Mould and Mycotoxins in Food

Mould on food is usually a sign to throw it out, not cut around it. Some moulds produce mycotoxins, invisible toxins that can spread beyond the visible fuzz and are not destroyed by normal cooking. In a food business, discard mouldy high-moisture foods entirely, store stock cool and dry to prevent growth, and never serve visibly mouldy product. This guide explains when mould is unsafe, what mycotoxins are, and what to discard. Key takeaways: For most high-moisture foods, visible mould means discard the whole item, not just the fuzzy part.. Some moulds make mycotoxins, invisible toxins that can spread through soft food and survive normal cooking.. Store stock cool, dry and covered, rotate stock, and control humidity to stop mould taking hold.. A few moulds are intended in foods like blue cheese and dry-cured salami; unexpected mould on these still means discard.. When in doubt, throw it out, and never serve visibly mouldy food to customers.. What mould is and why it matters Mould is a type of fungus that grows as threads (called hyphae) spreading through and across food, then produces spores that give the fuzzy, powdery appearance you can see. The visible patch is only part of the organism: fine root-like threads reach into the food well beyond what your eye picks up, especially in soft, moist products. Mould needs moisture, oxygen, warmth and a food source, which is why it thrives on bread, fruit, soft cheese, jams and cooked leftovers. In a food business, mould is both a spoilage problem and a potential safety hazard. Spoilage costs you stock and reputation; the safety concern is that certain moulds produce mycotoxins. Because you cannot tell by looking whether a particular mould is a toxin producer, the safe operating rule in a commercial kitchen is to treat visible mould on food as a reason to discard rather than salvage. What are mycotoxins? Mycotoxins are toxic chemicals produced by some (not all) moulds as they grow. They are a natural chemical contaminant, and Food Standards Australia New Zealand recognises them as a genuine food-safety hazard. Aflatoxins are the best-known group and can occur on crops such as peanuts, tree nuts, maize and dried figs, particularly where these are grown or stored in warm, humid conditions. Other mycotoxins include patulin (associated with rotting apples and apple products), ochratoxin A and fusarium toxins in grains. The important practical points: mycotoxins are invisible and tasteless, they can be present in food that looks only mildly affected, and they are heat-stable, so normal cooking, baking or boiling does not reliably destroy them. Health effects depend on the toxin and the level and length of exposure. This is general information rather than medical advice; for health concerns speak to a doctor or healthdirect. Aflatoxins: nuts, peanuts, maize, dried fruit, especially after warm humid storage.. Patulin: bruised, rotting apples and unpasteurised apple juice or cider.. Ochratoxin A and fusarium toxins: cereals and grains stored damp.. Key trait: invisible, tasteless and not reliably removed by cooking.. When mouldy food is unsafe (and the discard rule) The old advice to cut a couple of centimetres around a mouldy spot is not safe for most foods, because mould threads and any mycotoxins can extend beyond the visible growth, particularly in high-moisture and porous products. In a commercial setting the simplest defensible position is: if a high-moisture or soft food shows mould, discard the whole item. Bread and baked goods are porous, so mould spreads through the loaf even when only one slice looks affected, discard the lot. Soft cheeses, yoghurt, sour cream, cooked meat, cooked pasta and rice, casseroles, jams, sauces, soft fruit and vegetables, and any leftovers should be thrown out entirely once mould appears. There is a narrow exception for hard, low-moisture foods where mould cannot penetrate far, such as a block of hard cheese or a firm carrot, where trimming well clear of the mould can be acceptable at home. For a business, the risk-managed approach is still to discard, both for safety and because serving or displaying mouldy food is unacceptable under food-safety expectations. Moulds that are meant to be there Not all mould in food is a fault. Some foods are made with specific, safe cultures that are part of the product. Blue cheeses such as blue vein use Penicillium roqueforti; soft-ripened cheeses like brie and camembert have an intentional white bloomy rind; and traditional dry-cured salami often carries a deliberate white mould coating on the casing. These are controlled cultures chosen because they are safe to eat as part of that product. The catch for a food business is telling intended mould from spoilage. On a blue cheese, the blue-green veining is normal, but fuzzy grey, pink or black growth on the cut surface or an off, ammonia-like smell signals spoilage, discard it. On salami, an even, powdery white coat is expected, but green, black or fuzzy patches are not. If you cannot confidently distinguish the intended culture from contamination, treat it as spoilage and throw it out. How to store food to prevent mould Prevention is far more reliable than trying to judge whether mouldy food can be salvaged. Mould needs moisture, warmth, air and time, so good storage attacks all four. Keep cold food at or below 5C and hot holding at or above 60C, and keep dry-store areas genuinely cool, dry and well ventilated. Rotate stock on a first-in, first-out basis and use clear date-labelling so nothing sits long enough to spoil. Keep dry goods such as flour, nuts, grains and dried fruit in sealed, moisture-proof containers, because damp storage is exactly what favours mycotoxin-producing moulds. Buy nuts and dried products from reputable suppliers who manage storage properly. Cool cooked food quickly and refrigerate promptly rather than leaving it out, keep the fridge clean and not overloaded so air circulates, and fix any humidity, condensation or leak problems in storerooms. Cold at or below 5C, hot holding at or above 60C, dry stores cool and ventilated.. First-in-first-out rotation with clear date labels so stock does not linger.. Airtight, moisture-proof containers for flour, nuts, grains and dried fruit.. Cool and refrigerate cooked food promptly; do not overload the fridge.. Keep storage surfaces clean and dry; deal with condensation, leaks and humidity.. What to do if you find mould in your kitchen When you find mould, act deliberately rather than quietly binning one item. Remove the affected food carefully so you do not scatter spores across the kitchen, wrap or bag it, and discard it. Check nearby stock, because spores travel and neighbouring items in the same container, shelf or fridge drawer may also be affected. Clean and sanitise the shelf, container or surface where the mould was growing. Then look for the cause: was the item past its use-by, was the store too warm or humid, was a container left open, or is there a leak or condensation problem? Recording the finding and the corrective action supports your food-safety program and helps you spot recurring problems. If mouldy product may have already been served or sold, treat it seriously and follow your business procedures, and contact your state or territory food regulator if you are unsure of your obligations. Checklist: Discard the whole item when high-moisture or soft food shows any mould.. Never display, serve or sell visibly mouldy food.. Store dry goods (flour, nuts, grains, dried fruit) sealed and moisture-proof.. Keep cold at or below 5C, hot holding at or above 60C, dry stores cool and dry.. Rotate stock first-in-first-out with clear date labels.. Clean and sanitise any shelf or container where mould was found.. Record the finding and corrective action; look for and fix the cause.. Common mistakes: Cutting mould off bread or soft food and using the rest; threads and toxins spread beyond the visible patch.. Assuming cooking makes mouldy food safe; mycotoxins are heat-stable and survive normal cooking.. Storing nuts, grains or dried fruit in damp or open containers, which favours mycotoxin-producing moulds.. Confusing spoilage mould with the intended culture on cheese or salami and serving it anyway.. Binning one mouldy item without checking neighbouring stock or cleaning the surface..