Many Faces of Food Contamination

The work of food toxicologists can become even more complicated when they have to consider possible interactions among the various contaminants. Luckily a large body of data is available to help understand how the body metabolizes the various contaminants, so that safe limits can be set. However, it is also fair to say, that scientists are still learning to fully understand all the effects on how the body reacts to the simultaneous presence of a mixture of contaminants.

It should be noted that testing of suspect crops is extremely costly, thus stressing the need and value of preventative measures.

One Large Family of ‘Bad Guys’

It is reasonable to assume that there is no such thing as zero risk for food contaminants. Contaminants are a part of the food supply and when controlled and monitored properly, they do not represent an undue risk for public health. However, dioxins are contaminants that escape the “minimum limit” notion that can be applied to other food contaminants.

Dioxins are considered one of the most, if not the most toxic man-made substances. They may not necessarily cause acute health problems, but are harmful to health at very low levels. Dioxins are persistent organic compounds that once created, are extremely hard to eliminate. They are mostly fat soluble, accumulating in the fatty tissue of animals, including meat and dairy. Once consumed, these compounds do not degrade easily and will accumulate in the human body. Accumulation of dioxins has been linked to a number of health problems.

There are no tolerance levels of dioxins established by the FDA, but the agency is working in conjunction with the European Union and the EPA and USDA to address the issue of dioxins and other persistent organic compounds (such as PCBs) in animal feed.

In 1997, “ball clay,” a mined clay product used as an anti-caking agent in animal feed was found to be the source of high concentrations of dioxins in chicken, eggs, and catfish. After the findings, the FDA’s Center for Veterinary Medicine worked with industry to test feed samples for other sources of dioxins in mined feed ingredients. Today, the risk of dioxin contamination from clay is minimal as it is very well understood how to avoid the use of clays containing larger amounts of dioxins. In 2008, USDA’s Food Safety and Inspection Services (FSIS) completed a survey of 510 domestic beef, pork, and poultry samples for dioxins. The results of the survey showed very low levels of no toxicological concern, with turkey and beef presenting the higher concentrations.

There is not much consumers can do once dioxins are present in the food supply chain, but consumers can and should contribute to the reduction of dioxins creation. While dioxins cannot be generated in the home environment (temperatures needed to create dioxins are extremely high), one of the ways dioxins are created is through incineration of waste. Recycling metal materials, in particular copper – which catalyzes dioxin formation and is present in many household items, such as batteries – is a way to contribute to the reduction of dioxins in the environment.

Not All Harmful Contaminants are Man-Made

These contaminants are byproducts of fungi (mold) that essentially can grow on all foods provided that enough moisture is present. Not all molds produce mycotoxins, but once produced, they can get into the food chain and are extremely hard to eliminate. Preventing mold growth through good agricultural practices pre- and post-harvest are the only effective measures to limit the amount of mycotoxins in food. It should be noted that testing of suspect crops is extremely costly, thus stressing the need and value of preventative measures.