Effect of food processing on pesticide residues in citrus fruits and estimation of processing factor

Foods may be exposed to processes such as washing, peeling, freezing, drying, boiling, preserving and processing to fruit juice during the extension of their shelf life and until the period they are ready for consumption. Such processes can significantly affect the levels of pesticide residues in foods. The level of residues found in processed food may tend to increase or decrease depending on the physicochemical properties of the residue compared to the initial level found in unprocessed food. Processing factors need to be considered when the compliance of processed foods with maximum residue levels (MRLs) is evaluated. Processing factors are the ratio of the level of pesticide residue in the processed food to the level of pesticide residue in the unprocessed food. In this study, the effect of various food processing techniques on pesticide residues in citrus fruits and processing factors were investigated. For this purpose, fresh orange and lemon samples were dipped in to the solution of abamectin, buprofezin, ethoxazole, imazalil, and thiophanate-methyl at laboratory conditions and the pesticide residues in the samples were determined by LC-MS-MS applying QuEChERs analysis method. As a result of the study, it was observed that the pesticide residues were mostly distributed in citrus peels. Pesticide residue levels were reduced between 26% -100% and 2% to 84% as a result of different household treatments (washing with tap water, peeling, obtaining pulp, fruit juice processing, preserving and storage of frozen grated peels) and washing applications (washing with cold water, washing with different concentrations of sodium carbonate, sodium chloride, acetic acid, apple cider vinegar and grape vinegar), respectively. In drying processes (hot air, microwave pre-treated hot air, vacuum and microwave pretreated vacuum drying), it was observed that the concentration of pesticide residues increased. Accordingly, the processing factor was obtained as greater than 1 for processes including drying, peeling, and storage of frozen grated peels and less than 1 for the others.