SWI 132.1.1 Seed Program
Specific Work Instruction
Official Seed Sampling
Appendix II: Sampling Intensity
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The sampling intensities listed below are from the ISTA Rules Chapter 2. A representative sample of the seed lot must be obtained as described below.
For seed lots in bags or other containers of 15 kg to 100 kg capacities (inclusively), the following sampling intensities are minimum requirements:
|Lot Size||Number of Primary Samples to Be Taken|
|1 - 4 containers||Three (3) primary samples from each container|
|5 - 8 containers||Two (2) primary samples from each container|
|9 - 15 containers||One (1) primary sample from each container|
|16 - 30 containers||Fifteen (15) primary samples from the seed lot|
|31 - 59 containers||Twenty (20) primary samples from the seed lot|
|60 or more containers||Thirty (30) primary samples from the seed lot|
For seed lots in containers smaller than 15 kg capacity, containers must be combined into sampling units not exceeding 100 kg and the number of sampling units is used to determine the minimum sampling intensity.
When sampling seed in containers of more than 100 kg, or from streams of seed entering containers, the following sampling intensities are the minimum requirements:
|Lot Size||Number of Primary Samples to be Taken|
|up to 500 kg||At least five (5) primary samples|
|501-3,000 kg||One (1) primary sample for each 300 kg, but not less than five|
|3,001-20,000 kg||One (1) primary sample for each 500 kg, but not less than 10|
|20,001 kg and above||One (1) primary sample for each 700 kg but not less than 40|
In all cases, when sampling a seed lot of up to 15 containers, all containers must be sampled, and the same number of primary samples must be taken from each container.
The seed lot is six containers of 1200 kg each.
It is required that one primary sample per 500 kg be taken
7200 kg / 500 kg = 14.4 primary samples which must be rounded up to 15
15 primary samples from 6 containers = 2. 5 primary samples from each container which must be rounded up to 3. Therefore, 3 primary samples must be taken from each container.
Sampling Small Packages
When sampling seed in small packages (for export purposes), the sampling intensities stated in the ISTA rules are applicable. The sampling intensity table for packages up to 100 kg is applicable.
Seed lot size is 2000 kg packaged in 4 kg boxes (500 boxes at 4 kg = 2000 kg)
Combine the containers into units that are 100 kg.
2000 kg / 100 kg = 20 units (Each unit is considered to be a container for sampling purposes)
For sampling purposes, this seed lot is considered to be 20 containers (units) which would require 15 primary samples in total to be drawn.
The seed lot must be divided into 20 units. Each unit will contain 25 boxes (100/4 kg = 25 containers). Fifteen (15) primary samples in total are to be drawn from the 20 units.
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