The bioaccessibility of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) in cooked plant and animal origin foods

Abstract

In this study, we compared the effect of boiling and frying food preparation methods in determining the bioaccessibility of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) in rice, cabbage, milk powder, eggs, beef, and fresh water fish. We then used these data to calculate a toxic equivalent (TEQ) for risk assessment and compared it to published values that did not account for bioaccessibility.When the foods were prepared by boiling, the mean bioaccessibility (%) in rice (PCBs: 16.5±1.0, PCDD/Fs: 4.9±0.3) and cabbage (PCBs: 4.2±0.9, PCDD/Fs: 1.9±0.7) were lower than in animal origin foods (beef, PCBs: 49.0±3.3, PCDD/Fs: 7.8±0.9; egg, PCBs: 29.7±3.1, PCDD/Fs: 8.6±1.3; fish, PCBs: 26.9±2.5, PCDD/Fs: 7.9±1.3; milk powder, PCBs: 72.3±1.6, PCDD/Fs: 28.4±1.2).When fried in cooking oil, the bioaccessibilities of all analytes in all foods increased, but the increase in plant based foods (rice, PCBs: 3.4×, PCDD/Fs: 3.6×; cabbage, PCBs: 10.3×, PCDD/Fs: 7.9×) was greater than that of animal origin foods (beef, PCBs: 1.6×, PCDD/Fs: 3.4×; egg, PCBs: 2.1×, PCDD/Fs: 1.8×; fish, PCBs: 2.8, PCDD/Fs: 3.2×).Comparison of PCBs/PCDD/Fs bioaccessibility in rice and cabbage showed that bioaccessibility was greater in the low fat, high carbohydrate/protein content food (rice) than in the low carbohydrate/protein, low fat content food (cabbage), regardless of the method used to prepare the food.Adjusting for bioaccessibility reduced the gross estimated daily intake (EDI) of 112pgWHO-TEQ/day, by 88% and 63% respectively for foods prepared by boiling and frying.Our results indicate that: 1) The method used for cooking is an important determinant of PCBs/PCDD/Fs bioaccessibility, especially for plant origin foods, 2) there might be a joint fat, carbohydrate and protein effect that influences the bioaccessibilities of PCBs/PCDD/Fs in foods, and 3) use of bioaccessibility estimates would reduce the uncertainty in TEQ calculations.