Instruct: Classify Amazon reviews into positive or negative sentiment
Query: This bottle is bad for your health

The bottle performed well, but very much to my dismay I discovered that a bunch of the teflon coating had flaked off inside the bottle and I must have ingested it without noticing. I am particularly dismayed, because when I first bought the bottle and discovered that it had a teflon coating, I called US Zojirushi customer service and I was assured that the coating was safe, that it would not disintegrate due to the heated beverages (black and green teas). This obviously is not the case. For good health, I am now scouring the net for a portable glass-lined thermos bottle - very hard to find. The stainless steel one I had before (with a stainless liner) corroded inside.