Applications of Machine Olfaction - The Electronic Nose Artificial Olfaction Technology - page 207

milk, which are absent in raw milk before spoilage. Metal oxide semiconductor-
based E-nose sensors are used for real-time quality analysis of raw milk. The
sensors are empaneled and calibrated toward various concentrations of volatile
organic compounds (VOCs) which are liable for off-flavors (ethanol, trimethyla-
mine, acetaldehyde, dimethylsulfide, acetic acid, etc.) in milk produced due to
microbial contagion, chemical reactions, and genetic effects in cow.
An article published by S. Ampuero et al., which reviews E-nose applications
in the milk industry : i.e., examples of the analysis of Swiss and Cheddar cheese
aroma; the measurement of the ripening of Pecorino Toscano cheese (ewe's); the
detection of mold in Parmesan cheese; the categorization of milk by trademark, by
fat level, and by preservation process; the classification and the quantification of
off-flavors in milk; the evaluation of Maillard reactions during heating processes in
block-milk; and the identification of single strains of disinfectant-resistant bacteria
in mixed cultures in milk [ 5 ].
(b) Meat products
The major important factors in meat and meat products are microbiological
safety, shelf life of products, and temperature. E-nose measurement systems can
analyze changes in the headspace volatiles of aerobically packed meat. The E-nose
has the benefits of being rapid, non-destructive, and non-contact instrumental
testing [ 6 ]. Mahdi Ghasemi-Varnamkhasti et al. explain the applications of E-nose
systems for meat quality assessment, where fast detection methods are necessary
for proper product management. The outcome suggests the option of using this
new technology in meat handling [ 7 ].
(c) Fish and seafood products:
Freshness is the most important factor for fish quality. Electronic nose (E-nose)
can be used to identify odor variety, aroma intensity, and degree of freshness.
GholamHosseini, H. et al. proposed artificial neural networks (ANNs) to design an
intelligent system for measuring the freshness of spoiling fish. They proposed 32
sensory arrays-based portable E-noses [ 8 ].
(d) Fruity odors classification:
Kea-Tiong Tang et al. developed a prototype of a portable E-nose with the use
of eight sensor arrays which are commercially available sensors and this E-nose is
able to detect and identify the fragrance of fruity odors [ 9 ].
(e) Classification of beverages:
Mazlina et al. designed and developed an E-nose sensor system using 14 metal
oxide semiconductor gas sensors from Figaro Sensor, to classify different bever-
ages and working as good analytical instruments with good characteristics
(repeatability, reproducibility, and discriminative ability). It is also able to produce
different patterns for different samples [ 10 ].