Analytical methods for conventional and emerging disinfection by-products in fresh-cut produce

The formation of toxic disinfection by-products (DBPs) is among the main concerns in the use of chlorine sanitizers for washing fresh and fresh-cut produce to minimize microbial cross-contamination. Even so, robust analytical methods for measuring various DBPs in produce have been lacking. This study has established two liquid-liquid extraction methods, followed by gas chromatography with electron capture detection, to measure 32 conventional and emerging DBPs in different produce types including lettuce, cabbage and strawberry. Good recoveries (50-130%) were achieved for most DBPs in the different produce. The method detection limits were in the range of 0.3-10 ng/g for trihalomethanes, haloacetic acids, nitrogenous DBPs, and other carbonaceous DBPs. Preliminary screening analysis indicated one-third of the target DBPs were found in unwashed produce, and washing with chlorine significantly promoted DBPs' formation and concentrations in the produce. The developed analytical methods will be useful tools for future research on food DBPs.