voltage. In one example, the current measurement can be received by the processor 108 from the current sensor 112. As previously explained, current flowing between the two parallel electrodes depends on the constituents on the milk sample. At block 606, impedance provided by the milk sample can be computed

based on the current measurement. In an example, the impedance is computed by the processor 108 based on instructions fetched from the memory 109. [00052] At block 608, the computed impedance can be compared with a reference impedance of natural milk. In one example, the computed impedance maybe compared with the reference impedance of natural milk by the processor 108. The reference impedance of natural milk can be obtained from a database, such as database 110, based on the source of the milk sample. As explained previously, the reference impedance of natural milk can have the first threshold and the second threshold. [00053] At block 610, a presence of adulterants in the milk sample is detected based on the comparison. In one example, when the computed impedance is below a first threshold of the reference impedance of natural milk, it is indicative of the presence of chemical reagents. In another example, when the computed impedance is above a second threshold of the reference impedance of natural milk, it is indicative of the presence of synthetic milk, adulterants
[00054] Thus, the devices and methods of the present subject matter provide for fast and accurate detection of presence of adulterants in milk at any location. [00055] The present subject matter will now be illustrated with working examples, which are intended to illustrate the working of disclosure and not intended to be taken restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. It is to be understood that this disclosure is not limited to the particular methods and experimental conditions described, as such methods and conditions may vary depending on the process and inputs used as will be easily understood by a person skilled in the art.
EXAMPLES EXAMPLE 1: EFFECT OF DILUTION ON IMPEDANCE

[00056] Impedance of milk sample depends on dilution of the milk samples. In this example, the device 100 was used to correlate impedance of milk with dilution with water. Fig. 7 depicts a graph showing decrease of impedance with increasing dilution. In this example, the natural milk was diluted with water. This example depicts that the device 100 of the present subject matter is sensitive to dilution with water.
EXAMPLE 2: IMPEDANCE READING FOR NATURAL MILK OBTAINED FROM COW AND
BUFFALO
[00057] In this example, the impedance of natural milk obtained from cows and buffalos was obtained. Milk samples from 18 cows were taken and tested periodically over a period of 15 days. The impedance of natural milk obtained from cows was found to vary in a range of 1.2 -1.8. Results of impedance of cow milk was as shown in Table 1(a).
Table 1: Impedance of natural milk obtained from cow
[00058] Similarly, the impedance of natural milk obtained from buffalos was obtained. Milk sample from 10 buffalos were taken and tested periodically over a period of 30 days. The impedance of natural milk obtained from cows was found to vary in a range of 0.8 - 1.1. Results of impedance of buffalo milk was as shown in Table 2. The

impedance of natural milk obtained from buffalo was found to vary in a range of 0.7-1.1.
Table 2: Impedance of natural milk obtained from buffalo
[00059] Therefore, impedance of natural milk obtained from cow was found to vary from 1.2 - 1.8 and used to set the reference impedance with 1.2 as the first threshold and the 1.8 as the second threshold. Impedance of natural milk obtained from buffalo was found to vary from 0.8-1.1 and used to set the reference impedance with 0.8 as the first threshold and 1.1 as the second threshold.
EXAMPLE 3: CONSISTENCY OF IMPEDANCE READING IN DIFFERENT DEVICES [00060] In this example, the consistency of three different devices 100 in obtaining the impedance was tested. Three devices were compared for their impedance output against milk samples from 13 cows. Impedance obtained was found to be reproducible and remained consistent within the experimental group as shown in Table 3(a), 3(b), and 3(c).
Table 3(a): Cow Milk Sample - Device 1

EXAMPLE 4: IMPEDANCE WITH DETERGENT AS ADULTERANT
[00061] Adulteration with detergents and effect on impedance was studied. It was
observed that the device could easily detect the presence of detergent above 5 % by
weight of detergent.
Table 4(a): Impedance with detergent as adulterant
i 1 1 1 1 1

[00062] Further, a study was conducted with different detergent brands to determine
detergent added in milligram quantities to 200 ml of cow milk to obtain "over-range"
reading as shown in Table 4(b). Table 4(b) depicts minimum amount of each
commercial detergent that can be detected in the milk sample. Therefore, by using the
device of the present subject matter high accuracy of detection of detergent can be
obtained.
Table 4(b): Impedance with different detergent brands as adulterant

EXAMPLE 5: IMPEDANCE WHEN ADULTERATION IS WITH VARIOUS COMMON SALTS AND
COMPOUNDS
[00063] In this example, the device 100 was used to measure impedance when
adulteration was done with various common salts and compounds as shown in Table
5. The "No effect" in Table 5 indicates that the added chemical did not cause a
significant increase in impedance. In other cases, the concentration of the added
chemical provided a significant increase in impedance.
Table 5: Impedance reading using common salts and compounds

I I I I I I I
[00064] Thus, adulteration with individual chemical compounds could also be detected
for most of the common adulterants.
[00065] The present subject matter, therefore, provides a device 100 for detecting
adulteration of milk at point-of-collection or point-of-use without using any reagents.
Further, the device 100 detects presence of adulteration of milk with high accuracy and
is not time-consuming and laborious.
[00066] Although the subject matter has been described in considerable detail with
reference to certain examples and implementations thereof, other implementations are
possible. As such, the scope of the present subject matter should not be limited to the
description of the preferred examples and implementations contained therein.

I/We Claim:
1. A device (100) comprising:
an electrochemical sensor (102) to be introduced into a milk sample, wherein the electrochemical sensor (102) comprises two parallel electrodes (202a, 202b); and
an adulteration detection unit (104) to be electrically coupled to the electrochemical sensor (202a, 202b), wherein the adulteration detection unit (104) comprises:
a function generator (106) to provide Alternating Current (AC) voltage to the electrochemical sensor (102) at a frequency in a range of 10-30 kHz; and
a processor (108), wherein the processor (108) is to:
receive a current measurement corresponding to current flowing between the two parallel electrodes (202a, 202b) placed in the milk sample on application of the AC voltage;
compute impedance provided by the milk sample based on the current measurement;
compare the computed impedance with a reference impedance of natural milk; and
detect a presence of adulterants in the milk sample based on the comparison.
2. The device (100) as claimed in claim 1, wherein each of the two parallel
electrodes (202a, 202b) are fabricated from epoxy strips coated with metal selected
from the group consisting of nickel and stainless steel.

3. The device (100) as claimed in claim 1, wherein the electrochemical sensor (102) comprises a spacer (206) disposed between the two parallel electrodes (202a, 202b).
4. The device (100) as claimed in claim 1, wherein the adulteration detection unit (104) comprises a current sensor (112) to measure current between the two parallel electrodes (202a, 202b) on application of the AC voltage and to provide the current measurement to the processor (108).
5. The device (100) as claimed in claim 1, comprising a display module (114) to display a digital output corresponding to the presence of adulterants in the milk sample based on the comparison.
6. The device (100) as claimed in claim 5, wherein the display module (114) comprises a Light Emitting Diode (LED) display unit.
7. The device (100) as claimed in claim 1, comprising a housing (400) to house the adulteration detection unit (104), wherein the housing (400) comprises a connecting port (402) for coupling with the electrochemical sensor (102).
8. The device (100) as claimed in claim 7, wherein the housing (400) comprises a battery holder (412) to hold a battery.
9. The device (100) as claimed in claim 1, wherein the reference impedance of natural milk corresponds to a range having a first threshold and a second threshold, and wherein the processor (108) is to:
detect the presence of chemical reagents in the milk sample when the computed impedance is below the first threshold of the reference impedance; and

detect the presence of synthetic milk in the milk sample when the impedance is above the second threshold of the reference impedance of natural milk.
10. The device (100) as claimed in claim 9, wherein the processor (108) obtains the reference impedance of natural milk from a database (110) and wherein the database (110) stores the first threshold and the second threshold based on a source of natural milk.
11. The device (100) as claimed in claim 10, wherein the device (100) comprise an input-output (I/O) unit (115) to receive an input corresponding to the source of natural milk.
12. The device (100) as claimed in claim 1, wherein an amplitude of AC voltage is in range of lOmV - 50mV.
13. The device (100) as claimed in claim 1, wherein the device (100) comprises a sample cell (500) to hold the milk sample to be tested.
14. A method for detecting presence of adulterants in a milk sample, the method comprising:
operating a function generator (106) to provide Alternating Current (AC) voltage to an electrochemical sensor (102) at a frequency in a range of 10 - 30 kHz;
receiving a current measurement corresponding to current flowing between two parallel electrodes (202a, 202b) of the electrochemical sensor (102) on application of the AC voltage;
computing impedance provided by the milk sample based on the current measurement;

comparing the computed impedance with a reference impedance of natural milk; and
detecting a presence of adulterants in the milk sample based on the comparison.
15. The method as claimed in claim 14, wherein detecting the presence of
adulterants in the milk sample comprises:
indicating presence of chemical reagents in the milk sample when the impedance is below a first threshold of impedance of natural milk; and
indicating presence of synthetic milk in the milk sample when the impedance is above a second threshold of impedance of natural milk.
16. The method as claimed in claim 14, wherein the method comprises calibrating of the electrochemical sensor (102) with a buffer solution prior to detecting presence of adulterants in the milk sample.
17. The method as claimed in claim 15, wherein the method comprises obtaining the reference impedance of natural milk from a database (110) and wherein the database (110) stores the first threshold and the second threshold based on a source of natural milk.
18. The method as claimed in claim 17, wherein the method comprises receiving an input corresponding to the source of natural milk.