The socket of my refrigerator did not make a good contact, so I have to tweak it a little.
1W provides plenty light in a large refrigerator.
Update: After using it for a few months it failed.
Being an engineer I diagnosed the issue and found that the inrush resistor (630ohm SMD) cannot handle the continuous on and off operation as is typical in a refrigerator.
So nice LED, but poor quality. The manufacturer should consider replaceing the SMD resistor by a better quality leaded version.