Why is there white filaments like in the water coming out of our fridge? We have changed the water filter 2 weeks ago, still no improvement.
Unfortunately since you waited until after the problem started to replace the filter, your tap water likely reacted with the plastic in the refrigerator causing these white particles. If your refrigerator will allow you to dispense water without a filter attached, I would remove the filter and flush the system with unfiltered tap water by dispensing water from the refrigerator until the white particles are gone. This may take a lot of time and water, so that's why I recommend removing the filter to speed up the process and to not filter water that is going to be discarded. After the white particles have been removed, then reattach the filter and flush once or twice more to fill the system with filtered water to prevent it from happening again.
If you cannot dispense water while the filter is removed, dispense water while the filter is attached to flush the system.
Flushing your system by dispensing water from it will remove the white particles and solve the problem. Furthermore, If you want to prevent this from happening again then you either need to replace the filter more often (before it happens again), or add an additional activated carbon filter on the water line before it connects to your refrigerator. The preferred setup is having two activated carbon filters in series to make sure that anything the first filter missed will get captured by the second filter at least until the next service interval when both filters are replaced.
Most refrigerators with filters have a 1 stage carbon filter, but expensive ones have 2 stage carbon filters. If you want the ultimate water quality, you can remove the refrigerator filter and install a reverse osmosis water filter that feeds the refrigerator too. Adding a reverse osmosis system is a much larger project, but I'm including it in this answer for completeness.
Found this on Appliance 411:
I have heard a number of complaints recently that the chemicals (specifically chloramine - a mixture of chlorine and ammonia) used in some water treatment facilities are causing the material the molded plastic refrigerator water reservoirs are made from to break down resulting in white or whitish particles appearing as flakes, flecks or specs in the dispensed chilled water. In that case the water filter is not usually the cause, instead replacing of the chilled water reservoir itself may be necessary.
Most manufacturers originally used a molded plastic water reservoir which is what seems to be effected and breaking down. Many fridge manufacturers are now selling a coil of plastic tubing (like that used in the rest of the refrigerator's water system) in place of a molded plastic reservoir.