Why moisture is the main enemy
Agriculture.Institute's notes on packaging dehydrated produce say drying removes 75 to 90 percent of the water, which leaves a product that readily absorbs moisture. In humid conditions, it says, produce can take moisture back within hours, which encourages mould and bacteria.
Virginia Tech Extension explains water activity, the free water available to microbes. It says foods below 0.85 are considered water-activity controlled, and that dried fruit typically measures 0.60 to 0.75. The gap between the two is a safety margin, and a damp pouch can shrink it.
Pouch types in plain words
Packaging for dried fruit ranges from simple single-layer films to multi-layer laminates.
- Single-layer film: NRCG's publication on dried grapes recommends raisins packed in 400 gauge LDPE film bags that are food grade and comply with FSSAI rules.
- Multi-layer laminate: Agriculture.Institute describes an outer layer of PET or OPP for strength and printing, a barrier layer of aluminium foil, metallised polyester or EVOH, and an inner polyethylene layer for heat sealing.
- Rigid containers: it also lists composite cans and plastic tubs, which are durable and resealable.
Barrier performance is measured by water vapour transmission rate and oxygen transmission rate. Lower numbers mean less moisture and oxygen passing through. Ask your packaging supplier for these figures instead of choosing by look and feel.
Extras that help
Agriculture.Institute lists vacuum packing and nitrogen flushing, which remove or replace oxygen, as well as oxygen absorbers and desiccant sachets. It says vacuum packing can keep quality for 1 to 3 years at room temperature, but that is a general claim, and your own product and pack need your own testing.
What FSSAI says about materials
The FSSAI packaging compendium says candied and dried fruits can be packed in paper bags, cardboard or wooden boxes, new tins, bottles, jars, aluminium and other suitable approved containers. Plastics must meet the relevant Indian Standards, such as IS 10146 for polyethylene, IS 10910 for polypropylene and IS 12252 for PET.
Storage matters as much as the pouch
- Agriculture.Institute says dried fruit can typically be stored for up to one year at about 15 degrees Celsius, falling to roughly six months at about 27 degrees, with relative humidity kept below 60 percent.
- NRCG recommends raisins at 10 degrees Celsius and 50 to 60 percent relative humidity, and warns that above 25 degrees there is a greater risk of candying, clumping, syrup formation and fermentation.
- The UC Davis solar dryer manual advises a cool, dry, dark place, with relative humidity under 65 percent to prevent mould.
If your store room runs warmer or more humid than these figures, expect a shorter shelf life. Keep stock away from heat and direct sun, and keep pouches sealed until use.
Shelf life on the label
The FSSAI labelling regulations require date marking, with a date of manufacture or packaging and an expiry or use-by date. The right shelf life for a pack comes from testing the product in that pack, not from a general table.
Pack only when the fruit has cooled, as the UC Davis manual advises, and use dry, air-tight containers.
Frequently asked questions
Why does dried fruit go sticky or mouldy?
It readily takes moisture back from humid air, and extra moisture encourages mould, according to Agriculture.Institute's packaging notes.
Does FSSAI allow plastic pouches for dried fruit?
FSSAI says plastics must comply with specified Indian Standards, and lists suitable approved containers for dried fruits.
Which storage conditions do sources suggest?
Cool and dry. NRCG suggests 10 degrees Celsius and 50 to 60 percent relative humidity for raisins, and UC Davis says under 65 percent humidity.
Sources
- Agriculture.Institute: Packaging Dehydrated Fruits and Vegetables
- Virginia Tech Extension: Interpreting Water Activity Lab Results for Food Producers
- NRC for Grapes: Production of Quality and Safe Dried Grapes
- FSSAI: Compendium, Packaging and Labelling Regulations (2020)
- UC Davis: Chimney Solar Dryer Manual, Drying Fruits and Vegetables
- FSSAI: Labelling and Display Regulations compendium (Sept 2025)