The production of CO2 during the fermentation step and continuing on in the
finished product presents a unique packaging problem that can cause bulging of
containers and leakage of contents.102,110 In some countries, kefir has been either
produced or sold in glass bottles. However, polyethylene foil packs covered with
aluminum foil or plastic containers with an aluminum foil cover are more flexible
containers that can accommodate the gas produced after packaging.