Innovation That Matters

Lettuce Defender makes it easy to apply a unique tag to every head of lettuce, for easy tracing | Photo source Annika Biosciences

Microbial tags trace lettuce heads to help stop E. coli outbreaks

Food & Drink

A startup has developed a way to tag individual heads of lettuce with microbes containing a unique code, for rapid tracing of foodborne illness outbreaks

Spotted: Leafy greens are a common source of foodborne illness. Between 2009 and 2018 in the US alone, they were the source of 40 serious outbreaks of poisoning by E. coli bacteria. In fact, this type of E. coli is linked to about 265,000 illnesses each year. While most people recover in a few days, many do end up hospitalised with severe and even life-threatening illnesses. A startup called Annika Biosciences hopes to improve the situation with an edible biotag.

The company’s technology makes it possible to place invisible, edible microbial tags on each head of lettuce. In the event of an E. coli outbreak, all of the infected greens can then be rapidly and easily traced to their source. This is much easier than the current practice of combing through the paper records of the supply chain to identify the path of individual lettuce heads. The problem with this system is illustrated by an outbreak that killed five people in 2018, in which the CDC was only able to track to a general area in Arizona, and not to the particular farm or processor. 

Annika’s product, Lettuce Defender, starts with a common microbe that is often used as a probiotic and can be purchased from Amazon. As the microbe is inactivate, the company can edit the genome to create a unique signature, similar to a UPC code, which can be assigned to an individual farm or harvest. The tags can be added when the lettuce is first washed at a processing centre, in order to end up on every leaf.

Aanika’s research has revealed that the tags can withstand a wide range of environmental conditions and the information in the tags can be easily retrieved, using diagnostic-type tests. Annika’s Chief Scientific Officer, Dr Ellen Jorgensen, has confirmed that “The tags do not come off when produce is washed in running water for several minutes, are not destroyed by microwaving, frying, or steaming, and can even withstand weeks of produce decay.”

With all the focus on new techniques for gene editing, it is easy to forget progress being made in adapting microbes for new uses. At Springwise, we have covered a number of exciting innovations involving microbes. These include such recent advances as the use of microbes to “brew” fish food from methane and to “eat” toxic plastics such as polyurethane.

Written By: Lisa Magloff

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