Ultrasonic Techniques for the Milk Production Industry

Abstract

Ultrasound waves are propagated in upper frequencies from the limit of human hearing and have lower wavelength and more attenuation coefficient. Ultrasound in higher frequencies and low powers has a good sensitivity and no effects on mechanical or chemical properties of material but only causes vibrations in the molecules. High power ultrasound with lower frequencies has the acoustic energy packages which induces physical, mechanical, and chemical changes in the material. The major reason in this process is the cavitation phenomenon which provides high temperature and pressure by collapsing the micro-bubbles. Ultrasound applications are classified into high intensity and low intensity. Analytical ultrasound involves monitoring and quality control of dairy products based on the physicochemical variations during storage or processing. High intensity ultrasound has been employed for processing applications such as pasteurization, homogenization, fermentation, and extraction. This paper presents a comprehensive review on the potential applications of ultrasound techniques in milk industry.

Full text

Review
Ultrasonic techniques for the milk production industry
Vahid Mohammadi
a
, Mahdi Ghasemi-Varnamkhasti
a,
⇑
, Rahim Ebrahimi
a
, Maryam Abbasvali
b
a
Department of Mechanical Engineering of Biosystems, Shahrekord University, Shahrekord 115, Iran
b
Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord 115, Iran
article info
Article history:
Received 10 December 2013
Received in revised form 12 August 2014
Accepted 14 August 2014
Available online 28 August 2014
Keywords:
Ultrasound
Milk industry
Sensor
Quality control
Food machinery
abstract
Ultrasound waves are propagated in upper frequencies from the limit of human hearing
and have lower wavelength and more attenuation coefficient. Ultrasound in higher fre-
quencies and low powers has a good sensitivity and no effects on mechanical or chemical
properties of material but only causes vibrations in the molecules. High power ultrasound
with lower frequencies has the acoustic energy packages which induces physical, mechan-
ical, and chemical changes in the material. The major reason in this process is the cavita-
tion phenomenon which provides high temperature and pressure by collapsing the micro-
bubbles. Ultrasound applications are classified into high intensity and low intensity. Ana-
lytical ultrasound involves the monitoring and quality control of dairy products based on
the physicochemical variations during storage or processing. High intensity ultrasound
has been employed for processing applications such as pasteurization, homogenization,
fermentation, and extraction. This paper presents a comprehensive review on the potential
applications of ultrasonic techniques in milk industry.
Ó2014 Elsevier Ltd. All rights reserved.
Contents
1. Introduction . . . .......................................................................................... 94
1.1. Milk industry . . . . . . . . . . ............................................................................. 94
2. Low power ultrasound . . . . . . . . . . . . . . ....................................................................... 94
2.1. Use of low power ultrasound . . . . . . . . . . . . . ............................................................. 95
2.1.1. Pulse–echo technique. . . . . . . .................................................................. 95
2.1.2. Transmission technique . . . . . .................................................................. 96
2.2. Ultrasonic monitoring and quality control . . ............................................................. 96
3. Power ultrasound . . . . . . . . . . . . . . . . . . ....................................................................... 97
3.1. Generation of power ultrasound . . . . . . . . . . ............................................................. 98
3.2. Applications for processing. . . . . . . . . . . . . . . ............................................................. 98
4. Conclusion . . . . .......................................................................................... 99
References . . . . .......................................................................................... 99
http://dx.doi.org/10.1016/j.measurement.2014.08.022
0263-2241/Ó2014 Elsevier Ltd. All rights reserved.
⇑
Corresponding author. Tel.: +98 3814424403; fax: +98 3814424428.
E-mail address: ghasemymahdi@gmail.com (M. Ghasemi-Varnamkhasti).
Measurement 58 (2014) 93–102
Contents lists available at ScienceDirect
Measurement
journal homepage: www.elsevier.com/locate/measurement
Author's Personal Copy

1. Introduction
Recent developments in food sciences have led to pro-
duce high quality and fresh-like products [1]; furthermore,
consumers are wishful to use more pleasant foods. In other
words, manufacturers would produce the best products
with lower processes, time, and costs. Long shelf life, sta-
bility, low price, delectability are important factors which
all companies would like to attain [2].
Ultrasonic has expanded to the high level in many sci-
ences like food industry machinery, medicine, electronics,
oceanography, military, robotics, and so on. Therefore, in
many fields, it becomes a strong tool used for sensitive,
non-destructive, and non-invasive techniques. Ultrasonic
wave is the mechanical wave at frequencies above
16 kHz propagating by particles vibration in the medium
and travels through the bulk of material depending on
physical and mechanical properties, such as texture and
structure [1].
As emphasized in the literature [3–5] applications of
ultrasound in the food industry are classified into low-
intensity and high-intensity ultrasound. The low-intensity
(low power) ultrasound is known as a non-destructive tool
where it uses typically smaller power levels (<1 W/cm
2
)
and frequencies higher than 100 kHz. High-intensity (high
power) ultrasound uses intensities higher than 10 W/cm
2
at frequencies between 20 and 100 kHz, that are disruptive
and affects on physical, mechanical and chemical/bio-
chemical properties of foods [6,7].
Some research fields like electronics, chemistry, and
food science are interrelated in the most of ultrasound
applications in food industry. Therefore, ultrasound cannot
be simply utilized to meet the demands of different appli-
cations, and ultrasound equipment has to be custom
designed to provide a specific application [5].
1.1. Milk industry
Ultrasound methods have been used in many investiga-
tions on milk and its derivatives [8–13]. Many reports are
found in the literature for improving the quality of food
products [14–19], improving process efficiency [20–22],
simplifying manipulation and measurement [19,23] and
achieving a non-destructive method (e.g. detecting, char-
acterizing and monitoring methods) against common
methods [24–27].
A survey of applications in milk industry is presented in
Table 1.Methodology of applications indicates that some
factors such as frequency, power, and time of stimulation
can change applicability and results of ultrasonication.
Thus, a comprehensive view on physical, chemical, and
functional properties is needed for selecting or creating
appropriate ultrasonic system. In addition, operating con-
ditions well lead to optimum results [5]. At the following
sections, this review paper deals with different aspects of
ultrasound applications in milk industry.
2. Low power ultrasound
Non-destructive monitoring parallel with production
processes detects and achieves the risks associated with
manufacture, storage, and distribution of food products
and provides a fast maintenance in order to in-line control-
ling to solve or reduction of these risks in specific points of
Table 1
Applications of ultrasound in milk industry.
Application Mechanism/details Authors Advantages
Microorganism inactivation Cavitation phenomena; frequencies
about 20 kHz, high power
[14,28–31] Minor variation in physicochemical and
nutritional properties
Higher shelf life
Less energy consumption
Homogenization Using cavitation; frequencies from
20 kHz to 100 kHz, high power
[32,33] Reducing process temperature and time
Creaming Frequencies between 20 and 100 kHz [19] Promoting quality and security
Cutting Conversion of the mechanical
vibration energy into thermal energy,
frequency 40 kHz
[34,35] Rapid process
Reducing the pressure of process
Independent with temperature
Dissolution Power ultrasound [36] Decreasing the time of process
Viscosity decreasing Almost at 20 kHz and high powers [21,37] Controlling dairy viscosity
Preventing the ‘age thickening’
Fermentation Low frequencies and high intensity
ultrasound
[16,38] Accelerate the process
Better quality products
Less undesirable flavor
Filtration/fouling prevention Based on cavitation phenomenon;
20 kHz frequency, low power
[39–41] Higher permeate flux
Needing to lower pressures
More money saving
Extraction Based on collapsing micro-bubbles [42,43] Higher enrichment
Better quality
Monitoring/quality control Analyzing of signals, high frequencies
and low powers
[18,27,44–48] Non-invasive and non-destructive diagnosis
Fast and inline tests
Non-contact and without manipulation
94 V. Mohammadi et al. / Measurement 58 (2014) 93–102
Author's Personal Copy

the process phases [4,49]. In food industries, proceeding of
process, quality level, physical and chemical properties,
system safety, and security control are the factors which
can be monitored. Thus, in production line two points are
considered: detecting the occurrence of changes and risks,
and the ability to control and eliminate those. Many stud-
ies have demonstrated the capability of ultrasound for ana-
lytical applications by identifying different properties of
dairy products [50–52]. Investigations have involved
detection and identification of foreign bodies [45,53,54],
rheological measurements [55], characterizing and moni-
toring microbiological and enzymatic reactions [56], mon-
itoring changes of structural properties [18,44,57,58],
monitoring and food characterization [59–61], monitor
and detection of fouling [62,63], and solid fat content
determination [64].
2.1. Use of low power ultrasound
Transmitting an ultrasound wave through a substance,
gas, liquid or solid media changes the structural and elas-
ticity properties. Ultrasonic transducer which is in commu-
nication with molecules of the medium emits sound waves
into the substance and molecules transmit the motion to
the adjoining molecules before returning to approximately
their original position [65]. This phenomenon makes alter-
nating compression and decompression cycles depending
on material properties, which changes ultrasonic wave’s
characteristics such as wavelength, velocity, amplitude,
pressure, frequency and period [5]. Parameters being mea-
sured in majority of investigations are the ultrasonic veloc-
ity, attenuation coefficient and acoustic impedance [66].
Ultrasonic velocity (
m
) is determined with relationship
between density (
q
) and elasticity (E) of the medium [5]:
m
¼ffiffiffiffiffiffiffiffiffi
E=
q
pð1Þ
In principle, this equation shows that whatever elastic-
ity moduli be more, the ultrasonic velocity will be higher.
The moduli and densities of materials are the properties
which depend on structure, composition, and physical
state; therefore, ultrasonic velocity measurements can give
information about these properties [66]. Also, as cited in
the literature, in many applications, ultrasonic velocity as
a sensitive variable has been used [25,44,64,67–71].
Any factor which converts acoustic energy to other types
of energy or attenuates ultrasound waves during traveling
the medium is named ‘‘attenuation factor’’ [72]. The most
important causes of attenuation are adsorption and scatter-
ing. Physical mechanisms like fluid viscosity, thermal con-
duction, and molecular relaxation are the reasons for
generating adsorption and heterogeneous materials, such
as emulsions, suspensions, and foams [66]. Attenuation is
related to viscosity, compressibility, wall material, and scat-
tering and adsorption effects of material which can present
information about the physicochemical properties of food
materials including concentration, viscosity, molecular
relaxation, and microstructure [5]. Attenuation coefficient
measurements have been documented for prediction of
the reconstitution behavior of powders [18], to define the
extent and rate of dissociation of micellar calcium phos-
phate [73],and ultrasonic spectroscopy of rennet-induced
gelation of milk [44]. The attenuation coefficient (
a
)ofa
material is determined by the following equation [65]:
A¼A
0
e

a
x
ð2Þ
In the equation, A
0
is the initial amplitude of the sound
wave, and Ais the amplitude of the transmitted wave
through distance x. Almost the attenuation coefficient is
expressed in decibels per meter (dB/m). Another parame-
ter, acoustic impedance, governs the proportion of trans-
mission and reflectance of the sound beam at the
boundary between component phases [72]. Simplified
acoustic impedance is described by Z=
q
cwhere
q
and c
are the density and the speed of sound, respectively.
Reflection coefficient (R) which is affected by acoustic
impedance attains with the ratio of the amplitude of the
reflected wave (A
r
) on the incident wave (A
i
). For a plane
wave that is normally incident upon a plane boundary, this
equation is presented [66]:
R¼A
r
A
i
¼Z
1
Z
2
Z
1
þZ
2
ð3Þ
where Z
1
and Z
2
are the acoustic impedances of two mate-
rials. Likewise, acoustic impedance depends on composi-
tion and microstructure of the materials. Acoustic
impedance measurements based on ultrasound energy
reflectance are used to fouling detection [74], detecting
chemical additives in branded milk [75], detecting foreign
bodies [45,54,55], shear wave rheology of weak particle
gels [55], fat droplet size distribution in homogenized milk
[51], and quality measurements of dairy products [24].
There are various ways to employ ultrasonic tools for
characterizing and monitoring food processes in which
the relationships of linked instruments focus on increasing
the applicability and efficiency of non-destructive system.
However, applications can be considered in two major
methods: pulse–echo and transmission techniques.
2.1.1. Pulse–echo technique
In this method the pulsed sonic wave is shouted into
the material and the echo signal is received where a single
Fig. 1. Schematic diagram of pulse–echo technique for measuring ultra-
sonic velocity (
m
); time delay (t) and Lis the length of the material [66].
V. Mohammadi et al. / Measurement 58 (2014) 93–102 95
Author's Personal Copy

transducer acts as a transmitter and a receiver. In this case,
traveling time (t) of the wave is measurable and the length
of the material (L) is constant and available, then the sound
velocity can be calculated by the following equation:
m
¼2L=tð4Þ
As shown in Fig. 1, a basic experimental arrangement
can be constructed to measure the ultrasonic velocity. A
pulse generator produces an electrical pulse in an appro-
priate frequency that transducer works at it. Ultrasonic
transducer converts the electrical pulse into an acoustic
signal which passes through the sample material and after
striking the signal to the far wall of sample cell, it returns
and is detected by the transducer which converts the
received acoustic signal to an electrical pulse again. Time
difference of the signals can be calculated on the oscillo-
scope screen. Also, the ultrasonic velocity, attenuation
coefficient and acoustic impedance of sound waves can
be monitored and calculated using a personal computer
[6]. Pulse–echo technique is mostly used in the investiga-
tions because it can easily be automated, simply operated,
and rapidly measured [66].
2.1.2. Transmission technique
In this method an ultrasonic transmitter propagates
acoustic waves into the sample material which partly
reflect and partly pass to another side of the sample cell
(Fig. 2). Then the ultrasonic receiver detects the transmit-
ted signals and sends these signals to oscilloscope for mon-
itoring. Transducers are mutually placed on two sides of
the cell [65]. Both the transmitter and the receiver trans-
ducers are connected to the oscilloscope that provides
comparative condition to monitor and measure the time
delay [5]. A computer can be used as suit monitoring pro-
cess, calculating the parameters, running algorithms, and
operating other temperature and humidity control sys-
tems. Time of flight of the pulse which is the needed time
for traveling the original pulse through the sample, can be
measured extremely precise. Therefore, transmission tech-
nique is used for applications in which highly accurate
measurements are required [66], such as measuring
acoustic properties without contact to the sample [45],
microbiological quality evaluation [47],characterizing col-
loidal particles [27], and the rheological measurements of
weak particle gels [55].
2.2. Ultrasonic monitoring and quality control
Non-destructive ultrasonic methods have caused much
interest for measuring the quality of food products and
monitoring processes. Monitoring production cycle leads
to produce high quality outputs, and if this monitoring
be non-destructive it can prevent destruction from sam-
ples and then from wastage of overall costs; also, if moni-
toring be non-contact and non-destructive, it can remove
manipulations and time wastages. Therefore, ultrasonic
monitoring can be ideal in food production and processing.
Accordingly, in milk industry many studies have been
reported in which ultrasound has been used for monitoring
and identification [18,24,25,27,44,45,54,68,73,76–78].
Usually an ultrasonic system has been used for detect-
ing physicochemical changes of dairy products [24,47].
Indeed, research attempts of ultrasonic monitoring are
based on the analysis of acoustic signals. When ultrasonic
waves pass through a media, some of their properties may
be changed. Elvira et al. [47] detected growth of microor-
ganisms in UHT milk by using eight-channel ultrasonic
system. They reported that microbial contamination
induces changes in ultrasonic propagation parameters
which are detected by signal processing and analysis of
amplitude and time of wave flight [47,56]. Measuring pro-
cess was run by a software program, as the schematic rep-
resentation of the algorithm is illustrated in Fig. 3. After
acquiring data from temperature and moisture controller
and receiving acoustic signals, the software calculates FFT
algorithm, amplitude, and delay of waves. Finally, by ana-
lyzing the data, contamination or changes in the material
properties can be detected. Also, for determination of
microbial quality of UHT milk packages, 800 kHz frequency
was used [47]. Gan et al. [24] employed the transducers at
center frequency of 500 kHz to monitor coagulation pro-
cess. They reported that the amplitude of acoustic wave
changes with time transition after the pH is lowered [24].
Also, Koc and Ozer [26] used ultrasonic for non-destructive
Fig. 2. Schematic diagram of transmission technique; ultrasonic velocity (
m
) is determined by measuring the time delay using accommodation of original
and detected signals [5].
96 V. Mohammadi et al. / Measurement 58 (2014) 93–102
Author's Personal Copy

monitoring of rennet whole milk whilst cheese manufac-
tured. They reported that ultrasonic pulse–echo technique
at 1 MHz central frequency could determine optimum time
of coagulation and stated that the ultrasonic attenuation
coefficient changed with time of coagulation [26].
Some of ultrasound applications came into existence to
alter concerns of manufacturers because of existing foreign
bodies in food products. Low intensity ultrasonic tech-
niques can discover foreign bodies in many of dairy prod-
ucts such as milk, cheese, and yogurt [51]. Pallav et al.
[45] taking into account of application in production lines
performed a work to detect foreign bodies and additives
within cheese. They used a pair of transducers in transmis-
sion mode without contact to the sample. Also an investi-
gation reported the detection and identification of foreign
bodies in different kinds of cheese [54]. This work is based
on an ultrasound reflection measurement in the frequency
of 5 MHz. Foreign bodies consisted of bone, wood, plastic,
steel, stone, and glass with sizes from 1 to 14 mm in diam-
eter. They concluded that discrimination of foreign bodies
in homogeneous samples were easier than inhomogeneous
samples [54].
High resolution ultrasonic has a great sensitivity that
can identify the occurring changes in the smallest particles.
A non-invasive and non-disruptive ultrasonic technique
was used for fundamental understanding of the aggrega-
tion behavior of dairy systems capable for using in real
time monitoring of dairy processes [25]. Gülseren et al.
[27] used ultrasonic frequency ranging from 3 to
99.5 MHz for probing colloidal properties of skim milk.
According to their reports, electroacoustic spectroscopy
has well efficiency for monitoring acidification and heating
of skim milk [27]. It is worth mentioning, higher frequen-
cies provide a good sensitivity for monitoring and quality
control but it strongly raises attenuation in transmitted
waves. Selecting the matching layer plays an important
role in lowering attenuation parameter and to achieve
proper matching between ultrasonic transducer and mate-
rial [79].
3. Power ultrasound
Power ultrasound in lower frequencies within 20–
100 kHz is used for dairy processes in which the sound
intensity is in the range of 10–1000 W/cm
2
[7]. This type
of ultrasound has different physical and chemical effects
on the liquid food which is the result of acoustic cavitation.
Cavitation mechanism provides a remarkable energy
Fig. 3. Detecting process and software flow [47].
V. Mohammadi et al. / Measurement 58 (2014) 93–102 97
Author's Personal Copy

source that generates severe physical forces. In general, the
chemical, physical and biological effects of cavitation
depend on the type of cavitation (e.g. transient, stable, jet-
ting and fragmentary) and its location [80]. Also, some
physical forces such as vibration, heating, and physical agi-
tation can be generated as a result of ultrasonic waves in
the absence of acoustic cavitation [51,81]. Amplitude, pres-
sure, temperature, viscosity, and concentration of solids
are the parameters describing the ultrasonic liquid pro-
cessing as an energy function and acoustic waves intensity
[81].
3.1. Generation of power ultrasound
Ultrasonic transducers convert the electrical energy to
the acoustic energy which causes vibrations in the mole-
cules of the food material. In this case, the driving force
for ultrasonication is acoustic cavitation caused by the
ultrasonic waves passing the liquid [7]. When the ultra-
sonic waves pass through the liquid food, molecules
undergo some mechanical forces. Like any sound wave,
ultrasonic waves are transmitted as a series of compres-
sion and rarefaction cycles. Positive pressure forces the
components of the material, and negative pressure dilates
the molecules. These cycles frequently occur till a cavity is
generated as a result of reactions between rarefaction and
attractive force of molecules [82]. Then, size of cavities
grows in successive cycles which finally produce acoustic
cavitation bubbles. Ultimately, thousands of bubbles are
generated, some of which are relatively stable and others
are enlarged more to an unstable size, and a violent col-
lapsing occurs in millisecond scale by expanding the
attractive force between the molecules. This phenomenon
provides temperatures of about 5000 K and pressures up
to 100 MPa [7,65]. The released volume of energy during
cavitation depends on the kinetics of the bubble growth
and explosion of the bubble. Cavitation energy has a direct
relationship with bubble interface tension and it is in
inverse proportion with vapor pressure of the liquid food
[83].
Ultrasonication depends on main parameters of the
process. First, the frequency is inversely proportional to
the bubble size [84]. Therefore, low frequency ultrasound
produces large cavitation bubbles culminating to locally
higher temperatures and pressures. Second, increasing
the external pressure, it reduces the number of cavitation
bubbles as a result of elevating the cavitation [81].On
the other hand, increasing the external pressure, it incre-
ments the pressure in the bubble at the collapsing moment
resulting in a swifter but violent collapse [84]. Third, tem-
perature of the process influences the vapor pressure, sur-
face tension, and viscosity of the liquid medium [65]. The
higher temperature, the lower viscosity allows for a more
violent collapse. Hence, viscosity in an optimum tempera-
ture is low enough to generate apt violent cavitation bub-
bles, yet the temperature is low enough to avoid the
dampening effect by a high vapor pressure [81]. Further-
more, there is a direct proportion between the sonication
intensity and the square of the vibration amplitude of the
ultrasonic source. As a rule, increasing the intensity
increases the sonochemical effects [65].
3.2. Applications for processing
A large number of technologies have been used for pro-
ducing safe and high quality yielded, because this aim is
economical. Ultrasonic processing methods are utilized
for creaming [19,85], extraction [86,87], cutting [35],
dissolution [36], fermentation [16,88], hydrolysis [89],
microfiltration [39], ultrafiltration [90], homogenization
[32,33,91], encapsulation [92], reducing the allergenicity
of milk proteins [93], and decreasing viscosity [37].
Actually, ultrasound can improve production processes
and create environmental friendly processes [94].
However, for many of dairy applications mentioned above,
there are limited industrial scale ultrasonic reactor
designs, and more developments require an understanding
of the influence of ultrasound processes on milk quality
changes [11].
Zisu et al. [37] used ultrasonic frequency of 20 kHz at
power of 40–80 W to reduce viscosity of concentrated
milk. They observed that sonication lowered the viscosity
of skim milk, and once sonication applied, prevented the
viscosity of skim milk concentrates from increasing rap-
idly. Furthermore, the authors concluded sonication has
industrial application potential for spray drying by
decreasing the viscosity of concentrated milk. Recently,
Yanjun et al. [95] have reported that power ultrasound
can improve the functional properties of milk protein con-
centration, such as solubility, emulsification, and gelation.
In another investigation, it has been shown that power
ultrasound can increase lactose hydrolysis speed and
transgalactosylation of bifidobacteria in milk leading to
the products with lower lactose and higher oligosaccha-
rides and minimum undesirable flavor [16]. Nguyen and
Anema [96] reported that ultrasonication has a positive
effect on milk used in the formation of acid gels which
can improve milk properties for subsequent processing,
but it has been stated that these effects are small. Also,
Nguyen et al. [38] reported that ultrasonication could
reduce the fermentation time and has a potential to pro-
duce fermented milk with greater amount of oligosaccha-
rides and lower lactose concentration.
Shanmugam et al. [22] determined the effects of power
ultrasound on physical and functional properties of skim
milk. They employed ultrasound in 20 kHz frequency at
power of 20 and 41 W with controlled temperature condi-
tions. They reported that whey proteins and whey–whey
aggregates present in the milk were denatured and
formed soluble whey–whey/whey–casein aggregates. Also
for an industrial relevancy, they anticipated the potential
for optimizing ultrasound technique for dairy products.
In another work, Riener et al. [32] determined the effects
of ultrasonication on generating volatile compounds and
reported that ultrasound treatment produced several vol-
atiles caused by cavitation phenomenon. In an investiga-
tion, it was revealed that power ultrasound reduced
amount of milk fouling and this process could be used
as a fouling mitigation mechanism [20]. Accordingly,
ultrasound in membrane filtration, does not influence
the intrinsic permeability of the membranes and it
just prevent the membrane fouling. Low frequencies,
higher power intensities, intermittent sonication, lower
98 V. Mohammadi et al. / Measurement 58 (2014) 93–102
Author's Personal Copy

viscosities, lower temperatures and higher pressures are
the most important factors to improve the fouling
prevention and the flux ratio [97].
However, some investigations indicated that power
ultrasound deteriorated the flavor and composition of food
material. Marchesini et al. [15] reported a significant
increase in a burnt off-flavor with increasing intensity
and duration of the ultrasound treatment. Also they
observed the use of CO
2
appeared to significantly reduce
the disruptive effect of ultrasound, thus the formation of
oxidation products [15]. In another study, some weak
and ill-defined aromas were detected, none of which sug-
gested that any of those compounds contributed remark-
ably on an individual basis to the observed off-odor of
the sonicated milk [32].
Thermal pasteurization and sterilization are the pro-
cesses which can properly inactivate dangerous bacteria
in dairy products. Nevertheless, as a result of the high tem-
perature used, undesirable effects on nutritional and sen-
sory properties may be found in the products [14].
Nowadays, manufacturers have been interested to use
mild processing technologies such as thermosonication,
high pressure processing, pulsed electric field and ultravi-
olet radiation, to obtain high-quality products and addi-
tionally for using novel functionalities [1]. Indeed,
combining these methods with heating can decrease time
of sterilization process and increase the quality of product
[5]. Thus, many investigations are done to utilize ultra-
sound for destroying microorganisms in dairy products
[14,28,98–100].
Ultrasound treatment inactivates and kills the bacteria
by physical, mechanical, and chemical effects [7] that for
this purpose, very high acoustic energies are employed.
As pointed out in the literature, it has been observed that
processing variables such as ultrasound source and reactor
geometry, frequency, treatment time, and acoustic energy
intensity directly or indirectly affect inactivation mecha-
nism [28]. Also, the efficiency of bacteria inactivation
depends on media properties including temperature, vis-
cosity, treatment volume, and gas concentration [7].
Most of investigations done for inactivating the micro-
organisms have used frequency about 20 kHz [28].Sßengül
et al. [14] reported that photosonication destroyed total
and coliform bacteria in raw milk using an ultrasonic pro-
cessor (24 kHz and 400 W) and 3 ultraviolet lamps. Inacti-
vation rate for different microorganisms has various
results [30] which depend on bacterium resistance against
cavitation phenomenon. Cameron et al. [30] reported that
the application of ultrasound had various damage amounts
on microorganisms which had internal and external dam-
age on microbial cells. They concluded that power ultra-
sound (20 kHz, 750 W) could kill both Escherichia coli and
Saccharomyces cerevisiae more than 99% in milk. Also, they
reported that ultrasound inactivating for Lactobacillus aci-
dophilus has been achieved by 84% [30].
4. Conclusion
Flexibility and multiplicity of ultrasound applications
show apotential capability to use in many of industrial
processes. Also, ultrasound systems can be used as a labo-
ratory device for analyzing physicochemical properties of
dairy products. Ultrasonic techniques as effective method
are well suited for industrial applications, because they
do not destroy food products physically or hygienically.
To employ power ultrasound in milk industry, the effi-
ciency of system must be increased. Combining with other
techniques (e.g., heat, pressure, ultraviolet and so on) and
promoting ultrasonic transducers may be ways to get the
best response from ultrasonic system. By cavitation, power
ultrasound directly affects the structure of the food mate-
rial and changes mechanical and chemical properties,
which leads to reduction in time and power consumption
and increasing in quality through minimizing intensive
processes.
Monitoring and quality control for checking physico-
chemical and structure forming properties of food prod-
ucts using innovative instruments is an important aim to
produce the best products with high quality and stability
[101–109]. Analytical ultrasonic studies have shown desir-
able results in: (i) homogenous materials and (ii) processes
which involve distinguishable changes in structural prop-
erties. Therefore, by controlling process factors, favorable
results in high frequency and sensitivity ultrasound can
be obtained. In-line monitoring, adaptability, low costing,
simplicity, and portability are the reasons for exerting
ultrasonic methods in laboratories and factories. Thus,
ultrasonic, both for analytical works and processing appli-
cations have attracted researchers to employ it for several
decades. Ultrasonic non-destructive treatment has been
the most important motivation to continue investigations
in this field of research. The authors of this review paper
recently have tried to attach ultrasound methods to
large-scale and on-line processes for utilizing in produc-
tion lines. Such applications may be reported more in close
future.
References
[1] A.C. Soria, M. Villamiel, Effect of ultrasound on the technological
properties and bioactivity of food: a review, Trends Food Sci.
Technol. 21 (2010) 323–331.
[2] M. Ghasemi-Varnamkhasti, S.S. Mohtasebi, M. Siadat, Biomimetic-
based odor and taste sensing systems to food quality and safety
characterization: an overview on basic principles and recent
achievements, J. Food Eng. 100 (2010) 377–387.
[3] C. O’Donnell, B. Tiwari, P. Bourke, P. Cullen, Effect of ultrasonic
processing on food enzymes of industrial importance, Trends Food
Sci. Technol. 21 (2010) 358–367.
[4] F. Chemat, M.K. Khan, Applications of ultrasound in food
technology: processing, preservation and extraction, Ultrason.
Sonochem. 18 (2011) 813–835.
[5] T. Awad, H. Moharram, O. Shaltout, D. Asker, M. Youssef,
Applications of ultrasound in analysis, processing and quality
control of food: a review, Food Res. Int. 48 (2012) 410–427.
[6] S.N. Jha, Nondestructive Evaluation of Food Quality, Springer, 2010.
[7] B.K. Tiwari, T.J. Mason, Chapter 6 – ultrasound processing of fluid
foods, in: P.J. Cullen, B.K. Tiwari, V.P. Valdramidis (Eds.), Novel
Thermal and Non-Thermal Technologies for Fluid Foods, Academic
Press, San Diego, 2012, pp. 135–165.
[8] T. Leong, P. Juliano, L. Johansson, R. Mawson, S.L. McArthur, R.
Manasseh, Temperature effects on the ultrasonic separation of fat
from natural whole milk, Ultrason. Sonochem. 21 (2014) 2092–
2098.
[9] N. Porova, V. Botvinnikova, O. Krasulya, P. Cherepanov, I. Potoroko,
Effect of ultrasonic treatment on heavy metal decontamination in
milk, Ultrason. Sonochem. 21 (2014) 2107–2111.
V. Mohammadi et al. / Measurement 58 (2014) 93–102 99
Author's Personal Copy

[10] Z. Liu, P. Juliano, R.P. Williams, J. Niere, M.A. Augustin, Ultrasound
improves the renneting properties of milk, Ultrason. Sonochem. 21
(2014) 2131–2137.
[11] P. Juliano, A.E. Torkamani, T. Leong, V. Kolb, P. Watkins, S. Ajlouni,
T.K. Singh, Lipid oxidation volatiles absent in milk after selected
ultrasound processing, Ultrason. Sonochem. 21 (2014) 2165–2175.
[12] A.E. Torkamani, P. Juliano, S. Ajlouni, T.K. Singh, Impact of
ultrasound treatment on lipid oxidation of Cheddar cheese whey,
Ultrason. Sonochem. 21 (2014) 951–957.
[13] E. Chouliara, K. Georgogianni, N. Kanellopoulou, M. Kontominas,
Effect of ultrasonication on microbiological, chemical and sensory
properties of raw, thermized and pasteurized milk, Int. Dairy J. 20
(2010) 307–313.
[14] M. Sßengül, T. Erkaya, M. Basßlar, M.F. Ertugay, Effect of
photosonication treatment on inactivation of total and coliform
bacteria in milk, Food Control 22 (2011) 1803–1806.
[15] G. Marchesini, S. Balzan, F. Montemurro, L. Fasolato, I. Andrighetto,
S. Segato, E. Novelli, Effect of ultrasound alone or ultrasound
coupled with CO
2
on the chemical composition, cheese-making
properties and sensory traits of raw milk, Innovative Food Sci.
Emerg. Technol. 16 (2012) 391–397.
[16] T.M.P. Nguyen, Y.K. Lee, W. Zhou, Effect of high intensity ultrasound
on carbohydrate metabolism of bifidobacteria in milk fermentation,
Food Chem. 130 (2012) 866–874.
[17] D. Pingret, A.-S. Fabiano-Tixier, F. Chemat, Degradation during
application of ultrasound in food processing: a review, Food Control
31 (2013) 593–606.
[18] B. Richard, M. Toubal, J.-F. Le Page, G. Nassar, E. Radziszewski, B.
Nongaillard, P. Debreyne, P. Schuck, R. Jeantet, G. Delaplace,
Ultrasound tests in a stirred vessel to evaluate the reconstitution
ability of dairy powders, Innovative Food Sci. Emerg. Technol. 16
(2012) 233–242.
[19] P. Juliano, S. Temmel, M. Rout, P. Swiergon, R. Mawson, K. Knoerzer,
Creaming enhancement in a liter scale ultrasonic reactor at selected
transducer configurations and frequencies, Ultrason. Sonochem. 20
(2012) 52–62.
[20] S. Lin, X. Chen, A laboratory investigation of milk fouling under
the influence of ultrasound, Food Bioprod. Process. 85 (2007)
57–62.
[21] B. Zisu, R. Bhaskaracharya, S. Kentish, M. Ashokkumar, Ultrasonic
processing of dairy systems in large scale reactors, Ultrason.
Sonochem. 17 (2010) 1075–1081.
[22] A. Shanmugam, J. Chandrapala, M. Ashokkumar, The effect of
ultrasound on the physical and functional properties of skim milk,
Innovative Food Sci. Emerg. Technol. 16 (2012) 251–258.
[23] T. Kobayashi, H. Tai, S. Kato, Measurement method of particle
concentration and acoustic properties in suspension using a
focused ultrasonic impulse radiated from a plano-concave
transducer, Ultrasonics 44 (2006) e491–e496.
[24] T.H. Gan, P. Pallav, D.A. Hutchins, Non-contact ultrasonic quality
measurements of food products, J. Food Eng. 77 (2006) 239–247.
[25] M. Alexander, M. Corredig, Spectroscopic methods to determine
in situ changes in dairy systems–ultrasonic and light scattering, Le
Lait 87 (2007) 435–442.
[26] A.B. Koc, B. Ozer, Nondestructive monitoring of renetted whole milk
during cheese manufacturing, Food Res. Int. 41 (2008) 745–750.
[27] _
I. Gülseren, M. Alexander, M. Corredig, Probing the colloidal
properties of skim milk using acoustic and electroacoustic
spectroscopy. Effect of concentration, heating and acidification, J.
Colloid Interface Sci. 351 (2010) 493–500.
[28] C. Arroyo, G. Cebrián, R. Pagán, S. Condón, Inactivation of
Cronobacter sakazakii by ultrasonic waves under pressure in
buffer and foods, Int. J. Food Microbiol. 144 (2011) 446–454.
[29] D. Bermúdez-Aguirre, G.V. Barbosa-Cánovas, Study of butter fat
content in milk on the inactivation of Listeria innocua ATCC 51742
by thermo-sonication, Innovative Food Sci. Emerg. Technol. 9
(2008) 176–185.
[30] M. Cameron, L.D. McMaster, T.J. Britz, Electron microscopic analysis
of dairy microbes inactivated by ultrasound, Ultrason. Sonochem.
15 (2008) 960–964.
[31] K.A. Law, J.P. Derrick, S.P. Higson, Initial investigations into the
ultrasonic lysis of microbial cells for the release of adenosine
triphosphate, Anal. Biochem. 317 (2003) 266–267.
[32] J. Riener, F. Noci, D.A. Cronin, D.J. Morgan, J.G. Lyng,
Characterisation of volatile compounds generated in milk by high
intensity ultrasound, Int. Dairy J. 19 (2009) 269–272.
[33] H. Wu, G.J. Hulbert, J.R. Mount, Effects of ultrasound on milk
homogenization and fermentation with yogurt starter, Innovative
Food Sci. Emerg. Technol. 1 (2000) 211–218.
[34] G. Arnold, L. Leiteritz, S. Zahn, H. Rohm, Ultrasonic cutting of
cheese: composition affects cutting work reduction and energy
demand, Int. Dairy J. 19 (2009) 314–320.
[35] Y. Schneider, S. Zahn, C. Schindler, H. Rohm, Ultrasonic excitation
affects friction interactions between food materials and cutting
tools, Ultrasonics 49 (2009) 588–593.
[36] M. Yebra, A. Moreno-Cid, R. Cespón, S. Cancela, Preparation of a
soluble solid sample by a continuous ultrasound assisted
dissolution system for the flow-injection atomic absorption
spectrometric determination of iron in milk powder and infant
formula, Talanta 62 (2004) 403–406.
[37] B. Zisu, M. Schleyer, J. Chandrapala, Application of ultrasound to
reduce viscosity and control the rate of age thickening of
concentrated skim milk, Int. Dairy J. 31 (2013) 41–43.
[38] T.M.P. Nguyen, Y.K. Lee, W. Zhou, Stimulating fermentative
activities of bifidobacteria in milk by highintensity ultrasound,
Int. Dairy J. 19 (2009) 410–416.
[39] A. Mirzaie, T. Mohammadi, Effect of ultrasonic waves on flux
enhancement in microfiltration of milk, J. Food Eng. 108 (2012) 77–
86.
[40] S. Muthukumaran, S. Kentish, M. Ashokkumar, G. Stevens, Potential
uses of ultrasound in the dairy ultrafiltration processes, J. Acoust.
Soc. Am. 123 (2008) 3046.
[41] S. Muthukumaran, S. Kentish, S. Lalchandani, M. Ashokkumar, R.
Mawson, G.W. Stevens, F. Grieser, The optimisation of ultrasonic
cleaning procedures for dairy fouled ultrafiltration membranes,
Ultrason. Sonochem. 12 (2005) 29–35.
[42] H. Yan, X. Cheng, B. Liu, Simultaneous determination of six
phthalate esters in bottled milks using ultrasound-assisted
dispersive liquid–liquid microextraction coupled with gas
chromatography, J. Chromatogr. B 879 (2011) 2507–2512.
[43] M. Ashokkumar, D. Sunartio, S. Kentish, R. Mawson, L. Simons, K.
Vilkhu, C.K. Versteeg, Modification of food ingredients by
ultrasound to improve functionality: a preliminary study on a
model system, Innovative Food Sci. Emerg. Technol. 9 (2008) 155–
160.
[44] A.A. Lopez, M. Corredig, M. Alexander, Diffusing wave and
ultrasonic spectroscopy of rennet-induced gelation of milk in the
presence of high-methoxyl pectin, Food Biophys. 4 (2009) 249–259.
[45] P. Pallav, D.A. Hutchins, T. Gan, Air-coupled ultrasonic evaluation of
food materials, Ultrasonics 49 (2009) 244–253.
[46] V. Leemans, M.-F. Destain, Ultrasonic internal defect detection in
cheese, J. Food Eng. 90 (2009) 333–340.
[47] L. Elvira, L. Sampedro, F. Montero de Espinosa, J. Matesanz, Y.
Gómez-Ullate, P. Resa, F. Echevarría, J. Iglesias, Eight-channel
ultrasonic device for non-invasive quality evaluation in packed
milk, Ultrasonics 45 (2006) 92–99.
[48] U. Yucel, J.N. Coupland, Ultrasonic characterization of lactose
dissolution, J. Food Eng. 98 (2010) 28–33.
[49] B. Aernouts, E. Polshin, W. Saeys, J. Lammertyn, Mid-infrared
spectrometry of milk for dairy metabolomics: a comparison of two
sampling techniques and effect of homogenization, Anal. Chim.
Acta 705 (2011) 88–97.
[50] S. Meyer, V.S. Rajendram, M.J. Povey, Characterization of
reconstituted milk powder by ultrasound spectroscopy, J. Food
Qual. 29 (2006) 405–418.
[51] J. Chandrapala, C. Oliver, S. Kentish, M. Ashokkumar, Ultrasonics in
food processing–food quality assurance and food safety, Trends
Food Sci. Technol. 26 (2012) 88–98.
[52] K. Narsaiah, S.N. Jha, Nondestructive methods for quality evaluation
of livestock products, J. Food Sci. Technol. 49 (2012) 342–348.
[53] M. Graves, A. Smith, B. Batchelor, Approaches to foreign body
detection in foods, Trends Food Sci. Technol. 9 (1998) 21–27.
[54] E. Hæggström, M. Luukkala, Ultrasound detection and identification
of foreign bodies in food products, Food Control 12 (2001) 37–45.
[55] V. Buckin, E. Kudryashov, Ultrasonic shear wave rheology of weak
particle gels, Adv. Colloid Interface Sci. 89 (2001) 401–422.
[56] L. Elvira, C. Sierra, B. Galán, P. Resa, Ultrasonic non invasive
techniques for microbiological instrumentation, Phys. Procedia 3
(2010) 789–794.
[57] B.K. Cho, J. Irudayaraj, A noncontact ultrasound approach for
mechanical property determination of cheeses, J. Food Sci. 68
(2003) 2243–2247.
[58] G. Nassar, F. Lefbvre, A. Skaf, J. Carlier, B. Nongaillard, Y. Noêl,
Ultrasonic and acoustic investigation of cheese matrix at the
beginning and the end of ripening period, J. Food Eng. 96 (2010) 1–13.
[59] J. Benedito, J. Carcel, M. Gisbert, A. Mulet, Quality control of cheese
maturation and defects using ultrasonics, J. Food Sci. 66 (2001)
100–104.
100 V. Mohammadi et al. / Measurement 58 (2014) 93–102
Author's Personal Copy

[60] G. Nassar, M. Sabra, F. Lefebvre, M. Toubal, B. Nongaillard, Y. Noel,
Design of low-frequency ultrasonic sensors for the analysis of the
draining stage of cheese production, Ultrasonics 44 (2006) e1045–
e1050.
[61] H. Ogasawara, K. Mizutani, T. Ohbuchi, T. Nakamura, Acoustical
experiment of yogurt fermentation process, Ultrasonics 44 (2006)
e727–e730.
[62] K.R. Lohr, J.L. Rose, Ultrasonic guided wave and acoustic impact
methods for pipe fouling detection, J. Food Eng. 56 (2003) 315–324.
[63] E. Wallhäußer, A. Sayed, S. Nöbel, M.A. Hussein, J. Hinrichs, T.
Becker, Determination of cleaning end of dairy protein fouling
using an online system combining ultrasonic and classification
methods, Food Bioprocess Technol. 7 (2014) 506–515.
[64] A.P. Singh, D.J. McClements, A. Marangoni, Solid fat content
determination by ultrasonic velocimetry, Food Res. Int. 37 (2004)
545–555.
[65] F.P. Capote, M.L. de Castro, Analytical Applications of Ultrasound,
Elsevier, 2007.
[66] D.J. McClements, Advances in the application of ultrasound in food
analysis and processing, Trends Food Sci. Technol. 6 (1995) 293–
299.
[67] A. Mulet, J. Benedito, J. Bon, C. Rossello, Ultrasonic velocity in
cheddar cheese as affected by temperature, J. Food Sci. 64 (1999)
1038–1041.
[68] G. Nassar, B. Nongaillard, Y. Noël, Study by ultrasound of the impact
of technological parameters changes in the milk gelation process, J.
Food Eng. 63 (2004) 229–236.
[69] J. Benedito, S. Simal, G. Clemente, A. Mulet, Manchego cheese
texture evaluation by ultrasonics and surface probes, Int. Dairy J. 16
(2006) 431–438.
[70] Q. Wang, S. Bulca, U. Kulozik, A comparison of low-intensity
ultrasound and oscillating rheology to assess the renneting
properties of casein solutions after UHT heat pre-treatment, Int.
Dairy J. 17 (2007) 50–58.
[71] J. Telis-Romero, H. Váquiro, J. Bon, J. Benedito, Ultrasonic assessment
of fresh cheese composition, J. Food Eng. 103 (2011) 137–146.
[72] J.N. Coupland, R. Saggin, Ultrasonic sensors for the food industry,
Adv. Food Nutr. Res. 45 (2002) 101.
[73] D.G. Dalgleish, E. Verespej, M. Alexander, M. Corredig, The
ultrasonic properties of skim milk related to the release of
calcium from casein micelles during acidification, Int. Dairy J. 15
(2005) 1105–1112.
[74] P.M. Withers, Ultrasonic, acoustic and optical techniques for the
non-invasive detection of fouling in food processing equipment,
Trends Food Sci. Technol. 7 (1996) 293–298.
[75] S. Mohanan, P.T. Panicker, L. Iype, M. Laila, I. Domini, R. Bindu, A
new ultrasonic method to detect chemical additives in branded
milk, Pramana 59 (2002) 525–529.
[76] G. Nassar, B. Nongaillard, Y. Noel, Monitoring of milk gelation using
a low-frequency ultrasonic technique, J. Food Eng. 48 (2000) 351–
359.
[77] L. Elvira, L. Sampedro, J. Matesanz, Y. Gómez-Ullate, P. Resa, J.
Iglesias, F. Echevarría, F.M. de Espinosa, Non-invasive and non-
destructive ultrasonic technique for the detection of microbial
contamination in packed UHT milk, Food Res. Int. 38 (2005) 631–
638.
[78] L. Lehmann, V. Buckin, Determination of the heat stability profiles
of concentrated milk and milk ingredients using high resolution
ultrasonic spectroscopy, J. Dairy Sci. 88 (2005) 3121–3129.
[79] Y. Roh, C. Moon, Design and fabrication of an ultrasonic speaker
with thickness mode piezoceramic transducers, Sens. Actuators, A
99 (2002) 321–326.
[80] T. Leighton, Bubble population phenomena in acoustic cavitation,
Ultrason. Sonochem. 2 (1995) S123–S136.
[81] A. Patist, D. Bates, Ultrasonic innovations in the food industry: from
the laboratory to commercial production, Innovative Food Sci.
Emerg. Technol. 9 (2008) 147–154.
[82] G. Hunter, M. Lucas, I. Watson, R. Parton, A radial mode ultrasonic
horn for the inactivation of Escherichia coli K12, Ultrason.
Sonochem. 15 (2008) 101–109.
[83] D. Knorr, M. Zenker, V. Heinz, D.-U. Lee, Applications and potential
of ultrasonics in food processing, Trends Food Sci. Technol. 15
(2004) 261–266.
[84] J.P. Lorimer, T.J. Mason, Sonochem. Part 1 – the physical aspects,
Chem. Soc. Rev. 16 (1987) 239–274.
[85] P. Juliano, A. Kutter, L.J. Cheng, P. Swiergon, R. Mawson, M.
Augustin, Enhanced creaming of milk fat globules in milk
emulsions by the application of ultrasound and detection by
means of optical methods, Ultrason. Sonochem. 18 (2011) 963–973.
[86] E. Karageorgou, M. Armeni, I. Moschou, V. Samanidou, Ultrasound-
assisted dispersive extraction for the high pressure liquid
chromatographic determination of tetracyclines residues in milk
with diode array detection, Food Chem. 150 (2014) 328–334.
[87] S. Gao, X. Yang, W. Yu, Z. Liu, H. Zhang, Ultrasound-assisted ionic
liquid/ionic liquid-dispersive liquid–liquid microextraction for the
determination of sulfonamides in infant formula milk powder using
high-performance liquid chromatography, Talanta 99 (2012) 875–
882.
[88] B. Kwiatkowska, J. Bennett, J. Akunna, G.M. Walker, D.H. Bremner,
Stimulation of bioprocesses by ultrasound, Biotechnol. Adv. 29
(2011) 768–780.
[89] H. Uluko, H. Li, W. Cui, S. Zhang, L. Liu, J. Chen, Y. Sun, Y. Su, J. Lv,
Response surface optimization of angiotensin converting enzyme
inhibition of milk protein concentrate hydrolysates in vitro after
ultrasound pretreatment, Innovative Food Sci. Emerg. Technol. 20
(2013) 133–139.
[90] S. Muthukumaran, S. Kentish, M. Ashokkumar, G. Stevens,
Mechanisms for the ultrasonic enhancement of dairy whey
ultrafiltration, J. Membr. Sci. 258 (2005) 106–114.
[91] F. Martinez, A. Davidson, J. Anderson, S. Nakai, I. Desai, A. Radcliffe,
Effects of ultrasonic homogenization of human milk on lipolysis,
IgA, IgG, lactoferrin and bacterial content, Nutr. Res. 12 (1992) 561–
568.
[92] S. Ghasemi, S. Abbasi, Formation of natural casein micelle
nanocapsule by means of pH changes and ultrasound, Food
Hydrocolloids (2013) (in press).
[93] C.V. Tammineedi, R. Choudhary, G.C. Perez-Alvarado, D.G. Watson,
Determining the effect of UV-C, high intensity ultrasound and
nonthermal atmospheric plasma treatments on reducing the
allergenicity of
a
-casein and whey proteins, LWT-Food Sci.
Technol. 54 (2013) 35–41.
[94] C. Arzeni, K. Martinez, P. Zema, A. Arias, O. Perez, A. Pilosof,
Comparative study of high intensity ultrasound effects on food
proteins functionality, J. Food Eng. 108 (2012) 463–472.
[95] S. Yanjun, C. Jianhang, Z. Shuwen, L. Hongjuan, L. Jing, L. Lu, H.
Uluko, S. Yanling, C. Wenming, G. Wupeng, Effect of power
ultrasound pre-treatment on the physical and functional
properties of reconstituted milk protein concentrate, J. Food Eng.
124 (2014) 11–18.
[96] N.H. Nguyen, S.G. Anema, Effect of ultrasonication on the properties
of skim milk used in the formation of acid gels, Innovative Food Sci.
Emerg. Technol. 11 (2010) 616–622.
[97] H. Kyllönen, P. Pirkonen, M. Nyström, Membrane filtration enhanced
by ultrasound: a review, Desalination 181 (2005) 319–335.
[98] M. Villamiel, P. de Jong, Inactivation of Pseudomonas fluorescens and
Streptococcus thermophilus in Trypticase
Ò
Soy Broth and total
bacteria in milk by continuous-flow ultrasonic treatment and
conventional heating, J. Food Eng. 45 (2000) 171–179.
[99] S. Salo, G. Wirtanen, Ultrasonic cleaning applications in dairies:
case studies on cheese moulds and milk transportation crates, Br.
Food J. 109 (2007) 31–42.
[100] N. Gera, S. Doores, Kinetics and mechanism of bacterial inactivation
by ultrasound waves and sonoprotective effect of milk
components, J. Food Sci. 76 (2011) M111–M119.
[101] M. Ghasemi-Varnamkhasti, S.S. Mohtasebi, M.L. Rodriguez-
Mendez, M. Siadat, H. Ahmadi, S.H. Razavi, Electronic and
bioelectronic tongues two promising analytical tools for the
quality evaluation of non alcoholic beer, Trends Food Sci.
Technol. 22 (2011) 245–248.
[102] M. Ghasemi-Varnamkhasti, S.S. Mohtasebi, M. Siadat, H. Ahmadi,
S.H. Razavi, A. Dicko, Aging fingerprint characterization of beer
using electronic nose, Sens. Actuators, B 159 (2011) 51–59.
[103] M. Ghasemi-Varnamkhasti, M. Forina, NIR spectroscopy coupled
with multivariate computational tools for qualitative characteriza-
tion of the aging of beer, Comput. Electron. Agric. 100 (2014) 34–40.
[104] M. Ghasemi-Varnamkhasti, M.L. Rodriguez-Mendez, S.S.
Mohtasebi, C. Apetrei, J. Lozano, H. Ahmadi, S.H. Razavi, J.A. de
Saja, Monitoring the aging of beers using a bioelectronic tongue,
Food Control 25 (2012) 216–224.
[105] M. Ghasemi-Varnamkhasti, S.S. Mohtasebi, M.L. Rodriguez-
Mendez, A.A. Gomes, M.C.U. Araujo, R.K.H. Galvao, Screening
analysis of beer ageing using near infrared spectroscopy and the
Successive Projections Algorithm for variable selection, Talanta 89
(2012) 286–291.
[106] M. Ghasemi-Varnamkhasti, S.S. Mohtasebi, M.L. Rodriguez-
Mendez, J. Lozano, S.H. Razavi, H. Ahmadi, Potential application
of electronic nose technology in brewery, Trends Food Sci. Technol.
22 (2011) 165–174.
V. Mohammadi et al. / Measurement 58 (2014) 93–102 101
Author's Personal Copy

[107] A. Adelkhani, B. Beheshti, S. Minaei, P. Javadikia, M. Ghasemi-
Varnamkhasti, Taste characterization of orange using image
processing combined with ANFIS, Measurement 46 (2013) 3573–
3580.
[108] S. Shafiee, S. Minaei, N. Moghaddam, M. Ghasemi-Varnamkhasti, M.
Barzegar, Potential application of machine vision to honey
characterization, Trends Food Sci. Technol. 30 (2013) 174–177.
[109] M. Ghasemi-Varnamkhasti, Design, development and
implementation of a metal oxide semiconductor (MOS) based
machine olfaction system and bioelectronic tongue to quality
change detection of beers coupled with pattern recognition
analysis techniques, (2011) PhD Dissertation, University of
Tehran, Karaj, Iran.
102 V. Mohammadi et al. / Measurement 58 (2014) 93–102
Author's Personal Copy