From Farm to Fork: A Wireless-Sensor Approach to Food Safety

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The restaurant industry has very strict guidelines controlling food safety, as outlined by Hazard Analysis and Critical Control Points (HACCP) management system. According to the Food and Drug Administration (FDA), HACCP provides a systematic preventative approach to food safety by identifying, evaluating, and controlling factors that present hazards throughout the entire process (farm to fork). This includes everything from the raw materials to shipping to the finished product.

One aspect of food safety that requires special attention is controlling and monitoring food temperature, which is necessary to prevent problems that can cause foodborne illnesses. It’s important to note that both raw ingredients and cooked products must be kept at certain temperatures to prevent growth and/or provide a “kill” step during cooking. Temperature monitoring can be done manually by having someone check a thermometer and write the temperature on a sheet of paper, or automatically by utilizing wireless-sensor technology that electronically measures and records temperatures.

Application

The U.S. Centers for Disease Control and Prevention (CDC) estimates 48 million Americans (or about one in six people) get sick from a foodborne illness each year, of which 128,000 are hospitalized and 3,000 die.¹ Obviously, not all of these cases are associated with the restaurant industry, but this statistic highlights the need for improved food safety and for enforcing food-safety guidelines to reduce the number of cases in which people become ill after eating contaminated food.

One aspect of food safety is maintaining food temperatures at certain critical levels. Foods that need to be refrigerated or frozen must be kept at specified temperature levels to maintain adequate food safety, as well as prevent premature spoilage due to improper storage. Cooked foods must be heated to specific internal temperatures and then maintained at minimum temperatures. The temperature limits for coolers, freezers, and cooked foods are necessary to prevent the development of bacteria, viruses, and parasites leading to foodborne illnesses.

There are different ways to monitor and control food temperature. The manual method of checking a thermometer and recording the temperature has many drawbacks. Someone must actually do it, which cuts into his or her time when the focus could be on other tasks. The person must also be able to correctly use and read a thermometer and accurately record the temperature. He or she then must know what to do, as a corrective action, if the temperature is either too warm or cold.

Many cases of foodborne illness can be prevented if staff addressed the problem sooner rather than later. The aspect of human error exists, too, potentially leading to situations in which food temperature is improperly maintained.

Implementing an automatic method that uses sensors to electronically measure and record temperatures can substantially improve food safety. This method allows for a continuous data stream of temperatures—24 hours a day, 7 days a week, every day of the year. Temperatures are recorded consistently, on time, and leave little room for interpretation—just the facts and nothing but the facts.

The data can be stored in the cloud and accessed via any type of internet-connected device (be it smartphone, tablet, or computer). This means that the person responsible can retrieve the temperature readings from anywhere in the world at any time. Notifications can be established that will send real-time alerts if the temperature strays outside preset limits, allowing for immediate action to remedy the situation. Wireless sensors improve food safety by providing instant access to the food-temperature data.

Wireless Advantages

Wireless sensors, with their reliable record-keeping capability, make it easier for restaurants to comply with various regulatory agencies. While the FDA endorses participation in an HACCP management system, taking part is purely voluntary. HACCP has developed guidelines for establishing the necessary record-keeping and documentation procedures,² which lets restaurants have the required data on hand.

State and local regulatory agencies responsible for enforcing food safety in restaurants are able to adopt the model presented by the FDA’s Food Code;³ these agencies may have their own specifications as well. Some mandatory aspects of the Food Code, such as the food temperature requirements, have been incorporated in HACCP.

Wireless sensors collect the data needed to prepare for health inspections as well. Rather than having to search for the appropriate handwritten records, electronic temperature data is always available and complete, and the display format can be customized as needed.

The FDA has developed rules for the sanitary transportation of foods, as part of the Food Safety Modernization Act (FSMA),⁴ to keep foods safe from contamination during transportation by motor or rail vehicles. One of the goals is to require that foods are properly refrigerated during transport. This is done by specifying that the equipment is able to control and maintain the temperatures necessary for safe transport, as well as specify that records must be made and kept. The use of wireless sensors would help meet these requirements and provide precise temperature data, while significantly improving the safety of food products in transit.

Challenges

The restaurant industry is an especially difficult environment for using wireless temperature sensors. The work area usually consists of stainless-steel surfaces, concrete walls, and a variety of other obstacles that frankly do not play well with radio signals. That’s combined with potentially harsh temperature and moisture environments associated with putting sensors inside heavily insulated and sealed coolers and walk-in freezers. The distance between the food storage and preparation areas can be long, and their physical locations may be around corners, behind steel and concrete walls, and even on different floors. These factors provide a particularly unfavorable environment for transmitting wireless signals.

Wired sensors could eliminate many of the challenges faced by wireless sensors, but they bring their own issues relative to the wires themselves. For example, installing a wired sensor inside a walk-in freezer means that a hole must be drilled somewhere to accommodate the wire.

Also, the constant activity in a busy kitchen area means that sensors are prone to being damaged. A detached or mangled wired sensor would be detected fairly quickly when no data is transmitted from it, but it would take time to be repaired or replaced and valuable data could be lost. What happens if a cooler goes out during this repair period?

These issues create a situation in which a restaurant kitchen environment can be even harsher than those in some industrial and healthcare settings.

Solution

Current temperature sensor technologies using Bluetooth or Wi-Fi were appropriate years ago as the technology first started. Today, sensor technology has improved and will work better in the challenging restaurant environment. Specifically, LoRaWAN can provide the solution to this problem.

LoRa wireless technology is a long-range, low-power platform used extensively in Internet of Things (IoT) applications. LoRa technology provides low-power wide-area-network (LPWAN) connectivity between wireless sensors and the cloud. It’s much more effective and reliable than either Bluetooth or Wi-Fi in the restaurant kitchen environments.

Use Case

ComplianceMate, a leader in food-safety-monitoring technology, temperature monitoring, and HACCP compliance systems, and Laird, a leader in state-of-the-art wireless technology, have partnered in developing LoRa wireless sensors intended to monitor and control food temperatures, with the ultimate goal of enhancing food safety in restaurant kitchens (Fig. 1).