Juice Manufacturing

did you pasteurize it?

Let’s start with the basic: check the condition, reception, selection, etc, of the fruits and other materials in the plant
The hygiene of all the people and equipment , etc, involved in the process
The processes used for preparing fresh-cut fruits can induce mechanical injury in the tissue accelerating deterioration.
Desinfectation of the fruits before
Pasteurization
Conditions of storage
Every aspect of the process counts

Thanks a lot, this is useful & will apply; but the main part of my query i.e. 90% of quarry is pending, if you can give some knowledge like How to make, means how to prepare, means how shelf life will achieve , if thermal sterilisation needs than when? before filling or after filling overall process ; because the problem observed was may be our faulty process, like we have sterilise it 90seconds at 75Deg.Centigrade in PET Bottle and sealed.

yes 80 degree second time for 90 seconds.

so maybe there is a problem about pasteurization effeciency.

Did you check it?

What is the pH of the drink?

It sounds like the product is being filled into bottles while still hot, is that correct?

Is your filling equipment being sanitized properly?

You have a problem in three frontiers: quality of inputs, the process and hygiene.

* 100% of bottles have gas - indicates poor hygiene, insufficient processing or post processing contamination.
* 90% of bottles have bad smell - hygiene issue. How do you clean the processing and filling machines? How do you clean the bottles? Do the bottles have air-tight seals?
* 80% of bottles have fungus - hygiene and post processing contamination. Where do you store your bottles before packaging? Do you have pre-packaging sterilization program in place? What measures have you put in place to ensure that the air quality in the processing room is clean? Do you have a policy on PPE in place?

You have indicated that the formulation contains 12% sugar. At what point of the process do you add the sugar? It'd be great if you can share your processing flow chart for close scrutiny. Please note that addition of sugar affects the heat value of the mass, therefore, the pasteurization conditions you have indicated in your query above seem insufficient for complete pasteurization of the juice. I am sure you have a QA book in your processing facility for this specific product and the pasteurization conditions are indicated therein. Your QA manager is sleeping on the job and if you don't take responsibility, you will close your company in 3 months max.

Have you tried cushioning with nitrogen gas?

What is the lifespan of PET bottles aseptic products produced in the market?
I think 3.75 years is a very long shelf life.