About

The pistachio (, UK also ; Pistacia vera) is a small to medium-sized tree of the cashew family. The tree produces seeds that are widely consumed as food. Pistachios can be used as an ingredient in desserts, chocolate, candy, ice cream, and as a paste or butter. As a tree nut, pistachios are considered a priority allergen that may induce allergic reactions in susceptible people.

In 2024 the world production of pistachios was 1.4 million tonnes, with the United States, Iran, and Turkey combined accounting for 87% of the total.

How to grow it

The pistachio tree may live up to 300 years. The trees are planted in orchards, and take around 7 to 10 years to reach significant production. Production is alternate-bearing (biennial-bearing), meaning the harvest is heavier in alternate years. Peak production is reached around 20 years. Trees are usually pruned to size to make the harvest easier. One male tree produces enough pollen for 8 to 12 drupe-bearing females. In the United States and Greece, the fruit is often harvested with equipment to shake the drupes off the tree. After hulling and drying, pistachios are sorted according to open-mouth and closed-mouth shells, then roasted or processed by special machines to produce pistachio kernels.

Safety

As with other tree seeds, aflatoxin is found in poorly harvested or processed pistachios. Aflatoxins are potent carcinogens produced by molds such as Aspergillus flavus and A. parasiticus. The mold contamination may occur from soil or poor storage and be spread by pests. High levels of mold growth typically appear as gray to black filament-like growth. Eating mold-infected and aflatoxin-contaminated pistachios is unsafe. Aflatoxin contamination is a frequent risk, particularly in warmer and humid environments. Food contaminated with aflatoxins has caused frequent outbreaks of acute illnesses in parts of the world. In some cases, such as in Kenya, this has led to several deaths.

Pistachio shells typically split naturally before harvest, with a hull covering the intact seeds. The hull protects the kernel from invasion by molds and insects, but this hull protection can be damaged in the orchard by poor orchard management practices, by birds, or after harvest, which makes exposure to contamination much easier.

Where it grows

Pistachio is a desert plant and is highly tolerant of saline soil. It has been reported to grow well when irrigated with water having 3,000–4,000 ppm of soluble salts. Pistachio trees are fairly hardy in the right conditions and can survive temperatures ranging between −10 °C (14 °F) in winter and 48 °C (118 °F) in summer. They need a sunny position and well-drained soil. Pistachio trees do poorly in high humidity conditions and are susceptible to root rot in winter if they get too much water and the soil is not sufficiently free-draining. Long, hot summers are required for proper ripening of the fruit.

Uses

The kernels are often eaten whole, either fresh or roasted and salted, and are also used in Turkish delight candy, pistachio ice cream, traditional Persian ice cream, kulfi, spumoni, pistachio butter, pistachio paste, and confections such as baklava, pistachio chocolate, pistachio halva, pistachio lokum or biscotti, and cold cuts, such as mortadella. Americans make pistachio salad, which includes fresh pistachios or pistachio pudding, whipped cream, and canned fruit. Indian cooking uses pounded pistachios with grilled meats, and in pulao rice dishes.

Other Pistacia plants

Mt. Atlas mastic tree · Chinese pistache · Chinese Pistache · Mastic tree · Terebinth · Pistache