Content uploaded by Silvia Estrada-Flores
Author content
All content in this area was uploaded by Silvia Estrada-Flores on May 09, 2014
Content may be subject to copyright.
4
REVIEW ARTICLE
Bulletin 2008-4
ENGLISH
4
REVIEW ARTICLE
by
Silvia Estrada-Flores(a), David Tanner(b)
(a)e-mail: silvia@food-chain.com.au
(b)e-mail: david.tanner@zespri.com
Dr Silvia Estrada-Flores is Principal Consultant and founder of Food Chain Intelligence. Previ-
ously, Silvia was a Senior Researcher at Food Science Australia (a joint venture of CSIRO and the
Victorian Government) in Sydney. Silvia has over 16 years of experience in the management of
cold chains for food and pharmaceutical products. She is an Australian representative in Com-
mission D2 of the International Institute of Refrigeration and a member of the Australian Institute
of Refrigeration, Air Conditioning and Heating. Silvia recently joined the Advisory Board of the
International Journal of Refrigeration and she is a member of the Editorial Board of Food and
Bioprocess Technology (Springer). Silvia has published two book chapters and more than twenty
articles in scientifi c and trade journals. She currently publishes a newsletter entitled Chain of
Thought, accessible at www.food-chain.com.
Dr David Tanner is the Technical Manager – Global Supply Chain for ZESPRI International Ltd.
This role covers management of quality standards across seven international kiwifruit supply
regions, packaging management, quality audit management and technical support to operations
from kiwifruit harvest through to delivery to customer. Dr Tanner has over 14 years experience
in managing and conducting commercially-focused research and development, with specialist
experience in the modelling of refrigeration and packaging interactions. David has a Bachelors
degree in Horticultural Technology and a PhD in Food Engineering from Massey University in
New Zealand. He is active in the International Institute of Refrigeration (IIR), particularly in the area
of refrigerated storage and transport. He is current President of the Science and Technology
Council of the International Institute of Refrigeration.
INTRODUCTION
Much has been written about the need for temperature monitoring of the cold chain for environmentally sensitive
goods.1-4
The emphasis on this issue stems from the critical role that temperature has on the social, economic and environmen-
tal performance of food supply chains:
• in a social context, food safety is an important driver of quality
assurance systems in chilled and frozen goods. Temperature
is second on the list of factors causing food borne illness,
surpassed only by the initial microfl ora present in foods.1,5
Regarding health, pharmaceuticals and more widely health
products use more and more controlled temperature logis-
tics;
• in an economic context, the profi tability of fresh supply chains
is highly reliant on the reduction of product shrinkage. The IIR
fi gures indicate that about 300 million tonnes of produce are
wasted annually through defi cient refrigeration worldwide.6
The wastage problem is not particular to developing nations;
for example, in the US, the food industry annually discards
USD35 billion worth of spoiled goods;7
• in an environmental context, both food wastage and the wast-
age of resources used to grow the unused products need to
be highlighted.
Radio Frequency Identifi cation (RFID) technologies are said to improve the performance of perishable supply chains
through the following uses:
Figure 1. Conceptualization of an RFID system
for monitoring cargo and air temperatures
in a refrigerated transport system
5
REVIEW ARTICLE
Bulletin 2008-4
a) as a means to track the geographical position of individual packages, pallets, shipping containers, or trucks,
which can be stationary or in movement during distribution;
b) as a means to identify items through a unique electronic product code (EPC) or other barcode alternatives;
c) as a means to store real-time environmental data (including temperature) and transmit this information in near
real-time, allowing corrective actions to be taken before products are irrevocably damaged.
Although there is a scarcity of published studies that report the specifi c benefi ts of RFID on perishable supply chains,
case studies in the retail industry8 suggest potential savings at a retail level, especially: increase in sales, shrinkage
reduction, labour cost reduction and improved transparency in the supply chain.
These potential benefi ts have attracted industry interest. However, between 2004 and 2006, optimism turned to
scepticism about the technology and its benefi ts.9 A signifi cant proportion of RFID deployments remain exploratory:
companies are not taking for granted the potential benefi ts described by RFID vendors and are assessing the results
in their own chains with pilot projects. Often, companies undertake RFID pilot trials to fulfi l retailers’ requests and
to comply with food safety regulations, but fail to demonstrate a return on investment that justifi es the use of the
technology.
This review article note aims to explain the principles, advantages and disadvantages of RFID-based monitoring
technologies for the cold chain of perishables. A shorter version will be published in the near future in the form of an
Informatory Note: www.iifi ir.org
Principles of RFID technologies for cold chain applications
An RFID system for cold chain purposes generally encompasses a sensor, a tag and a reader, that communicate with
each other by means of radio transmission. RFID tags can store an EPC for logistics management purposes, and, if
equipped with the appropriate sensor and battery power, a limited number of temperature readings. RFID tags can
be separated into the following categories10:
1. Passive RFID tags. These tags rely on the power supplied by the reader. When radio waves from the reader are
encountered by a passive RFID tag, the coiled antenna within the tag forms a magnetic fi eld. The tag draws power
from it, energizing the circuits in the tag. The tag then sends the information encoded in the tag’s memory. The lack
of an integrated power supply means that passive tags can be very small. Therefore, passive tags can be embedded
in stickers and other similarly fl at presentations.
2. Active RFID systems are battery-powered. The reliability of active tags is typically higher than passive tags
due to the ability for active tags to conduct a “session” with a reader. Active tags also transmit at higher power levels
than passive tags, allowing them to be more effective in environments commonly found during food distribution. Ex-
amples of these situations could be the transmission of information in crowded enclosures (e.g. humans, cattle); data
transmission from tags attached to boxes, which may be placed in the middle of a tightly packed container of fruit,
meat or other products with high moisture contents; transmission through metallic walls (e.g. shipping containers,
trucks), or transmission from long distances (e.g. containers in transit).
3. Semi-passive tags. These systems are also battery-powered. However, they use the passive RFID interface,
thus allowing wireless access to the device without using the internal power source. The battery size is therefore
smaller than in the active tags.
The preferred RFID embodiments for environmental monitoring of food supply chains are semi-passive or active tags
coupled with sensors. Tags can collect a wide range of information11 such as temperature, humidity, shock/vibration,
light, radiation, and concentration of gases (e.g. ethylene). The information collected by the tags is “harvested” by a
gateway or hub, which then transmits the data to a server, though the use of digital mobile telephony (GSM) or local
area networks, which can be wireless (WLAN) or with wired Ethernet connection (LAN). Data collected in the server
can then be stored and analysed, allowing the automatic generation of notifi cations and events. A Web portal may
display historic temperature data, frequency data and may trigger alerts for the users, transmitted via SMS messages
or e-mails. Given that the information is in real-time, or near real-time, sudden situations that endanger the integrity
of the goods can be addressed promptly, as opposed to traditional monitoring techniques that only allow analysis
of past temperatures and events.
Limitations of cold chain monitoring
systems based on RFID
A number of concerns have been raised in regards to the use of RFID tech-
nologies. Some of these are general issues related to all RFID applications
(e.g. security and privacy concerns, legislative concerns, intellectual property
right issues and health risks linked to RFID frequencies). We emphasize in
the following paragraphs specifi c issues detected in cold chain applications:
• Reliability. For example, readers failing to register tagged pallets or that
boxes still exist, due to the harsh conditions in which tags have to operate Figure 2. An RFID tag. Courtesy of Mark
Lohmann, CHILL-ON project
6
REVIEW ARTICLE
ENGLISH
Bulletin 2008-4
(e.g. exposure to direct forklift impacts, excessive vibration, high humidity environments, multiple tag orientations
and distances with respect to readers).
• Lack of uniformity in global standards. Numerous standards and regulations on frequencies and radio spec-
trum have been adopted in different countries, which in turn have inhibited development of a global standard for
RFID. The two main global organizations undertaking work on RFID standards are EPCglobal and the International
Organization for Standardization, and efforts to unify the standards of both organizations are well underway.12
• Diffi culty of establishing a return on investment (ROI). The “cost” of this technology has been cited frequently
as a reason for the slow uptake.13 However, in the case of cold chain applications, the actual information may be
much more valuable than the cost of the tags. Rather than cost alone, the failure to accurately undertake a calculation
of ROI, including tangible and intangible benefi ts has been highlighted as a signifi cant factor for the slow growth of
RFID-based cold chain monitoring.14 Efforts carried out to investigate the economic impact of monitoring tempera-
ture during the distribution of perishables and the associated quality loss have been published.15-16 However, the
impact of depreciation, insurance premiums, labour added or taken out of the chain due to RFID monitoring, costs of
pilot trials and the distribution of RFID advantages to supply chain players has not been fully integrated in published
case studies.
• Troubleshooting and data-driven decision making tools. Active-RFID monitoring can potentially generate
large amounts of temperature data, and its interpretation can be overwhelming. Therefore, the full potential value of
RFID is limited by the structures and processes that companies have in place to take advantage of that potential.17
In current RFID applications, the tools to interpret real-time temperature information and provide practical steps to
correct temperature deviations or to plan the next stages for product distribution are underdeveloped.
• Accuracy. For most cold chain applications, a sensor accuracy of ±0.5°C or better is expected. However, mass
production of RFID tags requires a calibration method that is simple and inexpensive, yet reliable enough to ensure
the desired accuracy in all active tags manufactured. Calibration procedures may be different between manufactur-
ers and models.
• Placement of RFID sensors and representation of spatial variation of cargo temperatures. A company
may decide to instrument only a percentage of the total number of boxes moved through the supply chain with tem-
perature monitoring RFID sensors. In this case, care must be taken in placing these sensors in enough numbers and
in locations that are representative of the entire load. The thermal behaviour of transport and storage systems varies
signifi cantly depending on the type of product, stowage practices, packaging and many other factors. Therefore,
some experimental trials or the use of models will be necessary to select adequate locations for the RFID sensors.
• Lack of collaboration in the supply chain. Inevitably, the use of RFID sensors will disclose information that,
although benefi cial, can challenge beliefs and operations of growers, manufacturers, logistics providers or retailers
involved in the supply chain monitored. Therefore, an RFID strategy needs to account for the reaction of supply chain
partners to the information collected. These reactions will be driven by group and individual interests, personalities
and the level of cooperation in the chain. Obtaining the required level of trust and cooperation across the supply chain
is probably one of the greatest challenges for the successful adoption of RFID technologies.
• Consumer adoption of RFID. This topic involves a large number of issues, including concerns about the dis-
closure of private information (such as shopping habits) and health concerns. However, another obstacle is the lack
of apparent benefi t for consumers from RFID monitoring. After all, many consumers take food safety and quality for
granted and consumers trust that their favourite products and brands will be available every time they go to the su-
permarket. Therefore, the supply chain benefi ts of RFID may need to be more evident for consumers. One option is
the RFID-enabled domestic refrigerator. Several prototypes of RFID-enabled refrigerators have been developed by
appliance manufacturers with functions such as sending a shopping list to the owner’s cellphone or directly to the
supermarket. So far, the uptake of these refrigerators has failed to motivate manufacturers to scale up production.
Applications and benefi ts of RFID-based cold chain monitoring
There is no shortage of published examples of RFID applications in the food and pharmaceutical industries. However,
it is diffi cult to discern from the information publicly available which trials have evolved from pilot studies into full
commercial implementations. Furthermore, updated information about the outcomes of past commercial pilot trials
is sensitive and mostly unavailable to the general public.
Figure 3. An RFID tag.
Courtesy of Behnam Jamali, The University of Adelaide
7
REVIEW ARTICLE
Bulletin 2008-4
Table 1. Examples of commercial pilot trials of RFID cold chain monitoring
(Source: all of these cases were published in the RFID Journal Web site18)
Company Supply chain link Application Pilot
trial
year
Approximate
Implementation
Costs
Reason for RFID uptake
Ballantine Pro-
duce (US)
Grower and dis-
tributor
Tracking fresh fruit shipments
(nectarines, peaches, grapes) from
packing house to retail DC
2005 USD400 000 Competitive advantage (1st fruit
supplier to comply with Wal-
Mart’s RFID initiative)
Envirotainer
(Sweden)
Air freight Tracking air shipments of
temperature-sensitive goods
2002 Unknown Competitive advantage
DHL (Europe) Delivery and
logistics company
Monitoring temperatures of
refrigerated vans
2007 Unknown Quality assurance for
pharmaceuticals
Manor
(Switzerland)
Retail Monitoring of supermarket freezers
and refrigerators
2003 USD330 000
(30 stores
instrumented)
Decrease of shrinkage due to
food spoilage and better
response to equipment failures
Unilever
(Hungary)
Ice cream
manufacturer
Tracking of ice cream temperatures
from manufacturing to retail display
cabinets
2007 Unknown Quality assurance throughout
the chain
ASD Healthcare
(US)
Pharmaceutical
manufacturer
Monitoring of refrigerators and
individual packages at hospitals
2007 Unknown Quality assurance throughout
the chain
Apo Conerpo-
University of
Parma (Italy)
Grower Tracking the entire supply chain of
fresh cherries
2007 Unknown Quality assurance throughout
the chain and management of
ripeness
Rio Blanco
(Chile)
Grower Tracking of avocado temperatures
during road transport segments of
shipments from Chilean grower to
US buyer (i.e. excluding sea voyage)
2007 Unknown Quality assurance of avocado
shipments
Chiquita Brands-
University of Ar-
kansas-Deloitte
Consulting (US)
Marketer, producer
and distributor of
fresh fruit
Trial shipment of 20 pallets in a
refrigerated container transported
by road
2006 Unknown Quality assurance
Samworth (UK) Food marketer and
distributor
Tracking of temperatures inside
refrigerated trucks transporting
meats, salads, desserts and other
perishable items
2005 Unknown Maximize shelf life and avoid
shrinkage due to spoilage
TNT
(The Netherlands)
Logistics and
global express
services
Tracking temperatures of health-care,
pharmaceutical and chemical goods
as they move along the supply chain
(Asia only)
2006 USD500 000 Supply chain of TNT’s Life Sci-
ence Regional DC in Singapore
to a distribution hub in Bangkok,
Thailand, plus shipments fl own
from the Singapore DC to a hub
in Shanghai.
In retail, Wal-Mart stores and more recently Carrefour and Metro have adopted (and asked suppliers to adopt) digital-
tagging technologies, including RFID. However, at this stage Wal-Mart has not required temperature tracking of
perishable goods. The third largest retailer in the US, Kroger Co. (Kroger supermarket chain), has trialled RFID tem-
perature monitoring with their suppliers. However, the business case for RFID remains to be proven, as stated by a
Kroger spokesperson19: “We continue to execute internal pilots with our supplier partners where we see the potential
for compelling business process and operating improvements”.
Case studies in the retail industry suggest the following potential savings8:
• an increase in sales of 1–2% due to reduced out-of-stock;
• shrinkage reduction of 10%;
• labour cost reductions of 20% in warehouses;
• 20-30% reduction in inventory due to lower safety stock;
• improved return on investment;
• transformation to a demand-driven enterprise;
• improvement of visibility and transparency in the supply chain.
8
REVIEW ARTICLE
ENGLISH
Bulletin 2008-4
Looking into the future of RFID for cold chain applications
New developments include:
(a) The combination of RFID technology and time-temperature indica-
tors (TTI). This opens up the possibility of tracking shelf life of chilled
and frozen products remotely. In Europe, a prototype of an electronic
component that allows the connection of chemically based TTI to RFID
transponders has been designed. The RFID-TTI work programme is
being managed under an umbrella project (“CHILL-ON). A consortium
of 27 companies is backing the project.20
(b) Wireless technologies that allow gathering of data and exchange
of real-time information with supply chain partners. An example is the
wireless ‘mesh’ network technology.21
(c) Multi-sensing RFID nanosensors. The development of the smart
sensor is being funded through the EU’s GoodFood programme and
involves researchers and industry in Italy, Spain, and Germany. The
sensor will incorporate ultra-low-power gas sensors along with a thin
fi lm battery, allowing data acquisition and storage when no reader is
present. This design allows the user to access both the traceability
and sensor information even when the on-board battery is exhausted.22
(d) Temperature sensors integrated to RFID tags require continuous power, which is usually supplied by the battery
on the tag. The extra power required not only signifi cantly increases the cost of the hardware and makes it heavy and
bulky, but also limits a tag’s lifetime. Researchers at the Auto-ID Lab (St. Gallen, Switzerland) have proposed an ambi-
ent energy scavenging system as a method to power sensors on battery-free RFID tags for continuous temperature
monitoring. Work on this innovation continues.23
Conclusion
RFID is a promising technology that can provide numerous benefi ts in temperature monitoring and performance of
perishable supply chains. The main limitations are: (a) a relatively high cost; (b) diffi culties in calculating a ROI; and (c)
reliability and accuracy, which should be further improved for cold chain applications.
Recommendations
• A temperature-controlled supply chain is very important to ensure that the consumer receives high quality and
safe perishable products (e.g. food, vaccines or pharmaceutical products). The use of RFID technologies and similar
wireless monitoring systems to achieve these benefi ts should be further explored.
• Research and development should focus on: (a) further cost reductions; (b) a sound methodology for the calcula-
tion of ROI; and (c) improvements in reliability and accuracy of RFID monitoring systems tested under realistic cold
chain scenarios.
• The development of a global RFID standard would improve the uptake of the technology and would also help to
decrease the confusion around the required frequencies and radio spectra in each country.
• Transparency and collaboration across the supply chain are the greatest challenges for the successful adoption
of RFID technologies. The role of the IIR is to facilitate collaboration between the relevant supply chain partners,
through the dissemination of scientifi c information and the development of forums attended by academic and indus-
try experts worldwide.
Figure 4. One of the objectives of the
“CHILL-ON” project, an European initiative,
is the development of a tracking system that
integrates RFID and TTI principles. This hybrid
technology has signifi cant potential to enhance
safety and quality in food supply chains.
Photo on the left: courtesy of Mark Lohmann,
CHILL-ON project
1. Jol S, Kassianenko A, Wszol K, Oggel J. (2006). Issues in time and temperature
abuse of refrigerated foods. Food Safety, 11(6): 30, 32–35, 78
2. Estrada-Flores S, Tanner DJ, Amos ND. (2002) Cold chain management during
transport of perishable products. Food Australia 54 (7): 268-270
3. Bøgh-Sørensen L, Löndhal G. 2004. Temperature Indicators and Time-Tempera-
ture Indicators. 3rd Informatory Note on Refrigeration and Food. 3 pp.
4. Estrada-Flores S. 2008. Technology for temperature monitoring during storage
and transport of perishables. Chain of Thought – the newsletter of Food Chain
Intelligence (1): 2-5.
5. Shimoni E, Labuza T.P. 2000. Modeling pathogen growth in meat products: fu-
ture challenges. Trends in Food Science & Technology, 11(11): 394-402
6. IIR/UNEP. Industry as a Partner for Sustainable Development. Refrigeration.
2002. p. 80. ISBN: 92-807-2191-5.
7. Hoppough S. 2006. Shelf-life. Forbes Magazine. From the Web site:
http://www.forbes.com/business/forbes/2006/0424/052.html
8. BEA Systems Inc. 2006. RFID for Retail: Blueprints for Bottom-Line Benefi ts.
White paper. 23 pp.
9. Collins J. 2004. RFID’s ROI Tops User Concerns, RFID Journal. From the Web
page: www.rfi djournal.com/article/articleview/1207/1/1/
10. Dargan G, Johnson B, Panchalingam M, Stratis C. 2004. The Use of Radio Fre-
quency Identifi cation as a Replacement for Traditional Barcoding. 45-877. Final
Project Strategic Uses of Information Technology. Carnegie Mellon University.
11. Jedermann R, Lang W. 2007. Semi-passive RFID and beyond: steps towards
automated quality tracing in the food chain. Int. J. Radio Frequency Identifi cation
Technology and Applications, 1(3); 247-259.
12. EPCGlobal Inc. 2006. The pace of EPC/RFID adoption continues to accelerate.
EPCGlobal news release. From the Web site: http://www.epcglobalinc.org/
about/media_centre/press_rel/EPCglobal_Inc_1000th_sub_press_release.pdf
13. Collins J. 2004. RFID’s ROI Tops User Concerns, RFID Journal. From the Web
page: www.rfi djournal.com/article/articleview/1207/1/1/
14. Bertoni M, Thamworrawong K, Turner P. 2007. Cold Chain Logistics Challenges
for Active RFID Adoption: a Case Study from the Tasmanian Aquaculture Indus-
try. 18th Australasian Conference on Information Systems. University of Southern
Queensland, Towoomba, QLD: 566-577.
15. Emond JP. 2007. Quantifying RFID’s cold chain benefi ts. RFID Journal LIVE! 2007
Conference.
16. Smale N. 2005. Understanding the limitations of your supply chain and how you
can improve it. AIFST Conference.
17. Wang N, Zhang N, Wang M. 2006. Wireless sensors in agriculture and food in-
dustry –Recent developments and future perspective. Computers and Electro-
nics in Agriculture 50: 1–14.
18. http://www.rfi djournal.com
19. http://www.thekrogerco.com/fi nance/documents/SectionIV-4.pdf
20. Chill-on project: http://www.chill-on.com/description/state-of-the-art.html
21. Smale N. Case study: Quality assurance in refrigerated transport. In: Estrada-
Flores S, Smale N, East A, Scully A, Horsham AM, Steele R, Zerdin K. (2006)
Fresh perspectives on Global Food Supply Chains. Food Science and Nutrition.
A bulletin of Food Science Australia. Spring 2006.
22. http://www.goodfood-project.org/www/Results/paper/SPIE2007_Zampolli.pdf
23. Metzger C, Michahelles F, Fleisch E. 2007. Ambient Energy Scavenging for Sen-
sor-equipped RFID Tags in the Cold Chain, European Conference on Smart Sen-
sing and Context (EuroSSC), Kendal, UK.
REFERENCES
9
REVIEW ARTICLE
Bulletin 2008-4
