Quality Control

Iranian Pistachio Standards

Institute of Standards and Industrial Research of Iran (ISIRI) defines standards for the following Iranian pistachio products:
In-Shell Pistachio Nuts: ISIRI 15 4th revision
Mechanically Opened Pistachio Nuts: ISIRI 4919 1st revision
Closed Shell Pistachio Nuts: ISIRI 4921 1st revision
Pistachio Kernels: ISIRI 218 4th revision
Split Pistachio Kernels: ISIRI 3639 1st revision
Green Peeled Pistachio Kernels: ISIRI 4631 1st revision
Pistachio Oil: ISIRI 6655 no revision
Pistachio Paste: ISIRI 5691 no revision
Pistachio Powder: ISIRI 9636 no revision
The following table contains an abridged version of specifications for the five pistachio grades set out by ISIRI Standard 15 (4th Revision January 2009) for in-shell pistachio nuts (including raw dried and roasted pistachios):
 

Specifications

Superior Grade

Excellent Grade

Grade 1

Grade 2

Grade 3

Shell Defects (%) (allowable tolerances by weight)

Closed shell and blanks

1

2

3

4

5

Blanks

0.5

0.75

0.75

1

1

Adhering hull

0.5

0.75

1

1.25

1.5

Stained shell

1

1.5

4

5

6

Deformity (incl. opened from bottom)

1

2

3

5

6

Slightly open in-shell

5

10

18

25

N/A

Total shell defects

7

13

22

28

N/A

Kernel Defects (%) (allowable tolerances by weight)

Loose kernels

1

2

2.5

3

3.5

Pest damage

3

4

5

5

6

Obvious pest damage

1

2

3

3

3

Total kernel defects

3

4

5

6

7

Other Defects (%) (allowable tolerances by weight)

Foreign material

0.25

0.3

0.4

0.6

0.8

Foreign material excluding shells

0.2

0.2

0.25

0.25

0.3

Non-uniformity of variety

1

2

3

4

5

Non-uniformity of size

1.5

1.6

1.8

2

2.4



Maximum Allowable Moisture Content: For raw dried pistachios: maximum 5% free water content, and for roasted pistachios: maximum 3% free water content.
Some Definitions:
Foreign material: Glass, metal and live insects are considered completely prohibited foreign materials. Acceptable foreign materials are pistachio related debris such as hull, stems, shells and sand.
Variety: Iranian pistachios are categorized into two categories according to their shape: long pistachios, where the ratio of the length to the largest diameter is more than 1.52; and round pistachios, where the ratio of the length to the largest diameter is less than 1.52.
Non-uniformity of variety: The percentage of round pistachios in a sample of long pistachios or vice versa.
Non-uniformity of Size: Ratio of the total weight of the 10 largest nuts in a sample of 100 nuts to the weight of the smallest 10.