The effect of cooking processes on PCB levels in edible fish tissue

A significant factor in estimating human intake of polychlorinated biphenyls (PCBs) from fish consumption is the loss of PCBs during cooking. The total amount of PCBs actually consumed in the cooked fish may be significantly lower than the PCB level present before cooking because lipids and lipophilic compounds like PCBs tend to be removed from the fish during cooking. Several studies investigating the extent of loss of PCB compounds during the cooking process have been published in the peer-reviewed literature. However, because of what is perceived as inconsistent and inadequate data on the removal of these compounds, federal and state regulators typically do not assume that cooking reduces contaminant levels (EPA, 1990; 1991). In this paper, an attempt was made to reduce the uncertainty in the findings of these studies on PCB losses during the cooking process. This was accomplished by (1) eliminating studies that lacked statistical power to determine the degree of reduction, (2) reporting all of the results in a common format, and (3) characterizing studies by cooking method. In addition, the studies that reported increases in PCB concentration after cooking were carefully reviewed to provide a possible explanation of this occurrence. Based upon this analysis, it was concluded that cooking processes such as baking, broiling, microwave cooking, poaching, and roasting remove approximately 20 to 30% of the PCBs. Frying appears to remove more than 50%. PCB cooking losses also appears to be a function of the initial lipid concentration in the fish. Based upon this analysis, it is clear that the information from these studies do provide a reasonable basis for federal and state regulators to permit a quantitative adjust of PCB intakes.