SWI 132.1.1 Seed Program
Specific Work Instruction
Official Seed Sampling

7.0 Sampling Equipment and Procedures

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7.1 Principles when Sampling with Manual Instruments

The equipment listed in Appendix I must be used for drawing official samples including export samples. This appendix lists the triers and sizes that are approved for the crop kind being sampled. Only triers designated as approved for sampling in Appendix I may be used.

When selecting the appropriate trier for sampling:

  1. the trier must not select or separate seed during sampling, due to seed size, shape density, chaffiness or any other quality trait;
  2. it must not damage the seed being sampled.

Each primary sample is obtained by passing the sampling equipment through the seed once. Each trier or pass of the sampling equipment is one primary sample.

7.2 Triers

When selecting the appropriate trier for sampling, the sampler should consider the species being sampled, the size and type of the containers. When sampling containers, all positions inside the container must be accessible.

Appendix I specifies appropriate trier sizes for each crop kind. The principle on which the trier size is based is that the width of the opening should be not less than two times the diameter of the seed (diameter meaning the longest part of the seed) for sampling. At no time is it permissible to use a trier that is smaller than that specified in Appendix I for the species being sampled unless the sampler provides evidence to the laboratory that the width of the opening is, at a minimum, two times the diameter of the seed.

There are triers with single or multiple chambers and also combination types. These instruments may have more than one opening (slot/hole). The sampler must check the trier and other equipment for cleanliness before use.

The sampler must state the type and size of trier or the method used for sampling on the SSF (Appendix V). When the trier used is smaller than that specified in Appendix I for the species being sampled, the sampler must provide evidence that the width of the opening is, at a minimum, two times the diameter of the seed on the SSF.

7.2.1 The Nobbe Trier

This trier is a pointed tube with an oval opening near the pointed end. This trier is relativity compact and small, making it easy to transport. The risk of contamination is low as the trier is easy to keep clean. If sampling from the end of the bag, the trier must be long enough that the opening (slot/hole) reaches the centre of the bag. If sampling from the side of the bag, the trier must reach the opposite side.

A Nobbe trier is suitable for sampling free-flowing seed in bags (legumes, timothy, rapeseed, mustard) but not in bulk. It may only be used horizontally. Its use is limited to penetrable containers.

7.2.1.1 Procedure for Nobbe Trier Use

The sampler must use the following procedure when sampling with a Nobbe trier:

  1. the trier is inserted gently into the centre of the bag with the trier opening facing downwards;
  2. the trier is inserted into the bag upwards at an angle of approximately 30 degrees to the horizontal:
    1. when sampling from the end of a container, the opening of the trier must reach the centre of the container. The trier is inserted as close to the bottom edge of the container as possible (i.e., below the stitching that seals the end of the bag to achieve the 30-degree angle);
    2. when sampling from the side, the opening of the trier must reach the opposite side of the container. The trier is inserted at the bottom edge of the container such that the 30-degree angle is achieved;
  3. the trier is then rotated through 180 degrees, bringing the hole to face upwards;
  4. the trier is withdrawn:
    1. when sampling from the end, with decreasing speed so that the quantity of seed obtained from successive locations increases progressively from the centre to the side of the container;
    2. when sampling from the side, with a constant speed;
    3. the trier should be gently agitated as it is being withdrawn to help maintain an even flow of seed. The trier must not be agitated without withdrawing it;
  5. each primary sample must be placed into a suitable clean container(s) (pan, pails) to allow for checking for uniformity prior to adding to the previously drawn primary samples.

7.2.2 Double Sleeve Trier

This type of trier is suitable for sampling seed in bags, large containers or in bulk as is the case of sampling containers that are 100 kg or greater such as, mini-bulk containers or in static bulk lots of both small or large seeded crop kinds. This trier may be more suitable for drawing samples from the bottom rows of palletized containers that are stored at floor height than a Nobbe trier. This trier consists of a hollow tube with a close fitting inner tube such that seed cannot slip between them. A handle is fitted to the inner tube so that it can be twisted inside the outer tube. The outer tube has a solid pointed end. Openings (slots/holes) are cut into both the inner and outer tubes. The trier consists of:

  1. multi-openings without partitions; or
  2. multi-openings with partitions.

The opening in the inner tube can be opened and closed by turning the inner tube until the openings in the inner and outer tubes are aligned. There is a greater risk of contamination with this type of trier. Care must be taken to verify that all the openings in both the inner and outer tubes are clean.

A double sleeve trier with partitions may be used:

  1. horizontally;
  2. vertically in both open and closed penetrable containers.

The contents of the entire trier represent one primary sample. A double sleeve trier without partitions may be used horizontally only.

Care must be taken when closing the openings as there is a risk of damaging the seed trapped between the edges of the slots. The risk of damaging the seed can be reduced by slowly closing the openings to the point when resistance is felt.

There is no possibility of varying the amount of seed obtained from the inner and outer part of the container by adjusting the speed with which the trier is withdrawn as the trier draws the same size sample in each sampling action. The trier must always be long enough to reach the opposite end of the container on the diagonal. When sampling the containers vertically, the trier must be partitioned and reach the bottom of the container.

7.2.2.1 Procedure for Multi-Opening Types Without Partitions

This type of trier can only be used horizontally. The following method must be used:

  1. the trier is carefully inserted diagonally on the horizontal plane into the container in the closed position until it reaches the opposite corner of the container. The outer tube opening must be facing upward. Care should be taken not to push the trier through the opposite corner of the container;
  2. the trier is opened until the inner and outer openings are aligned and agitated slightly to allow the openings to fill;
  3. the trier is gently closed (to point of resistance) and withdrawn;
  4. each primary sample must be placed into a suitable clean container(s) (pan/pail) to allow for checking for uniformity.

7.2.2.2 Procedure for Multi-Opening Types With Partitions

This type of trier may be used horizontally or vertically. If the sampling is done on the horizontal plane, the method for unpartitioned triers is to be used. If the trier is to be used vertically:

  1. the trier is carefully inserted into the top of the container in the closed position on an angle until it reaches the bottom of the container;
  2. the trier is opened until the inner and outer openings align and agitated slightly to allow the openings to fill;
  3. the trier is gently closed and withdrawn;
  4. the primary sample is placed onto a clean long piece of paper or into a suitable clean container that is the same length as the trier to allow for checking for uniformity.

7.3 Principles of Seed Stream Sampling

When the seed is processed in a closed system and is packed into sealed, marked containers, the primary samples may be taken from the seed stream.

Sampling from the seed stream can be conducted manually or by seed sampling devices. When devices are controlled automatically, they are called automatic seed samplers. Where there are open flow streams, manual sampling from the stream at the end of processing may be the best technique. The advantage to this technique is that each individual primary sample can be examined for uniformity.

For drawing stream samples, these conditions must be met:

  1. the primary samples are to be taken during the process as the last step before the seed enters the containers which are to be sealed;
  2. the equipment used for sampling must not select or separate seed during sampling, due to seed size, buoyance and chaffiness;
  3. the entire cross section of the seed stream must be sampled;
  4. seed entering the sampling instrument must not bounce out again;
  5. sampling the flow of the seed stream should be at regular intervals, to the extent practical.

7.3.1 Automatic Sampling

There are many types and designs of automatic sampling devices. An automatic sampling device is to be used and maintained within a seed establishment's quality system. When an automatic sampling device is used for sampling for the purpose of:

  1. the issuance of Orange International Seed Lot Certificates or for sampling under the AEP, CFIA must review and approve the validation system. The inspector may refer to Appendix XX for more details;
  2. drawing an officially recognized sample by an establishment, the licensed sampler must validate the system and keep records.

7.3.2 Manual Stream Sampling

An appropriate container must run through the entire cross section of the seed stream so that uniform primary samples are obtained. The container must not permit seed to enter and bounce out again. The sampler should draw primary samples at regular intervals. Sufficient primary samples need to be taken to verify that at least the minimum number of primary samples taken is that specified in Appendix II.

The container used for taking primary samples from the seed stream must be designed as follows:

  1. the opening must be at least two times larger than the largest diameter of the seed;
  2. the sides of the container must be high enough to prevent seeds from bouncing out;
  3. it must be of sufficient length to enable the container to cut a complete cross section of the seed stream;
  4. it must be large enough to prevent any overflow when taking a primary sample;
  5. it must be such that it can be cleaned properly between seed lots.

7.4 Principles of Hand Sampling

This method can be used for all species but is most suitable for chaffy, non free-flowing grasses where the seed would be damaged by use of a trier, specialty seed (e.g., seed mats, seed tapes), retained samples stored in containers making sampling with use of a trier or divider not practical or where there could be separation and selection of the seed or where there could be separation and selection of the seed.

Examples of chaffy, non-free-flowing grasses include Agropyron, Psathyrostachys and Elytrigia (wheatgrasses), Agrostis (bentgrass and redtop), Alopercurus, Bromus (bromegrass), Dactylis (orchardgrass), Elymus (wildrye), Festuca (fescues), Lolium (ryegrasses), Poa (bluegrass), Native Species such as Anthoxanthum, Arrhenatherrum, Axonopus, Chloris, Cynodon, Cynosurus, Deschampsia, Digitaria, Holcus, Melinis, Panicum, Paspalum, Pseudoroegneria, Trisetum and Zoysia.

All positions inside the seed container must be accessible. When it may be impossible to obtain samples from the lower parts of bags or bins, the seed sampler must request that the containers be partially or completely emptied in order to gain access to all positions of the container. The sampler must be able to reach the bottom of the container.

The following procedures must be followed when:

  1. open containers are greater than 40 cm in depth; primary samples are taken directly from the open bag which has been emptied sufficiently to allow sampling from all parts of the bag. After sampling, the seed is repackaged into the appropriate container and sealed. This shall be done under the supervision of the sampler when the purpose of sampling is for the issuance of Orange International Seed Lot Certificates or for sampling under the AEP;
  2. containers are less than 40 cm in depth; seed presented in this size container permits access to all parts of the seed lot containers. Primary samples are drawn. After sampling, the seed is repackaged into the appropriate container and sealed;
  3. samples are taken from the seed stream as the container is emptied and refilled into a new container. The procedures for manual stream sampling in 7.3.2 are to be used.

In the case of seed tapes or mats, the container(s) for sampling has to be opened and a sufficient number of units (tapes or mats) or a sufficient part, in the case of a long tape, has to be taken from the container.

7.4.1 Procedure for Hand Sampling

The following method must be used for hand sampling:

  1. if the sampler is wearing long sleeved apparel, s/he must first verify that the sleeves are sufficiently rolled up so as not to capture seed or otherwise interfere with the sampling process;
  2. the open hand is inserted through the top of the bag with fingers held tightly together, until the desired depth is reached;
  3. the hand is then closed with the fingers held tightly together so that few, if any, seeds escape, and the hand slowly withdrawn;
  4. this process is repeated a number of times in different parts of the seed lot and at different depths, until the required sample size is obtained.

7.5 Other Equipment Requirements

In addition to the approved trier, the following list of equipment may be required:

  1. seals;
  2. supply of suitable tape for patching openings made in the poly, cotton, or paper seed lot containers by the sampling trier;
  3. pails (2-4) for collecting the primary samples or sheets of long clean paper, "nonstatic" stainless steel or metal seamless scoops, pans/pails are recommended;
  4. Sample Submission Form;
  5. note pad;
  6. pocket light;
  7. safety equipment, as necessary;
  8. containers for submission of samples to the laboratory: cotton bags, or manilla envelopes, plastic bags for treated or inoculated seed.
  9. moisture-proof containers for submission of samples for moisture determination (see Section 13.3.2.1).

7.6 Cleaning and Care of Sampling Equipment

All equipment used for sampling must be thoroughly cleaned before each use, and free from all extraneous matter including crop and weed seeds; disease bodies or spores; any seed parts, chaff, dust and inert foreign bodies; chemical residues such as seed treatments. Triers with residue seed could cause cross contamination of other seed lots or samples.

For the Nobbe trier: The more polished the inner surface of the trier is, the more freely the seed will flow.

For the double sleeve trier, the rough edges and point of a sleeve trier should be occasionally dressed (removing sharp edges) with a file, emery or very fine sandpaper. This will greatly improve its use through jute or poly bags. The sleeves of the trier must fit together tightly. All triers must be undamaged with smooth bores and points.

The method for cleaning will be based on the type of equipment and may be based the purpose and test for which the sample is to be drawn, i.e., treated seed or seed for disease tests.

Recommended cleaning methods are:

  1. cleaning wipes;
  2. cleaning solutions, such as hand or dish soap, citric acid, rubbing alcohol or water;
  3. compressed air;
  4. the use of bottle cleaning or gun cleaning tools.
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