The alcohol, low oxygen content, relatively low pH, hops extracts (alpha-acids) and dissolved carbon dioxide in beer inhibit the growth of pathogenic bacteria. That is why beer has been a safe drinking alternative for so many centuries. However, there are microorganisms that can survive and even thrive in beer and spoil the flavor and aroma of any good brew.
The goal of pharmaceutical water system operators is to produce bacteria-free water that meets or exceeds required purity standards. Water systems use several filters to protect system components and to assure that the water dispensed for use is free of bacteria and most other particle contaminants.