Purpose: This study evaluated how the flume wash and single-pass wash systems differ in the potential to form DBPs during fresh-cut produce processing with chlorine sanitizer. The investigation included a range of conventional and emerging DBPs that are recognized for toxicity concerns to gain a comprehensive understanding.
Methods: The study was conducted at a produce processing plant that employed flume wash and single-pass wash systems in separate processing trains. Water and lettuce samples (n>28) were collected at multiple points from each train and analyzed for the levels of various DBPs (including trihalomethanes (THMs), haloacetic acid (HAAs), halonitriles, halonitromethanes, haloacetamides, chloral hydrate and chloropropanones) using appropriate analytical methods. Other monitored parameters included water pH, temperature, and chlorine level. The water supply to the plant and unwashed lettuce were analyzed as background samples.
Results: Results thus far show that the levels of DBPs were nearly 10 times lower in the single-pass water than in the flume water after washing shredded lettuce. The difference is less dramatic for DBP residues in lettuce, about 0.5 to 2 times lower for the single-pass wash system than for the flume. A final fresh water rinse at the end of the flume wash system was found to be important to reduce the final DBP residue levels in lettuce.
Significance: This study is among the first for a comprehensive evaluation of DBP levels from the flume wash versus single-pass wash systems. Results will be useful for the produce processing industry and research community working to improve food safety.