The pistachio industry in Iran is made up of three main sectors: farming, post-harvest processing, and trade; each is explained in more detail below:
Due to the botanical characteristics of the pistachio tree, there are limited geographical locations on the planet with favorable climatic conditions for economically-viable pistachio production. Pistachios have been cultivated in Iran for thousands of years. Commercial cultivation of pistachios in Iran started expanding about one hundred years ago. The upward trend of production has continued ever since.
It is estimated that the amount of pistachios produced in Iran rose from around 2,000 tons in the 1950s to about 25,000 tons in 1975. The average nationwide production in the closing years of the millennium exceeded 150,000 tons.
At present, around 150,000 farmers harvest the crop from about 290,000 hectares of pistachio orchards nationwide; more than 70% of the production is coming from small-scale producers (those who manage orchards of 2 hectares or less). Currently, annual pistachio production capacity in an "on" year is up to 280,000 metric tons. This is from orchards in Kerman, Yazd, Khorasan, Fars, Semnan, Markazi and some other provinces. Despite its declining role due to a province-wide water shortage, Kerman will still have the dominant share of orchards and production for the coming decade. It should be noted that the decline in Kerman™s production is more than compensated by the production increase in other provinces.
All pistachio orchards in Iran are hand-harvested. Average annual yield of bearing Iranian pistachio orchards is 800 kg per hectare. Individual farms may produce from 300 to 3000 kg per hectare. The gradual decrease in the yield of pistachio orchards in Iran is mainly caused by a severe decrease in the quantity and quality of irrigation water coming from deep wells. This malaise results from over-issuance of government permits to bore deep wells in a diminishing aquifer. The problem is exasperated by the breaking up of the orchards to smaller units resulting from inheritance laws.
It is hoped that new plantings in areas with abundant water resources by corporations rather than individuals would, in future, open the way for the establishment of modern, industrial-scale orchards. Iran Pistachio Association is already promoting such initiatives through the Model Pistachio Orchard Project.
Post Harvest Processing
The pistachio processing industry in Iran is gradually moving from traditional, low-capacity, home or farm based, sun-drying units towards specialized, industrial high-capacity plants utilizing hot forced air for drying. Traditionally, processing plants acted as service providers to the growers. Therefore, each grower retained possession of his/her produce after processing. However, with the advent of new industrial processing plants and the rising costs of processing in small scale units, new collective processing agreements are becoming more popular. In such schemes, the processing unit may even make the decisions about the selling of the processed pistachios on behalf of the growers.
Currently, the largest industrial pistachio processing plant in the country has a capacity of 350 tons of fresh pistachios per day. Although the number of high-capacity plants is small, the total number of mechanized processing units is quite large and growing every year.
A typical modern Iranian pistachio processing plant processes freshly harvested pistachios as follows:
Weighing, unloading, and sampling: The trucks loaded with freshly harvested pistachios are weighed prior to and after unloading to get the net weight of the pistachios. The pistachios are unloaded into unloading bays (where samples are taken randomly) and are then moved onto conveyor belts to start the processing phase.
Hulling: Fully mechanized dry-operated rotating hulling machines remove the outer hull of the pistachios. The pistachios continue to the next step, while the removed hulls and other debris are rejected from the main product stream.
Water floatation tank: Blank nuts and nuts with immature kernels are removed from the main product stream when the pistachios are passed through a floatation tank. The underweight and blank pistachios (floaters) float to the top while the larger, heavier pistachios (sinkers) sink to the bottom.
Heated, forced air continuous pre-drying: The pistachios pass through a high-temperature pre-dryer, where the surface moisture added in the previous stage is removed and as a result, the next stage machine for removing nuts with adhering hull can operate more efficiently.
Adhering hull separation and removal: The pistachios drop over a large diameter roller, where pistachios with adhering hull are removed from the product steam through differential friction. These pistachios with adhering hull are returned to the beginning of the line for re-hulling.
Dryer and sun drying: Using batch or continuous forced-hot-air dryers, the pistachios are heated to reduce the moisture content to 7-11%. Then the pistachios are dried in the sun or by forced-ambient-air ventilation to reduce the moisture content to less than 5%.
Mechanical separation of open-shell nuts from closed-shell nuts: Open-shell nuts are separated and move to the next stage (closed-shell nuts are processed separately).
Mechanical sizing: The pistachios are separated into two or three grades depending on size.
Picking conveyor belt and/or picking table: The nuts with visible defects are removed.
Packing: The pistachios are packed in 50 kg sacks ready for transport or storage. Recently, there is a trend towards packing pistachios in big-bags.
Iran is the largest net-exporter of pistachios in the world with an average annual amount of 160,000 tons (dry basis) and an estimated current grand total value of around USD 1.5 billion. This amounts to more than 60% of the world net-export figures. Most pistachio exports are in bulk: raw dried pistachios, roasted pistachios, pistachio kernels, and green peeled pistachio kernels. The main consumer markets for Iranian pistachios are the Far East, the European Union, CIS countries, the Middle East and the Indian subcontinent in that order. However, the market trend for Iranian pistachios is shifting from affluent countries towards an increasing number of developing countries. Pistachios are exported according to the buyers' requirements and standards, provided they meet the minimum Iranian national standards.
There are tens of export houses in Iran. Of this number, some are dedicated pistachio exporters, while others export other dried agricultural commodities in addition to pistachios. These established exporters, as a group, command about 95% of total Iranian pistachio exports. There are also a group of exporters that are generally of much smaller size, but varying in number from year to year, who will export on a sporadic basis, depending on the immediate profitability of the export of pistachios compared to all other exportable goods.
The domestic trade in pistachios is conducted exclusively by local traders who assemble pistachios, bought from small to medium sized producers, into lots of from tens to hundreds of tons. The bigger exporters buy their needs from such traders, whereas, exporters who focus on quality mainly buy from medium to large farmers or processors.
Growers of pistachios, especially the medium to large sized ones, can and often do, sell their products directly to the established pistachio export houses. Such transactions are usually facilitated by either professional pistachio brokers or commission agents. This particular avenue of export provides a unique opportunity for product traceability from the hands of the international consumer, back to the producing orchard in Iran.
The large number of producers, buyers, exporters, and importers of Iranian pistachio makes for conditions of perfect competition in its trade. This creates a fairer trading environment for those engaged in buying and selling Iranian pistachios.
Minimizing Aflatoxin Contamination Risks
Aflatoxins are naturally occurring mycotoxins (the toxic secondary metabolite of molds) that are produced by some strains of Aspergillus flavus and Aspergillus parasiticus. Aflatoxins are toxic and among the most carcinogenic substances known.
Aflatoxin-producing members of Aspergillus are common and widespread in nature. Host crops are particularly susceptible to infection by Aspergillus following prolonged exposure to a high humidity environment or damage from stressful conditions such as drought, a condition which lowers the barrier to entry.
Aspergillus is commonly found in soil and their spores are transported by air. Decaying vegetation, hay, and grains undergoing microbiological deterioration can be an ideal media for the propagation of the fungus. It afflicts many crops on the farms, including corn, rice, cottonseed, peanuts, figs and all tree nuts such as pistachios.
In pistachios, aflatoxin mostly occurs on the farms just prior to harvest. Therefore, they can best be avoided by timely and speedy harvest.
The Iranian pistachio industry is attempting to minimize the risk of aflatoxin contamination through the following measures:
- Observing GAP in the orchards
- Timely and speedy harvest
- Industrial scale fresh pistachio processing utilizing high capacity forced-hot-air dryers
- Use of water floatation tanks to remove high-risk pistachios from the product stream
- Manual sorting of dried pistachios to remove nuts with shell or kernel defects
- Observing GMP in fresh and dry processing plants
- Observing sanitary guidelines during warehousing and transport
- Supporting research projects for understanding the nature and cause of aflatoxin contamination in different sections of the pistachio industry and finding ways for its elimination.