Dr. Elisabeth Hagen, USDA’s Under Secretary for Food Safety, announced in a press conference on May 2, 2012 that the government is changing its traceback policy for contaminated beef that test positive for shiga-toxin producing E. coli bacteria (STEC).
“Our keys goals are to strengthen our ability to protect consumers and to bolster prevention-based public safeguards,” she said. “We are going to use traceback policies as a proactive measure, launching the investigations earlier to identify contaminated products before they reach consumers.”
Traceback is the path investigators follow to find out where the contaminated product came from, and to discover where bacteria were introduced into the product. The new policy will allow the USDA to begin traceback and investigations if “presumptive positive” test results occur.
There are three steps in the polymerase-based chain reaction (PCR) test used to test for bacteria in meat. First, a “potential positive” test gives investigators a signal that there may be bacteria present. The second test is called “presumptive positive”, and finally the “confirmed positive” test is conducted if the second test is positive. The whole process can take 24-48 hours.
The old policy started the traceback procedure only when the PCR based testing process showed a “confirmed positive” test for Shiga toxin-producing bacteria. By starting the traceback process at the “presumptive positive” stage, investigators can save 24-48 hours in tracing the problem back to the supplier or processor, starting the recall sooner, or holding the product before it enters commerce.
When a presumptive positive test occurs, investigators will “link the contamination to a sole source if possible, then see if that source material was used in other products,” Hagen said. “Then companies will be required to recall all common source material. We also want to focus quickly on production conditions during the time of contamination at the plant, and look at how the plant manages high event conditions.”
This new policy is a recognition that inspectors need to focus on a preventative or proactive approach, rather than reacting when an outbreak occurs. Dr. Hagen said that, “meat sampling is conducted on a daily basis. Inspectors look at these processing systems every day. The accumulation of our experience and data led to this change.”
When the USDA inspectors pull samples, they record information about the supplier of the meat, so information about where the product came from is on hand when a product tests positive.
Dr. Daniel Engeljohn, Assistant Administrator for the Office of Policy and Program Development of the USDA, said that there are 13,000 to 15,000 samples pulled every year in the U.S. ”Fewer than 100 are presumptive positive tests, and generally about 60 samples are confirmed positive in one year,” he said.