Soliton Light Pulses and usage in real time

1. DIFFERENT KIND OF LIGHT
PULSES AND USAGE IN REAL
TIME
B.SURYA

2. Introduction
• As the human evolution progressed, the way food being
consumed and their priorities have also been evolved. The
consumption of processed foods is on the rise due to change in
lifestyle, particularly in urban areas. Traditional thermal-based
food-processing methods such as appertization,
pasteurization,and canning have been dependent on high
temperature,to ensure prolonged shelf life and food safety.
Although thermal processes are efficient tools for microbial
inactivation, they also contribute to undesirable changes in
food matrix such as structural alterationof proteins and
polysaccharides, production of free radicals, affecting the
functionality of food and flavour, textural softening, and
destruction of colours and vitamins (Devlieghere et al., 2004).

3. • High-temperature short-time processes, electromagnetic
radiation-based microwave, radio frequency heating, and
ohmic heating techniques have gained focus in the recent
past as alternative and rapid heating techniques to
minimize the severity of heat treatment and thereby
enhance product quality.
• Over the past few years, consumer demand for fresh,
natural, and minimally processed foods with better quality
has increased. To address this, researchers are working on
developing alternative techniques that not only meet the
consumer demand but also energy-efficient, cost-
effective, and rapid. Many novel technologies that do not
involve heat processing have been developed to inactivate
microorganisms

4. PL Processing
• PL technology is a non-thermal technology, where
decontamination of foods such as fruit juices, meat
products, vegetables, and fruits is achieved by using high-
intensity light pulses for a short duration of time. The PL
includes a wide wavelength range of 200–1100 nm, which
includes ultraviolet (UV): 200–400 nm, visible (VIS):
400–700 nm, and near-infrared region (IR): 700–1100
nm (Elmnasser et al., 2007; Palgan et al., 2011).

5. • The term pulsed light is known since 1980 and was first
adopted by the US Food and Drug Administration (FDA) for
food processing in 1996 (FDA, 1996).
• To increase the safety of fruit and vegetable juices, US FDA
regulation has implemented 5-log pathogen reduction
process (US FDA, 2004).
• Significant microbial reduction in very short treatment
time, low environmental impact, and its high flexibility
are some of the major benefits of PL (Uesugi and Moraru,
2009; Oms-Oliu et al., 2010b).

6. • Even though the PL processing is considered as ‘non-
thermal’, it has the limitation of sample heating due to
longer treatment time, which may cause thermal
inactivation of microbes.
• Significant temperature increase caused due to longer PL
treatments has an extra effect on microbial reductions
depending on the matrix properties (Bialka and Demirci,
2008; Huang and Chen, 2014).
• PL has potential applications in food processing that
requires a rapid disinfection where surface contamination
is a concern for microbial contamination such as fresh
whole fruit and vegetable commodities, hard cheeses or
meat slices, and so on.

7. PL TreatmentSystemsfor Microbial
Load Reduction
• The pioneer company producing PL equipment for
application in water purification systems and virus
inactivation systems for biopharmaceutical manufacturers
is Purepulse Technologies Inc. (San Diego, California), a
subsidiary of Xenon Corp., which commercialized the
PureBright™ system (Dunn et al., 1995).

10. Mode of Action of PL on Microbes
• UV was the only agent responsible for the inactivation of
pathogens and no antibacterial effect attributed to IR or
VIS light was found (Paškevičiūtė and Lukšienė,
2009; Ramos-Villarroel et al., 2014; Kramer et al., 2015).
• In addition, it has been shown that both the VIS and IR
regions of PL in combination with its high peak power also
contribute to the destructive effect on microorganisms
(Elmnasser et al., 2007).

11. • The antimicrobial properties of UV light on bacteria are attributed
to absorption of radiation by conjugated carbon–carbon double
bonds in nucleic acids and proteins, and subsequent DNA
structural changes (Ramos-Villarroel et al., 2012).
• Cheigh et al. (2013) identified the cell damage on the foodborne
pathogen, L. monocytogenes treated with UV-C and IPL with the
help of transmission electron microscopy (TEM).
• UV-C–treated L. monocytogenes cells were similar in structure to
that of untreated cells except for a blurry and indistinct cell wall
(Figure 3).
• In contrast, IPL-treated cells showed the destruction of cell wall
structures, cytoplasm shrinkage, and rupture of the internal
organization leading to leakage of cytoplasmic content and
ultimately to cell death (Cheigh et al., 2012).

14. Effect of PL on Liquid Foods
• PL processing is being applied on various liquid products for
decontaminatingthe foodborne pathogens that affect the
human health status.
• Inactivation of these pathogens on liquid food complexes are
mentioned in Table 1. PL processing is influenced by various
factors that dictate its efficiency on microbial inactivation,
retention of quality, and other properties of the product.
• Importantfactors that determine the effectiveness of PL is the
fluence level applied on the sample, the amount of energy (dose
or number of pulses) and wavelength of light/compositionof
the spectrum (Ramos-Villarroel et al., 2012).

15. • Inactivation of microbes is higher for PL treatment with
higher pulse number and higher intensity (MacGregor et
al., 1998; Maftei et al., 2014; Ramos-Villarroel et al., 2014).
• It is indicated that when the spectral range of the PL
treatments, particularly the UV component, is altered by
using filters, the inactivation of E. coli and Listeria
innocua is lower (Ramos-Villarroel et al., 2012).
• And among the sub-divisions of UV, UV-C–containing
spectrum was more effective in inactivating B.
subtilis and A.