High current drawn by 3 phase 90 KW Induction Motor during the last part of batch mixing in a toilet soap making factory.
Does the work asked of the motor, in terms of torque load applied to the motor shaft, increase as the batch nears completion?

Is that maximum load within the design constraints of the motor?

If so then it is possible that the motor was not properly sized for the job it is being asked to perform. 

It is normal behavior that as the torque load on a motor increases the current drawn by the motor increases. This increase can continue up to within the ratings for the motor. If more torque is applied the motor could get to a point of stalling with the current draw limited only by the resistance of the windings. 

An overloaded motor or one at near stall behavior is likely to overheat and either shut off if it has an over-temperature cutout or burn up its windings. 

You have several things that you can look into. First find out if a motor more suitably fitted for the work load demand is available and change over to that. 

An alternative to look into is to see if you can give the motor a mechanical advantage. The simplest thing for this is to use a gear box. For example a box with a gear ratio of 3::1 will lower the mechanical load demands on your motor to 1/3 as much as before. There is a price paid for that in terms of the 1/3 as much output speed that will be derived.