Impact of non-processing technology in dairy products for microbial safety | Foodresearchlab

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IMPACT OF NON-PROCESSING TECHNOLOGY IN DAIRY
PRODUCTS FOR MICROBIAL SAFETY
An Academic presentation by Dr. Nancy Agnes,
Head, Technical Operations, FoodResearchLab
Group www.foodresearchlab.com Email
info_at_foodresearchlab.com
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Today's Discussion
OUTLINE Introduction Pulsed electric Field
(PEF) High Pressure Processing (HPP)
Ultrasound (US) Plasma and low plasma Technology
(PT) Conclusion
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INTRODUCTION
Dairy products, especially milk is highly
perishable as it

• contains ample nutrition and high in moisture
  content for the microorganism to grow and
  multiply.
• To enhance food safety and protect the quality,
  non- thermal processing technologies are gaining
  significant attention in the Food Industry.
• Currently, consumers are opting for minimally
  processed foods that are close to natural
  tastes.
• Hence the dairy industries are moving towards
  non- thermal processing technologies which
  deliver fresh and nutritious foods with better
  shelf-stability.

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The microbial inactivation during the processing
is critical for improving the shelf- life of
milk. Common methods such as pasteurization,
ultra-high temperature processing have been
investigated in great depths to inactivate and
destroy the pathogenic and spore-forming
microorganisms.
Listeria cereus, for the
Researchers have worked closely on pathogenic orga
nisms such as
monocytogenes, Salmonella spp.,
Staphylococcus aureus, Escherichia
Campylobacter spp, which are the
coli, major
Bacillus causes
occurrences of foodborne illness worldwide.
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The main challenge with thermal treatments is
that they damage some nutritional components
while microbial inactivation, which also involves
undesirable flavour changes. QTo avoid these
nutritional and organoleptic changes, non-thermal
treatments such as pulsed electric field (PEF),
high-pressure processing (HPP), ultrasound,
membrane filtration and non-thermal plasma have
been deployed.
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PULSED ELECTRIC FIELD (PEF)
PEF has gained significant popularity as it destro
ys both spoilage and pathogenic bacteria and
fungi.
PEF also inactivates enzymes related to quality de
terioration without causing any changes in
flavour and taste.
PEF treatment (35 kV/cm, 2.3 µs pulse width, at
65 C for lt 10 sec) shown significant
pasteurization results similar to a high-
temperature short time (HTST) pasteurization. Mor
eover, the sensory properties of PEF treated
products were found to have a better consumer
acceptance rate compared to the thermal
counterparts.
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Table 1 Effect of PEF on microbes present in
dairy products. Adapted from 1
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HIGH
PRESSURE PROCESSING (HPP)
HPP employs high pressure in the range of 100-600
MPa for up to 20 min duration to eliminate
pathogenic and spoilage microorganisms to
increase the stability and shelf life of food
Product development.
HPP can alter the protein characteristics
depending on the duration of treatment and the
temperature applied, creating irreversible
changes in the structure. The particle size of
skim milk decreases substantially from 200 to
100nm, when subjected to HPP treatment at 300MPa.
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HPP is also mainly chosen for minimal nutrient los
s and significant microbial load reduction.

• To maintain the organoleptic properties of the
  milk, HPP treatment combinations could be used
  to provide an increased shelf-life and fresh
  sensory properties.

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Table 2 Effect of HPP on microbes present in
dairy products. Adapted from 1
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ULTRASOUND (US)
The US technology is the most commonly used
technology in the food industry around the globe
as it is eco-friendly, non- toxic and showcases
various applications in the food industry.
The US is greatly used in the homogenization and
inactivation of microbes (via sonication) present
in milk and in novel dairy products which have
unique physio-chemical functional
properties. The use of the US in the food
industry is limited compared to the other
non-thermal processing techniques. However, the
US can be used in the removal of gases and
homogenization of fat and also improve the
availability of antioxidants.
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Table 3 Effect of US on microbes present in dairy
products. Adapted from 1.
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PLASMA AND LOW PLASMA TECHNOLOGY (PT)
PT is the newest addition to the non-thermal techn
ologies, having various application to the food
and dairy industry.
PT has proven to improve the quality of the end
product with enhanced microbial safety from both
pathogenic and spoilage microbes.
Just like HPP and PEF, PT has also shown to
preserve the sensorial, organoleptic and
nutritional properties of the foods.
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The mechanism of PT is based on the additional
gas energy which is getting fed by electrical
discharge turning it into energy-rich
plasma. Plasma consists of free radicals and
electrons which is highly reactive. Moreover, it
is important to note that PT induces modification
on the surface of the food as the radicals react
on the surface and are not capable of penetrating
the matrix. PT is also used for enzyme
modification and inactivation, wastewater
treatments and modified food packaging.
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The operational cost of HPP continues to decrease
due to its increased demand in the industry.
CONCLUSION
The average processing cost of HPP ranges between
0.05 to 0.5US per kg of food. The operational
cost of PEF ranges between 0.01 to 0.02 US per
litre of food. This cost of non-thermal
techniques operation is 10 times greater than
conventional thermal processing cost. US
technology can be used cost-efficiently for
extraction and rapid crystallization procedures,
providing increased yield in less time.
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Moreover, the current limitations with
non-thermal processing technologies are that it
involves huge investment and lack regulatory
support in a few countries. To sum, although
these novel non-thermal technologies are capable
of reducing the microbial load similar to
thermal processing techniques, with an added
benefit of minimal loss of nutritional
contents. A combination of these techniques
called hurdle technology can be used to obtain
massive results, such as destroying pathogenic
microbes which is not possible
otherwise. Therefore, there is great scope in
the near future for these techniques to go
mainstream however, manufacturers should look
into the drawbacks which are holding them back.
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