SETTING PARAMETERS IN THE COLD CHAIN(Ajuste de parámetros en la cadena de frío)

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Abstract
Breaks in the cold chain are important economic losses in food and pharmaceutical companies. Many of the failures in the cold chain are due to improper adjustment of equipment parameters such as setting the parameters for theoretical conditions, without a corresponding check in normal operation. The companies that transport refrigerated products must be able to adjust the parameters of the equipment in an easy and quick to adapt their functioning to changing environmental conditions. This article presents the results of a study carried out with a food distribution company. The main objective of the study is to verify the effectiveness of Six Sigma as a methodological tool to adjust the equipment in the cold chain. The second objective is more specific and is to study the impact of: reducing the volume of storage in the truck, the initial temperature of the storage are a in the truck and the frequency of defrost in the transport of refrigerated products.
Resumen
Las rupturas en la cadena de frío representan importantes pérdidas económicas en las empresas farmacéuticas y alimentarias. Muchos de los fallos en la cadena de frío se deben a un inadecuado ajuste en los parámetros de los equipos, como por ejemplo el ajuste de los parámetros para condiciones teóricas, sin su correspondiente verifi cación en condiciones normales de operación. Las empresas que transportan productos refrigerados deben ser capaces de ajustar los parámetros de los equipos de una manera fácil y rápida para adaptar su funcionamiento a los cambios en las condiciones ambientales. En este artículo se presentan los resultados
de un estudio llevado a cabo con una empresa distribuidora de alimentos. El principal objetivo de estudio es verifi car la efectividad de la metodología “Seis sigma” como herramienta metodológica para ajustar los parámetros de los equipos en la cadena de frío. El segundo objetivo es más específico y consiste en estudiar el impacto de: la reducción del volumen de almacenamiento en el camión, la temperatura inicial del área de almacenamiento en el camión y la frecuencia de descarche en el transporte de productos refrigerados.

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Setting parameters in the cold chain
Ajuste de parámetros en la cadena de frío
VICTORIA RODRÍGUEZ
Ingeniera de producción agroindustrial, doctora en Ingeniera Industrial. Docente
de la Universidad de Navarra. Pamplona, España. vrodriguez@unav.es
ITXASO AMORRORTU
Ingeniera en organización industrial. Docente de Mondragon Unibertsitatea.
Mondragon, España. iamorrortu@eps.mondragon.edu
MARÍA JESÚS ÁLVAREZ
Ingeniera agrónoma, doctora en Ingeniería Agrónoma. Docente de la Escuela de
Ingenieros Universidad de Navarra. Pamplona, España. mjalvarez@tecnun.es
Clasificación del artículo: Investigación (Conciencias)
Fecha de recepción: 30 de mayo de 2011 Fecha de aceptación: 29 de agosto de 2011
Key words: Cold chain, control, parameter setting, six sigma methodology.
Palabras clave: Cadena de frio, control, ajuste de parámetros, metodología !Seis sigma".
main objective of the study is to verify the effec-ABSTRACT
tiveness of Six Sigma as a methodological tool
to adjust the equipment in the cold chain. The se-Breaks in the cold chain are important economic
losses in food and pharmaceutical companies. cond objective is more speciÞ c and is to study the
impact of: reducing the volume of storage in the Many of the failures in the cold chain are due to
truck, the initial temperature of the area improper adjustment of equipment parameters
in the truck and the frequency of defrost in the such as setting the parameters for theoretical con-
transport of refrigerated products. ditions, without a corresponding check in normal
operation. The companies that transport refrigera-
ted products must be able to adjust the parameters RESUMEN
of the equipment in an easy and quick to adapt
their functioning to changing environmental con- Las rupturas en la cadena de frío representan im-
ditions. This article presents the results of a study portantes pérdidas económicas en las empresas
carried out with a food distribution company. The farmacéuticas y alimentarias. Muchos de los fa-
Tecnura Vol. 15 No. 30 set pp. 71 - 81 ting parameters in the cold chain Julio - Diciembre de 2011 71
VICTORIA RODRÍGUEZ / ITXASO AMORRORTU / MARÍA JESÚS ÁLVAREZcon-ciencias
llos en la cadena de frío se deben a un inadecuado distribuidora de alimentos. El principal objetivo de
ajuste en los parámetros de los equipos, como por estudio es veriÞ car la efectividad de la metodolo-
ejemplo el ajuste de los parámetros para condicio- gía !Seis sigma" como herramienta metodológica
nes teóricas, sin su correspondiente veriÞ cación en para ajustar los parámetros de los equipos en la ca-
condiciones normales de operación. Las empresas dena de frío. El segundo objetivo es más especíÞ co
que transportan productos refrigerados deben ser y consiste en estudiar el impacto de: la reducción
capaces de ajustar los parámetros de los equipos del volumen de almacenamiento en el camión, la
de una manera fácil y rápida para adaptar su fun- temperatura inicial del área de almacenamiento en
cionamiento a los cambios en las condiciones am- el camión y la frecuencia de descarche en el trans-
bientales. En este artículo se presentan los resulta- porte de productos refrigerados.
dos de un estudio llevado a cabo con una empresa
* * *
accordance with the speciÞ c conditions of each 1. INTRODUCTION
delivery; characteristics such as the type of route
to be covered and the geographic area of opera-Though processes related to the food industry are
tion, among others. widely regulated and associated with a series of
practices [1, 2], European Standard EC 2073/2005,
Next, results will be presented from a project the application of these practices does not guaran-
which had the following objectives: a) to verify tee that a determined product has not suffered a
the effectiveness of the Six Sigma methodology breakage in its cold chain. This fact has trigge-
to quickly deÞ ne parameter adjustment procedu-red constant concern for food distribution com-
res and b) to study the impact of the truck volume panies regarding the control of their cold chain.
reduction system, the temperature at the begin-Even though this control is costly from both an
ning of the route and the frequency of defrosting economic and operative perspective [3], it is com-
during temperature maintenance in the transpor-pensated with the reduction of costs produced by
tation of frozen products. This paper is structu-the deterioration of products. An interesting way
red in the following way: in the Þ rst section, the to improve the quality of the perishable products
most relevant aspects of the cold chain will be is to assure the stability of cold chains in the cold
discussed, in the following section the main re-chains management [4].
search question will be presented, followed by an
explanation of the methodology used and results A number of variables intervene throughout the
yielded. Finally, conclusions will be presented. cold chain, such as the temperature and humidity
that surround the refrigeration units, maintenan-
ce practices and equipment control parameters, 2. THEORETICAL BACKGROUNDS
among others. Some of these variables are un-
controllable. In transportation, for example, the- With the aim of preventing the deterioration and
se variables determine the operation of a speciÞ c contamination of food, a number of conservation
techniques are used, some of which incorporate unit used for transporting frozen products. There-
fore, it is impossible to establish standard opera- additives, treatments with microorganisms, sub-
ting parameters for a speciÞ c unit. This challenge jecting products to high pressure, drastic changes
in temperature or cooling [5]. Of all of these tech-highlights the need to adjust these parameters in
72 Tecnura Vol. 15 No.30 Julio - Diciembre de 2011con-ciencias
niques, cooling is the least aggressive in terms of left out of the refrigeration units for an excessive
how it affects the product [2]. Studies such as the amount of time. The latter case occurs frequently
one carried out by [6] reveal that the use of time- during the loading and unloading of trucks and
temperature indicators can be more effective in the process of product repositioning on
regards to product quality control compared to a store shelves.
simple microbiological count.
Two methods are used to ensure the traceability
One of the fundamental objectives of governments of a product and the conditions under which it has
worldwide is to increase the level of protection of been stored, one of which consists of measuring
public health. In order to achieve this, different or- the temperature of the product at different points
ganizations have been created with the aim of esta- of the cold chain. The second method is based on
blishing a foundation to boost the security of food controlling the air temperature in which the product
products [1, 7]. One of these organizations is the is being stored. The Þ rst method only allows the
International Institute of Refrigeration, which was detection of breakage of the cold chain that occurs
created by various governments to raise awareness moments before measurement and if the breakage
of all areas of refrigeration worldwide [2]. In accor- signiÞ cantly alters the product’s temperature.
dance with European EC 2073/2005, !the security
of food products can be mainly guaranteed through A number of techniques are used to control the
a preventative approach, such as the adoption of storage conditions of the product, such as : a) the
sound hygienic practices and the application of manual measurement of selected parameters along
procedures based on HACCP principles". different points of the cold chain, such
as speciÞ c humidity or the temperature of the pro-
Controlling the cold chain is a fundamental aspect ducts at speciÞ c points of the cold chain; b) the
for all companies in the food and health industries. use of technologies that allow the monitoring of
The use of cooling in the food sector has increased the product’s storage and transportation condi-
signiÞ cantly over the years due to globalization tions (tracking) with radio frequency-based te-
and an increase in the consumption of pre-cooked chnologies (RFID) [11] [12], ZigBee technology
products. Pre-cooked products are those whose [13] or those based on GPRS. The pharmaceutical
raw materials undergo a higher rate of manipula- industry employs product temperature-slowing
tion and in which many cases have an extended life strategies based on the introduction of special gel
cycle [8]. During the last years progress in the con- packets into containers [14]. Despite the fact that
trol of the cold chain have been directed to transpa- these measures are fairly effective, the resulting
rency, information and tracking, which stems from cost increase when applied to food renders these
the development of new technologies [9, 10]. measures to be impractical.
In order to guarantee food quality, it is necessary The economic losses suffered by distribution com-
to ensure that the cold chain does not break along panies due to cold chain breakages is signiÞ cant;
any of its links. Breakage in the cold chain could in the health sector, in accordance with graphs
happen under any of the following circumstances: presented by a warehouse distribution inspector
the doors of the refrigeration unit remaining open for the Medicines and Healthcare products Regu-
for an excessive period of time, equipment fails latory Agency’s (MHRA) 2001 meeting, 22% of
to cool correctly due to an excessive amount of serious infractions reported during inspections in
ice in the cooling coils, failure of the tempera- 1999/2000 were related to the control and moni-
ture control’s thermocouples or if the product is toring of in-transit temperatures [14]. Maintaining
setting parameters in the cold chain 73
VICTORIA RODRÍGUEZ / ITXASO AMORRORTU / MARÍA JESÚS ÁLVAREZcon-ciencias
the cold chain throughout a product’s entire life Despite the fact that cold chain control is such an
cycle is costly but fundamental as any breakage important factor to distributors, methodologies
causes product deterioration. The proper control and tools to systematize control have yet to be
of the cold chain can be advantageous [9]. developed from an academic perspective. Tools
such as Total Quality Management (TQM) or Six
Food distributors are able to control the cold chain Sigma exist within the quality Þ eld, which allow
up to the moment that the product leaves the refri- problem resolution systematization.
geration or freezing unit. However, a number of
studies show consumers rarely treat products ade- SpeciÞ cally, Six Sigma is a tool that can be very
quately after purchase [15]. This fact highlights useful for organizations because it is based on
the importance of maintaining a rigorous control measurable aspects of problems which a number
of product storage conditions on the part of food of authors have considered to be a weak point of
distributors, as a product in optimum conditions the methodology [17]. When it comes to contro-
would be able to better withstand being submit- lling the cold chain, the use of measurable aspects
ted to inappropriate conditions compared to one is advantageous because temperature acts as the
which has suffered deterioration on a store shelf. product quality control parameter and the abili-
ty to measure the impact that different practices
One of the main problems faced by those who have on temperature can justify the change of a
maintain the cold chain is the difference between certain procedure or parameter.
the theoretical behavior of its refrigeration sys-
tems and the real behavior of these systems. This In the case of transportation, it could be said that
difference is a result of the fact that equipment that as a general guideline, distributors subcontract
makes up the system is designed for a theoretical part or all of which puts stress on
situation; while during daily company activity there the relationship between both the company and
is a great number of hard-to-control variables that the subcontractor as both parts seek to improve
interfere with the process and considerably affect the quality of the product at the lowest possible
the performance of the system. Therefore, those cost.
who utilize refrigeration equipment should main-
tain a permanent relationship with cooling mainte- The impact that any modiÞ cation proposed during
nance companies, which are in charge of ensuring established procedures has on product quality
the proper performance of cooling equipment. and costs should be clearly justiÞ ed, as this often
implies renegotiation of certain contractual ele-
Uncontrollable variables are of a different type, ments. Considering that the quality of the product
for example the temperature of a structure en- (measured in terms of temperature) and costs are
casing the refrigeration unit, the product being measurable aspects, Six Sigma is an appropriate
stored in the unit, the level of humidity and the tool to carry out the study.
loading and unloading methods of trucks, among
others. That is why, in the case of the cold chain, Six Sigma is a tool that has been successfully uti-
it is necessary to adjust equipment performance lized by many organizations. However, it is also
parameters for real conditions. Furthermore, the true that it has failed for many organizations; one
system should be permanently controlled to ve- of the reasons for these failures resides in the lack
rify if the value of the established parameters is of guidelines for the effective implementation of
correct. In the food industry, conÞ rmatory studies Six Sigma [18]. In the study presented in this pa-
of real situations are common [16, 6]. per, Six Sigma has been used as a methodological
74 Tecnura Vol. 15 No.30 Julio - Diciembre de 2011con-ciencias
tool which obtained useful results for the com- of temperature during the transportation of fro-
pany in question. zen products. A serious incident has been deÞ -
ned for this project as one in which the average
temperature is above -18ºC. Critical factors can 3. PROJECT DESCRIPTIONS
be seen in Fig. 2 and will be described in the
following section.The case presented here was developed for a food
distribution company in its transport processes.
The Þ rst step in the project was to deÞ ne the pro- 4. METHODOLOGY
ject team, which included two university resear-
chers and one person in charge of the process of In this section, the way in which each phase of
transporting frozen goods. the DMAIC (DeÞ ne, Measure, Analyze, Improve
and Control) was carried out will be described in
Once the project team was established, the analy- the frozen product transportation analysis.
sis process was studied. The phases of the trans-
portation process can be seen in Fig. 1.
4.1. Define
st nd th
Warehouse 1 stop 2 stop 3 stop The Þ rst step was to create a deÞ nition and com- Transport Transport Transport
mitment page for the project. This document was
Transport titled !Project deÞ nition." On this page, the pro-
ject title, description of the problem, quantiÞ ed
objectives, team and project description appear.
Fig. 1. Transportation Process.
The Þ sh-bone diagram, which can be seen in Fig.
The second step was to identify the factors that 2, was essentially the Þ rst step in deÞ ning the pro-
could inß uence the loss of product quality and blem and the experiments. It was observed that the
factors that could have inß uenced product quality to deÞ ne the project. The following project
objective was established: to reduce both the were controlled by company policy. For example,
number of serious incidents and the variation company policy requires doors to remain closed
Fig. 2. Fish-bone diagram.
setting parameters in the cold chain 75
VICTORIA RODRÍGUEZ / ITXASO AMORRORTU / MARÍA JESÚS ÁLVAREZcon-ciencias
as long as possible during unloading, while, on The volume adjustment systems consisted of a
the other hand, the refrigeration system must be moving curtain and thermal blanket insulation.
running during unloading. The moving curtain is made up of a series of plas-
tic pieces hanging from a moving rail installed
in the ceiling of the refrigeration unit (Fig. 3A), It was considered fundamental during this initial
while the thermal blanket consists of one piece of analysis to study the impact that the following
insulation hanging from a moving rail (Fig. 3B).factors had on temperature maintenance: refri-
geration unit at the beginning of the
When it came to the frequency of defrosting, two route, the volume adjustment system and the fre-
conditions were chosen for analysis: the equip-quency of defrosting. A complete design of ex-
ment default defrosting system and the deactiva-periments, including three factors at two levels,
ted defrosting system. The design of experiments was chosen to be carried out for the study. Factors
can be seen in Table 2.with corresponding levels can be seen in Table 1.
Table 2. Design of experiments.
Table 1. Factors.
F 01 F 02 F 03
Levels
Factors Exp 01 + + +
+ -
Exp 02 - - -
F01 Initial temperature Tº < -10ºC -5ºC< Tº <0ºC
Exp 03 + - -
F02 Volume adjustment Thermal blanket Moving curtain
system insulation Exp 04 - - +
F03 Defrosting system Off On Exp 05 - + +
Exp 06 + + -
The Þ rst step was to determine the following: Exp 07 - + -
average temperature, percentage of incidents and
Exp 08 + - +
standard temperature ß uctuation. For our purpo-
ses, an incident will be deÞ ned as any time tem- The conditions under which the experiments were
peratures exceed -18ºC. conducted can be seen in Table 3.
Fig. 3. a) Moving curtain b) Thermal blanket insulation.
76 Tecnura Vol. 15 No.30 Julio - Diciembre de 2011con-ciencias
Table 3. Conditions of experiments.
Truck with 15 pallets.
Only one evaporator.
Installed rear curtain.
Always the same driver.
Analysis of average (t=3) temperature.
The product enters the truck at Tº<-18ºC.
Route of 150 km with three stops.
Air temperature out of the truck between 8ºC and 15ºC. Fig. 4. Positions of sensors.
Programmable loggers and the GPRS thermo- tablished to deÞ ne the steps that the driver should
couple installed to control the refrigeration sys- take at each stop. This procedure was explained
to the driver before the route commenced. tem acted as the instruments of measurement.
The exact time at which the Þ rst (initial register)
temperature gauging and Þ nal register, which co- 4.3. Analyze
rresponded with the beginning of the experiment,
were carried out were recorded in the loggers. In this phase, average temperature, percentage of
Furthermore, the frequency of the registers was incidents and temperature variation were analyzed.
closely watched and temperatures were logged
every 2 minutes in every case. Each logger is
4.4. Improve equipped with two thermocouples, one of which
was used to measure product temperature while
Once the parameter values were determined and
the other was utilized to measure the temperature
the performance guidelines deÞ ned, they were
surrounding the product.
passed along to everyone involved in the process
of transporting frozen food and put into practice.
4.2. Measure
4.5. Control
In each experiment, three loggers were placed on
the upper part of three pallets located in different
Controlling the effectiveness of the measures
positions within the truck. Logger 1 left the truck
taken is carried out through the control center of during the Þ rst unloading, 2 during the se-
the company, which constantly receives informa-
cond and Logger 3 during the last. The positions
tion regarding registered temperatures and inci-
of all three loggers within the truck can be seen
dents. This results in the calculation of the cold in Fig. 4.
indicator.
Product temperature was measured by cutting a
bar of ice in half and inserting a thermocouple. 5. RESULTS
The ice and the logger were then placed in a
Tupperware container. The ice, logger and Tu- The variables analyzed were the average tempera-
pperware container remained in the frozen pro- ture of every register, the percentage of incidents
duct unit from the night before until the time the and temperature variation. These three variables
experiment was conducted. A procedure was es- were initially obtained at three points: three pa-
setting parameters in the cold chain 77
VICTORIA RODRÍGUEZ / ITXASO AMORRORTU / MARÍA JESÚS ÁLVAREZcon-ciencias
llets at different positions within the truck and the
Main Effects Plot for R03data registered by the truck’s GPRS (truck sys-
Data Means
tem). Of all the registers taken by the loggers on F01 F02
0,96
the multiple-positioned pallets, only the analysis 0,92
0,88of the last logger to leave the truck was taken into
0,84consideration because the loggers unloaded du-
0,80
ring the Þ rst two stops did not yield sufÞ cient data -1 1 -1 1
F03
0,96to carry out the analysis. The analyzed variables
0,92can be seen in Table 4.
0,88
0,84
Table 4. Experiment answers. 0,80
-1 1
Variables Meaning
Interaction Plot for R03
Data MeansR01 Average Tº of the environment near product
-1 1 -1 1
F01R02 % of incidents in enviroduct
1,0 -1
1
R03 Range of Tº in environment of product F01 0,8
R04 Average ot the Tº of product
0,6
F02
1,0 -1R05 % of incidents in product
1
F02 0,8
R06 Range of Tº in product
0,6
Average Tº in the environment registered by
R07
truck system
F03
R08 % incidents registered by truck system
R09 Range of Tº registers by truck system
After analyzing the effects and interactions of the Fig. 5. Effects and interactions to R03.
three factors in the nine variables, it can be seen
Fig. 5 illustrates that the effect which most im-
that the variation of the factors only affects the
pacts temperature variation in product environ-range of temperatures registered in the environ-
ment is the current state of the defrosting system ment near the product and the temperatures regis-
(F03). Therefore, it could be said that deactivating tered by the truck system (R09). Therefore, factor
the truck’s defrosting system reduces temperatu-variation does not impact any of the variables re-
re variation. The interaction between temperature gistered inside the product (R04, R05 and R06).
at the beginning of the route (F01) and the de-This is noteworthy because, in order to achieve
frosting system (F03) (Fig. 5b) shows that having temperature variation in the center of the product,
the defrosting system shut on or off produces a the change must be long-lasting, so-
greater impact on temperature variation when the mething which never occurred.
temperature of the truck at the beginning of the
route is between 0 and -5ºC compared to when it On the other hand, it could be observed that para-
is at a temperature below -10ºC. This is a plausi-meter variation affected neither the average tem-
ble result, since when the truck starts its route at perature nor the percentage of incidents in the en-
vironment near the product (R01 and R02). This 0ºC, the system tends to cool at -18ºC, while if the
result was also found in the temperatures registe- truck leaves at -10ºC, and temperature variation
red for the truck system (R07 and R08). is lower.
78 Tecnura Vol. 15 No.30 Julio - Diciembre de 2011
Meancon-ciencias
Fig. 6. Effects and interactions to R09.
In Fig. 6 a and b it can be seen that leaving the turned off as this would have eventually broken
defrosting system deactivated (F03) produces, in the refrigeration equipment. In these experiments,
every case, a reduction in temperature variation the evaporator was revised at each stop to verify
in the registers taken by the truck system (R09). It that no icing had accumulated. It could be seen
can also be seen that the change in the volume ad- that because of the characteristics of the route
justment system (R02) produces a much greater (duration and number of stops), it is possible to
impact on temperature variation when the initial carry out these revisions without activating the
temperature of the truck is between 0 and -5ºC defrosting system.
(R01). As was explained in the prior case, tempe-
rature during the route tends to stay at -18ºC. The experience of this project was very positive
for the company involved because it allowed for
project development standardization to control
6. CONCLUSIONS
the cold chain through the utilization of Six Sigma
as an improvement tool. The development of this
In accordance with the results, it can been seen
project has been a learning experience where the
that the variable which most impacts the reduc-
team deÞ ned a procedure type to develop projects
tion of environmental temperature variation wi-
and academics provided the necessary statistical
thin the truck, both in the data registered by the
analysis to develop subsequent projects.
truck system as well as in the environment near
the product, is the state of the defrosting system.
It can be seen that if the system is deactivated, the 7. ACKNOWLEDGMENTS
environmental temperature becomes more stable.
In agreement with these results, a subsequent stu- We are grateful to the food distribution com-
dy was proposed to more precisely adjust the pa- pany that Þ nanced this project, to the employees
rameters of the truck’s defrosting system. Not all involved and to the invaluable members of the
routes can be covered with the defrosting system team.
setting parameters in the cold chain 79
VICTORIA RODRÍGUEZ / ITXASO AMORRORTU / MARÍA JESÚS ÁLVAREZcon-ciencias
REFERENCIAS
[1] S. Jol, A. Kassianenko, K. Wszol and J. Og- [7] K. Likar and M. Jevsnik, !Cold chain
gel, !The cold chain, one link in Canada’s maintaining in food trade," Food Control,
food safety initiatives," Food Control. vol. vol.17, no. 2, pp.108–113, Feb. 2006.
18, pp. 713-715. Nov. 2005.
[8] S. Beasley, !The current state of the cold
chain in the Philippines," United States [2] D. Coulomb, !Refrigeration and cold chain
Department of Agriculture. Trade and serving the global food industry and creat-
Investment Program of Food Industries ing a better future: two key IIR challenges
Division, Foreign Agricultural Service. for improved health and environment,"
1998.Trends in Food Science & Technology, vol.
19, no, 8, pp. 413-417, 2008.
[9] R. Montanari, !Cold chain tracking: a
managerial perspective," Trends in Food [3] J. Kuo and M. Chen, !Developing an ad-
Science & Technology, vol. 19, no. 8, pp. vanced multi-temperature joint distribu-
425-431, Aug. 2008.tion system for the food cold chain," Food
Control, vol. 21, no. 4, pp. 559-566, Apr.
[10] T. Moe, !Perspectives on traceability in
2010.
food manufacture," Trends in Food Sci-
ence & Technology, vol. 9, no. 5, pp. 211-[4] M. Bogataj, L. Bogataj, and R. Vodopivec,
214, May. 1998.
!Stability of perishable goods in cold lo-
gistic chains," International Journal of
[11] E. Abad, et ál, !RFID smart tag for trace-
Production Economics, vol. 93-94, pp. ability and cold chain monitoring of foods:
345-356, Jan. 2005. Demonstration in an intercontinental fresh
Þ sh logistic chain," Journal of Food Engi-
[5] B. Marcos, A. Jofré, T. Aymerich, J. Mon-
neering, vol. 93, no. 4, pp. 394-399, Aug.
fort and M. Garriga, !Combined effect of
2009.
natural antimicrobials and high pressure
processing to prevent Listeria monocyto- [12] C. Metzger, F. Michahelles and E. Fleisch,
genes growth after a cold chain break dur- !Ambient energy scavenging for sensor-
ing storage of cooked ham," Food Control, equipped RFID," Smart sensing and con-
vol. 19, no. 1, pp. 76-8, 2008. text- Second European Conference. Berlin.
2007.
[6] M. Smolander, H. Alakomi, T. Ritvanen, J.
Vainionpaa and R. Ahvenainen, !Monitor- [13] A. Carullo, S. Corbellini, M. Parvis, L.
ing of the quality of modiÞ ed atmosphere Reyneri and A. Vallan, !A measuring sys-
packaged broiler chicken cuts stored in tem for the assurance of the cold-chain
different temperature conditions. A. Time– integrity," Presented at the IEEE Interna-
temperature indicators as quality-indicat- tional Instrumentation and Measurement
ing tools," Food Control, vol. 15, no. 3, pp. Technology Conference, Vancouver, May.
217-229, Apr. 2004. 2008.
80 Tecnura Vol. 15 No.30 Julio - Diciembre de 2011