Effectiveness of Commercial and Homemade Washing Agents in Removing Pesticide Residues on and in Apples.
Level 5 - mechanism / opinion, no new human data
Bench laboratory experiment evaluating chemical washing methods on fruit; graded Level 5 by design analogy.
PubMed 29067814 · doi:10.1021/acs.jafc.7b03118
What was done
Researchers used surface-enhanced Raman scattering (SERS) mapping and liquid chromatography tandem mass spectrometry (LC-MS/MS) to test the removal of surface and internalized pesticide residues from apples. Apples were treated with thiabendazole or phosmet at 125 ng/cm² for 24 hours and washed with a 10 mg/mL sodium bicarbonate (baking soda) solution, tap water, or a commercial Clorox bleach solution.
What was found
A 10 mg/mL sodium bicarbonate solution completely removed surface thiabendazole in 12 minutes and surface phosmet in 15 minutes, outperforming tap water and standard 2-minute Clorox bleach washing. However, LC-MS/MS demonstrated that 20% of applied thiabendazole and 4.4% of applied phosmet penetrated into the apples during the 24-hour exposure period. Thiabendazole penetrated 4-fold deeper into the peel than phosmet, and these internalized residues could not be removed by washing with sodium bicarbonate.
Why it matters
This study shows that a simple baking soda solution is more effective than plain water or bleach at degrading and clearing surface pesticide residues on apples. It also demonstrates the physical limit of washing methods when pesticides penetrate into the fruit tissue.
Limits
The abstract does not report the total number of apples tested. Testing was restricted to a single fruit type (apples) and two specific pesticides (thiabendazole and phosmet) applied at a single concentration and exposure duration. Effects on fruit texture, taste, and other pesticide classes were not assessed.
Cited by
- context Studies at the University of Massachusetts showed that pesticides sprayed on apples penetrate 20% deep into the skin of the apple.