No Quick Fix With 12-Hour Test
Jim Prevor’s Perishable Pundit, August 2, 2007
Our little piece, Hold The Train…12-Hour Test May Not Be Best Answer, regarding the new 12-hour test being used as part of many testing programs for Salmonella and E-Coli, may have lifted the veil of an important food safety issue — which includes attempts to intimidate into silence some of the trade’s most respected food safety experts.
The piece was based on this note we received from a processor:
After reading the Pundit on True Leaf and the false positives, I couldn’t help but think there may be an issue regarding the effectiveness of the 12-hour PCR based tests on the market. Many in the industry, us included, are using it based on pressure from accounts and not necessarily based on scientific accuracy. The PCR is a presence / absence test, that looks for genetic material of e-coli and salmonella. It does not tell you if the cells are dead or alive, if it was one or one million cells, or if the genetic material was from a current or past event (i.e., a bird strike on the ground 12 months ago).
The developer stands behind the results and is very reputable so there is no issue from that standpoint. However, no one seems to have the scientific data (at least it’s not shared) that helps us determine the true accuracy. We all know painfully well the rate of false positives with the conventional testing methods. There was also a symposium held May 31, in Chicago, in which FDA and CA Dept of Health participated. One concern raised was the accuracy of the PCR test based on the very limited data complied and the speed at which the industry is ramping it up.
In follow-up to this piece, we’ve now heard from three very prominent food safety experts expressing both some strong concerns regarding this test and concerns with the degree to which advocates of the test are attempting to stifle free debate.
Also there are concerns that the use of the test may be giving a veneer of food safety to an unsafe system. Here is how one expert expressed the situation:
A visiting scientist from the UK commented on how flabbergasted he was by the entire concept and the lack of critical commentary from the food safety community associated with the fresh produce industry.
We let him know that many of us agree with his comments but have been advised to keep our opinions to our selves.
The primary advocate for this program calls for a massive level of testing. When the dust settles, I don’t believe this will be viewed as one of the fresh produce industry’s brighter moments.
It is taking a validation tool and turning it into the center of a food safety program. That should, in and of itself, raise questions.
There are many problems with the program but the largest is the over selling of the effectiveness of the sampling effectiveness in identifying sporadic contamination events.
In reality much of the testing is primarily used to test artificially reduced lot sizes to minimize economic damage. This will ultimately be challenged by the FDA. Only time will tell if the program accomplishes this goal. These are not dollars spent to address the problems.
A few issues the industry might consider before we join a bandwagon for this test:
The test is not AOAC approved. Advocates have been saying it will be AOAC approved in 4 to 6 weeks. Unfortunately they have been saying that for nine months! AOAC is the third-party arbiter, devoted to analytical excellence, that gives the recognized “stamp of approval” to these types of tests.
The test is not widely used by professional microbiologists. It is limited to a single firm and not part of standard industry practice.
The industry seems to be attempting to “test in” quality or safety, Unfortunately, though testing can be useful for verification, substantive improvements in process are necessary for significantly enhanced safety. Resources spent on testing programs are typically not available for more substantive efforts.
Testing is a feel-good approach for buyers who prefer a simple test rather than having to wrestle with the difficult task of prevention.
Resources are being pulled away from the implementation of preventative and more sustainable solutions.
The testing program provides a false sense of security. Testing — if you are testing for that thing — may be a good way to identify certain types of things such as a chemical incorrectly applied to a whole field. However, testing for bacteria cannot reliably find things such as E. coli 0157:H7, which may be due to sporadic animal entry in one tiny part of the field.
The sampling from a fresh produce matrix (in contrast to homogenized liquids) may not deliver the level of assurance claimed. We don’t actually know enough about this test yet, to leap to the conclusion that it can have any place much less the determinative place in our industry food safety programs.
The math on testing is daunting. Has anyone attempted to project the increased testing in the fresh produce industry required to accomplish gains similar to the improvement in beef? For example, if the beef industry has succeeded in lowering a 1.5% level to say 0.6%, what level of testing might it require in produce if our contamination level starts at, say, 0.015% or even lower?
Testing is one of those things that sounds great but really isn’t that helpful. The key point is that our product is so safe that, literally, it would probably be easier to find a needle in a haystack than to randomly stumble on an affected bag of produce.
What is happening, though, is very bad:
First, buyers seem to be looking for a quick fix. Instead of really evaluating different vendors and their food safety systems, these buyers want to buy from the cheapest guy — but demand testing. That is a disaster waiting to happen.
Second, vendors are recognizing that their financial interest is to reduce lot sizes. So by testing every X boxes and defining that as a lot, they reduce their expenses if a lot must be destroyed. But, as our correspondent relates, this is an “artificial” lot, not joined to any authentic characteristics — field, day of harvest, etc. — that might impact food safety.
Lots do need to be made smaller — but authentically by making sure no product delivery is from mixed fields, by sanitizing machinery so as to create breaks between different batches of product, etc.
Third, the constant drumbeat of negative test results — which only tells us what we already knew: that well in excess of 99% of our product is very safe — is relaxing pressure — especially pressure from buyers — to improve food safety systems.
Fourth, that many in the industry are not encouraging the environment of free-and-open debate and discussion on these matters that might actually produce better food safety. This is the most frightful thing of all.