Innovation Comes to the Produce World

A new technology could allow the produce workers in every grocery store to verify if there is pesticide residue on fruits and vegetables.

The Environmental Working Group’s 10 worst and 10 best list is out. It’s all about listing those produce items that have the most pesticides and the least. And if we have any hope it is that this year’s list is the last they have to publish. A new technology could allow the produce workers in every grocery store to verify if there is pesticide residue on fruits and vegetables.

Why is this important? Because many retailers who have strict rules for their produce suppliers don’t have a way to check if each shipment that comes to their stores are pesticide-free when a supplier says it is. The technology is currently being developed by researchers from ITMO University (Russia), the National University of Singapore, and the University of Rovira i Virgili (Spain). 

Here’s how it works. The product itself is a thin flexible film that is produced by combining silver nitrate and the organic compound melamine, then adding the mixture to a Petri dish containing a base layer of agar gel. The silver nitrate reacts with the other ingredients, forming crystals. Upon being exposed to light, these decompose to form silver nanoparticles. The contents are then dried, forming the light and flexible film. When that film is placed on a piece of fruit and wetted with alcohol, the melamine draws in any pesticide molecules that are present on the fruit's skin. Then at store level, using a handheld optical spectrometer, a supermarket produce manager or associate can then check the manner in which light is reflected by the silver nanoparticles in the film; if any pesticides are present the spectrometer then flashes a warning message – and the shipment could be rejected if it doesn’t meet the store’s specifications.

Just imagine the marketing advantage that this system, once put in place, can have to build trust and confidence in the produce department!