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):

	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.

Pistachios in the Shell Grades and Standards

Grades of Pistachio Nuts in the Shell

U.S. Fancy, U.S. Extra No. 1, U.S. No. 1, and U.S. Select consists of pistachio nuts in the shell which meet the following requirements:
1. Basic requirements:
  1. Free from:
    1. Foreign material;
    2. Loose kernels;
    3. Shell pieces;
    4. Particles and dust; and,
    5. Blanks.
2. Shells:
  1. Free from:
    1. Non-split shells; and,
    2. Shells not split on suture.
  2. Free from damage by:
    1. Adhering hull material;
    2. Light stained;
    3. Dark stained; and,
    4. Other External (shell) defects.
3. Kernels:
  1. Well dried, or, very well dried when specified in connection with the grade.
  2. Free from damage by:
    1. Immature kernels;
    2. Kernel spotting; and,
    3. Other Internal (kernel) defects.
  3. Free from serious damage by:
    1. Minor insect or vertebrate injury;
    2. Insect damage;
    3. Mold;
    4. Rancidity;
    5. Decay; and,
    6. Other Internal (kernel) defects.
4. The nuts are of a size not less than 30/64 inch in diameter as measured by a round hole screen.
5. For tolerances, see §51.2544.
U.S. Artificially Opened consists of artificially opened pistachio nuts in the shell which meet the following requirements:
1. Basic Requirements:
  1. Free from:
    1. Foreign material;
    2. Loose kernels;
    3. Shell pieces;
    4. Particles and dust; and,
    5. Blanks.
2. Shells:
  1. Free from:
    1. Non-split shells; and,
    2. Shells not split on suture.
  2. Free from damage by:
    1. Adhering hull material;
    2. Light stained;
    3. Dark stained; and,
    4. Other External (shell) defects.
3. Kernels;
  1. Well dried, or, very well dried when specified in connection with the grade;
  2. Free from damage by:
    1. Immature kernels;
    2. Kernel spotting; and,
    3. Other Internal (kernel) defects.
  3. Free from serious damage by:
    1. Minor insect or vertebrate injury;
    2. Insect damage;
    3. Mold;
    4. Rancidity;
    5. Decay; and,
    6. Other Internal (kernel) defects.
4. The nuts are of a size not less than 30/64 inch in diameter as measured by a round hole screen.
5. For Tolerances, see §51.2544.
U.S. Non-Split consists of non-split pistachio nuts in the shell which meet the following requirements:
1. Basic requirements:
  1. Free from:
    1. Foreign material;
    2. Loose kernels;
    3. Shell pieces;
    4. Particles and dust; and,
    5. Blanks.
2. Shells:
  1. Free from damage by:
    1. Adhering hull material; and,
    2. Dark stain.
3. Kernels:
  1. Well dried, or very well dried when specified in connection with the grade.
  2. Free from damage by:
    1. Immature kernels;
    2. Kernel spotting; and,
    3. Other internal (kernel) defects.
  3. Free from serious damage by:
    1. Minor insect or vertebrate injury;
    2. Insect damage;
    3. Mold;
    4. Rancidity;
    5. Decay; and,
    6. Other Internal (kernel) defects.
4. The nuts are of a size not less than 30/64 inch in diameter as measured by a round hole screen.
5. For Tolerances, see §51.2544.