Fate of Chlorpropham during High Temperature Processing of Potatoes.

Chlorpropham is a widely used sprouting inhibitor applied on potatoes during their storage. Currently, severe concerns are raised regarding the potential formation of 3-chloroaniline from chlorpropham during heat treatment. The reactions degrading the molecule in matrix are quite complex under harsh processing conditions and a molecular investigation is thus challenging. This study aims to decipher the reaction pathways and to discover new metabolites in typical high temperature food processing steps. For this purpose, potatoes were treated with C-radiolabelled chlorpropham, stored for up to six months and subjected to the traditional preparation steps boiling, frying and baking. A quantification method including an acidic hydrolysis was developed for analysis of free and bound analytes. All conducted processing steps led to a substantial mitigation of chlorpropham residues in the consumable products. 17 ± 6% of residues remained in boiled tubers, while 27 ± 3% and 22 ± 3% remained in the fried and baked products, respectively. Chlorpropham was transferred into the surrounding media (boiling water, frying oil, and air, respectively). 3-Chloroaniline was only (raw tubers) or predominantly (processed tubers) present as bound analyte and was shown to form during storage but not during processing. Additionally, non-extractable and non-quantified residues were detected in the baked and in the long-term stored tubers after processing. Future studies will have to balance beneficial (mitigating) and potentially hazardous aspects of these results. By transferring the C-food processing approach to a variety of substances, ingredients and processes, it will be possible to further understand chemical reactions in food processing - finally leading to safer food.