Survey of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and non-ortho-polychlorinated in U.S. beef livers and comparison to paired fat samples

Authors: Lupton, Sara; Duverglas, Laurent; OCHOA, CRISTIAN - Food Safety Inspection Service (FSIS)

Submitted to: International Symposium on Halogenated Environmental Organic Pollutants
Publication Type: Abstract Only
Publication Acceptance Date: 8/16/2022
Publication Date: 10/10/2022
Citation: Lupton, S.J., Duverglas, L., Ochoa, C. 2022. Survey of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and non-ortho-polychlorinated in U.S. beef livers and comparison to paired fat samples. International Symposium on Halogenated Environmental Organic Pollutants. Abstract.

Interpretive Summary:

Technical Abstract: Introduction: The U.S. Department of Agriculture (USDA) conducted a survey of domestic beef liver to determine the residue levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and nonortho-polychlorinated biphenyls (no-PCBs) in commercial beef liver and to do a comparison to paired fat samples collected from the same animals. Liver is an important edible tissue known to accumulate PCDD/Fs and no-PCBs to higher concentrations than fat and muscle. By comparing fat and liver concentrations within animals, a regression can be determined to help predict liver concentrations based on fat concentrations. Additionally, there are minimal data on the PCDD/F and no-PCB concentrations in U.S. beef liver. In the past there have been issues with exported liver which doesn’t meet regulatory limits of import countries. Materials and Methods: Fifty-nine beef liver samples were collected with fat samples from U.S. federally inspected slaughter facilities, ground, processed by pressurized liquid extraction and multi-column cleanup, and analyzed for 17 PCDD/Fs and 3 no-PCBs using isotope dilution with high resolution gas chromatography – high resolution mass spectrometry (HRGC-HRMS). Toxic equivalency (TEQ) concentrations were calculated using 2005 toxic equivalency factors (TEFs). Results: Beef liver concentrations ranged from 0.02 – 4.67 pg TEQ/g wet weight (ww; 0.85 – 164.58 pg TEQ/g lipid), while the corresponding fat samples ranged from 0.09 – 14.34 pg TEQ/g lipid. On a lipid basis, liver concentrations were on average 15 times higher than the corresponding fat sample from the same animal. Fat (pg TEQ/g lipid) and liver concentrations (pg TEQ/g ww) were significantly correlated (r2 = 0.79; p<0.05), however a few animals with higher concentrations greatly impacted the correlation. For example, when fat concentrations < 2 pg TEQ/g lipid were correlated with the corresponding liver values, the least-squared regression was significant (p<0.05) but the r2 decreased to 0.45. Additionally, congener patterns did differ between fat and liver samples. The OCDD concentrations were higher in liver, the HpCDD concentration in fat was equal to OCDD, but the liver concentrations were higher for OCDD than HpCDD. Liver also had higher OCDF concentrations, and a higher detection frequency compared to the corresponding fat samples. TCDD and PeCDD, the most toxic congeners, had low detection frequency (<5%) and low levels when detected in liver compared to fat which had 38% detection for TCDD and 90% detection for PeCDD. Conclusions: Consistent with other studies, the liver concentrations were typically higher than fat, indicating a higher accumulation of PCDD/Fs and PCBs in liver. There appeared to be higher accumulation of the octa congeners in the liver and lower accumulation of TCDD and PeCDD in the liver compared to corresponding fat samples.