Granite is a natural stone so it is a slightly porous surface however this does not make it a breeding ground for bacteria. If you keep your granite countertops clean and dry you will not have any bacteria problems. No matter what your countertops are made of, you should never place raw meat on them. If this happens make sure to clean the area thoroughly to avoid cross contamination. If you are still concerned with bacteria you can use anti-bacterial dish soap and very hot water to clean your countertops or use anti-bacterial cleaners or wipes on them. If you use an anti-bacterial cleaner, make sure that it is as ph neutral as possible or you may have to seal your countertops more often.