30 minute E. coli test

In this note we discuss a recent study where we measured the E. coli in five bags of spinach.


We measured the E. coli by both traditional agar plate measurements and using the E. coli sensor for FoodSense.

Back ground

Zimmer and Peacock has licensed and commercialized several Food Industry tests from the University of Oxford around the applications of Food Quality and Food Safety.

At the time of writing this document Food Sense now has eight Food Quality and Food Safety test on the FoodSense, all these are run on the same hardware.


The current eight tests are: capsaicin in chili, diallyl disulfide in garlic, gingerol in ginger, pH , curcumin in turmeric vanilla aldehyde in vanilla and  E. coli.



In this study we took five samples of spinach and care was taken not to introduce additional bioburden, and the samples were prepared in accordance to ISO 16649-2:2001. All equipment was sterilized, and appropriate PPE was worn throughout.


Each sample was tested by agar plate cell count method and using the FoodSense Product.

Plate cell count method

500 µL of each sample was pipette onto the agar plate. The plates were left in the 37C thermostat oven overnight, where the E. coli cells were counted afterwards.

FoodSense Testing

We tested 500 µL of each sample on the FoodSense.

The protocol was:

1) Step One – The sample was added to the sensor, and the app performed a 30 minute countdown.

2) Step Two – The sample was removed from the sensor (E coli was left bound to the sensor.

3) Step Three – The FoodSensor App read the number of E. coli bound to the sensor.



The results from the FoodSense 30-minute test versus the plate reading/counting are shown in the adjacent table.

if you have any questions regarding FoodSense please don't hesitate to contact us.