Analyzing Pesticide Presence in Apples with LC-MS/MS

One hundred apple samples from Turkey were analyzed for the presence of 225 different pesticide residues during the 2022-2023 harvest season. Pesticide extraction was performed using the QuEChERS ("quick, easy, cheap, effective, rugged, and safe") method, followed by detection through liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS). Fifteen distinct pesticides (ten insecticides and five fungicides) were detected in 64 out of the 100 apple samples analyzed. Eleven samples contained pesticide residues that exceeded the maximum residue limit (MRL) set by the Turkish Food Codex and the European Union (EU). The results of this analysis were recently published in the journal Foods (1).

Due to the growing adoption of healthy eating habits, the global production and consumption of fruits has been steadily increasing. A popular pome fruit worldwide because of its delicious taste and abundance of micronutrients and bioactive compounds, the nutritional composition of a medium-sized apple (Malus domestica) includes a significant amount of dietary fiber (18% of the recommended daily value), minerals (potassium, iron), and vitamins (vitamin C, vitamin K, vitamin B6, riboflavin), as well as a variety of antioxidant components (2). (Pome fruits are fruits that develop from a single flower ovary and have an edible fruit core containing seeds.) The nutritional value and health benefits associated with apples are attributed to the presence of polyphenols (procyanidins, hydroxycinnamic acids, catechins, epicatechins, and quercetin) and other phytochemicals (2,3). The fruit is recognized for their antioxidant properties, which contribute to promoting heart health, reducing cancer risk and cardiovascular diseases, and enhancing the immune system (4).

While pesticide use plays a crucial role in increasing agricultural productivity, reducing crop losses, and preventing epidemic diseases, their improper and excessive use may lead to direct or indirect environmental and human health problems. While primarily applied to trees or soil, pesticides can also become airborne particles transported by wind or other atmospheric movements, reaching non-targeted plants, water bodies, and habitats, thus exerting toxic effects on other living organisms (5). Pesticides are therefore a major cause of soil pollution, posing a significant threat to soil microorganisms that contribute to the nutrient cycle and plant function. Although soil microorganisms generally exhibit resistance to repeated pesticide applications, some species may be affected, which leads to a decrease in microbial diversity. The amount of pesticide used can alter microorganism metabolic rates and pathways as well. The presence and persistence of pesticides, in the longrun, can therefore limit the ability of plants to grow in the soil, which reduces the land’s suitability for agricultural and ecological purposes (6).

The previously mentioned QuEChERS extraction method, as proposed by the Association of Official Analytical Chemists (AOAC) (7), was used for the analysis of multiple residues in apple samples. The approach consists of two stages: liquid micro-extraction with the dispersive solid-phase extraction (d-SPE) cleanup step. Of the 225 apple samples analyzed, 36 were found to contain no measurable pesticide residues, while 64 samples had residues of 15 different pesticides. In 11 of these samples, the residue levels for two pesticides (diflubenzuron and methoxyfenozide) exceeded the MRLs. Among the samples with detected residues, 13 contained a single residue, whereas 51 samples had multiple pesticide residues. Furthermore, six of the detected pesticide residues were not authorized for use in the EU. The pesticide most frequently detected was thiophanate-methyl (34%), followed by chlorantraniliprole (28%), acetamiprid (24%), sulfoxaflor (22%), bifenazate (18%), indoxacarb (13%), diflubenzuron (12%), and carbendazim (10%) (1).

The authors of the article believe that their study uniquely offers a comprehensive pesticide risk assessment for apple consumers in Turkey, focusing on cumulative exposure to multiple residues across different age groups. The data obtained will provide important information about the type and amount of pesticides used in apple production and help raise food safety standards by expanding the existing knowledge on the monitoring and evaluation of pesticide residues in apple production in Turkey. In addition, the authors state that there should be a greater emphasis on advancing biological pest control methods (biopesticides) rather than relying solely on synthetic pesticides and fertilizers. To further reduce health risks from pesticide exposure, consumers should be educated on the importance of thoroughly washing fruits and vegetables under running water, as well as peeling them, since washing alone may not fully remove pesticide residues due to skin penetration. (1).

Spraying apple orchard to protect against disease and insects. : © branex - stock.adobe.com

References

1. Odabas, E.; Keklik, M.; Golge, O.; González-Curbelo, M. Á.; Kabak, B. Monitoring and Risk Assessment of Multi-Pesticide Residues in Apples: A Focus on Consumer Safety. Foods 2024, 13 (19), 3186. DOI: 10.3390/foods13193186

2. Tsao, R. Apples. Encyclopedia of Food and Health; Caballero, B., Finglas, P.M., Toldrá, F., Eds.; Academic Press, 2016, pp. 239–248.

3. Wang, L.; Huang, J.; Li, Z.; Liu, D.; Fan, J. A Review of the Polyphenols Extraction from Apple Pomace: Novel Technologies and Techniques of Cell Disintegration. Crit. Rev. Food Sci. Nutr. 2023, 63, 9752–9765. DOI: 10.1080/10408398.2022.2071203

4. Boyer, J.; Liu, R.H. Apple Phytochemicals and Their Health Benefits. Nutr. J. 2004, 3, 5. DOI: 10.1186/1475-2891-3-5

5. Delen, N.; Durmuşoğlu, E.; Güncan, A.; Güngör, N.; Turgut, C.; Burçak, A. Türkiye’de pestisit kullanımı, kalıntı ve organizmalarda duyarlılık azalışı sorunları. In Proceedings of the Türkiye Ziraat Mühendisliği VI, Teknik Kongre, Ankara, Turkey, 3–7 January 2005; pp. 629–648.

6. Söderqvist, T.; Bergman, L.; Johansson, P.O. An Economic Approach. In Pesticide Risk in Groundwater; Vighi, M., Funari, E., Eds.; CRC Press, 2019, 241–258.

7. AOAC International. Pesticide residues in food by acetonitrile extraction and partitioning with magnesium sulphate. J. AOAC Int. 2007, 90, 485–520.