How Pre-Shipment Samples Are Drawn and Sealed

Why a pre-shipment sample carries contractual weight

In bulk food trade, the pre-shipment sample is the physical reference against which the shipped lot is judged. When a contract for spices, pulses or rice specifies moisture, foreign matter, grain length or microbiological limits, the sealed sample is the agreed evidence that the goods offered met those limits before loading. If a dispute arises on arrival, both parties return to the sealed portions, not to memory or to photographs.

For that reason the way a sample is drawn matters as much as the test results. A sample taken from the top of three bags at the front of a stack tells you very little about a 20 tonne lot. A sample drawn by a documented plan, composited, reduced, split, sealed and signed by both parties is accepted as evidence by third-party laboratories and inspection agencies.

The sample sequence in an export order

Most bulk orders pass through three or four sample stages, and buyers should know which one they are being sent.

Type or approval sample

Drawn from current stock or a recent production run to show the grade being offered. It fixes the visual and sensory standard: colour, size, aroma and level of admixture. It is not drawn from the lot that will ship.

Pre-shipment sample

Drawn from the actual packed lot after processing, cleaning and packing are complete and before container stuffing. This is the sample the buyer approves or rejects, and the one that is sealed and split.

Retained or arbitration sample

A sealed portion of the pre-shipment sample held back by the supplier and, where agreed, by an inspection agency. It is opened only if the shipped goods are contested.

Arrival sample

Drawn by the buyer or a surveyor at the destination warehouse. Comparison with the sealed pre-shipment portion shows whether any deviation arose in transit (condensation, infestation, taint) or was already present before loading.

Defining the lot and the sampling plan

Sampling begins on paper. The lot must be defined: one product, one grade, one packing run, one set of bag or carton markings. Combining two production dates into a single lot for sampling defeats the purpose.

The plan then sets how many packages are opened. Established practice for bagged spices and grains follows the ISO sampling standards for the commodity (ISO 948 for spices and condiments, ISO 24333 for cereals and cereal products), which use a square-root approach: for a lot of n packages, roughly the square root of n is sampled, rounded up, with a minimum of about five packages and, for very small lots, every package. For a 20 ft container of chana dal in 50 kg bags, around 400 bags, that means opening about 20 bags drawn from different positions in the stack, not a single row.

Each opened package yields an increment. Increments are combined into a bulk sample, mixed, and reduced to the laboratory sample by quartering or with a riffle divider. For basmati rice, where grain length and broken percentage are contract terms, the reduction must be done carefully; tipping a bulk sample onto a sloping surface segregates long and short grains and skews the result.

Tools and technique by product type

Whole spices, seeds and pulses

A bag trier or sampling spear is inserted diagonally through the bag so that material is taken from the top, middle and bottom of the package, not just the surface. Small seeds such as ajwain pack densely and the spear must be pushed fully in. Increments go into a clean, dry, food-grade container. For microbiological testing, a separate aseptic increment is taken with a sterilised spear into a sterile bag before any other handling.

Ground spices, flours and powders

Powders segregate less than seeds but are sensitive to moisture pickup. Sampling is done quickly, in a dry area, and the composite is mixed by rolling on a clean sheet rather than stirring, which can lose fines as dust and alter the particle size distribution.

Pastes, sauces and pickles

For jars, pouches or cans, the sample unit is the sealed retail or catering pack. A number of intact packs are drawn from different cartons and different positions on the pallet. For bulk drums of ginger garlic paste the drum is stirred to uniformity and a dip tube is used to draw from the full depth, since oil, water and solids stratify on standing.

Oils and ghee

Liquids are sampled with a dip tube or zone sampler after the tank or drum is mixed. Sample bottles are amber or opaque glass, filled to leave a small headspace, and kept cool until sealed.

Splitting and sealing the sample

Once the laboratory sample is prepared, it is divided into at least three identical portions. The table below shows a typical distribution and the quantities that give a laboratory enough material for a full round of tests plus a repeat.

Portion	Held by	Purpose	Typical quantity (varies by product)
A	Buyer	Approval testing before shipment release	Spices 250-500 g; pulses and rice 500 g-1 kg; pastes 2-3 sealed units; oils 250-500 ml
B	Supplier	Reference and internal record	Same as A
C	Inspection agency or supplier, sealed	Arbitration if the arrival lot is contested	Same as A
D (optional)	Third-party laboratory	Independent certificate of analysis	Per laboratory instructions

Each portion goes into a tamper-evident bag, or a glass jar with a tamper-evident closure for liquids, and is closed with a uniquely numbered seal. The seal number is the link between the physical sample and the paperwork; it appears on the sampling report, on the laboratory request form and, where the buyer requires it, on the commercial documents.

The label on each portion should carry the same set of fields:

• Product name and grade as stated in the contract
• Lot or batch number and packing date
• Contract or proforma invoice number
• Number of packages in the lot and number sampled
• Date, place and method of sampling
• Seal number
• Names and signatures of the persons present

Where a third-party inspection agency attends, the surveyor draws or supervises the sample, applies the agency seal and issues a sampling certificate. Buyers who cannot attend in person often nominate an agency for this reason; the cost is small relative to the value of a container.

Chain of custody and retention

A sealed sample is only evidence if its history is clear. The sampling report should record who drew it, who witnessed it, how it was stored and who couriered it. Portions sent to the buyer travel by tracked courier with the seal number quoted on the airway bill.

Retained portions are kept under conditions that do not change the product: cool, dry and dark for spices and grains; refrigerated where the product itself is chilled. Retention typically runs from arrival of the goods at destination through the agreed claims window, commonly 30 to 90 days after arrival for quality claims, and many suppliers keep portion C for the full declared shelf life of the lot. Retention periods vary by product and by what the contract specifies.

What the buyer should check on receipt of the sample

When portion A arrives, check the seal number against the sampling report before opening, and photograph the intact seal. Then test against the contract specification. Common parameters for products in this category include moisture, total ash and acid-insoluble ash, foreign matter and admixture, volatile oil for whole spices, broken percentage and average grain length for rice, defective and damaged grain for pulses, and microbiological counts, aflatoxin and pesticide residues where the destination market requires them. Acceptance limits vary by grade, season and destination regulation, so they should be written into the contract rather than assumed.

If the sample passes, the buyer confirms in writing, quoting the seal numbers, and the lot is released for stuffing. If it fails, the buyer has a documented basis to reject, renegotiate or request re-processing before any freight is committed. That is the purpose of the exercise: to resolve quality questions while the goods are still on the ground and the cost of correction is lowest.

How ODOD handles pre-shipment samples

ODOD LLC draws pre-shipment samples from every bulk lot according to a written plan agreed with the buyer, splits and seals portions with numbered tamper-evident seals, and issues a sampling report with each set. Third-party inspection and laboratory testing can be arranged with the buyer's nominated agency or laboratory. Certificates for our US FDA registration, ISO, Halal, HACCP and GMP systems are provided with each quotation, and the origin of goods is stated on the quotation and shipping documents.

To discuss sampling terms, specifications or a specific product, request a quotation and our sourcing team will respond with the applicable sampling plan and documentation for your order.