Tuesday, March 30, 2010

AMS Testing for Fake Wine: A Bridge too Far?

Recently, online news outlets have been atwitter with news of a new application of an old technique (accelerator mass spectrometry (AMS)) for detecting fake wine.  The technique utilizes technology, historically utilized for dating archaeological artifacts, to determine the level of carbon 14 in wine. When correlated with the known levels of carbon 14 in the environment in each year over the past 50 years, an accurate determination of a wines' vintage can be made.

The research was led by Dr. Graham Jones (http://www.adelaide.edu.au/directory/graham.jones) of the University of Adelaide in Australia and the findings (http://www.eurekalert.org/pub_releases/2010-03/acs-dfw030810.php) were presented at a meeting of the American Chemical Society.  According to Dr. Jones, the technique can be used as a tool to combat the incidence of fake wine, a problem which he sees as affecting 5% of wine sales. 

Fake wines have always been a problem for the wine industry and was one of the reasons that the Bordeaux chateaus began to bottle their wines in-house.  Most recently, the high-profile Rodenstock case (http://www.newyorker.com/reporting/2007/09/03/070903fa_fact_keefe;  Benjamin Wallace, The Billionaire's Vinegar) has brought this problem into even greater focus.  But is this technique a realistic "arrow in the quiver" of the folks battling this problem? Or is it just an academic exercise?

The authors of the study had first signaled their intent in a 1999 Australian publication (http://www.abc.net.au/science/articles/1999/03/03/19512.htm) wherein a broad description of the approach was provided.  According to the article, an accurate record of the variation in atmospheric radiation over the last 50 years had been determined by reading the isotope records in trees.  By comparing the isotope measurement in a specific sample of wine, a clear identification of the vintage was possible.  The tool used for this purpose was the Australian Nuclear Science and Technology Organization (ANSTO) Australian National Tandem Research Accelerator (ANTARES), which had been procured from Rutgers University (NJ) in 1991 and had been upgraded on numerous occasions to provide additional/broader analytical capabilities.  ANTARES can detect concentrations of carbon isotopes in red wines as low as one atom in a thousand million million.  It can also detect additives which were not a part of the initial fermentation and, thus, cannot be foiled in its vintage identification efforts even by "topping up" of the wine.

As can be seen by the picture above, ANTARES is not a simple university lab analytical tool.  According to data from Purdue University (http://www.cfs.purdue.edu/fn/bot/Downloads/Publications/Jackson.pdf), there were only 30 AMS facilities worldwide in 2001 and sample turnaround can range from a few weeks to several months.  According to information provided at http://www.uga.edu/cais/analytical_services/radioistope_table.htm a standard sample would be turned around in 30 days, at a cost of $450 per sample, while a 14-day rush would cost $700 per sample.

I have not read the actual report underlying the research (I have requested a copy but it has not been provided as yet) but a number of questions are raised by the available information.  Most accelerators require a breakdown of a sample into an ion beam in order to detect the isotopes of interest.  In the case of the wine being tested, this would require securing a sample of the wine of interest ( a destructive test), and, more specifically, a sample from every bottle in the lot.  The issues of how the samples would be obtained, the cost of the tests, and the timeframe for the tests  all call this technique into question in terms of broad applicability.  If the team has solved the problem of non-destructive testing, it would mitigate a number of the questions raised but still would not minimize the fact that the sample would have to be sent to one of a few places in the world that has the technical capability and only one place in the world with the personnel with the specific expertise.  It should be noted that the Australian Wine Research Institute (AWRI), which is a part of the Wine Cluster along with the University of Adelaide, has used spectroscopy for non-destructive, in-bottle measurement of wine composition and quality, but those tests have been conducted using near-infrared (NIR) spectroscopy rather than accelerator mass spectrometry.  It is not clear whether these techniques have been in anyway incorporated into the AMS research.

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