1999 Steel Alliance Study Flaws
How hard is it to clean or sanitize natural stone anyway?
Like many fabricators, I have found myself drawn into the fabrication of quartz
and granite along with the solid surface and laminate that I have done for years.
Researching the newer materials has lead me to conflicting views on whether
or not the stone or quartz need sealing and/or sanitizing on a regular basis. If
there is a potential danger that sealing can address, or that homeowners can
address by sanitizing procedures, it is an important issue.
From my research, probably the most widely distributed study I can find is, "The
Reduction of E. Coli on Various Countertop Surfaces" authored by O. Peter
Snyder, Jr., Ph.D., Hospitality Institute of Technology and Management, March
22, 1999. This study, although often quoted on stone-related Web sites, has
left me with many unanswered questions. The testing has been adopted by the
Marble Institute of America and other stone groups, despite its shortcomings.
There were several things about the study that I found puzzling. First, solid
surface wasn't tested along with the other materials, some of which have
comparatively miniscule market share in the countertop industry. Solid surface
has been approved by the National Sanitation Foundation (www.nsf.org) , is
widely used and is the preferred choice in hospital resurfacing projects,
according to the requirements listed in the American Institute of Architects
Guidelines for Design and Construction of Hospital and Healthcare Facilities,
which was updated in 2006. Why would they exclude it?
Another point I found odd was the use of vinegar and water as the sanitizer in
the study. The Marble Institute warns consumers that vinegar will damage many
stone surfaces. The Marble Institute has this posted on their website:
"Caution: The reader is cautioned that although vinegar was used as a
disinfectant for the purpose of this test, there are some granite species that
contain trace mineral groups which could be attacked by exposure to acidic
solutions. Some sealers, impregnators, or other agents applied to the stone
may also be subject to attack or discoloration from mild acids. Do not use
vinegar as a cleaning agent without consulting your stone supplier as to the
mineralogy of your particular granite as well as the compatibility of any sealer or
impregnator that may have been applied to the stone. Vinegar should never be
used on calcareous stones such as marble, limestone, or travertine."
And, using the study's method, over 140 gallons of sanitizer and rinse water
would be needed to clean a average kitchen. The test was conducted on 81
square inches of countertop, or around a half square foot. The average
countertop is 75 square feet, so if you do the math, that is the equivelant of 133
of their 81 square inch samples. The test used two liters of soapy water and
two liters of clean rinse water, a total of four liters per sample. Four liters =
1.056 gallons x 133 = over 140 gallons. Imagine taking 532, two liter bottles of
soda or water and dumping it on your top to clean it. It is highly unlikely a
homeowner would use this method.
In another test by Dr. Snyder, one type of granite neutralized the vinegar
sanitizing solution, resulting in a failed 5 log reduction of bacteria. A 5 log
reduction means that if there are 100,000 bacteria present on the sample, a
five log reduction would leave one bacteria alive. In reality, there might be a
thousand bacteria still alive, but the numbers have been reduced to a point
where your immune system can deal with them.
On the original test, the granite used was called Lelajaross, yet I have been
unable to find any information on this type of stone. (A Google search, which
usually comes up with more information on a subject than I can possibly read,
returned no mention of the stone except in connection to this study.) Without
being able to duplicate the study with the same stone, it is impossible to verify
the accuracy of the study. Nor is it possible to assess any damage done to the
stone during the testing. In fact, only two of the six materials tested were
described with enough accuracy to enable others to duplicate the test, which is
unheard of in scientific circles.
The most troubling point, in my opinion, is that the study seems to count the
amount of bacteria killed on each surface during testing. However, under this
methodology, wouldn't the material that supported the most bacterial growth, or
allowed the most bacterial adhesion also have the highest number of dead
bacteria present? Overall, the details in the study are extremely sketchy. The
study was not submitted for peer review by other scientists, which is unusual,
the drying time after contamination is not given and the type of granite that they
used is unobtainable. More surprisingly, the stone forums I have contacted
never heard of Lelajaross, except in the study.
Another concern I have is that, although credit was given to Porter Novelli for
providing materials for the test, from reading the report, one would not guess
that Porter Novelli was a public relations and lobby firm that worked for The
Steel Alliance between 1997 and 2003. Further research proved that The Steel
Alliance, a consortium of more than 120 steel producers and affiliated
organizations, also paid for the study as part of a 100 million dollar public
relation campaign. Why were these critical facts not made clear in the study
report? It seems to me that the report can be likened to a press release, and
why would a press release be presented as a scientific study?
Snyder also was the author of a sanitizing study on granite and quartz, issued
as a technical bulletin by the Marble Institute, where many of the same
concerns were present, but that is another story. The Stone Network reported
that the new version of the study was paid for by the Marble Institute, a fact not
contained in the study, but of importance in determining its validity.
Strangely enough, no one challenged this "study" for years, and the Marble
Institute paid the original "scientist" to redo the study, when stone fabricators
started selling quartz materials, the including quartz. The study was somewhat
better, at least the materials tested could be identified. In a few weeks, we will
publish a response to this "study", showing the inconsistencies and flaws.