**2.2 Digestion of samples**

The canned fish preservative medium (tomato sauce, curry sauce and soybean oil) was carefully decanted in the laboratory, rinsed with deionized water and samples were oven dried to constant weight at a temperature of 80°C for 72 hours. Each sample in three replicates per brand/month was milled separately to powder form using a porcelain mortar and pestle. They were stored in labeled plastic packs, sealed and stored at −10°C prior to digestion and analysis during the period of study. Fish samples were digested using the organic extraction technique described by Sreedevi et al. [29].
