Few people realize that cashew apples and shells contain toxic compounds, despite cashew nuts being widely recognized for their nutritional benefits. This article explores the hidden dangers associated with cashew processing and the impact of toxic compounds on workers and consumers.
The Hidden Dangers of Cashew Nuts Processing
Workers worldwide shell most cashews manually, with over a million people in India alone handling them daily. A single worker processes around 80 kg (175 lbs) of cashew nuts per day, equating to over 52,000 individual nuts. Due to tight profit margins and intense global competition, many cashew production facilities lack protective equipment such as gloves or machinery, exposing workers to hazardous conditions.
The shells contain highly caustic and toxic substances that cause severe skin burns upon contact. Entire families, including children, often endure painful injuries from handling cashew shells. Additionally, the roasting process releases harmful fumes that can lead to respiratory issues, causing symptoms such as breathing difficulties, lung tightness, and persistent coughing.
Toxic Compounds in Cashew Shells
Cashew nut shells contain several harmful chemicals, including:
- Anacardic Acid – A derivative of urushiol, causing allergic skin reactions similar to poison ivy.
- Cardol – Chemically related to urushiol, contributing to skin irritation.
- Urushiol – A toxic oil found in poison ivy, poison oak, and cashew shells, leading to contact dermatitis characterized by redness, swelling, blisters, and itching.
Cashew Nuts Shell Liquid (CNSL) Poisoning
CNSL, a byproduct of cashew processing, consists mainly of anacardic acid (80.9%), along with cardol (10–15%) and trace amounts of methyl derivatives. While it shares a phenolic structure with other toxic substances, CNSL poisoning presents unique health risks. Exposure can cause nausea, vomiting, dizziness, cardiovascular issues, and, in severe cases, systemic toxicity.
Industrial Uses of Cashew Shells
Industries increasingly utilize cashew shells as a valuable resource, despite their toxicity. From 1 ton of dry cashew nuts, processors obtain approximately 250–300 kg of kernels and 700–750 kg of shells, which yield around 154 kg of oil. Cashew nut shell oil serves various purposes, including:
- High-quality adhesives
- Marine paints and coatings
- Heat-resistant materials
- Electrical and chemical industries
Due to production challenges and investment risks, most businesses prioritize cashew oil over cardanol oil. Additionally, cashew shells are exported for use as fuel, particularly in markets like South Korea, where their properties make them ideal for combustion in cold climates.
How Cashew Shell Toxins Affect Humans
Direct contact with urushiol can cause allergic contact dermatitis, a condition similar to poison ivy exposure. Symptoms include itchy, inflamed skin, burning sensations, and swelling. Ingesting raw cashews before proper processing may trigger severe allergic reactions. However, commercially available cashews labeled as “raw” have already undergone steaming or roasting to eliminate urushiol.
Precautions to Avoid Cashew Poisoning
When purchasing cashews, ensure they have been heat-treated to remove toxic residues. Always check that so-called “raw” cashews have undergone proper steaming or roasting processes. Roasting at high temperatures effectively neutralizes toxic oils, making commercially prepared cashews safe for consumption.
Understanding the hidden dangers of cashew shell toxins highlights the importance of ethical production practices, worker safety, and consumer awareness. While cashew nuts offer numerous health benefits, proper processing is crucial to ensure their safe consumption.
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