SWI 132.1.1 Seed Program
Specific Work Instruction
Official Seed Sampling

8.0 Sealing of Seed Lots of Seed Lots

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8.1 Conditions for Sealing the Seed Lot

All containers must be self-sealing or sealed (capable of being sealed). Any seed lot presented for the issuance of an Orange International Seed Lot Certificate, whether the seed is pedigreed or non-pedigreed, must be sealed in tamper-proof containers or be packaged in self-sealing or sealed (capable of being sealed) containers. In the case of seed lots tagged with OECD tags, the seed lot will be deemed to be sealed if the stitching that seals the bag opening also secures the tag to the bag. Seed lots must be sealed in such a manner that if the container is opened, the seal is broken and cannot be reused. This includes seed in bins, bags and mini-bulk bags. The sealing of the seed lot must be conducted by or under the direction of an official seed sampler. The following must be noted:

  1. when the seed lot to be sampled is packaged in bags, the seed lot must be sealed before sampling (an exception would be any samples that must be taken by hand sampling);
  2. when the samples are taken from bins, bulk bags or unsealed packages, they must be sealed under the supervision of the official seed sampler immediately after the sample is drawn;
  3. when the seed is being sampled by an automatic sampler, the container into which the conditioned seed is fed must be sealed.

When sampling for other official purposes (e.g., marketplace surveillance), a pedigreed seed lot must be sealed when packaged in containers capable of being sealed, such as bags. The seed lot will be deemed to be sealed if the stitching that seals the bag opening also secures the tag to the bag.

8.2 Types and Methods of Sealing the Seed Lot

  1. Snap on Seals.
    Snap on seals are made of metal and can be closed by squeezing between the finger and thumb. They should close with a snap sound. These seals are designed to break along the spine as evidence of tampering. As an identifier, there is to be a logo, sign or sequential number printed on each seal. The seal must be applied to the string, tie or stitching so it cannot be removed without destroying the integrity of the seal. The official seed sampler may delegate the attachment of the seals to other individuals under his or her supervision. Care must be taken so that individuals do not gain unauthorized access to the seals.
  2. Adhesive Patches
    (Appendix XVIII) and Tapes and Adhesive Labels. These are used for seed lot identification and can also be used to close the containers or holes made in the containers while sampling. The seal must have strong adhesive qualities as well as special cuts in the label such that it cannot be removed without destroying the integrity of the label, and therefore, the seal. These labels can close, seal and mark the container in one step. The labels should have sequential numbers to identify the containers. These types of labels may not be effective in dusty conditions, on some types of containers (cardboard boxes, woven plastic) and are only effective in specific temperature ranges.
  3. Self-sealing Containers.
    This system is acceptable for seed that is the size of Triticum spp.(wheat) or larger. A self-sealing container (valve-pack) has a sleeve-shaped valve as part of the bag. Once the bag is filled, the pressure of the seed closes the valve inside the bag. To comply with the ISTA Rules, the sleeve must be at least 20% of the width of the bag. If valve-pack containers are used for seed smaller than Triticum, or if the sleeve is less than 20% of the width of the bag, the bag is not sealed. A direct sealing method must be used to seal the bags such as, sealing tape, a label, a patch, by gluing the mouth of the bag or sealing with a metal clip.
  4. Sealing by Stitched Label.
    The method of sealing by sewing a single line of stitching through the label (e.g., tear resistant labels, an OECD tag, or adhesive label) and closing the bag or adhesive labels, which must be glued directly onto the container, can only be used when the official seed sampler has control of the tags. A tag inventory must be kept. Care must be taken to verify that the stitching does not perforate any of the information on the label. If there is evidence that there is a second line of stitching that was not within the official seed sampler's control, the stitching must be sealed with a metal seal if the seed lot is for the issuance of an Orange International Seed Lot Certificate.

    The container must be also sealed by use of metal seals or non-removable adhesive labels, where there are only company tags stitched onto the containers, provided all the containers in the seed lot are uniquely identified by a lot designation/number, if the seed lot is for the issuance of an Orange International Seed Lot Certificate.

  5. Hermetically Sealed.
    Containers which cannot be opened without causing damage to the package may be regarded as sealed without undertaking any additional sealing. These may be paper bags or boxes that are closed with glue on all sides, sealed tins, sealed bottles (not screw top types) or heat sealed foil packages. These containers must have a printing design on the package which would indicate if part of the original container is missing. These types of containers are difficult to sample as they are destroyed in sampling. The repackaging of these containers must be conducted in the presence of the sampler.
  6. Tie / Strip Seals.
    The tie/strip seals are usually made of plastic. They are closed by drawing the end through a self-locking device which prevents it from being opened without destroying the label. When a tie/strip is identified with a logo or sign approved by the ISTA accredited laboratory, it could become a seal.
  7. Stapling of Labels on Stitched Bags.
    This method of sealing may be used when the company has stitched the containers closed and then staples the labels onto the bags, provided that all the containers in the seed lot are uniquely identified. This method of sealing is not acceptable for sampling for the issuance of an Orange International Seed Lot Certificate as well as not acceptable for the EU.
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