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TOWAROZNAWCZE PROBLEMY JAKOŚCI 2(51)/2017
75
Marta BIEGAŃSKA
Poznań University of Economics and Business
Faculty of Commodity Science
Department of Commodity Science and Ecology of Industrial
Products
Shelf-life monitoring
of food using
time-temperature
indicators (TTI)
for application in
intelligent packaging
Key words: food safety, shelf-life, TTI, distribution chain,
food quality monitoring
Słowa kluczowe: bezpieczeństwo żywności, okres trwałości produk-
tu, wskaźniki TTI, łańcuch dostaw, monitorowa-
nie jakości żywności.
1. Introduction
Globalization and growing international food trade
present a major quality and safety problem. These
globalized food chains are a challenge for food
monitoring and control. Within them temperature
control plays one of key factors in maintenance of food
quality and safety. The concept of supply chain
management especially in the field of perishable
products (e.g. food, beverage and pharmaceuticals) is
challenging, because of their short shelf life and a
number of strict requirements. Improper storage
conditions in the distribution chain regarding
temperature not only lead to shelf life reduction, but
also significant economic losses [1]. Temperature abuse
can occur at any point in the distribution chain, such as
loading and unloading of products, temperature
conditions in walk-in-coolers or
even during transport to
consumer's home [2]. The reason
for this is that the distribution
chain rarely has the facilities to
store each commodity under its
optimal conditions. Fresh or
ready-to eat (RTE) vegetables,
cheeses etc. that require different
storing temperatures are stored in
walk-in-coolers, cooled food
displays or mixed produce freight
containers that are adjusted to a
specific temperature (too low or
to high for some of the stored
products) sometimes greater or
equal to 9oC [3-5].
The use of intelligent
packaging e.g. time-temperature
indicators (TTIs) could lead to
introduction of an effective system
for monitoring the temperature
conditions of individual products
along the distribution chain and to
showing their remaining shelf life
not only 'use by date'. Such system
would go in line with already
existing Hazard Analysis Critical
Control Point method (HACCP)
and Good Manufacturing and
Hygiene Practices as monitoring
of critical control points may be
achieved by using TTI labels/tags.
The TTI tag should then be
selected or pre-adjusted so that the
activation energy required to
produce a colour change is similar
to that required to initiate
significant deterioration in the
food being monitored.
The use of TTI tags would
enable indication of problem
areas in the distribution system
and allow their resolving. It
would also help in facilitating the
scheduling of products distribution
so that the products approaching
the end of their shelf life are
moved first at the warehouse and
in the retail system. This approach
TOWAROZNAWCZE PROBLEMY JAKOŚCI 2(51)/2017
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would not often go in line with currently practiced policy first-in first-out (FIFO), that makes
the products that came to the warehouse first move out of the warehouse first as well, not
taking into account the real condition, quality and remaining shelf-life of stored products
[1, 2, 6].
2. Time-temperature (TTI) technologies
Time-temperature indicators or integrators (both names can be found in the literature) are
devices or tags that can show an accumulated time-temperature distribution function. The
TTIs are based mainly on three systems: mechanical, chemical or enzymatic that change
irreversibly starting from the time of their activation. Their response is visible through
a mechanical deformation, colour movement or colour change [1, 2, 5-14]. The rate of that
visible/measurable change is temperature dependent and it increases at higher temperatures. In
order for a TTI to be reliable it's necessary that the temperature dependence of its response is
similar to that of the food quality loss. Moreover, the TTIs end point should coincide with the
end of product's shelf life [5, 15].
In the last decades there have been many studies on developing new and efficient TTIs.
However, only several of them got to be patented and commercialized and some reached
a prototype stage. An example of probably the one remaining on the market for the longest
time is a 3M Monitor Mark TM (St. Paul, MN, USA). It has achieved one of the first significant
applications of TTIs since it was used by the World Health Organization (WHO) for
monitoring of refrigerated vaccine shipments. Monitor MarkTM is based on diffusion of
patented polymer materials [1, 5, 6]. With increasing temperature above the threshold of the
specific TTI a blue dyed fatty acid ester diffuses through a porous wick (made from a high
quality blotting paper), thus giving a measurable response – similar to reading a thermometer.
This indicator also requires activation, in this case by adhesion of the two materials. Before
use Monitor MarkTM can be stored for a long period at ambient temperature [2, 5, 6, 9, 12].
However, before activation it should be conditioned for at least two hours at the same
temperature as the product is stored at.
a) b)
Fig. 1. Example of the CheckPoint® label where a) has a green dot signalling the product is OK to use and
b) where the dot is red meaning do not use
Rys. 1. Przykład etykiety CheckPoint® a) zielone wnętrze koła (tzw. kropka) sygnalizuje, że produkt jest zdatny do
spożycia, b) kropka jest czerwona, co oznacza, że produkt nie nadaje się do spożycia
Source/Źródło: a) http://vitsab.com/wp-content/uploads/2013/09/Why-TTI_2.jpg
b) http://vitsab.com/wp-content/uploads/2013/12/Endpoint.jpg.
The first enzymatic indicator I-Point Time Temperature Monitor, was later succeeded by
the VITSAB CheckPoint® Time Temperature Indicator (Limhamn, Sweden) shown in Figure
1. It was based on a colour change occurring from controlled enzymatic hydrolysis of a lipid
substrate (pH decrease). It comes in a variety of response lives and temperature dependencies
which are the effect of using different combinations of enzyme-substrate concentrations. It
requires activation that occurs through mechanical breaking of a separating barrier inside the
TTI which causes mixing of the enzyme and substrate. Hydrolysis of the substrate causes acid
TOWAROZNAWCZE PROBLEMY JAKOŚCI 2(51)/2017
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release, and the pH drop induces a colour change of a pH indicator from deep green to bright
yellow to orange red [1, 2, 6, 12]. In order to maintain long shelf life of these TTIs, they need
to be kept chilled before activation [5].
Moreover, the Lifelines Freshness Monitor® and Fresh-Check® TTI (Morris Plains, NJ,
USA) are examples of chemical systems, as they are based on a solid state polymerization
reaction that results in a highly coloured polymer; the response of this TTI is a colour change
measured as a decrease in reflectance. The Fresh-Check® is based on the property of
disubstituted diacetylene crystals to polymerize through a lattice-controlled solid-state reaction
resulting in a highly coloured polymer. The colour of the active centre of the TTI label has to
be compared with the reference colour of a surrounding ring. These indicators are active from
the time of their production and in order to significantly slow down their response prior
application, they need to be stored at deep frozen temperatures [1, 2, 5, 6, 12].
Another commercially available TTI is the Ciba OnVuTM (SW) shown in Figure 2. It's also
based on a solid-state reaction, but in this case in a crystal phase. Photosensitive compounds
(e.g. benzylpyridines) are excited and coloured by exposure to low wavelength light. The
coloured state (dark blue) is reversible and goes back to its initial colourless state at a
temperature-dependent rate. The temperature sensitivity and response lives can be set by
controlling the type of photochromic compound and the time of light exposure during
activation. The OnVuTM TTI can take the form of a photosensitive ink and thus gives a wide
range of applications [1, 5, 6, 12]. It is one of the leading TTIs as it can be easily activated at
the point of application by exposure to UV light from a special activator supplied by the
manufacturer. It can be printed directly onto packaging in a cost-effective manner [15].
Fig. 2. Example of an OnVuTM TTI label
Rys. 2. Przykład etykiety OnVuTM na której ciemny punkt w środku okręgu wskazuje, że produkt jest świeży,
a zgodnie z jaśniejącymi polami u dołu rysunku, gry zmieni barwę na jasnoszarą jest już nieświeży
Source/ Źródło: http://freshpoint-tti.com.keam.co.il/_userfiles/labels/OnVu1.gif.
Worth mentioning is also the (eO)® TTI (Gentilly, France) which is based on a pH change
that is expressed as colour change from green to red using suitable pH indicators. The colour
change is continuous an can be perceived through visual recognition or measured
instrumentally. The latter allows its application in shelf life management schemes. This pH
change is obtained through a controlled microbial growth in a gel. The response lives and
threshold temperatures are adjusted for select microorganisms by appropriate variations in the
gel composition. The manufacturer of the (eO)® claims that it mimics microbial spoilage of
the monitored products, because its response is based on the growth characteristics of similar
microorganisms (select patented strains of Carbonbacterium piscicola, Lactobacillus
fuchuenis, Leuconostoc mesenteroides) [6, 12]. Before use the (eO)® needs to be stored frozen
to prevent the bacterial growth and activation is simply by defrosting them at room
temperature for a few minutes [5].
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The TT SensorTM (USA) is another example of a diffusion-reaction concept. In this TTI
diffusion of a polar compound between two polymer layers occurs and the change of its
concentration results in a colour change of a fluorescent indicator from yellow to bright pink
[6]. The TTI can be stored in an inactive form. It comes as two separate components: an
indicator label and a transparent activator overlay. To activate the sensor the two layers are
brought together automatically by a dual-spindle applicator. Unlike some TTIs this one doesn't
require refrigeration before application, comes at different sensitivities and offers a six-month
shelf life [15].
A recently available full-history TTI is Keep-it® (Oslo, Norway). It is shown in Figure 3
and is primarily based on a chemical reaction between an immobilized reactant (e.g. Fe3+) and
a mobile reactant (i.e. ferrocyanide) that initially are in separate compartments separated by
a sealing. Once the sealing is removed (activation) the reaction begins – mobile reactant in
a time-temperature dependent way is brought into contact with the immobilized one resulting
in a visual reaction signal [5].
Fig. 3. Example of the Keep-it® shelf life indicator in which the dark blue rod moves to the left-hand side with
time and temperature showing the remaining days of products shelf life
Rys. 3. Przykład wskaźnika Keep-it®, w którym granatowe zabarwienie pręcika z upływem czasu oraz dodatkowo
przy zmianach temperatury przesuwa się w lewo wskazując ilość pozostałych dni do spożycia produktu
Source/Źródło: keep-it.com.
2.1. Commercial applications of TTIs
In order to give a better view of where TTIs can and are used here are some market
examples. Fresh-Check® is being used on vaccines supplied to the UNICEF Children's
Vaccine Campaigns worldwide (e.g. measles). Moreover, it is used on food products by
Monoprix retail chain (France) on several of their own label perishable products, Carrefour
retail chain uses this TTI on packed fruit and salads sold via e-shopping. They are also present
on Milco® dairy and juice products.
The (eO)® TTI has its application also by Monoprix, but on packed fresh pork. It is also
used by LECLERC in Bretagne on ”Marque Repère” and fresh packed sandwiches by
Auchan, Coran and Elior.
The CheckPoint® is applied to vacuum- or modified atmosphere (MA) packed fresh
seafood imported to the U.S. by several importing companies. The import of these products is
covered by FDA's Import Alert #16-125. Such products are placed on detention unless
importers are on the Green List. To qualify to the list, manufacturers, shippers, or importers
have to provide the information to FDA to establish that controls are in place to prevent C.
botulinum toxin formation or provide a visual indication of a potential problem. The L5-8
CheckPoint® TTI response conforms to these requirements.
CheckPoint® Flight label 1 based on B7-24 label, on the other hand, is a flight label used
on board British Airways flights for monitoring temperature for proper handling of served
meals.
The OnVuTM is used on all packages of Kneuss fresh chicken produced and distributed by
Ernst Kneuss Geflügel A.G. (Switzerland) [6].
The Keep-it® is used by a Norwegian retail chain Rema 1000, an e-shop Kolonial.no, but
also by Oslo Universitetssykehus (hospital), Gilde, Nortura and Stange (meat and meat
TOWAROZNAWCZE PROBLEMY JAKOŚCI 2(51)/2017
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products manufacturers), Godehav and Salmar (fish and fish products manufacturers)
[keep-it.com].
3. Legal aspects of TTIs as intelligent packaging
Examples of intelligent packaging, ones having the ability to communicate information
about the requirements known to ensure product quality like time-temperature history are
TTIs. Such packaging technology is already implemented in the United States, Japan and
Australia. However, legislative restrictions in the EU have delayed its development and
implementation. The reason for this is among other things the differences in approach in
regulations for food contact materials. In Europe it's based on the theory that all materials
should be explicitly cleared and publicized in regulations and that all clearances must be based
on toxicological evaluations of the listed substances. On the other hand in the U.S. substances
in the TTI should not cause any toxicological concern due to minimal dietary exposure, based
on analytical chemistry data and extrapolations. The U.S. regulations for those food contact
materials that are considered to be ”food additives” are under the Federal Food, Drug, and
Cosmetics Act. As long as any substance in the intelligent packaging system isn't intended to
be added to the food or to have a technical effect in the food, there are no special regulations
in place for food contact materials. Whereas in the EU the regulations are more detailed. For
example, Regulation 1935/2004/EC states that materials or articles should be manufactured
according to good manufacturing practice (GMP). They also shouldn't transfer their
constituents to food in quantities sufficient to cause a danger to human health, and shouldn't
cause unacceptable change in food composition or cause deterioration of the organoleptic
characteristics.
Another EU regulation gives additional specific requirements in this area. Regulation
450/2009/EC states that only substances that are legally included in an EU list should be used
in active and intelligent components. The substances can be put in a separate container or be
directly incorporated into the packaging material. If they are not positioned on the outer
surface of the package or if there isn't a barrier made from food contact material preventing
the migration of substances into the food, then they are subject to requiring legal permission
[9, 10].
4. Experimental
4.1. Materials
The 3M Monitor MarkTM indicators (9860B: threshold 5oC and 9860C: threshold 10oC,
both with response time of 48h) were used to evaluate the TTIs' responses at dynamic
temperature conditions (simulating temperature abuse). The second part of the experiment
involved the packaging material effect on the TTIs' responses. This was designed to show
whether their response was or wasn't dependent on the type of packaging material to which
they were attached to.
4.2. Methods
Both MonitorMarkTM TTIs were preconditioned at room temperature (25oC) and placed on
a polystyrene (PS) tray used for food packaging or on a cardboard (CB) box used as
a secondary packaging as shown in Figure 4. Three TTIs of each threshold (9860B: threshold
5oC – B5 and 9860C: threshold 10oC – C10) were used at each packaging material (PS, CB).
They were first stored at room temperature for 2.5 h, then placed in a laboratory coldbox
set to 4oC ± 1 for 21.5h and finally after 24h from activation placed again at room temperature
for the next 40h to reach their end points.
TOWAROZNAWCZE PROBLEMY JAKOŚCI 2(51)/2017
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The responses of the investigated TTIs were measured using a slide caliper. Each time the
distance from the starting point of the TTI's window to the front of the blue colour visible on
the indicator were measured. Measurements were taken at different time intervals. The blue
dyes movement in each TTI attached to the PS or the CB surface was measured three times.
5. Results
Figure 4 shows the visual response of the investigated MonitorMarkTM TTIs. As one can
see the movement of the blue dyed fatty acid was clearly visible and the length of the blue
colour could be measured easily. This movement also confirms that above threshold
temperatures for both B5 (bottom three labels) and C10 (top three labels) TTIs the diffusion
occurred giving the sensors response. Although, stored at the same temperature the distances
of the blue dye colour movement in B5 and C10 were slightly different. These responses
varied even within the same type of TTI.
As shown in Figure 5 and 6 the packaging material to which the TTIs were attached didn't
have any effect on the investigated Monitor MarkTM indicators responses. The measured
lengths of the blue colour were almost the same independently from the packaging material,
on which they were placed, in the B5 and C10 indicators respectively. This leads to the
conclusion that the effect of the packaging material used in the experiment has little or no
effect on the TTIs performance and can be neglected.
a) b)
Fig. 4. The visual response of the MonitorMarkTM TTIs B5 and C10 showing movement of the blue dyed fatty
acid ester when subjected to room temperature (25oC) much above the thresholds of the indicators. In
a) sensors placed on cardboard box (CB) and b) placed on a PS tray.
Rys. 4. Wizualna odpowiedź wskaźników MonitorMarkTM B5 i C10 przedstawiająca dyfuzję estru kwasu tłuszczo-
wego zabarwionego na niebiesko, przechowywanych w temperaturze pokojowej (25oC) znacznie powyżej
temperatur progowych wskaźników. Na a) widoczne są wskaźniki umieszczone na pudle tekturowym, a na b)
umieszczone na polistyrenowej tacce
Source/Źródło: Own picture.
TOWAROZNAWCZE PROBLEMY JAKOŚCI 2(51)/2017
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Moreover, these two Figures (5 and 6) show that after designed 48h of response time both
B5 and C10 didn't reach their end points. Furthermore, when stored at 4oC (below threshold of
B5 and C10) the rate of the diffusion dropped in the case of C10, whereas the blue colour
movement was still visible in the B5 indicators.
Fig. 5. The length of the blue dye movement in B5 TTIs at different temperature conditions in time and at two
packaging materials (CB and PS)
Rys. 5. Długość niebieskiego zabarwienia wskaźników B5 w różnych temperaturach i po określonym czasie,
umieszczonych na dwóch materiałach opakowaniowych (CB i PS)
Source/Źródło: Own work.
Fig, 6. The length of the blue dye movement in C10 TTIs at different temperature conditions in time and at
two packaging materials (CB and PS)
Rys. 6. Długość niebieskiego zabarwienia wskaźników C10 w różnych temperaturach i po określonym czasie,
umieszczonych na dwóch materiałach opakowaniowych (CB i PS)
Source/Źródło: Own work.
0
1
2
3
4
5
6
0 5 10 15 20 25 30 35 40 45 50 55 60 65
B5/ CB
B5/ PS
The lenght of the colour movement
0
1
2
3
4
5
6
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Time [h]
C10/ CB
C10/ PS
The lenght of the colour movement
in the TTI in cm
Time [h]
TOWAROZNAWCZE PROBLEMY JAKOŚCI 2(51)/2017
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Fig. 7. The length of the blue dye movement in B5 and C10 TTIs at different temperature conditions in time
placed on CB
Rys. 7. Długość niebieskiego zabarwienia wskaźników B5 i C10 w różnych temperaturach i po określonym czasie,
umieszczonych na CB
Source/Źródło: Own work.
Fig. 8. The length of the blue dye movement in B5 and C10 TTIs at different temperature conditions in time
placed on PS
Rys. 8. Długość niebieskiego zabarwienia wskaźników B5 i C10 w różnych temperaturach i po określonym czasie,
umieszczonych na PS
Source/Źródło: Own work.
The graph for B5 indicators was linear and for C10 showed a lag phase when stored below
threshold temperature. This is rather alarming, especially when we take into account that B5
indicator can be used for perishable food products monitoring, that need to be stored at
temperatures below 5oC. This shows that even below or even to threshold temperature B5
indicators gave visual response (diffusion occurred). This however, needs further research in
0
1
2
3
4
5
6
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Time [h]
B5/ CB
C10/ CB
The lenght of the colour movement
in the TTI in cm
0
1
2
3
4
5
6
0 5 10 15 20 25 30 35 40 45 50 55 60 65
Time [h]
B5/ PS
C10/ PS
The lenght of the colour movement
in the TTI in cm
TOWAROZNAWCZE PROBLEMY JAKOŚCI 2(51)/2017
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order to confirm this kind of sensors' behaviour close to threshold temperature leading to false
indications of the time-temperature history.
Figures 7 and 8 show the investigated TTIs' visual responses at cardboard box and PS tray,
respectively. It is noticeable that in the case of both packaging materials the rate of blue dyed
fatty acid was greater in case of C10 indicator. The responses of B5 and C10 were similar
within first 30 hours of the experiment both on CB and PS. After which C10 sensor showed
faster blue dye movement compared to B5. This is surprising, as from the 24th hour of the
experiment they were both store at room temperature. It was expected that the rate of
coloration in B5 should be greater than in C10, due to different temperature thresholds.
According to the performance of the investigated TTIs the rate of the diffusion is greater
with increasing temperature above threshold, because the reaction is temperature dependent.
In this case the higher the storing temperature the faster dye diffusion. As the temperature
difference between the storage and the threshold temperature was greater for B5 than for C10,
the blue dye movement in B5 should be faster. Obtained result however, showed that it was
faster for C10.
6. Conclusions
In this work two MonitorMarkTM TTIs were evaluated under dynamic temperature
conditions (simulating temperature abuse) and the effect of packaging material, to which
indicators were attached to, on their responses was investigated. The type of packaging
material had little or no effect on the TTIs responses. This suggests that both TTIs, cardboard
box, and PS tray had close or even same temperatures throughout the experiment and no
cooling or heating of the TTI by the packaging materials took place.
More interesting were the results showing movement of the blue dye in B5 indicator and a
lag phase in C10 when stored below threshold temperature. Besides, both TTIs reached their
end points long after designed 48h. Also the diffusion rate of the dye in B5 was higher than in
C10 when stored above threshold (room temperature) after 30h of the experiment (around 6h
after removing from coldbox). This could lead to misleading or even false readings of the B5
TTI (9860B: threshold 5oC, response time 48h) in real applications, however due to limited
number of samples and only two storing temperatures, this requires further research.
The problem of food waste due to its quality deterioration is not only the problem within
the distribution chain but also, and perhaps most importantly, because of inappropriate storing
conditions at the consumer level. Europeans and North Americans produce around 95-115 kg
of food waste annually per capita. This accounts to more than one-third of the food production
in these countries. The problem lies in the lack of basic knowledge of where in the refrigerator
should different food be placed, which products can be frozen or even what temperature
should the refrigerator be set to [5, 16]. Application of TTIs would not only facilitate the cold
chain management, but would also provide consumers with information on food products'
remaining shelf life leading to food waste reduction.
7. References
[1] Eden M., Raab V., Kreyenschmidt, Hafliðason T., Olafsdóttir G., Bogason S.G. (2011)
Continuous temperature monitoring along the chilled food supply chain. In: Food Chain
Integrity. A Holistic Approach to Food Traceability, Safety, Quality and Authenticity,
115-129. Woodhead Publishing Ltd.
[2] Fu B., Labuza T.P. (1992) Considerations for the application of time-temperature
integrators in food distribution. Journal of Food Distribution Research, 23 (1), 9-17.
[3] Kou L., Luo Y., Park E., Turner E.R., Barczak A., Jurick II W.M. (2014) Temperature
abuse timing affects the rate of quality deterioration of commercially packaged ready-to-
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eat baby spinach. Part I: Sensory analysis and selected quality attributes". Postharvest
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[4] Badia-Melis R., Mc Carthy U., Uysal I. (2016) Data estimation methods for predicting
temperatures of fruit in refrigerated containers. Biosystems Engineering, 151, 261-272.
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safety management. Trends in Food Science & Technology, 43, 236-244.
[6] Taoukis P.S. (2010) Commercialization of time-temperature integrators for foods, [in:]
Case studies in novel food processing technologies. Innovations in Processing,
Packaging, and Predictive Modelling, 351-366. Woodhead Publishing Ltd.
[7] Pereira Jr. V.A., Queiroz de Arruda I.Z., Stefani R. (2015) Active chitosan/PVA films
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[8] Kim K., Kim E., Lee S.J. (2012) New enzymatic time-temperature integrator (TTI) that
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[11] Park H.R., Kim K., Lee S.J. (2013) Adjustment of Arrhenius activation energy of
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[12] Ellouze M., Augustin J-C. (2010) Applicability of biological time temperature integrators
as quality and safety indicators for meat products. International Journal of Food
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[13] Brizio A.P.D.R., Prentice C. (2015) Development of an intelligent enzyme indicator for
dynamic monitoring of the shelf-life of food products. Innovative Food Science and
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[14] Yam K.L. (2012) Intelligent packaging to enhance food safety and quality, [in:] Emer-
ging Food Packaging Technologies. Principles and Practice, pp. 137-152. Woodhead
Publishing Ltd.
[15] Sharrock K.R. (2012) Advances in freshness and safety indicators in food and beverage
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Summary
Shelf-life of products, their safety and quality is strictly dependent on storage time
and temperature especially when fresh and minimally-processed food is concerned. The paper
presents issues concerning food products deterioration due to temperature abuse in the
distribution chain and possibilities of monitoring them using time-temperature indicators
(TTIs). It focuses mainly on fresh or minimally-processed chilled and frozen food products
and different TTIs for monitoring their shelf-life. It also gives commercial examples of TTIs
applications and mentions legal regulation regarding active packaging. The paper also shows
the studies on the 3M Monitor MarkTM responses/colour changes under different temperature
conditions and on different packaging materials (cardboard, polystyrene trays).
TOWAROZNAWCZE PROBLEMY JAKOŚCI 2(51)/2017
85
Marta BIEGAŃSKA
Uniwersytet Ekonomiczny w Poznaniu, Wydział Towaroznawstwa,
Katedra Towaroznawstwa i Ekologii Produktów Przemysłowych
MONITOROWANIE OKRESU TRWAŁOŚCI ŻYWNOŚCI Z WYKORZYSTANIEM
WSKAŹNIKÓW CZASU I TEMPERATURY (TTI) DO ZASTOSOWANIA
W OPAKOWANIACH INTELIGENTNYCH
Streszczenie
Okresy trwałości produktów, ich bezpieczeństwo oraz jakość w dużej mierze uzależnione
są od czasu i temperatury przechowywania, zwłaszcza w przypadku świeżej i minimalnie
przetworzonej żywności. Artykuł porusza kwestie związane z pogorszeniem jakości żywności
wynikającej z nieprawidłowości w reżimie temperaturowym w łańcuchu dostaw, a także moż-
liwego ich monitorowania przy wykorzystaniu wskaźników czasu i temperatury (TTI). Praca
skupia się głównie na wskaźnikach TTI zastosowanych do monitorowania okresu trwałości
świeżych i minimalnie przetworzonych produktów przechowywanych w warunkach chłodni-
czych oraz mroźniczych.
W pracy znalazły się także przykłady komercyjnych zastosowań wskaźników TTI oraz
wspomniano o regulacjach prawnych dotyczących opakowań inteligentnych. Artykuł prezen-
tuje ponadto wyniki badań wizualnych zmian odpowiedzi/zabarwienia wskaźników Monitor
MarkTM (3M) w różnych warunkach temperaturowych oraz na różnych materiałach opakowa-
niowych (tektura, tacki polistyrenowe).
dr inż. Marta BIEGAŃSKA
Poznań University of Economics and Business
Faculty of Commodity Science
Department of Commodity Science and Ecology of
Industrial Products
al. Niepodległości 10, 61-875 Poznań, Poland
e-mail: marta.bieganska@ue.poznan.pl