there's more to shelf life than pasteurization - sanovo technology group

THE ULTIMATE PASTEURIZATION SOLUTION
THERE’S MORE TO SHELF
LIFE THAN PASTEURIZATION
by Roberto Colavitti and Christoffer Ernst, SANOVO TECHNOLOGY GROUP
Extended shelf life (ESL) egg
products continue to grow in
popularity, with requests from
processors seeking ways to better
control and planning of their
production. With ESL, it is possible
to optimize the daily production and
to provide long lasting products to
customers.
End users want a product of good
quality which is able to last longer,
at a reasonable price and in
accordance with food regulations.
WHAT IS SHELF LIFE
When defining shelf life, there are
two main parameters to consider:
a) “obligatory aspects”
b) “optional aspects”
Obligatory aspects are parameters
that the product must fulfil in
accordance with local regulations.
Optional aspects refer to rules that
companies set themselves to ensure
production of a safe and good
product.
The methodology with which the
“obligatory aspects” and “optional
aspects” are measured is very
important. It needs to be as objective
as possible, and the shelf life must
be defined mainly by experimental
measurements where the difference
between the “obligatory aspects” and
“optional aspects” must be kept at an
acceptable level.
Another aspect to be considered is
the degradation phenomena, such
as bad smell and coagulation. These
phenomena, are mainly due to Nonpathogen
bacteria that survive the
pasteurization. These non-pathogens
need to be considered in the shelf
life of the products and the producer
needs to reduce them to the absolute
minimum, in order to achieve ESL.
As an example, figure 1 shows some
Microbiological Criteria generally
followed to get a good product:
FIGURE 1
Based on this, the first quality aspect
in the egg products depends on the
microbiological status in terms of
Quality-Quantity. A zero tolerance
of pathogenic elements (obligatory
aspects ) with a bacterial residual
charge at the lowest level (optional
aspects ), in order to reduce
the degenerative aspects to the
minimum.
Other “optional aspects” are
related to the residual functionality
of the egg product in terms of “
performance aspects” , such as heat
setting properties, whipping, binding,
emulsifying, among many others.
Mesophilic Aerobic Bacteria 100.000 UFC/g
Enterobacteriaceae 100 UFC/g
Staphylococcus Aureus absence/g
Salmonella absence/25g
Listeria Monocytogenes absence/25g
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The Quality Manager should create a
list of thermal resistant bacteria to be
tested during analysis. In the last few
years, stocks of Salmonella pathogen
for humans have become interesting.
For example, S. Typhimurium
has shown a very good thermal
resistance threshold.
In Europe, the responsibility of the
Producer, in disclosing the safety of
the product, has increased after the
application of the “Hygiene Packet (*) ”
law.
The definition of the parameters for a
product being labeled “edible” is not
completely regulated by laws. There
are only some guide lines that every
producer, in the most objective way
possible, must define their limits of
acceptance.
Further, methods to measure, verify
and certify these limits are extremely
important. So, it is crucial to define
procedures in order to obtain the
bacteriological data and which types
of analysis to do.
When looking at “bacterial counting”
it is necessary to specify the
guidelines taken as reference
to define the measurement
methods, admitted precision and
repetitiveness. For example in
Europe, a regulation that thoroughly
describes the analysis methodology
is ISO 4833 (“Microbiology of
food and animal feeding stuffs
— Horizontal method for the
enumeration of microorganisms —
Colony-count technique at 30 °C”).
In this regulation one of the well
described parameters is the
incubation period. To compare
different products, the incubation
period must be respected, otherwise
the results can be completely
incomparable. In fact, an incubation
time of 48 hours would show a
much better product compared
with 72 hours because the bacteria
growth is exponential. In addition,
the use of preservatives must be
considered, with regards to shelf life,
as the addition of preservatives can
significantly extend the shelf life.
Once the limits and procedures
followed to analyze the products are
defined, it is also necessary to define
the percentage of admissibility, i.e.
the Probability of Microbilogical
Failure. For instance, a product for
which there is a probability of 0,1%
to be expired after “x” days might
be considered good, or it could be
acceptable with a probability of 0,5%.
These two values, even if close to
each other have a big influence on
the declared “shelf life”.
To give an example:
After several samples and analysis,
suppose that a product, statistically,
has shelf life of:
15 days with a expiring probability
of 0,000%
30 days with a expiring probability
of 0,001%
45 days with a expiring probability
of 0,020%
60 days with a expiring probability
of 0,150%
It is then possible to consider that
after 45 days the probability that
the product is unexpired is 99,98%,
while after 60 days the probability is
99,85%.
Minute differences (only 0,13%) in
the admissibility result in substantial
differences in the lasting of the
product.
All of this proves, that there are
several parameters to be considered,
while differing analysis methods, or
parameters evaluated differently, will
provide differing shelf life results.
TO OBTAIN A GOOD SHELF LIFE
On average, the efficiency of an egg
products plant is evaluated based on
the starting total plate count (TPC) of
the raw product and the final TPC of
the packaged product.
It should be pointed out that with
the TPC, bacterial charge of the
sample is estimated by means of
small selective growth conditions
with mesophile temperatures (32°C).
However, we know that the micro
organisms responsible for the
degeneration during refrigeration
time are the psicrofili which remain
active at temperatures equal to or
below 5°C.
With a small selective analysis
like the TPC, we can estimate
the content of the bacteria in the
product but we cannot identify their
characteristics. It is only known that
they are thermal resistant, but their
metabolism and their degenerative
aspects during the preservation time
are not known. Therefore, under the
same TPC we can have different
performances in the packaged
product.
It is also very important to underline
that the shelf life of an egg product is
not only the result of a pasteurization
process but depends also on many
other factors:
Type of product
The production of long shelf life
products (ESL) is first determined by
a fresh, and high quality shell egg,
that has not suffered stress during
storage. Consider, for example,
micro-cracks created during transport
and handling, or sudden temperature
changes (thermal shock), can cause
pre-contamination of the product
before breaking.
(*) The Hygiene Packet includes 4 community regulations:
Regulation (CE) n. 852/04 - Alimentary Hygiene Products.
Regulation (CE) n. 853/04 - Defines Hygiene Specifications and Rules for Animal Foods.
Regulation (CE) n. 854/04 - Defines Specification Rules and establishes an Official Agency for the Control of Animal Foods for Human Consumption.Regulation (CE) n.
853/04 -
Regulation (CE) n. 882/04 - Establishes Official Verification Rules for Conformity of Food and Feeds for the Health and Wellbeing of Animals.
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SANOVO SAF
Automatic
Filter
Treatment of the product during
breaking operations
This is a very critical concern, as this
is the first contact the product will
have with the external environment
and it is extremely important that
the breaking machine is designed
in respect of the maximum level of
hygiene and ensures a thorough
cleaning cycle. For example, one
processor decided to exchange their
old breakers with new OptiBreakers,
to handle a total daily production of
150 tons of egg products. Previously,
the UHST pasteurised egg had a
bacteria count at an average of
950.ufc/g . After the installation of
the new Optibreakers, the bacteria
count was reduced to an average of
60.UFC/g. This is the equivalent of
one log reduction of the bacteria.
In order to confirm how difficult it
is to define the meaning of Shelf
Life, it is important to underline that
the bacteriological result has been
obtained from the final product
(pasteurized), so it is clear that the
effect of the pasteurizer (in terms
of killing rate) is strongly connected
to the quality of raw product used
and the production equipment
and hygiene in between the
breakers and the pasteurizer
Furthermore, it is important that
the product is filtered (to eliminate
possible shell parts) and cooled
down as soon as possible after
breaking, in order to inactivate
bacteria growth.
As an example, figure 2, illustrates
the generation time of some bacteria
in relation to time and temperature:
This clearly illustrates how important
it is to keep the products below 4°C
in order to avoid bacteria growth.
FIGURE 2
Bacteria Generation Time @ 4°C Generation Time @ 10°C
Pseudomonas
Fluorescens
CASE STUDY
During tests in order to study the
efficiency of the killing rate of our
pasteurizers we faced a very strange
result: The pasteurizer was not
operating well (low killing rate) even
though the hygienic conditions,
temperatures and holding times
were strictly respected.
Pasteurization temperature and
holding times were increased
dramatically, without regards to
functional properties, nevertheless
the killing rate remained
unsatisfactory.
Focus was then put on the
equipment used before
pasteurization, locating finally a
contamination point in the treatment
of raw egg. The section was
contaminated due to insufficient
cleaning. After this had been
resolved, the pasteurizer started
giving the expected results.
It is interesting to note that a
contamination point had generated
the presence of a thermally resistant
bacteria, that not even the highest
temperatures were able to destroy.
Finally packaging and filling are
equally important areas to consider
10 – 11 hours 2,5 – 3 hours
Listeria Sp 30 – 45 hours 8 – 10 hours
Escherichia Coli Infinite 5 –19 hours
Staphylococcus
Aureus
SANOVO
OptiBreaker
Infinite 42 – 50 hours
when producing ESL products.
In short, packaging is one of the
most critical points in a processing
facility, because the product exits
from the pipes and is exposed to
outside elements providing a high
contamination risk.
We can conclude that every
pasteurization facility is unique
because every plant generates
bacteria for differing reasons. The
definition of shelf life is not solely
related to the pasteurization plant,
but also to the whole production
system, the quality and kind of raw
product used. Every plant should
create its own data base of cases
and analyze the production process
form a general point of view and not
only from a single machine point of
view.
HIGH TEMPERATURE
PASTEURIZERS
Therefore, it can be unfortunate
to choose a system based on
promises of extended shelf life.
Any pasteurizer can claim to
produce ESL, but there are losses
that need to be considered within
the final functional properties. A
company may claim to be able to
guarantee ESL production on their
pasteurizer, but the egg processor
45

SANOVO WAVE TECHNOLOGY
needs to consider all the peripheral
factors that play a role in the end
product. If the pasteurizer turns out
to be incapable of generating the
promised results, the manufacturer
can always claim that this is due to
outside factors not within the scope
of the pasteurizer, such as raw
shell egg quality or handling of the
finished products.
Until now, there are no miracle
pasteurizers available, that can
guarantee to produce extended
shelf life while also maintaining the
important functional products, but
this is changing.
WAVE TECHNOLOGY
SANOVO is now launching the first
real revolutionary pasteurization
technology that can claim to
produce extended shelf life
products while maintaining the
functional properties. SANOVO’s
new WAVE TECHNOLOGY, is a
technology that exposes the liquid
to electromagnetic waves producing
an electric field. Under this process,
the water molecules point in the
same direction as the electric field.
The continuous reversion of the
electric field polarity generates
kinetic energy which in turn creates
a heating effect. The heat is created
by intermolecular friction, stressing
bacteria but not the functional
properties.
The SANOVO WAVE
TECHNOLOGY instantaneously
transfers a tremendous quantity of
energy in a fraction of a second. The
energy is transferred to the entire
product mass allowing a uniform
heating as the product is heated
indirectly by the kinetic energy,
making it possible to heat the
product to just below the coagulation
point.
With SANOVO WAVE
TECHNOLOGY a processor can
achieve 10 times more bacterial
inactivation compared to traditional
pasteurizers, without influencing the
functional properties.
Standard pasteurization
SANOVO WAVE TECHNOLOGY
The SANOVO WAVE
TECHNOLOGY has undergone
extensive testing at a commercial
processing plant in Europe for over
two years. During this real time
testing and operation, data has been
collected and monitored and the
process has been fully refined and
optimized.
The SANOVO WAVE
TECHNOLOGY has achieved >17
weeks shelf life where the TPC after
17 weeks was 73°C >71°C >64°C
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