- Email: [email protected]
Ultrasonic Evaluation of UHT Milk Quality after Opening
Available online at www.sciencedirect.com
ScienceDirect Materials Today: Proceedings 2 (2015) 4684 – 4688
SURFOCAP 2015
Ultrasonic evaluation of UHT milk quality after opening E. Ouachaa, *, A. Mouddena, B. Faiza, I. Aboudaouda, H. Banounia, , M. Boutaiba, D. Izbaima, H. Bitaa a
Ibn Zohr University, Faculty of Sciences, Dept of Physics, Metrology and Information Processing Laboratory, Agadir, Morocco
Abstract
Non invasive techniques based on ultrasonic have advantageous features to study the food products. Our objective of this study is developed the ultrasonic transmission technique to characterize and evaluating UHT milk quality. To check the reliability of this technique, we followed the evolution of these ultrasonic parameters for different temperatures for sterilized milk packet and no-sterilized milk packet. The results obtained from these both cases, we confirmed the reliability of this emerging technique to the difference between these two cases, that is to say, for detecting the validity of UHT milk after opening of the packaging at a given temperature. ©2015 Elsevier Ltd. All rights reserved. © 2015 Elsevier Ltd. All rights reserved. Selection andpeer-review peer-reviewunder under responsibility of the Conference Committee Members of International Workshop on Selection and responsibility of the Conference Committee Members of International Workshop on Functionalized SurfacesforforSensor Sensor Applications (Surfocap’15). Functionalized Surfaces Applications Keywords: Type your keywords here, separated by semicolons ;
1. Introduction The quality control is an important aspect in food production. The major purpose of this control is to verify the acceptability of food in terms of nutritional value and safety. The development of new techniques for the quality control continues to increase according to the requirements imposed by the consumers and the authentication of food security. Several non-destructive methods are being developed for food quality control, we mention the following examples: the near-infrared spectroscopy, Raman spectroscopy, biosensors and ultrasound.
* Corresponding author. Tel.: +212-662-511-117. E-mail address: [email protected]
2214-7853 © 2015 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the Conference Committee Members of International Workshop on Functionalized Surfaces for Sensor Applications doi:10.1016/j.matpr.2015.09.023
E. Ouacha et al. / Materials Today: Proceedings 2 (2015) 4684 – 4688
The potential of ultrasound as a tool for non-destructive quality control of food products is currently under investigation. The ultrasonic waves have a valuable feature that consists in its ability to characterize opaque materials such as packed UHT [1] and packed fruit juice [2]. Recently, ultrasonic techniques were used to monitor lactic fermentation of milk [3] [4], measurement of milk compositions [5] and control of milk coagulation [6]. Ultrasound technology has recently made a very sensitive task that directly affects a critical need of consumers. This major advantage consists in detection of microbial contamination of milk. In this context, we mention the following published works: [7] have patented an ultrasonic inspection method for liquid food products; [8] was able to detect early infection in modified milk pack submerged in water; [9] have developed a device for detection of microbial growth within the UHT milk pack; [10] analyzed the performance of their ultrasonic device to perform nondestructive and rapid detection of microbial contamination of UHT milk packs. UHT milk quality is determined by the absence of any air-trace in the package. Industrials take, according to a specific sampling, a number of packets of UHT milk per day for destructive testing. However, this procedure creates a problem that keeps pushing especially if we take into account the fact that sometimes we find in reality individual UHT milk packages which are partially or totally damaged and yet it is mentioned above that is still valid for consumers. Our prime objective in this works is to develop an ultrasonic technique which aims to characterize all UHT milk packets instead to characterize just a few ones. This characterization aims to detect non-destructively the presence of any air-trace in the package since its presence will have a negative influence on UHT milk quality during storage time, and sometimes this happens before the expiration date is exhausted. 2. Material and methods 2.1. The experimental device of ultrasonic measurements The figure.1 shows the experimental setup of ultrasonic measurements used in this work in order to follow the evolution of the ultrasonic parameters. In this method, we used two identical transducers. These transducers and the samples were immersed in water inside a thermostat. The transducers (0.5 MHz as a central frequency) are mounted face to face on the opposite sides of the UHT package.
Fig. 1. Illustration of ultrasonic device used in experiments.
During this experimental work, we exploited the LabVIEW environment as a plate-forme to pilot the PicoScope and manage the ultrasonic signals traveled through UHT milk pack: acquisition, recording, visualization, calculation of the FFT and the application of signal processing techniques to perform the ultrasonic parameters measures. ,
4685
4686
E. Ouacha et al. / Materials Today: Proceedings 2 (2015) 4684 – 4688
2.2. Ultrasonic measurements of flight-time In our case we measure flight-time by exploiting the cross correlation method. The principle of this technique is to take the first signal transmitted as a reference (Fig.2.). Then we calculate the correlation function between this reference signal and the acquired signal in each acquisition until the end of experiment. ܴሺݐሻ is the cross-correlation function between the reference signal and the signal transmitted at a given acquisition, ሺሻthe Hilbert transform of the function ܴሺݐሻ, the envelope of the correlation ܴሺݐሻ is given by the following formula [11]:
E ( R(t )) = R 2 (t ) + H 2 (t )
(1)
The figure 3 below shows the result of the application of this method in a given acquisition. The flight-time corresponds at the most of the envelope. In the platform developed in this work, we apply this technique for every acquisition of which the purpose to follow the evolution of the flight-time.
1,5
80
Amplitude ( V)
Amplitude (v)
signal of cross correlation envelope of the cross correlation
60
1,0 0,5 0,0 -0,5 -1,0
40 20 0 -20 -40 -60
-1,5 30
40
50
60
70
30
80
45
60
75
90
105
120
Time (μs)
Time (μs) Fig. 2. Example of the ultrasound signal transmitted through the UHT milk package.
Fig. 3. The envelope of the cross correlation function.
3. Results We present at first the results found for the sterile and the unsterile packages of the UHT milk. Figures 4 and 5 represent respectively the evolution of flight-time for the different temperatures: 27°C; 30°C; 35°C; 37°C and 40°C for the two cases studied in this work. 27°C without 30°C without 35°C without 37°C without 40°C without
Flight-time (μ s)
55,2 55,0 54,8
55,4
27°C with 30°C with 35°C with 37°C with 40°C with
55,2
Flight-time (μs)
55,4
54,6 54,4 54,2 54,0 53,8
55,0 54,8 54,6 54,4 54,2 54,0 53,8
53,6
53,6
0
10
20
30
40
50
60
70
Time (h) Fig. 4. The evolution of flight-time in different temperatures
0
10
20
30
40
50
60
70
Τime (h) Fig. 5. The evolution of flight-time in different temperatures.
4687
E. Ouacha et al. / Materials Today: Proceedings 2 (2015) 4684 – 4688
The figure 4 illustrates the evolution of flight-time of different with temperatures. This figure shows clearly dependence between the flight-time and the temperature and it countered very obvious at the level of the beginning of every experience. Specifically and as shown in Figure 4, we observe that the flight-time decreases according to increasing temperatures. The maximum flight-time is recorded for temperature 27°C and its minimum value is marked for the temperature 40°C. But after the start and provided fixed temperature in each experiment, we note that the evolution of flight time continues to increase as differently to temperatures next time. Indeed, analyzing the curves shown in Figure 7 we deduce two different paces: The first look is an almost linear growth and the second represents exponential growth. The evolution of flight time for the two temperatures 27°C and 30°C has an increasing pace that is almost linear. The evolution of flight time in the temperature 35°C is apparently typical compared to other temperatures because if we look at the evolution deeply about this temperature. For the temperature 37°C and 40°C we observe that the evolution of flight time is growing exponentially we see from the look that the evolution of flight time is just starting to stabilize. The figure 5 shows the evolution of flight-time in different temperatures. We can report the same conclusion as before in the case of packages without hole. We note that this trend keeps growing pace during each experiment with a slight difference with this type of look that can be either nearly linear or nonlinear. At the beginning we have a certain dependence between the flight-time and temperature, the more we increase the value of the temperature more we note a decrease in the value of the flight-time. After this initial moment, we note that the evolution of flight-time is of increasing velocity provided fixed temperature in each experiment. Indeed, we have an almost linear increasing velocity in temperatures 27°C, 30°C and a quasi-linear and nonlinear increasing pace in temperatures 35° C, 37°C and finally a nonlinear increasing pace in the temperature 40°C. 4. Discussion
The figure 6, 7, 8, 9, 10 below shows an illustration of the evolution of flight-time in different temperatures for the both cases studied in this work: sterilized UHT milk package (without air intrusion) and unsterilized UHT milk package (with air intrusion). Each package of the milk is examined in both cases for each temperature. The intrusion of air is achieved thanks to an infinitesimal hole on the package using a syringe. 54,4
27°C without hole 27°C with hole
54,6
54,6
30°C without hole 30°C with hole
54,3
54,5
54,4
54,4 54,3 54,2 54,1
54,2
Flight-time (μ s)
Flight-time (μ s)
Flight-time (μ s)
35°C without hole 35°C with hole
54,5
54,1 54,0 53,9
54,2 54,1 54,0 53,9 53,8
53,8
54,0
54,3
53,7 0
10
20
30
40
50
60
70
0
Time (h) Fig.6. The evolution of flight-time at the temperature 27°C.
30
40
50
60
70
55,2
Flight-time (μ s)
55,0
54,6 54,4 54,2 54,0
54,8 54,6 54,4 54,2 54,0 53,8
53,8
53,6
53,6 0
10
20
30
40
50
60
Time (h) Fig.9. The evolution of flight-time at the temperature 37°C.
70
0
10
20
30
40
10
20
30
40
50
60
Fig.8. The evolution of flight-time at the temperature 35°C.
40°C without hole 40°C with hole
55,4
0
Time (h)
Fig.7. The evolution of flight-time at the temperature 30°C.
54,8
Flight-Time (μ s)
20
Time (h)
37°C without hole 37°C with hole
55,0
10
50
60
Time (h) Fig.10. The evolution of flight-time at the temperature 40°C.
70
70
4688
E. Ouacha et al. / Materials Today: Proceedings 2 (2015) 4684 – 4688
The figures above show the evolution of flight time at different temperatures for the following two cases: sterilized package (air intrusion of absence) and unsterilized package (presence of air intrusion). We note that the flight time is an ultrasonic parameter given information on the medium studied. This is being said because the flight time shows a difference very clearly between the sterilized-trace and unsterilized-trace. This study shows that the temperature of 35°C has an exception because in this temperature also shows a difference between the two studied cases at an early stage. Furthermore, this technique ultrasound confirmed that the temperature of 35°C is the ideal temperature for bacterial growth [10] because in that temperature where we found bacterial activity early compared to other temperatures. Indeed, after 4 hours, the bacterial growth began at this temperature 5. Conclusions In this experimental study, we have demonstrated the reliability of the ultrasound transmission technique for evaluate the UHT milk quality after the opening of packaging. In addition, this study also confirmed that the temperature of 35 degrees is the ideal temperature for bacterial growth because it is within this temperature where we found an early time or UHT milk validity to consumer after the opening of packaging in comparison with the other temperatures. Reference [1] [2] [3] [4] [5] [6] [7]
[8] [9] [10]
[11]
R.R.B. Singh, A.P. Ruhil, D.K. Jain, A.A. Patel, G.R. Patil " Prediction of sensory quality of UHT milk – A comparison of kinetic and neural network approaches " Journal of Food Engineering 92, 2009, 146–151. Luis Elvira, Carmen M. Durán, José Urréjola, Francisco R. Montero de Espinosa " Detection of microbial contamination in fruit juices using non-invasive ultrasound" Food Control 40, 2014, 145-150. Taifi. N, Bakkali. F , Faiz. B, Moudden. A, Maze. G and Decultot. D. " Characterization of the syneresis and firmness of the milk gel using au ultrasonic technique", Meas-Sci. Technol, 17 , 2006, 281-287. Mohammadi, M. Ghasemi-Varnamkhasti, R. Ebrahimi, M. Abbasvali, "Ultrasonic Techniques for the Milk Production Industry", Measurement ,2014. Michele S. Pinto, Ana C.S. Pires, Helena M.P. Sant’Ana , Nilda F.F. Soares, Antonio F. Carvalho "Influence of multilayer packaging and microfiltration process on milk shelf life", food packaging and shelf life xxx , 2014, xxx -xxx. Bakkali F., Moudden A., Faiz B., Amghar A., Maze G., Montero de Espinosa F., Akhnak M., "Ultrasonic measurement of milk coagulation time", Meas Sci Technol, 12, 2001, 2154–2159. Elvira, L., Montero de Espinosa, F., Resa, P. & Gomez-Ullate, Y. "Deteccion y analisis no invasivo de microorganismos en productos lacteos envasados en recipientes laminados basados en papel o carton utilizando ondas elasticas por acoplamiento en seco", Patent PCT/ES, 2003, 03/00287. Nagata, M., Kaneoka, T., Imano, S. & Matumoto, H. "Ultrasonic method of inspecting contents of a package and apparatus thereof", Fujimori Kogyo Co. Ltd.. EP269815, 1987. Heaggstrom, E. "Ultrasound detection of microbe contamination in premade food”, Acta Polytechnica Scandinavica Applied Physics Series, 214, 1997, 1-115. L. Elvira, L. Sampedro , J. Matesanz,Y.Gomez-Ullate , P. Resa , J.R. Iglesias, F.J. Echevarrı, F. Montero de Espinosa "Non-invasive and non-destructive ultrasonic technique for the detection of microbial contamination in packed UHT milk", Food Research International 38, 2005, 631–638. E. Ouacha, B. Faiz, A. Moudden, I. Aboudaoud, H. Banouni, M. Boutaib, H. Bita "Non-destructive characterization of the air influence on the UHT milk quality by ultrasonic technique", IEEE, pp. 296-299, 2015.
ScienceDirect Materials Today: Proceedings 2 (2015) 4684 – 4688
SURFOCAP 2015
Ultrasonic evaluation of UHT milk quality after opening E. Ouachaa, *, A. Mouddena, B. Faiza, I. Aboudaouda, H. Banounia, , M. Boutaiba, D. Izbaima, H. Bitaa a
Ibn Zohr University, Faculty of Sciences, Dept of Physics, Metrology and Information Processing Laboratory, Agadir, Morocco
Abstract
Non invasive techniques based on ultrasonic have advantageous features to study the food products. Our objective of this study is developed the ultrasonic transmission technique to characterize and evaluating UHT milk quality. To check the reliability of this technique, we followed the evolution of these ultrasonic parameters for different temperatures for sterilized milk packet and no-sterilized milk packet. The results obtained from these both cases, we confirmed the reliability of this emerging technique to the difference between these two cases, that is to say, for detecting the validity of UHT milk after opening of the packaging at a given temperature. ©2015 Elsevier Ltd. All rights reserved. © 2015 Elsevier Ltd. All rights reserved. Selection andpeer-review peer-reviewunder under responsibility of the Conference Committee Members of International Workshop on Selection and responsibility of the Conference Committee Members of International Workshop on Functionalized SurfacesforforSensor Sensor Applications (Surfocap’15). Functionalized Surfaces Applications Keywords: Type your keywords here, separated by semicolons ;
1. Introduction The quality control is an important aspect in food production. The major purpose of this control is to verify the acceptability of food in terms of nutritional value and safety. The development of new techniques for the quality control continues to increase according to the requirements imposed by the consumers and the authentication of food security. Several non-destructive methods are being developed for food quality control, we mention the following examples: the near-infrared spectroscopy, Raman spectroscopy, biosensors and ultrasound.
* Corresponding author. Tel.: +212-662-511-117. E-mail address: [email protected]
2214-7853 © 2015 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the Conference Committee Members of International Workshop on Functionalized Surfaces for Sensor Applications doi:10.1016/j.matpr.2015.09.023
E. Ouacha et al. / Materials Today: Proceedings 2 (2015) 4684 – 4688
The potential of ultrasound as a tool for non-destructive quality control of food products is currently under investigation. The ultrasonic waves have a valuable feature that consists in its ability to characterize opaque materials such as packed UHT [1] and packed fruit juice [2]. Recently, ultrasonic techniques were used to monitor lactic fermentation of milk [3] [4], measurement of milk compositions [5] and control of milk coagulation [6]. Ultrasound technology has recently made a very sensitive task that directly affects a critical need of consumers. This major advantage consists in detection of microbial contamination of milk. In this context, we mention the following published works: [7] have patented an ultrasonic inspection method for liquid food products; [8] was able to detect early infection in modified milk pack submerged in water; [9] have developed a device for detection of microbial growth within the UHT milk pack; [10] analyzed the performance of their ultrasonic device to perform nondestructive and rapid detection of microbial contamination of UHT milk packs. UHT milk quality is determined by the absence of any air-trace in the package. Industrials take, according to a specific sampling, a number of packets of UHT milk per day for destructive testing. However, this procedure creates a problem that keeps pushing especially if we take into account the fact that sometimes we find in reality individual UHT milk packages which are partially or totally damaged and yet it is mentioned above that is still valid for consumers. Our prime objective in this works is to develop an ultrasonic technique which aims to characterize all UHT milk packets instead to characterize just a few ones. This characterization aims to detect non-destructively the presence of any air-trace in the package since its presence will have a negative influence on UHT milk quality during storage time, and sometimes this happens before the expiration date is exhausted. 2. Material and methods 2.1. The experimental device of ultrasonic measurements The figure.1 shows the experimental setup of ultrasonic measurements used in this work in order to follow the evolution of the ultrasonic parameters. In this method, we used two identical transducers. These transducers and the samples were immersed in water inside a thermostat. The transducers (0.5 MHz as a central frequency) are mounted face to face on the opposite sides of the UHT package.
Fig. 1. Illustration of ultrasonic device used in experiments.
During this experimental work, we exploited the LabVIEW environment as a plate-forme to pilot the PicoScope and manage the ultrasonic signals traveled through UHT milk pack: acquisition, recording, visualization, calculation of the FFT and the application of signal processing techniques to perform the ultrasonic parameters measures. ,
4685
4686
E. Ouacha et al. / Materials Today: Proceedings 2 (2015) 4684 – 4688
2.2. Ultrasonic measurements of flight-time In our case we measure flight-time by exploiting the cross correlation method. The principle of this technique is to take the first signal transmitted as a reference (Fig.2.). Then we calculate the correlation function between this reference signal and the acquired signal in each acquisition until the end of experiment. ܴሺݐሻ is the cross-correlation function between the reference signal and the signal transmitted at a given acquisition, ሺሻthe Hilbert transform of the function ܴሺݐሻ, the envelope of the correlation ܴሺݐሻ is given by the following formula [11]:
E ( R(t )) = R 2 (t ) + H 2 (t )
(1)
The figure 3 below shows the result of the application of this method in a given acquisition. The flight-time corresponds at the most of the envelope. In the platform developed in this work, we apply this technique for every acquisition of which the purpose to follow the evolution of the flight-time.
1,5
80
Amplitude ( V)
Amplitude (v)
signal of cross correlation envelope of the cross correlation
60
1,0 0,5 0,0 -0,5 -1,0
40 20 0 -20 -40 -60
-1,5 30
40
50
60
70
30
80
45
60
75
90
105
120
Time (μs)
Time (μs) Fig. 2. Example of the ultrasound signal transmitted through the UHT milk package.
Fig. 3. The envelope of the cross correlation function.
3. Results We present at first the results found for the sterile and the unsterile packages of the UHT milk. Figures 4 and 5 represent respectively the evolution of flight-time for the different temperatures: 27°C; 30°C; 35°C; 37°C and 40°C for the two cases studied in this work. 27°C without 30°C without 35°C without 37°C without 40°C without
Flight-time (μ s)
55,2 55,0 54,8
55,4
27°C with 30°C with 35°C with 37°C with 40°C with
55,2
Flight-time (μs)
55,4
54,6 54,4 54,2 54,0 53,8
55,0 54,8 54,6 54,4 54,2 54,0 53,8
53,6
53,6
0
10
20
30
40
50
60
70
Time (h) Fig. 4. The evolution of flight-time in different temperatures
0
10
20
30
40
50
60
70
Τime (h) Fig. 5. The evolution of flight-time in different temperatures.
4687
E. Ouacha et al. / Materials Today: Proceedings 2 (2015) 4684 – 4688
The figure 4 illustrates the evolution of flight-time of different with temperatures. This figure shows clearly dependence between the flight-time and the temperature and it countered very obvious at the level of the beginning of every experience. Specifically and as shown in Figure 4, we observe that the flight-time decreases according to increasing temperatures. The maximum flight-time is recorded for temperature 27°C and its minimum value is marked for the temperature 40°C. But after the start and provided fixed temperature in each experiment, we note that the evolution of flight time continues to increase as differently to temperatures next time. Indeed, analyzing the curves shown in Figure 7 we deduce two different paces: The first look is an almost linear growth and the second represents exponential growth. The evolution of flight time for the two temperatures 27°C and 30°C has an increasing pace that is almost linear. The evolution of flight time in the temperature 35°C is apparently typical compared to other temperatures because if we look at the evolution deeply about this temperature. For the temperature 37°C and 40°C we observe that the evolution of flight time is growing exponentially we see from the look that the evolution of flight time is just starting to stabilize. The figure 5 shows the evolution of flight-time in different temperatures. We can report the same conclusion as before in the case of packages without hole. We note that this trend keeps growing pace during each experiment with a slight difference with this type of look that can be either nearly linear or nonlinear. At the beginning we have a certain dependence between the flight-time and temperature, the more we increase the value of the temperature more we note a decrease in the value of the flight-time. After this initial moment, we note that the evolution of flight-time is of increasing velocity provided fixed temperature in each experiment. Indeed, we have an almost linear increasing velocity in temperatures 27°C, 30°C and a quasi-linear and nonlinear increasing pace in temperatures 35° C, 37°C and finally a nonlinear increasing pace in the temperature 40°C. 4. Discussion
The figure 6, 7, 8, 9, 10 below shows an illustration of the evolution of flight-time in different temperatures for the both cases studied in this work: sterilized UHT milk package (without air intrusion) and unsterilized UHT milk package (with air intrusion). Each package of the milk is examined in both cases for each temperature. The intrusion of air is achieved thanks to an infinitesimal hole on the package using a syringe. 54,4
27°C without hole 27°C with hole
54,6
54,6
30°C without hole 30°C with hole
54,3
54,5
54,4
54,4 54,3 54,2 54,1
54,2
Flight-time (μ s)
Flight-time (μ s)
Flight-time (μ s)
35°C without hole 35°C with hole
54,5
54,1 54,0 53,9
54,2 54,1 54,0 53,9 53,8
53,8
54,0
54,3
53,7 0
10
20
30
40
50
60
70
0
Time (h) Fig.6. The evolution of flight-time at the temperature 27°C.
30
40
50
60
70
55,2
Flight-time (μ s)
55,0
54,6 54,4 54,2 54,0
54,8 54,6 54,4 54,2 54,0 53,8
53,8
53,6
53,6 0
10
20
30
40
50
60
Time (h) Fig.9. The evolution of flight-time at the temperature 37°C.
70
0
10
20
30
40
10
20
30
40
50
60
Fig.8. The evolution of flight-time at the temperature 35°C.
40°C without hole 40°C with hole
55,4
0
Time (h)
Fig.7. The evolution of flight-time at the temperature 30°C.
54,8
Flight-Time (μ s)
20
Time (h)
37°C without hole 37°C with hole
55,0
10
50
60
Time (h) Fig.10. The evolution of flight-time at the temperature 40°C.
70
70
4688
E. Ouacha et al. / Materials Today: Proceedings 2 (2015) 4684 – 4688
The figures above show the evolution of flight time at different temperatures for the following two cases: sterilized package (air intrusion of absence) and unsterilized package (presence of air intrusion). We note that the flight time is an ultrasonic parameter given information on the medium studied. This is being said because the flight time shows a difference very clearly between the sterilized-trace and unsterilized-trace. This study shows that the temperature of 35°C has an exception because in this temperature also shows a difference between the two studied cases at an early stage. Furthermore, this technique ultrasound confirmed that the temperature of 35°C is the ideal temperature for bacterial growth [10] because in that temperature where we found bacterial activity early compared to other temperatures. Indeed, after 4 hours, the bacterial growth began at this temperature 5. Conclusions In this experimental study, we have demonstrated the reliability of the ultrasound transmission technique for evaluate the UHT milk quality after the opening of packaging. In addition, this study also confirmed that the temperature of 35 degrees is the ideal temperature for bacterial growth because it is within this temperature where we found an early time or UHT milk validity to consumer after the opening of packaging in comparison with the other temperatures. Reference [1] [2] [3] [4] [5] [6] [7]
[8] [9] [10]
[11]
R.R.B. Singh, A.P. Ruhil, D.K. Jain, A.A. Patel, G.R. Patil " Prediction of sensory quality of UHT milk – A comparison of kinetic and neural network approaches " Journal of Food Engineering 92, 2009, 146–151. Luis Elvira, Carmen M. Durán, José Urréjola, Francisco R. Montero de Espinosa " Detection of microbial contamination in fruit juices using non-invasive ultrasound" Food Control 40, 2014, 145-150. Taifi. N, Bakkali. F , Faiz. B, Moudden. A, Maze. G and Decultot. D. " Characterization of the syneresis and firmness of the milk gel using au ultrasonic technique", Meas-Sci. Technol, 17 , 2006, 281-287. Mohammadi, M. Ghasemi-Varnamkhasti, R. Ebrahimi, M. Abbasvali, "Ultrasonic Techniques for the Milk Production Industry", Measurement ,2014. Michele S. Pinto, Ana C.S. Pires, Helena M.P. Sant’Ana , Nilda F.F. Soares, Antonio F. Carvalho "Influence of multilayer packaging and microfiltration process on milk shelf life", food packaging and shelf life xxx , 2014, xxx -xxx. Bakkali F., Moudden A., Faiz B., Amghar A., Maze G., Montero de Espinosa F., Akhnak M., "Ultrasonic measurement of milk coagulation time", Meas Sci Technol, 12, 2001, 2154–2159. Elvira, L., Montero de Espinosa, F., Resa, P. & Gomez-Ullate, Y. "Deteccion y analisis no invasivo de microorganismos en productos lacteos envasados en recipientes laminados basados en papel o carton utilizando ondas elasticas por acoplamiento en seco", Patent PCT/ES, 2003, 03/00287. Nagata, M., Kaneoka, T., Imano, S. & Matumoto, H. "Ultrasonic method of inspecting contents of a package and apparatus thereof", Fujimori Kogyo Co. Ltd.. EP269815, 1987. Heaggstrom, E. "Ultrasound detection of microbe contamination in premade food”, Acta Polytechnica Scandinavica Applied Physics Series, 214, 1997, 1-115. L. Elvira, L. Sampedro , J. Matesanz,Y.Gomez-Ullate , P. Resa , J.R. Iglesias, F.J. Echevarrı, F. Montero de Espinosa "Non-invasive and non-destructive ultrasonic technique for the detection of microbial contamination in packed UHT milk", Food Research International 38, 2005, 631–638. E. Ouacha, B. Faiz, A. Moudden, I. Aboudaoud, H. Banouni, M. Boutaib, H. Bita "Non-destructive characterization of the air influence on the UHT milk quality by ultrasonic technique", IEEE, pp. 296-299, 2015.