Freeze-Dried Strawberry Specification: Moisture, Water Activity, Microbiology and the COA
A freeze-dried strawberry specification fixes moisture at ≤5.0% (typically 2.0–3.5%), water activity at ≤0.30 (typically 0.15–0.25), ready-to-eat microbiology with Salmonella not detected in 25 g, and colour against the approved sample. FruitBuys Vietnam releases every full-container lot against a third-party COA for those lines, with virus and residue panels booked before loading where your market needs them.
Two numbers carry most of the weight: water activity decides whether the fruit stays crisp, red and microbiologically stable on an ambient shelf, and the COA decides whether your QA team can prove it. This guide sets out every line of the specification with its limit, method and frequency, explains the berry-specific food-safety questions (norovirus, hepatitis A, Cyclospora), and shows how to read the COA and check a lot on arrival. The buying guide is freeze-dried strawberries in bulk.
The specification at a glance
| Parameter | Limit | Method | Frequency |
|---|---|---|---|
| Moisture | ≤5.0%; released at ≤3% target | Vacuum oven, AOAC 934.06 | Every container lot (COA) |
| Water activity | ≤0.30 | ISO 18787 | Every container lot (COA) |
| Total plate count | ≤10⁴ CFU/g | ISO 4833-1 | Every container lot (COA) |
| Yeasts and moulds | ≤10² CFU/g | ISO 21527-2 | Every container lot (COA) |
| E. coli | <10 CFU/g | ISO 16649-2 | Every container lot (COA) |
| Salmonella | Not detected in 25 g | ISO 6579-1 | Every container lot (COA) |
| Lead, arsenic, aflatoxin (total, B1) | Destination limits | Accredited lab methods | Periodic surveillance |
| Pesticide multi-residue | Destination MRLs | LC-MS/MS and GC-MS/MS screens | Per programme, before loading |
| Hepatitis A, norovirus | Not detected | ISO 15216-1 RT-qPCR | Per programme, before loading |
| Colour, cut size, breakage | As the approved pre-shipment sample | Visual, sieve, weight | Every lot |
| Foreign matter | Metal detection, Fe 1.5 / non-Fe 2.0 mm | Detector check | Continuous, recorded |
Lot COAs come from an independent ISO/IEC 17025 accredited third-party laboratory in Vietnam, in 3–5 working days. Trial and LCL orders ship with the in-house release QC log (moisture, water activity and sensory per batch) and the latest surveillance report; any independent test your QA needs on a trial lot is credited in full against your first container.
Moisture or water activity: which one should you accept on?
Write both into the contract; accept on water activity.
- Moisture is the total water left in the fruit. It is the commercial number: at ≤5.0%, you pay for strawberry solids, not shipped water. Typical lots run 2.0–3.5%: about 2.0–3.0% in the dry season and 3.0–4.2% in the rainy season.
- Water activity (aw) is how free that water is to move, react and support growth, on a scale from 0 to 1. It is the behaviour number. A freeze-dried strawberry is about half natural fruit sugar, and sugar holds water unevenly, so two lots at the same 4% moisture can sit on either side of aw 0.30.
At aw ≤0.30, the fruit is crisp, free-flowing and stable: no bacterium, yeast or mould can grow, and the red pigment is protected. Above about 0.35–0.40, the pieces lose their snap, turn leathery and start to clump in a hopper. Typical lots release at 0.15–0.25, well inside the limit, which is the margin that carries the product through a warm warehouse.
One precision your QA team will appreciate: low water activity stops microbes growing, it does not kill them. That is why the release test for Salmonella still applies to a dry product, and why hygiene at washing and hulling matters as much as the drying.
Need the full specification and a COA template for your QA file? Email [email protected] or WhatsApp +84 919 739 589. REQUEST SPEC SHEET / SAMPLE →
What microbiology limits apply for ready-to-eat use?
Freeze-dried strawberries usually go to the consumer without further cooking, in cereal, snacks, toppings, drinks and chocolate, so the release limits are written for ready-to-eat food: TPC ≤10⁴, yeasts and moulds ≤10², E. coli <10 CFU/g and Salmonella not detected in 25 g. The E. coli and plate count on each COA also show that hygiene at washing, hulling and cutting is working, container after container.
For products that are baked through, such as muffins and cookies at 180–200 °C, the TPC and yeasts and moulds limits can sit at the international commercial range (≤5×10⁴ and ≤500 CFU/g), while Salmonella and E. coli stay unchanged. Extended microbiology such as Listeria and Enterobacteriaceae is an optional panel for programmes that ask for it.
Berry food safety: norovirus, hepatitis A and Cyclospora
Berries are a known food-safety category: they are hand-picked, eaten without peeling and often not cooked. Three pathogens come up in every QA questionnaire:
| Hazard | What it is | How it is controlled |
|---|---|---|
| Norovirus, hepatitis A | Viruses carried by people and water; the main risk in frozen berries worldwide | Picker hygiene and clean water at source, chlorinated or ozone wash, and an ISO 15216-1 RT-qPCR virus panel on your lot before loading for ready-to-eat programmes |
| Cyclospora | A parasite linked to fresh produce, carried by contaminated water and soil | Control at source: clean irrigation and wash water, picker hygiene, fruit grown under polytunnels and off the soil; a molecular (qPCR) panel can be booked for programmes that require it |
| Salmonella | Bacterium; the standard release test for dry, ready-to-eat foods | ISO 6579-1, not detected in 25 g, on every container lot |
Freezing and drying are not relied on as a kill step for viruses or parasites, so the controls sit where they work: at the grower, at the wash and in testing before the container is sealed. FruitBuys books the virus panel at an accredited laboratory of your choice, such as Eurofins or SGS in Vietnam, and puts the report in the dossier, so the answer is in your file before your customer asks. How the fruit is grown, washed and frozen within 24 hours of picking is set out in how freeze-dried strawberries are made.
Pesticide residues and heavy metals
Residues are read against the destination’s limits: the EU’s maximum residue levels under Regulation (EC) No 396/2005 and US EPA tolerances. Limits are set for fresh strawberries, so a result on the dried product is divided by a processing factor of about 9–11 (based on the moisture change only) before it is compared. Without that step, a compliant lot can look non-compliant on paper. For EU and UK retail programmes, a multi-residue panel is booked on your lot before the container is stuffed. Strawberries from Vietnam are not on the EU list of foods under increased border controls, so containers move through routine checks.
Heavy metals and aflatoxin reflect the growing area rather than the individual lot, so lead, arsenic and aflatoxin (total and B1) are covered by periodic third-party surveillance, read against EU contaminant limits, with reports on request. Cadmium can be added as an optional panel. Market-by-market rules are in importing freeze-dried strawberries: HS code, US, EU.
How do you read a FruitBuys COA?
Check five things, in this order:
- Lot number and production date match the cartons and the packing list.
- Moisture and water activity are measured numbers, not “pass”, and both sit inside the limit.
- Microbiology is reported with units and limits: CFU/g for counts, “not detected in 25 g” for Salmonella.
- Methods and the laboratory’s ISO/IEC 17025 accreditation are stated.
- The date is after production and before loading.
Read water activity against the limit (≤0.30), not against the decimal on the COA: aw shifts slightly with the instrument and room temperature between laboratories, so a reading of 0.24 in Vietnam and 0.26 at destination is the same lot. Ask any supplier, including us, for measured numbers rather than “complies”; it tells your QA team more about how the lot will behave in your warehouse than anything else on the sheet. Powder COAs follow the same pattern and are covered in freeze-dried strawberry powder specification.
How do you check a lot when it arrives?
With a two-minute dock check, within 48–72 hours of devanning:
- Open two or three sealed bags from different rows of the container.
- Snap a slice within 60 seconds of cutting the bag open. A clean, dry snap and a crisp, open interior are a good quick screen.
- Check colour and breakage against the approved pre-shipment sample.
- Read water activity: the snap test screens, but aw ≤0.30 is the number that decides.
- Photograph the container interior and the sealed bags as found.
That record, together with the retained sample FruitBuys keeps from every container lot for the full shelf life, settles any question quickly, including a marine insurance or carrier claim if a container ever took on water at sea. Claims windows are 14 days from devanning for packaging, appearance, breakage and water activity, and 30 days for laboratory results.
Can freeze-dried strawberries go bad?
Not while the bag stays sealed and dry. At aw ≤0.30 nothing can grow, so freeze-dried strawberries do not spoil in the way fresh fruit does; what they lose over time is quality: crunch if moisture gets in, and colour if light and oxygen get in. Sealed in foil with a desiccant, they keep 12 months at ≤25 °C and RH ≤60%, and 18–24 months in cool storage at ≤18 °C and RH ≤50%. Once a bag is opened, use it within the production batch; bulk bags of 1–5 kg are sized for that. A part-used bag, resealed with its desiccant, stays usable for about two weeks.
Which specification fits your product?
| Your product | What to write into the spec |
|---|---|
| Retail snack in a window pouch | Full COA per lot; aw ≤0.30 as acceptance figure; colour as approved sample; high-barrier pack |
| Cereal, granola, toppings, drinks | Ready-to-eat limits; virus panel for EU and UK retail |
| Bakery inclusion baked through | Salmonella ND and E. coli <10 unchanged; TPC ≤5×10⁴ and Y&M ≤500 CFU/g acceptable |
| Yogurt, dairy, chocolate | Ready-to-eat limits plus a 4-week trial in your base for crunch and colour |
| EU destination | Add the multi-residue and virus panels before loading |
| Private label with a long printed date | Add an accelerated shelf-life study on your final pack |
If your brief says organic: FruitBuys strawberries are conventional, from known Lam Dong grower areas, and the residue question is answered directly with a multi-residue panel on your lot against your destination’s limits.
Get the specification for your QA file
Send your destination market and application. FruitBuys returns the full product specification, a COA template for a container lot, the surveillance programme and the panel options, so your QA team can approve the supplier before the sample lands. Product details are on the freeze-dried strawberries page.
REQUEST SPEC SHEET / SAMPLE →
Email [email protected] · WhatsApp Export +84 919 739 589
FAQ
What moisture should freeze-dried strawberries have?
At or below 5.0% in the contract, with lots typically released at 2.0–3.5%. Below that, you pay for strawberry solids rather than water, and the fruit stays crisp. Accept the lot on water activity, which tells you more about how it will behave.
What is the water activity of freeze-dried strawberries?
At or below 0.30, with typical lots at 0.15–0.25. At that level no bacterium, yeast or mould can grow, and the pieces stay crisp and free-flowing; above about 0.35–0.40 they turn leathery and clump.
Are freeze-dried strawberries safe from Cyclospora?
Cyclospora is controlled at the source: clean irrigation and wash water, picker hygiene and fruit grown off the soil under polytunnels, followed by a chlorinated or ozone wash. Drying is not relied on as a kill step, so programmes that require it can add a qPCR panel on the lot before loading.
Can freeze-dried strawberries go bad?
Sealed and dry, they do not spoil, because nothing can grow at water activity ≤0.30. Over time they can lose crunch if moisture gets in and colour if light gets in. Unopened, they keep 12 months at ≤25 °C or 18–24 months in cool storage.
Do you provide a COA for every lot?
Yes, for every full-container lot: an independent ISO/IEC 17025 accredited laboratory COA for moisture, water activity, TPC, yeasts and moulds, E. coli and Salmonella. Trial and LCL orders ship with the in-house release QC log and the latest surveillance report.
