If you discover fuzzy, discolored patches on your potatoes, the immediate concern is not just food spoilage but a potential health hazard. Unlike mold on hard cheese or firm fruit, which can sometimes be cut away, the structure of a potato means that visible mold is a sign of deeper contamination. Eating a moldy potato is a serious matter because the fungi produce toxic substances that can cause acute illness, and standard cooking methods will not destroy these poisons. Understanding the specific nature of this contamination is important for protecting your health.
The Specific Toxicity of Mold on Potatoes
The primary danger from mold on potatoes comes from invisible toxic compounds known as mycotoxins. These substances are naturally produced by fungi, such as Fusarium, Penicillium, and Alternaria, that commonly infect potatoes during storage. When mold is visible, the fungal threads (hyphae) have already penetrated deep into the dense potato tissue, carrying mycotoxins throughout the tuber. Therefore, cutting away the moldy area does not guarantee safety, as the entire potato is likely contaminated.
One common mold, Fusarium, often appears as a white, pinkish, or purplish mold and produces mycotoxins like fumonisins. Mycotoxins are chemically stable and highly resistant to heat, meaning they will survive boiling, baking, and frying temperatures. The ingestion of these fungal toxins poses the direct health risk, not the mold itself. This fungal contamination is separate from natural plant toxins called glycoalkaloids, which accumulate when potatoes turn green or sprout due to light exposure.
Glycoalkaloids are natural defense chemicals that accumulate near the skin and sprouts, often giving the potato a bitter taste. Although poor storage can cause both mold growth and glycoalkaloid accumulation, the primary risk from mold is due to mycotoxins. The presence of either mold or significant greening is a clear indication that the potato should be discarded entirely.
Potential Health Effects Following Ingestion
The immediate and most common reaction to ingesting mycotoxins is acute gastrointestinal distress. Symptoms typically include nausea, vomiting, abdominal pain, and diarrhea, as the body attempts to rapidly expel the toxic compounds. The severity depends on the amount and type of mycotoxin consumed, and the individual’s overall health status.
Acute toxicosis can lead to dehydration due to vomiting and diarrhea, which may require medical attention. Beyond these immediate effects, mycotoxins can pose more serious health consequences, particularly with repeated or long-term exposure. Certain mycotoxins are toxic to the liver and kidneys, and some, like fumonisins, are classified as potentially carcinogenic with chronic consumption.
While a single accidental ingestion is unlikely to cause long-term harm, the chemical stability of mycotoxins means they can accumulate in the body over time. Chronic exposure is associated with a greater risk of immune system suppression and a higher incidence of certain cancers. Any symptoms that are severe or persist beyond a few hours should warrant professional medical advice.
Immediate Steps and Proper Storage
If you accidentally eat a moldy potato, monitor yourself for symptoms of poisoning, such as nausea, vomiting, or significant stomach cramps. Staying well-hydrated is important, especially if vomiting or diarrhea occurs, to replace lost fluids and electrolytes. If the reaction is severe, involving persistent vomiting, fever, difficulty breathing, or neurological symptoms, contact a healthcare professional or poison control center immediately.
To prevent recurrence, proper storage is the most effective defense against both mold growth and glycoalkaloid accumulation. Potatoes should be kept in a cool, dark, and dry environment, ideally between 7°C and 10°C (45°F and 50°F). Warm, damp conditions encourage the rapid growth of mycotoxin-producing mold species.
Storing potatoes in a well-ventilated basket or paper bag, rather than a sealed plastic bag, helps manage humidity and prevent moisture buildup that fosters mold. A dark storage area also prevents light exposure, which triggers the production of glycoalkaloids that cause greening. Discarding any potatoes that show signs of mold, greening, or sprouting upon inspection is the safest practice.