Consumer Health, the Economic and Ethical Responsibility of Pistachio Producers

Food contaminants are divided into two main groups:

The first group includes microorganisms such as bacteria, viruses, and fungi, which have an immediate effect on consumer health. The second group consists of chemical contaminants, including pesticide residues, mycotoxins, heavy metals, and other chemicals, which have delayed effects, and their consequences on human health become apparent over the long term. Since they do not have immediate effects, perhaps the sensitivity existing regarding microorganisms does not apply to this category, despite their significance possibly being greater than the first group. Another issue with the second category is that, unlike microorganisms, chemical contamination of food cannot be eliminated by heat; for example, microbial contamination of pistachios can be removed through pasteurization or roasting processes, but contamination by aflatoxin, ochratoxin, or pesticide residues cannot be eliminated by these methods and cannot be economically separated from the pistachio kernel by any method that does not damage the pistachio’s nature. The following points are important when determining permissible limits for chemical contaminants:

The permissible limit must be set at the lowest possible level that is economically, operationally, and practically achievable. To determine this limit, first, the toxicity level of the contaminant should be considered, and second, the average consumption of that particular substance in the daily diet of society, especially in specific groups such as infants and pregnant women who are more sensitive. The permissible limits for essential foods are determined much more sensitively than for foods consumed as snacks.

Another issue to be considered is food security; that is, overly strict limits for a chemical contaminant should not lead to a situation where the production of that product becomes impractical, resulting in such a significant reduction in production that the global population faces a shortage of food.

The livelihoods of farmers are another factor to consider when determining permissible limits; that is, changes or determinations of permissible limits should not endanger farmers’ livelihoods. The internationally recognized standard for permissible limits, accepted by all countries, is Codex, which is established by combining the Food and Agriculture Organization (FAO) and the World Health Organization (WHO). If a country sets stricter limits below those defined by Codex, there is a possibility of complaints being filed against that country through the World Trade Organization.

Aflatoxin

Aflatoxin is a toxic substance produced by the fungus Aspergillus. This fungus is ubiquitous, but aflatoxin is not a normal secretion in the life of this fungus; however, it may produce this substance under stress conditions. The factors conducive to aflatoxin production are moisture, temperature, and time. If any of these three factors are not adequately provided for the fungus's activity, aflatoxin will not be produced. It is a fact that during processing, whether wet or dry processing, even water-splitting or storage, by following a series of simple, practical, and low-cost guidelines, one can ensure that aflatoxin does not increase in the pistachio product. However, there is no way to prevent the production of this toxin in the orchard, and some level of aflatoxin will always form in the orchard and enter subsequent stages, as all three factors—moisture, temperature, and time—are present in the orchard. In the orchard, efforts can only be made to reduce the production of aflatoxin. Suggested strategies include the following:

• Strengthening the tree through proper nutrition and irrigation management; the stronger the tree, the less likely conditions will arise for aflatoxin production on the tree.
• Protecting the health of the soft skin on the pistachio; as long as the soft skin remains undamaged, the Aspergillus fungus cannot penetrate the pistachio.
• Implementing a drip irrigation system; this method reduces the orchard's moisture compared to flood irrigation and also prevents water stress on the tree.
• Controlling and combating pests and diseases.
• Timely harvesting; this does not necessarily mean premature harvesting, which could harm the farmer, but delaying harvesting after the pistachio is ripe greatly increases the risk of aflatoxin contamination.
• Complete and rapid processing and drying immediately after harvesting.
• Using a water tank to separate floating pistachios; typically, kernels contaminated with aflatoxin float to the surface.
• Separating kernels suspected of aflatoxin contamination, such as oily and black kernels, or yellow and rust-colored ones, either manually or with the help of sorters. It should be noted that no sorter can definitively and completely detect and separate aflatoxin-contaminated kernels. Sorters are merely tools to reduce manual labor in separating kernels suspected of contamination. A sorter alone is by no means efficient and may require manual follow-up sorting by workers after the sorter process. Therefore, the notion that acquiring a sorter will solve the aflatoxin problem is naive and incorrect. In a batch of pistachios, the number of kernels contaminated with aflatoxin is very small, but unfortunately, since definitive detection of contaminated kernels is impossible, one might have to set aside, for instance, 10% of the batch as potentially contaminated. The question then arises: what happens to this 10% of the potentially contaminated product? Obviously, as long as these suspected contaminated kernels fetch a good price in the market, coercive measures cannot dictate that they not be sold.

Currently, the only definitive method for separating aflatoxin from pistachios is through the process of extracting oil from the pistachio kernels and separating the aflatoxin from the pistachio oil using a clay filter. However, due to the high price of pistachios suspected of contamination and the very limited market for pistachio oil, this is not considered an economically viable solution.

Pesticide Residues

Unlike aflatoxin, the issue of pesticide residues in pistachio shipments cannot be resolved by any economic cleaning method; therefore, the only solution is to prevent it in the orchard. In the European Union, aflatoxin and ochratoxin testing are mandatory; however, since pistachios are not a staple food, pesticide residue testing is not mandatory, and some strict companies voluntarily perform this test to gain a marketing advantage over competitors and demand that suppliers and producers control it. For this reason, pesticide residues in pistachios are not yet as critical an issue as aflatoxin. However, for green pistachio kernels, the most luxurious pistachio product, pesticide residues are extremely important and significantly affect its price.

Based on the experience of pistachio farmers who have been grappling with this challenge for several years, the risk of pesticide residues can be minimized by observing the following points:

• Proper tree care to increase the tree's resistance to pests.
• Frequent spraying and washing of trees with fertilizers and soaps.
• Using protective and pest-repellent substances such as sulfur and kaolin.
• Applying organic pesticides made from plant extracts or minerals.
• Using pesticides that leave minimal residues.
• Using pesticides with higher permissible limits.
• Avoiding pesticide application close to harvest and ensuring timely harvesting.