Vol. 11, Special Issue 9 (2022)

The free and bound formaldehyde concentration in six commercially important fishes from five major fish markets of Tamil Nadu, India were analyzed. The highest concentration of free and bound formaldehyde (9.8 and 6.45 mg/kg) was observed in Sphyraena barracuda and the lowest (0.8 and 0.5 mg/kg) concentration was observed in Lethrinus lentjan. Storage of S. barracuda in ice indicated a significant (p<0.05) increase in formaldehyde concentration after 3 days. S. barracuda stored in a deep freezer (-20 °C) for 30 days showed that there was no significant (p>0.05) increase in formaldehyde concentration upto 15 days after which there was a significant increase upto 30 days. S. barracuda spiked with various concentration of formaldehyde followed by boiling for 15 min indicated no significant reduction (p>0.05) in formaldehyde concentration. Formaldehyde treated S. barracuda washed after different time intervals indicated that washing reduces upto 41 to 60% of treated formaldehyde.