Temperature monitoring and logging also can be accomplished with RFID labels. A credit-card–size "smart" label with a 13.56-MHz RFID chip and paper-thin battery provides 2 kB of read-and-write memory to record data. Available in disposable and reusable designs, labels can withstand temperatures from –15 °C to +50 °C. Labels can be set to monitor and log temperatures automatically at programmed intervals ranging from 10 s to 16 h. On-chip intelligence optimizes memory usage by only storing values outside the two temperature limits established by the user plus the minimum and maximum temperatures experienced. Data are retrieved via an RFID reader (KSW–TempSens smart label with temperature monitoring function, KSW-Microtec, Dresden, Germany, http://www.ksw-microtec.com/). To test the system, the company offers a demonstration kit that includes 10 smart labels, a reader with USB port, Microsoft Windows-compatible software, and a command set and user manual.

Another RFID-based system tags shipments of refrigerated goods and begins monitoring with the push of a button. In the event of a temperature excursion, the tag displays a warning light. The custom-programmable tags include both disposable and reusable models (LogIC active RFID sensors, American Thermal Instruments).

Whether time–temperature indicators, data loggers, or RFID technology are used, it is likely that insulated shippers and refrigerants will be necessary to maintain products at the proper temperature.

Nestable insulated shippers stack inside each other to reduce the space occupied in shipping and storage. A larger top half provides space for refrigerants and provides optimum placement for chill penetration. Eight stock sizes permit the shipper to be matched to the product and the environmental conditions it will encounter (ThermoChill nestable overnight insulated containers, PolarTech, Genoa, IL, http://www.polar-tech.com/).

For pallet-size loads, a modular system offers a mix-and-match array of refrigerants, blankets, and bags to deliver ultimate protection (ThermoChill modular component perishable pallet system, PolarTech).

Reusable, iceless containers maintain specific refrigerated or below-freezing temperatures during transportation and storage regardless of hotter or colder ambient conditions. Designed for the military to protect blood shipments and developed in conjunction with the Walter Reed Army Institute of Research (Silver Spring, MD, http://wrair-www.army.mil/), the concept won an Army Greatest Invention award in 2004. The top-opening corrugated case with two side flaps and tab-lock top flap houses vacuum insulated panels on all six sides plus a thermal isolation chamber made up of hinged hollow panels filled with a phase change liquid. Hinged panels make it possible to flatten the chamber for more compact chilling. Insulated shipper weighs less than 30 pounds. One style of shipper maintains contents between 1 and 10 °C for at least 60 hours. Frozen products can be held at –18 °C for at least 48 hours (Golden Hour 4 °C Shipping Container and Golden Hour Minus 20 °C Shipping Container, Minnesota Thermal Science, LLC, Plymouth, MN, http://www.mnthermalscience.com/). Shippers can be designed in various sizes and maintain other temperatures. Two other stock products maintain a temperature of 22 °C or –50 °C.