Although GMP is very important but to solve this issue you need a deep analysis ( root cause analysis )
1- Raw fruits :
As I understand that your main ingredient is Fruits ,we should prioritize it in the analysis .
Depending on whether your Fruits are from the farms or from a supplier make further processing ( timing , cutting , peeling ,.... )
If you are receiving it as trimmed or pre-prepped , some times the hair contamination occurred at this stage , so you need to audit your supplier and visit the processing area , your GMP inspection for the dressing code , hair protection and do not miss that the awareness is very important , the workers must be interviewed to assure that the process is stable and well maintained all the time , some suppliers use women ( villagers ) to make harvest without awareness , training or proper hair covering , also if it is more than one shit we must visit all of them .
then during receiving an inspection for a quite fair samples to make sure that it is OK , you may use a sorting station before packing it ( it is a big cost , so I prefer to improve the supplier )
Other Material and packaging Material :
do the same analysis for all the other martial how it may be contaminated with a hair , even the water , also do the same for packaging material .
2- Personal dressing code :
your dressing code is quite satisfactory as long it is respected by your team , specially the proper usage of hair net strainer .
you can also use a vacuum cleaner for eliminating any probability of carry over through the uniform or coats .
3- GMP awareness :
run a refreshment training for all the team , after each compliant and discuss it ( brainstorming ; do not limit them ) , make it in their working area and show the evidence with the complain , and what is the sequences of it , this is a very effective to trigger them to be focusing in this issue .
good luck .