Hello,
Mr Maricmargot,
It seems you are packing unpasteurised juices (probably made from single strength/concentrated refrigerated or aseptically processed pulp). Such juices are stored under refrigeration conditions and have a very short shelf life (< 1 month) under refrigeration conditions and are prone to microbial spoilage . A holding temperature as close to the juice freezing point as possible (-1 to -3ºC, depending on soluble solids), combined with efficient preparation and exceptional sanitation in preparation and packaging can extend storage life up to a month.
Thus the juice then has a shelf life limited by sanitary conditions and freezing conditions.
Thus minimal processing employing hurdles is called for. The hurdle principle is based on the premise that while any single barrier to microbial growth may be inadequate for desired protection, a number of barriers together can enhance product stability.
Thus good sanitation is the first barrier to reduce microbial load; low storage temperature further retards growth. An acid environment of pH less than 4.5 (ideally less than 3.5) restricts the growth of many organisms. Fortunately most juices are acid, or amenable to acidification. The exclusion of oxygen is an additional barrier. (IMPORTANT- anaerobic conditions are dangerous with low acid foods ,and can set the stage in low acid products for anaerobic pathogenic organisms, i.e.clostridium botulinium) .Hence always check the pH of filled juice is below 4.5 .To prevent spoilage from mold and yeasts ,Antimicrobial substances, sorbic acid, sulphites, benzoates can be added (depends upon regulatory requirements of your country) either natural or chemical preservatives, also assist. Proper use of hurdles can appreciably lengthen shelf life of unpasteurized juices without unduly affecting quality.
Also properly disinfecting your packing materials (plastic bottles &caps ) with approved disinfectants can help.
Regards
Sushil