Bacterial studies currently available

Brazilian granite countertop study

Some relevant points on the Brazilian study
This is an excellent study on bacteria on granite and plastic surfaces.  It was
published for peer review in an international trade journal.  The footnotes
support all statements made that weren't part of the study.

This study took granite and two types of plastic and exposed them to four types
of bacteria, two from a package of chicken, two from human food poisoning
cases.  While the study is a hard read, the main conclusion is that granite is
more prone to colonization than either plastic in the study, from 120% to 590%
more bacterial growth depending on the strain.  

There is a graph showing which strains liked the bacteria the most, and we
have received the raw data that the graphs were made out of from one of the
authors to back up the percentages.  This study directly contradicts the stone
and stainless steel studies that claim that stone is easily cleaned.

Studies relied upon by the granite and quartz trade

1999 Steel Alliance "study"
This "study" was paid for by the Steel Alliance, as part of a $100 million public
relations campaign ran in part by Porter Novelli, a big PR firm.  It is full of holes,
as shown in the article below.   It is presented as a scientific study, but the lack
of footnotes supporting their assumptions, lack of publication ,and lack of
review by peers lands it in the realm of press release, not study.  The Marble
Institute picked up on the study because it showed granite in a positive light,
and the winner of the study, stainless steel, is hardly competition for kitchen
countertops.

Why the Steel Alliance "study" is deeply flawed
The author was contacted for a response, in the process he quoted a fee for
redoing the "study"  but once we started asking questions, he stopped replying.

2006 Marble Institute "Cleanability" study

The 2006 Marble Institute "cleanability study" was done by Dr. Snyder, the
same guy that did the 1999 Steel Alliance study.  In this study, they
contaminated granite, marble and quartz samples, then cleaned them and
tested for remaining bacterial.   It has many of the same flaws that the first study
had and some new ones as well.

Again, the material association that paid for the study came test competing
materials, just their own products.   Their point was to show that the materials
they sold were capable of being cleaned adequately.

While Quartz does have a NSF 51 rating for food zone prep area use, the other
materials do not and most likely never will, so this is the MIA's attempt to get
around the lack of food safety certification.   In the section on Granite Bacteria
and Granite Heavy Metal Contamination, you will see why granite and marble
won't pass the NSF 51 certification process.

Why the 2006 Marble Institute "Cleanability" Study is Deeply
Flawed

The NASA sponsored study on bacteria that inhabit the interior
of stone
This was something that surprised many, myself included.  Microscopic crevices
within the granite created when the minerals in the granite cooled from the
magma state, cracks and fissures, as well as pores and fissures that continually
form once granite is cut from the ground and processed into slabs.   We need
to remember that most soil and all sand started off as a granite mountain.