Quantification of Trihalomethanes in Nile Tilapia Fillets Sanitized with Chlorine

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 aim of this study was to evaluate different concentrations of chlorine in the water used to sanitize Nile tilapia fillets on the formation of trihalomethanes (THM) in fresh and frozen products at different storage times. 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 binomial chlorine concentration in the washing water and time storage; fresh fish presented higher THM levels than frozen fish.