California Polytechnic Studies E. coli and Bagged Greens

The Sensor Wireless software interprets the data, then makes the sensor and location results available to researchers. If the temperature or humidity level exceeds a specified threshold, the Sensor Wireless software will send an alert to a designated point of contact at California Polytechnic. With the SCIs sending information every two minutes, researchers expect to receive 720 temperature and humidity readings from each sensor for every 24-hour period, with as many as 405 sensors transmitting at any given time, depending on how many of the 15 trucks are in operation.

Each of the packing plants and DCs will be equipped with a GPRS modem, though Vorst says he expects there will be segments along the supply chain at which there will be no cellular connection. If an SCI loses its GPRS signal, it will store sensor data until coming within range of another one. At the retail store, the sensors will be removed from the cartons of produce, and reused on another shipment, and the bagged lettuce and spinach will then be sold to consumers.

In the meantime, the temperature and humidity data will be used by researchers at Michigan State University to re-create the temperature and humidity conditions that the vegetables experienced in transit. During that simulation, a batch of salad mix or other leafy greens will be inoculated with E. coli, and the researchers will then study the pathogens' growth.

One question Vorst hopes to resolve with this study is whether this technology could be used by the food industry to prevent food-borne illness based on pathogen growth. "There is zero tolerance of food-borne pathogens in the food supply," he states, "and yet, obviously, it's still happening." Some pathogen growth may be occurring within the supply chain, he says, yet there is still little understanding of the environmental conditions of produce in the supply chain, and precisely what results from those conditions. "There's just insufficient data out there."

This is phase one of the study. The first year of the research will consist of tracking vehicles on the road, as well as obtaining temperature and humidity data from those shipments. The following year will be spent analyzing the information. After that, Vorst indicates, researchers will set up wireless sensing technology at retail locations to track temperatures and humidity levels where the product is kept on a store shelf or in a back room.

If the system works as expected, McNally says, Sensor Wireless' solution could be used by the food industry to track the condition of its fresh food, at a cost of approximately $200 per SCI, and $40 to $60 per month to access data from the sensors.

Following the study, California Polytechnic intends to make the results available to those in the industry, in the form of a video for food handlers, truck drivers and trucking companies, as well as food manufacturers, distributors and merchandisers. The video will also be available for use in university classrooms.