Appendix IV

 USING TOLERANCE LEVELS 

 

When making comparison of the information given on label with the results reported by the laboratory, note that the percentages of germination and pure seed given on label need not necessarily be equal to or higher than the results reported by the laboratory on the basis of the Inspector’s sample but can be lower than the results reported up to a certain level called the “tolerance level”. If the percentage of germination or pure seed given on label is equal to or less than what is reported by the laboratory but is still conforming to the minimum limits prescribed, labelling is satisfactory. If the percentage of germination or pure seed on the label is higher than reported by the laboratory, verify whether or not the difference between the details on the label and he results from the laboratory is within the tolerance. If this indifference is within the tolerance, labelling is satisfactory. 

            To verify whether or not the difference between the details on the label and the results from the laboratory is within tolerance or whether it is large enough to consider labelling as faulty, use the prescribed tolerance tables. Six types of tolerance tables as in Table II to Table VII are applicable for different situation as below: 

Table II           To be used when comparing laboratory’s results on pure seed, inert matter, other crop seed and weed seed, with the details on label. To use this table both the laboratory’s results and the details on label should be in percentage by weight.

Table III          To be used when comparing laboratory’s results on foreign seed count viz. other crop seed and weed seed with the details on label. To use this table both the laboratory’s results and the details on label should be in number per unit weight. 

Table IV          To be used when comparing laboratory’s results on germination with the details on label.

Table V           To be used when comparing laboratory’s results on pure seed, inert matter, other crop seed and weed seed with the minimum standards prescribed. To use this table both the laboratory’s results as well as the minimum standards prescribed should be in percentage by weight.

Table VI          To be used when comparing laboratory’s results on foreign seed count viz. other crop seed and weed seed with the minimum standards prescribed. To use this table both the laboratory’s results as well as the minimum standards prescribed should be in number per unit weight.

Table VII         To be used when comparing laboratory’s results on germination with the minimum standards prescribed. 

Use Tables II to IV in comparing laboratory’s results with the details given on label. Use Tables V to VII in comparing laboratory’s results with the minimum standards prescribed. Comparison of the laboratory’s results with the minimum standards for verification of correctness of  labelling may be necessary for seed packed to a net weight of less than 250 grams when detailed information on label is not required. Note that the use of tolerance tables is required only when the laboratory’s results show lower germination or pure seed content or higher inert matter, other crop seed or weed seed content than what is given on the label. 

The following steps are involved in verifying whether or not the difference between the laboratory’s results and the details given on label is within the tolerance level: 

For purity components by weight: 

a.                  calculate the average of the two viz.  Laboratory’s result and the percentage given on label. The average should be in two decimals.

b.                   fit in the average in the suitable class interval in column A or B of Table II; against this interval read the tolerance level in column C or D. 

c.                   if the difference between the two viz. laboratory’s result and information on label is equal to or less than the tolerance level in column C or D, then the difference is permissible and labelling is satisfactory. If the difference is more than the tolerance  level, labelling is wrong and requires further action. 

For foreign seed count by number per unit weight: 

a.                  follow the same procedure as above but use Table III. 

For germination:

a.                  follow the same procedure as above but use Table IV. 

The following steps are involved in verifying whether or not the difference between the laboratory’s results and the minimum standards prescribed is within the tolerance level:

 For purity components by weight:

 

a.                  Fit in the minimum standard prescribed in the suitable class interval in column A or B in Table V and against this class interval read the tolerance level in column C or D. 

b.                   if the difference between the standard prescribed and the laboratory’s results is equal to or lower than the tolerance level labelling is  satisfactory. 

For foreign seed count by number per unit weight: 

a.                  follow the same procedure as above but use Table VI. 

For germination: 

a.                  follow the same procedure as above but use Table VII. 

Each of the above six situations is illustrated below: 

a.                  Comparison of  laboratory’s result with label:

i.          for any purity component in percentage by weight:

            ( e. g.) Pure seed of what i.e. non-chaffy.

 

Laboratory’s result                  :           97.0%

On label                                   :           98.7%

Average                                   :           (97.0 + 98.7) = 195.7
                                                                       2                            2

:           97.85% 

                                    Class interval in

                                                column A of Table II   :           97.75 – 97.99

                                    Tolerance level in

                                                column C of Table II   :           .88

                                    Difference between

laboratory’s result and

label information        :           (98.70 – 97.00) = 1.70

 

Conclusion:     Since the difference between the laboratory’s result and information on label is higher than the tolerance level, labelling is wrong.                       

ii.                 for foreign seed component by number per unit weight:

(e.g.) Weed seed

Laboratory’s  result     :           77/Kg.

On label                       :           73/Kg.

Average                       :           (77 + 73) = 150 = 75
                                                        2                      2 

Class interval in

            Column A of Table III :           75

Tolerance level in

            column B of Table III  :           97

Difference between

            laboratory’s result and

            label information        :           77-73 = 4 

Conclusion:     Since the difference between the laboratory’s result and information on label is less than the tolerance level, labelling is satisfactory. 

iii.               for germination:

Number of tests conducted     :           2

Laboratory’s result                  :           89%

            On label                                   :           91%

             Average                                   :           (89 + 91) = 180 =90%  
                                                                                            3           2
                                                                     

 

Class interval in column A
           
of Table IV                                :           90
Tolerance level in column E
           
of Table IV                                 :           4

 

Difference between
laboratory’s result and
label information                                      :           (91- 89) = 2

           

Conclusion:     Since the difference between the laboratory’s result and the information on label is less than the tolerance, labelling is satisfactory.

 

b.                   Comparison of  laboratory’s result with the minimum standard prescribed :

 

i.          for any purity component in percentage by weight :

            (e.g.) Inert matter in bhindi (e.g.) non-chaffy.

 

Laboratory’s result                              :           1.48%

Standard                                             :           1.00%

Class interval in column B of Table V:          1.00 – 1.24

Tolerance level in column C

            of Table V                                :           .48

Difference between the standard and

            the laboratory’s result                        :           (1.48 – 1.00) = .48

          

            Conclusion:     Since the difference between the standard and laboratory’s result is equal to the tolerance level, labelling is satisfactory.

 

ii.                 for foreign seed count by number per unit weight :

(e.g.) Other crop seed

 

                        Laboratory’s result                              :           27/Kg.

                        Standard                                             :             5/Kg.

                        Class interval in column A

of Table VI                               :             5

                        Tolerance level in column B

of Table VI                               :           10

                        Difference between the Laboratory’s

result and standard                :           (27 – 5) = 22

           

            Conclusion:     Since the difference between laboratory’s result and standard is more than the tolerance level labelling is wrong and needs to be redone or alternatively re-grading needs to be done.

 

iii.               For germination :

 

                                    Number of replicates              :           4 with 100 seeds each

                                    Number of seeds                     :           400

                                    Laboratory’s result                  :           77%

                        Standard                                             :           80%

                        Class interval in column A

                                    of Table VII                              :           80

                        Tolerance level in column C

                                    of Table VII                              :           5

                        Difference between the laboratory’s

                                    result and the standard          :           (80 – 77) = 3

           
Conclusion:         Since the difference between the laboratory’s result and the       

                                                         Standard    is   less  than  the  tolerance level,   labelling   is       
                       satisfactory.

 

Only when the label is showing germination or pure seed more than what is reported by the laboratory or inert matter, other crop seed or weed seed  less than what is reported by the laboratory apply the tolerance levels to verify whether or not the difference between the laboratory’s result and the detail on the label is within acceptable limits. Labelling is satisfactory if the difference is within the tolerance level. It is unsatisfactory and calls for further action as required if the difference is not within the tolerance level.