So with all the recent hype regarding granite countertops and radon gas emissions, I thought I'd combine granite countertops with one of my other ‘hot topic' specialties: mold investigation.
On the scale of hygiene, the typical granite countertop falls somewhere below Stainless and Corian, well ahead of ordinary laminates, and relatively even with quartz (aka "engineered stone"). A special variation of engineered quartz called "Silestone" exists that is advertised as having built-in anti-microbial properties. This is due to the addition of a special chemical compound during its manufacture.
Unlike engineered stone however, granite benefits greatly from the addition of a sealer. Left unsealed, granite can absorb small amounts of liquid, which may lead to staining. Similarly, open pores in granite surfaces can also harbor small amounts of liquid. These situations may lead to bacterial growth.
The great news about granite however, is its superior ability to be cleaned. In a study by the Hospitality Institute of Technology and Management, granite was beaten only by Stainless Steel in a standardized hygiene test. The study showed that washing a granite surface with ordinary yellow dish soap and water reduced E.Coli bacteria levels by 36,000 times. If the dish soap was followed up by a 10% solution of household vinegar, the reduction of E. Coli increased to 80,000,000 times! Because caustics like vinegar can damage some sealers, its best to just stick with the dish soap.
So here are a few tips to keep in mind:
Granite should be initially sealed and then reapplied following the manufacturers recommendations
Avoid cutting raw food directly on a granite surface - use a cutting board.
Wipe up any spills immediately and wash down when completed.
Avoid using bleach or other caustics as this can damage the sealer
Avoid placing hot objects directly on the surface as this may also damage the sealer.
Follow these quick tips and keep your surface dry and clean - and you can be sure mold won't be hiding in the depths!