Researchers from the University of São Paulo and the Federal University of Visoza in Brazil have developed an environmentally friendly sensor that is placed directly on the surface of fruits and vegetables and detects the possible presence of pesticides.
The new “wearable” fruit and vegetable device is made from cellulose acetate which is derived from wood pulp.
Improving food safety
The device presented in a publication in the scientific journal “Biomaterials Advances” promises to improve food safety by detecting substances in fruits and vegetables that can be highly burdensome for public health and the environment.
50% of pesticides end up in soil, water and food
Pesticides are used on crops widely around the world and are usually applied by spraying – yet only 50% of the substances reach their target. The remaining 50% ends up in the soil, the water table, surface water, drinking water, sewage and even food.
The control of pesticide levels in water, soil and food is vital in order to prevent exposure of the population to toxic substances which can be done through the skin, respiratory or digestive system.
The disadvantages of existing tools and the advantages of the new sensor
The analytical tools commonly used to test for the presence of pesticides in fruits and vegetables involve chromatographic techniques which are effective but associated with disadvantages such as the need for sample pretreatment, the use of expensive, non-portable equipment and specialized laboratory personnel, and the prolonged time required to conduct the analysis.
“Alternatively electrochemical sensors combine low cost, rapid detection capability, portability, small size, ease of use, large-scale production. Our invention possesses all these features. The analysis is done directly on the surface of the fruit, vegetable or leaves. Hence, we are talking about a ‘wearable’ plant device,” said Paulo Augusto Raimundo-Pereira, lead author of the study and a researcher at the Carlos Institute of Physics at the University of São Paulo.
High precision “wooden” sensor
The researcher added that the new device is highly environmentally friendly: “Instead of the usual materials, which are not environmentally friendly and take a long time to break down – such as ceramics or polymers – we used cellulose acetate, a material derived from wood that has a minimal impact on the environment – it biodegrades completely in 340 days or less depending on the conditions of each area”.
Using the new… wooden sensor, the researchers conducted laboratory experiments in which lettuce and tomatoes were sprayed with a solution containing the fungicide carbendazim and the herbicide paraquat (note that the use of paraquat was banned in the European Union in 2003 due to its harmful effect on human health organization but continues to be used in Brazil).
The sensor was placed on lettuce and tomatoes and the measurements it made showed detection levels comparable to those offered by the chemical materials used in the sensors.
Pesticides do not wash away with water
As part of the study, the researchers also looked at whether washing vegetables or soaking them in a liter of water for two hours were effective methods for removing pesticide residues.
Based on the findings, these methods removed only 40% of carbendazim and 60% of paraquat from lettuce and 64% of both substances from tomatoes. “Washing and soaking vegetables in water were clearly insufficient tactics to remove pesticide residues. At least 10% remained in the leaves or the peel” noted Dr. Raimundo-Pereira.
Lots of uses
The new technology could prove valuable for food control authorities worldwide, according to the researcher, as well as for organic producers to certify that their products do not actually contain pesticides.
It can also be an important tool in the hands of all farmers who will be able to measure the levels of pesticides in the field and apply only the necessary doses. “Thus, the use of pesticides will decrease while production will increase, ultimately leading to lower product prices” concluded Dr. Raimundo-Pereira.
#Device #worn #fruits #vegetables #measures #pesticides
