Pesticide residues in organic apples: determining the amounts of thiabendazole, diphenylamine, and myclobutanil in organic apples
Tan, Ying (author)
Sidhu, Bobby (Advisor)
Soulsbury, Kevin (Advisor)
Bower, Bob (Advisor)
British Columbia Institute of Technology School of Health Sciences (Degree granting institution)
Objectives: The popularity of organic diets continues to increase even without sound evidence that these diets are healthier than conventional diets. As its popularity increases, organic foods become more readily available and accessible to the public, and genuinity comes into question as farmers and retailers find ways to profit from this trend. Although organic produce will never be completely free of pesticides, they are expected to have considerably lower amounts. In recent years, pesticide residues in organic apples have been found to be at levels higher than normal background levels, indicating intentional application by farmers. Thiabendazole, diphenylamine, and myclobutanil are some of the more common synthetic pesticides that have been found in organic apples; therefore, the following study tested whether or not the levels of thiabendazole, diphenylamine, and myclobutanil in organic apples were below the acceptable organic standards of 5% of their respective Maximum Residue Limits (MRLs). Methods: A modified QuEChERS method involving juicing and extraction was used to recover pesticides from the organic apples. Two additional samples were spiked with 1 ppm of each pesticide as controls to determine if the method was able to detect the pesticides. One sample was spiked before the juicing step, and the other sample was spiked after the juicing step. Samples were then analyzed using gas chromatography. Results: Thiabendazole, diphenylamine, and myclobutanil were not detected in all 30 organic apple samples. Furthermore, these pesticides were only detected in the one of the spiked samples – the sample which was spiked after it was juiced. Conclusion: Organic apples grown in BC meet the organic standard of containing pesticide residue levels below 5% of the MRL, at least for thiabendazole, diphenylamine, and myclobutanil. However, since pesticides were not detected in the sample which was spiked before juicing, the methodology of this study may require modification. One possible reason for this finding is that pesticides may be concentrated in the pulp that is separated during juicing, therefore suggesting that juicing apples may be a good practice for reducing the consumption of pesticides.
© Ying Tan 2015. All rights reserved. No part of this work covered by the copyright heron may be reproduced or used in any form or by any means – graphics, electronic, or mechanical including photocopying, taping, or information storage and retrieval systems – without written permission of the author.
Project submitted in partial fulfillment of the requirement for the degree of Bachelor of Technology in Environmental Health, British Columbia Institute of Technology, 2015.