Effect of different thermal processing methods on potentially toxic metals in the seafood, Penaeus vannamei, and the related human health risk assessment

The presence of a significant amount of toxic metal in seafood has raised human health concerns worldwide. This study investigates the effect of heat processing/cooking methods (boiling, frying, grilling, and microwave cooking) on toxic metals concentration in farmed shrimp and estimates its potential human health risks. Pacific white leg shrimps (Penaeus vannamei) farmed along the Gulf of Mannar region were used to evaluate the toxic metal uptake by consuming raw and cooked shrimps. Toxic heavy metals such as Cd, Hg, and Pb were found below the maximum residual limit (MRL) of 0.5 mg/kg set by the European Union. The concentration of Cu, Zn, and As were below the MRLs of 30 mg/kg, 100 mg/kg, and 76 mg/kg set by the World Health Organization and Food Safety and Standard Authority of India, respectively. The target hazard quotient (THQ) for individual metals and total THQ (TTHQ) for combined metals were 1, indicating no health risk for shrimp consumers. The lifetime cancer risk (LCR) for toxic heavy metals (Cr, Ni, As, Sr, Cd, and Pb) were found between the recommended level of 10-6 to 10-4, indicating no carcinogenic health consequences. With the estimated maximum allowable consumption rates (CRmm), an adult can safely consume 30 raw or cooked shrimp meals/month with no adverse health consequences. Therefore, culinary processes such as boiling and grilling are recommended as suitable methods to reduce toxic metals risk. However, it is recommended to monitor their concentration before and after cooking shrimps collected worldwide and ensure they are within the regulatory limits.