Who cut the cheese…and PCBs?

Crawford's Country Store World's Largest Cheese at LA Cty Fair JPEG

Polychlorinated biphenyls (PCBs) are organochlorine compounds having a double ring structure where one to ten chlorine atoms are substituted. At one time, these compounds where used as coolant fluids and in various products like electronics, paints and adhesives. These compounds are considered toxic because they have been linked to carcinogenic and mutagenic biological changes. Because of this, manufacturing of PCBs has been banned throughout most of the world. Unfortunately, we still live with these compounds because they are persistent in the environment, being found in air, water and soil.

One main route of human exposure is through contaminated food. For example, oils used in food and feed production can be contaminated at facilities that process oil for both food additives and for industrial applications. When oil is recycled legacy PCBs are contained in the older oil. There are several cases of this non-food oil contaminating oil intended for consumption including the “Dioxin Affair” in Belgium (1999) and in pork products in the Republic of Ireland. More recent evaluation of PCBs in food and feed indicate that about 9% of food samples tested contained levels of dioxin like-PCBs (DL-PCBs) higher than the maximum level permitted. (EFSA Journal 2012;10(7):2832 [82 pp.]., http://www.efsa.europa.eu/de/efsajournal/pub/2832.htm )

As a cheese lover, I was saddened to see that PCB contamination was recently reported for various cheese samples. In fact, PCBs were found in all samples! Fortunately, the researchers at the University of Las Palmas de Gran Canaria (1) concluded that most of the cheese showed levels below the maximum level set by the EU. However, some of the toxic DL-PCBs exceeded these levels.

Need some ideas for testing PCBs…Restek has a GC column specifically designed and optimized for analysis of PCBs, the Rtx®-PCB . We have standards too; PCB Congeners, PCB Congener Standard #1, PCB Congener Standard #2 , PCB Congener Mix, Method 8082A. For other parameters like injection liners check out some chromatograms and other resources.

Aroclor PCBs on Rtx®-PCB

Aroclor 1242/1254/1262 PCBs on Rtx®-PCB

Why Do We Chromatographers Persist in Delivering Inaccurate Data to Our Clients? The Case of the Indicator PCB 138 and its Coeluting Congeners 163 and 164

Polychlorinated Biphenyls (PCBs): Closing the book on PCBs; problem solved.


  1. Maira Almeida-González, Octavio P. Luzardo, Manuel Zumbado, Ángel Rodríguez-Hernández, Norberto Ruiz-Suárez, Marta Sangil, María Camacho, Luis A. Henríquez-Hernández, Luis D. Boada. “Levels of organochlorine contaminants in organic and conventional cheeses and their impact on the health of consumers: An independent study in the Canary Islands (Spain)”. Food and Chemical Toxicology 50: 4325, December 2012.


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