Quantification of trihalomethanes in Nile tilapia fillets sanitized with chlorine

Abstract Fish is a food with high nutritional value, but its quickly perishable nature requires a hygiene process to maintain product quality and increase shelf life. The objective of this study was to evaluate different chlorine concentrations in water for sanitizing Nile tilapia fillets on the formation of trihalomethanes (THM) in fresh and frozen stored fish fillets. A completely randomized experimental design was used, in a 2×3 split-plot arrangement, with 15 replications; the plots consisted of fresh and frozen fish fillets, and the subplots consisted of the three chlorine concentrations in the water for sanitizing the fillets (100, 175, and 250 mg L-1). Fresh fish analysis showed the following variations in THM levels: 1.4 to 6.8 μg kg-1 (chloroform), 0.5 to 3.2 μg kg-1 (bromodichloromethane), and 0.4 to 1.2 μg kg-1 (dibromochloromethane). Bromoform ranged from 3.7 μg kg-1 to undetected levels in the different tested storage times. Frozen fish analyses showed concentrations ranging from 2.1 to 5.2 μg kg-1 (chloroform) and 0.6 to 2.0 μg kg-1 (bromodichloromethane), while dibromochloromethane and bromoform levels were below the technique's quantification limits in all storage times. THM formation depends on the chlorine concentration in the washing water and the storage time and temperature; fresh fish presented higher THM levels than frozen fish.