Occurrence, formation mechanism, detection methods, and removal approaches for chloropropanols and their esters in food: An updated systematic review

•The formation mechanism of chloropropanols is firstly divided into internal and external factors in this study.•The GC–MS or LC-MS after sample derivatization treatment is still the common analytical methods of chloropropanols or their esters in food matrices.•There are still some places where potential risk of 3-MCPDEs and GEs exceeding intake in infant formula are still existed.•The factors of chloropropanol formation in cooking foods with complex substrates need further study. Chloropropanols, one of the major contaminants in food, and the corresponding esters or glycidyl esters (GEs) are of great concern in terms of product safety due to their potential carcinogenicity. During heat processing, glycerol, allyl alcohol, chloropropanol esters, sucralose, and carbohydrate in mixed foodstuffs are probable precursors of chloropropanol. The standard analytical techniques for chloropropanols or their esters are GC–MS or LC-MS following sample derivatization pretreatment. By comparing modern data against that five-year-old before, it appears that the levels of chloropropanols and their esters/GEs in food products have somewhat decreased. 3-MCPD esters or GEs may yet exceed the permitted intake set, however, especially in newborn formula which requires particularly stringent regulatory measures. Citespace (6.1. R2) software was employed in this study to examine the research focii of chloropropanols and their corresponding esters/GEs in the literature.