Effect of Cooking Processes on Persistent Lipophilic Compounds in Edible Fish Tissue Using PCB as an Example, 1993 Environmental Conference Proceedings

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 in comparison to the PCB level present before cooking because lipids and lipophilic compounds in them such as PCBs, polychlorodibenzo-p-dioxin (PCDD), polychlorodibenzo-p-furans (PCDF), and halogenated pesticides tend to be removed from the fish during cooking. Several studies investigating the extent of loss of lipophilic 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 (1.2).

In this paper, an attempt to reduce the uncertainty in the findings of these studies on PCBs, which is one of the most common lipophilic compounds. 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. Prying 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.