Leakage in pet bottles

If in a product of liquid orals leak test and torque sealing test is complying then what is the reason behind the leakage of bottles when sent to market?

Hello, a couple of questions: what kind of bottles are you referring to? And waht kind of leakage was described in the complaints?

I think the best you could do is to ask the customer for those defective bottles and inspect them to see how exactly is the leakege present in the product, and initiate root cause analysis more effectively.

In plastic containers, a common cause could be damage during transportation and/or small pinholes or gaps in the container-closure system, that can cause a very small leak, meaning that it is very difficult to detect by a traditional leak test, under normal conditions, and actual leakage can be observed only until some time has passed (days).

Also make sure that tour leak tests and torque sealing tests are validated, to ensure calibration, repeatability and reproducibility.