Mold and Fungal Contamination in Food Recalls: When to Worry and When Not To

Mold is a type of fungus that grows in visible colonies. Many molds are harmless to humans; some are deliberately used in food production (the molds used to make brie and blue cheese are intentional). The food safety concern with mold is not usually the mold organism itself but mycotoxins — toxic chemical compounds produced by certain mold species under specific growth conditions.

Mycotoxins are problematic because they are not destroyed by cooking. If a grain, nut, or spice has been contaminated by a mycotoxin-producing mold, processing or cooking the food does not render it safe. This is why mycotoxin contamination can affect processed foods made from contaminated raw materials — the toxin persists through manufacturing.

The most commonly encountered mycotoxins in food recalls are aflatoxins (produced by Aspergillus species, typically in nuts, grains, corn, and spices), ochratoxin A (produced by Aspergillus and Penicillium species, found in cereals, coffee, and dried fruits), and patulin (produced by Penicillium and other molds, found in apple products).

Spices and dried herbs — particularly paprika, chili powder, cumin, and black pepper — are among the most common products recalled for aflatoxin or other mycotoxin contamination. The molds that produce aflatoxins thrive in the warm, humid conditions common in spice-growing regions, and inadequate drying or storage allows contamination to develop.

Tree nuts and peanuts — particularly pistachios, almonds, and peanut butter — are also a recurrent category for aflatoxin recalls. The FDA sets strict maximum levels for aflatoxin in peanuts and tree nuts because aflatoxin B1 is a potent liver carcinogen.

Apple juice, apple cider, and apple-based products have been recalled for patulin contamination. Patulin is produced by Penicillium expansum, the mold that causes brown rot in apples, and can concentrate in juice made from damaged or rotting fruit. The FDA has set an action level of 50 parts per billion for patulin in apple juice.

Visible mold in bread, produce, or other perishable foods typically does not trigger formal FDA recalls unless a specific pathogen or toxin is identified. The common guidance — discard moldy bread entirely, cut visible mold off hard cheese with at least an inch margin — addresses the risk of toxin migration in soft versus hard foods.

Soft foods with visible mold should be discarded entirely: bread, soft cheeses, yogurt, soft fruits, and cooked foods. Mold hyphae can penetrate soft foods before visible growth appears on the surface, and mycotoxin contamination can extend beyond the visible growth.

Hard cheeses and hard vegetables with small surface mold spots can generally have the affected portion cut away with a significant margin, as mold penetration is limited by the dense texture. However, if mold is visible throughout a product or if the product smells strongly of mold, discard it entirely.

Check the lot numbers, best-by dates, and UPC codes on your product against the recall notice. Because mycotoxin contamination typically originates in a specific ingredient batch or production run, not every unit of a product is affected.

Do not taste the product to check whether it seems moldy. Mycotoxin contamination is not detectable by taste or smell — contaminated products may appear and smell completely normal. If your lot is recalled, dispose of the product or return it to the store.

Acute toxicity from a single exposure to aflatoxin at levels typically found in recalled foods is unlikely in healthy adults. The primary concern with mycotoxin contamination is chronic exposure over time. This means that eating recalled peanut butter once before the recall was announced is unlikely to cause acute harm, but you should still discard or return remaining product and switch to an unaffected brand.