Temp log
Frozen storage −18°C or colderChilled foods 0 to 5°C typicalBananas avoid below ~13°CDanger zone 5–60°CIce cream hardening −25°C to −30°CLeafy greens 0–2°C, high humidityChocolate around 15–18°C, dryLive seafood species-specificBlast freezer air −30°C to −40°CCured vanilla cool, dry, sealedFrozen storage −18°C or colderChilled foods 0 to 5°C typicalBananas avoid below ~13°CDanger zone 5–60°CIce cream hardening −25°C to −30°CLeafy greens 0–2°C, high humidityChocolate around 15–18°C, dryLive seafood species-specificBlast freezer air −30°C to −40°CCured vanilla cool, dry, sealed

Food Tech

IoT data loggers and real-time monitoring for food logistics: a buyer's overview

From single-use USB loggers to cellular trackers and warehouse sensor networks, the options for monitoring temperature have multiplied. Here is how to choose.

By Editorial desk · · 3 min read

Main types
Single-use loggers, reusable loggers, real-time trackers, fixed sensor networks
Connectivity
Bluetooth, LoRaWAN, cellular (LTE-M/NB-IoT), Wi-Fi
Buyer priority
Accuracy, calibration, alerts and data integration

Temperature monitoring has changed a lot in recent years. Food companies that once relied on a paper chart or a downloaded logger at the end of a trip can now see temperatures in real time, receive alerts and build data histories across their supply chain. This overview looks at the main types of monitoring device, what they are good for and what buyers should check.

Types of device

Single-use data loggers. Small devices placed in a shipment, often with a USB or PDF output. They record temperature throughout the journey and are read on arrival. They are cheap and simple but do not provide real-time alerts.

Reusable data loggers. Higher-accuracy devices used for repeated journeys or in storage. They can be calibrated and reused but need to be returned and managed.

Real-time trackers. Devices with cellular connectivity that report temperature, location and sometimes light, humidity or shock in real time. They allow intervention during transit, such as contacting a driver when temperature rises.

Fixed sensor networks. Wireless sensors installed in cold rooms, warehouses, trucks and display cases that report to a central system. They replace manual temperature checks and provide continuous records.

Refrigeration unit telematics. Many refrigerated trailers and containers have built-in monitoring that reports unit settings, return air temperature, door openings and alarms.

Connectivity options

  • Bluetooth: low power and short range, often read by a phone or gateway.
  • LoRaWAN and similar low-power networks: long range and low power, suitable for warehouses and campuses.
  • Cellular (LTE-M, NB-IoT): good for tracking shipments across regions.
  • Wi-Fi: common in fixed sites where infrastructure exists.

Coverage matters. A tracker that loses signal in a steel-lined freezer or a remote area may store data and upload later, which is fine for records but not for real-time alerts.

What to measure

Most devices measure air temperature. For better insight into product condition, some systems use probes placed in products or simulated product, such as a sensor in a glycol bottle that responds more like food. Humidity matters for fresh produce. Door sensors explain spikes. Location data shows where excursions occur.

Accuracy and calibration

Buyers should ask:

  1. What is the accuracy across the temperature range used?
  2. Is the device calibrated, and is calibration traceable to recognised standards?
  3. How often does it need recalibration?
  4. Does it meet relevant standards for food or pharmaceutical monitoring where required?

Alerts and response

Real-time monitoring is only useful if alerts lead to action. Good systems allow:

  • thresholds and time delays to avoid false alarms;
  • escalation to the right people;
  • records of who responded and what was done.

Alert fatigue is a real risk. Too many alerts and staff start ignoring them.

Data integration

The value of monitoring increases when data connects to other systems: warehouse management, transport management, quality and HACCP records. Buyers should check:

  • whether the system has an API or standard data exports;
  • how long data is stored and who owns it;
  • whether data can be shared with customers and suppliers;
  • how data integrity is protected for audits.

Costs and sustainability

Costs include devices, connectivity subscriptions, software and staff time. Single-use loggers create electronic waste, so many companies look for return programmes or reusable devices. Battery life also matters.

A buyer's checklist

  1. Define what decisions the data will support.
  2. Choose devices that match the journey or site.
  3. Check accuracy, calibration and certification.
  4. Test connectivity in real conditions.
  5. Set up alerts with clear responsibilities.
  6. Plan integration and data retention.
  7. Consider device recovery and reuse.

Monitoring will not keep food cold by itself. It shows where the cold chain is failing so that people can fix it.

Key figures above are general reference points, not regulatory limits.