If you clean your plastic bottles after each time you use them, like you would for any other drinking container (i.e. drinking glasses, etc), then there will be no need for you to be concerned with bacteria. Plastics are by nature extremely sanitary materials, and plastic bottles are no more likely to grow bacteria than packaging or drinking containers. Bacteria growth occurs in warm, moist environments and can be found in any drinking container (coffee mugs, drinking glasses, serving pitchers, etc…).
To prevent bacteria growth in drinking containers always clean with hot soapy water and dry thoroughly between uses. Bottles like our filtered water bottles and portable water filters are designed with wide openings so that they allow the use of cleaning instruments and easy drying. The sanitation process for Biological Water Filters is a little different. Make sure you read the directions for use of these products.