Aflatoxins in Nuts, Grains and Spices

Aflatoxins are toxic, cancer-causing compounds produced by Aspergillus moulds that grow on nuts, grains, dried fruit and spices stored warm and damp. You cannot cook, see or smell them away. Australian food businesses control aflatoxins by sourcing from reputable suppliers, keeping commodities cool and dry, rotating stock, and rejecting mouldy or off deliveries. The Food Standards Code sets maximum levels for aflatoxins in certain foods. Key takeaways: Aflatoxins are natural mould toxins produced by Aspergillus moulds on nuts, grains, dried fruit and spices, and the most common form is classed as a human carcinogen.. They are heat-stable, invisible and tasteless, so cooking, roasting and baking do not make contaminated food safe, you cannot detect them by eye or smell.. The Australia New Zealand Food Standards Code sets maximum levels for aflatoxins in specified foods such as peanuts and tree nuts, and food over the limit must not be sold.. The two controls that actually work are sourcing from reputable, assured suppliers and storing commodities cool, dry, sealed and rotated on a first-in, first-out basis.. If you find mouldy, damp or musty stock, discard it rather than sorting it, and follow your supplier and recall procedures if sold product may be affected.. What are aflatoxins? Aflatoxins are naturally occurring toxins made by moulds in the Aspergillus family, mainly Aspergillus flavus and Aspergillus parasiticus. These moulds live in soil and can colonise crops in the field or, more often for food businesses, during storage and transport. When conditions suit them, they produce aflatoxins as a by-product of their growth. The commodities most often affected are peanuts and tree nuts such as almonds, pistachios and brazil nuts, maize and other grains, oilseeds, dried figs, and a range of spices including chilli, paprika, pepper and nutmeg. Because these are dry, shelf-stable ingredients, businesses often assume they are low risk, but poor storage can still let mould and toxin develop. Aflatoxins are among the most potent naturally occurring carcinogens known. They are heat-stable, so normal cooking, roasting and baking do not destroy them, and they are invisible and tasteless at the levels that matter. That is why prevention through sourcing and storage, rather than treatment, is the only reliable control. Why aflatoxins are a health risk Aflatoxins are toxic to the liver. Long-term dietary exposure to low levels is linked with liver damage and an increased risk of liver cancer, and international health authorities classify the most common form as a human carcinogen. Very high single doses can cause acute poisoning, though this is rare where food is well regulated and well stored. Because the risk is cumulative and dose-related, the goal is to keep total dietary exposure as low as reasonably achievable rather than to tolerate a set amount. Children, and people with existing liver conditions or hepatitis, may be more vulnerable to harm. For a food business, the practical point is that you cannot rely on your senses or on cooking to make a contaminated batch safe. A nut, grain or spice carrying aflatoxin looks and tastes normal and stays hazardous through every step of preparation. Controlling the hazard means never letting it into your food in the first place. How aflatoxins form in stored commodities Aflatoxin-producing moulds need three things: a food source, warmth and moisture. Warm, humid conditions speed up both mould growth and toxin production, which is why warmer growing regions and poorly ventilated stores carry higher risk. Cool, dry conditions slow the moulds dramatically. Moisture is the master variable. Nuts, grains and spices are safe when properly dried and kept dry, but even small amounts of added moisture, from condensation, a leaking roof, damp packaging or a humid store, can push them over the threshold where mould thrives. Physical damage matters too, because cracked, insect-damaged or broken kernels give mould an easy way in. Time compounds the problem. The longer a commodity sits in marginal conditions, the more opportunity mould has to grow and make toxin. Old stock, forgotten sacks and slow-moving lines are classic trouble spots, which is why stock rotation is a genuine food-safety control here, not just good housekeeping. What the Food Standards Code requires Contaminants in food are regulated under the Australia New Zealand Food Standards Code, which sets maximum levels for certain contaminants and natural toxicants, including aflatoxins, in specified foods such as peanuts and tree nuts. Food that exceeds an applicable maximum level must not be sold. Check the current Code for the exact foods and limits that apply to your products. Your general obligations under the food safety standards, Standard 3.2.2 and Standard 3.2.2A, also apply. You must take all practicable measures to protect food from contamination, receive food only from sources you can rely on, and store it in conditions that keep it safe. For aflatoxins, that translates directly into supplier assurance and storage control. Imported nuts, grains and spices are subject to Australia's border food-inspection arrangements, and aflatoxins are among the hazards monitored for higher-risk foods. Buying from suppliers who can demonstrate testing and compliance is a straightforward way to support your own due-diligence duty. Sourcing controls: start with your supplier The single most effective aflatoxin control is buying from reputable suppliers who manage the hazard upstream. Aflatoxin risk is largely set before a commodity ever reaches you, in how it was grown, harvested, dried, transported and stored, so your supplier's practices matter more than anything you can do once it arrives. Ask suppliers what assurance they can provide, and keep the documentation as part of your food safety records. For higher-risk commodities such as peanuts, tree nuts, maize and spices, meaningful assurance is what tells you the hazard has been managed before purchase. Buy from established, reputable suppliers rather than informal or unknown sources.. Use written specifications that reference the relevant maximum levels for aflatoxins.. Ask for testing certificates or certificates of analysis for higher-risk lines.. Keep an approved-supplier list and review it periodically.. Retain supplier documentation so you can demonstrate due diligence.. Storage controls: keep commodities cool and dry Once product is on site, your job is to hold it in conditions that stop mould developing. Keep nuts, grains and spices in a cool, dry, well-ventilated store, protected from moisture, and follow the supplier's storage and use-by guidance. Refrigerated or frozen storage further slows mould in high-value or high-turnover lines such as nut meals and ground spices. Protect stock from damp at every point. Store off the floor and away from walls, keep packaging sealed, fix leaks and condensation promptly, and never store dry commodities beside wet operations or wash-down areas. Inspect deliveries and stored stock for mould, dampness, musty or off smells, insect activity or caking, and reject or discard anything affected. Rotate stock on a first-in, first-out basis so nothing lingers past its best. Label and date deliveries, use older stock first, and clear out slow-moving or forgotten lines. Good rotation limits the time any commodity spends in storage, which is exactly what aflatoxin control needs. Responding to a suspected problem If you find mouldy, damp or off-smelling nuts, grains or spices, segregate and discard the affected stock rather than trying to sort or clean it. Toxin can be present in product that still looks sound, so picking out the visibly mouldy pieces does not make the rest safe. Record what you found and the action you took. If you suspect a product you have sold or used may be contaminated, or a supplier notifies you of an issue, act quickly. Contact your supplier, stop using the affected batch, and follow your recall and withdrawal procedures. FSANZ coordinates food recalls in Australia and provides guidance for businesses on how to manage them. Checklist: Higher-risk commodities (nuts, maize, grains, dried fruit, spices) are identified and managed.. Suppliers are reputable and can provide specifications or testing for aflatoxins.. Supplier and delivery documentation is kept in your records.. Deliveries are inspected for mould, damp, musty smells, insects and caking on receipt.. Nuts, grains and spices are stored cool, dry, sealed, off the floor and away from walls.. Leaks, condensation and humidity in storage areas are fixed promptly.. Stock is labelled, dated and rotated on a first-in, first-out basis.. Mouldy, damp or off-smelling stock is discarded, not sorted, and the action is recorded.. Recall and withdrawal procedures are in place if sold product may be affected.. Common mistakes: Assuming dry, shelf-stable nuts, grains and spices are automatically low risk.. Trying to roast, cook or bake aflatoxins out of contaminated stock, they are heat-stable.. Picking out visibly mouldy pieces and keeping the rest, when toxin may still be present.. Buying from unknown or informal suppliers with no assurance or documentation.. Storing commodities in humid, poorly ventilated areas or near wet operations.. Letting old or slow-moving stock linger instead of rotating it out..