Traditional fruit cleaning methods may not be sufficient to completely eliminate pesticides, according to a new study published in
Nano Letters. Researchers have developed an innovative technique to detect the presence of pesticides at extremely low levels, challenging the effectiveness of usual washing practices for ensuring food safety.
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The study focuses on a method called surface-enhanced Raman spectroscopy (SERS), used to identify traces of pesticides on agricultural products. This technique uses metallic nanoparticles to amplify signals from molecules exposed to a laser beam, allowing the detection of minute amounts of chemical compounds. The team, including Dongdong Ye, Ke Zheng, and Shaobo Han, designed a metal-coated membrane that can be applied to fruits and vegetables to detect pesticides. Tests showed that this membrane can identify pesticide residues not only on the surface of fruits but also under the skin and in the outer layers of the pulp.
The researchers first applied pesticides to apples, then washed them as an ordinary consumer would. Using their SERS membrane, they were able to detect the pesticides despite the low concentrations present. Results indicated that, even after washing, pesticides remained in the skin and pulp of the apples. Consequently, they suggest that to minimize the risk of ingestion, it would be necessary to peel fruits in addition to washing them.
This discovery has important implications for food safety. It suggests that current fruit washing practices, although they remove some contaminants, may not be sufficient to fully protect consumers. Besides apples, the SERS technique was also effective in detecting pesticide residues on other foods, such as cucumbers, shrimp, chili powder, and rice.
Although the skin of fruits and vegetables contains beneficial nutrients, peeling them could reduce the risk of ingesting pesticides while avoiding digestive discomfort caused by certain insoluble fibers. The technology used in this study could become a valuable tool for scientists and health authorities, allowing them to deepen their understanding of pesticide persistence in food.
Article author: Cédric DEPOND