Lorna Zach, M. Ellin Doyle,

Dominique Brossard

What should be done to dispose of large quantities of food contaminated with hazardous agents? This was the main issue raised during a workshop held in May 2007 at the University of Wisconsin–Madison, where multiple stakeholders expressed concerns and highlighted priorities regarding the disposal of such contaminated food.

Examples of hazardous agents that might find their way into foods via intentional contamination or corrupt practices include viruses, bacteria, biological toxins, chemicals, and radioactive compounds. While the Bioterrorism Act requires recall and traceability efforts for one step forward and one step backward, little attention has been focused on disposal of this material, except by those who have struggled to deal with it. Most contaminated solid foods would probably be sent to a landfill because incineration and alkaline digestion would be least 25 times more expensive than landfill disposal. Contaminated liquid food would probably end up at a wastewater treatment plant.

A small-scale example of such an incident happened in 2006 with naturally occurring anthrax on untanned animal hides illegally imported into New York City. Although the hides were subsequently autoclaved, no solid waste landfill in the state of New York would accept them for disposal. Disposal companies would not touch the material unless the state certified it as pathogen-free because they were not insured against this type of liability, and unions would not allow their workers to handle the material. Similar disposal problems occurred in 2003 when landfills refused to accept deer carcasses possibly infected with chronic wasting disease, and officials had to temporarily store the carcasses for six months while dealing with testing, disposal cost and capacity, and cross-jurisdictional regulatory issues.

Disposal options for solid contaminated foods include municipal solid-waste landfills, hazardous-waste landfills, and low-level radioactive-waste landfills. Municipal solid-waste landfill operators have responsibility and liability for their sites for 30 years after closure and would probably hesitate to accept food contaminated with harmful agents—even with an emergency permit and a promise of indemnification from the government.

Some chemical and biological agents, such as anthrax spores, survive 50 years or more in soil and may be present long after a landfill is closed. The presence of these agents may preclude future use of the land for another purpose. In addition, liability issues may prevent employees from handling such potentially hazardous materials. Another concern is the fact that local and state regulations may not permit transport across their jurisdictions. Finally, public perception of the danger posed by some “high-profile” agents may also restrict disposal options.

The disposal of contaminated liquid foods brings up a different scenario. Wastewater treatment plants are part of the public health system and cannot refuse incoming wastewater from a community or stop the flow of material through the plant. If contaminated liquid foods have already been sold to the public, consumers would most likely pour the liquids down the drain, which would raise liability issues for the food industry. In contrast, if the contamination is detected before foods reach consumers, the liquid waste may be contained as a point source that could be trucked to a treatment plant. Some chemical agents may have corrosive effects on pumps and other machinery at a treatment plant. Depending on the properties of the agent and the volume and nature of the contaminated liquids, the plant could refuse to accept it because it might harm the beneficial microbes that decompose organic matter in the wastewater.

Participants at the workshop stressed that an effective response to a hazardous-substance contamination incident would require coordination among federal, state, and local government agencies; food processors and distributors; transportation companies; and solid and liquid waste disposal facilities, as well as effective risk communication.

Specific plans for a coordinated response need to be formulated now. As a quality assurance manager from a major dairy company stated during the workshop, we cannot afford to have tons of recalled, contaminated product sitting in the back parking lot while regulators, disposal operators, and food plant managers try to decide what to do with it.

A follow-up conference to examine these issues and to promote communication among all stakeholders is planned for April 30–May 1 at the University of Wisconsin–Madison.

Lorna Zach, Ph.D., ([email protected]) is Assistant Scientist, Center for Human Performance and Risk Analysis, University of Wisconsin–Madison. M. Ellin Doyle, Ph.D., ([email protected]) is Researcher, Food Research Institute, University of Wisconsin–Madison. Dominique Brossard, Ph.D., ([email protected]) is Assistant Professor, School of Journalism & Mass Communication, University of Wisconsin–Madison.