Can you eat moldy mushrooms?
In this brief article, we will answer the question, “Can you eat moldy mushrooms?”. We will also elaborate on some common molds that grow on mushrooms, and different ways to minimize their growth along with the safe handling of mushrooms with mold on it.
Can you eat moldy mushrooms?
No, you can not eat moldy mushrooms. Many molds provoke allergic responses and respiratory issues. And some molds, in the appropriate conditions, secrete mycotoxins, which are toxic substances that can make you ill.
Diseases caused by fungi are spread by direct implantation or inhalation of spores. Similar to all infectious agents, a spectrum of medical conditions can result from fungal exposure. This may range from a superficial skin disease such as tinea to invasive internal organ pathology such as pulmonary aspergillosis. The main fungal contaminant of mushroom, Trichoderma ssp, produce mycotoxins, including trichothecenes, which are sesquiterpenoid chemicals characterized by a tetracyclic 12-13-epoxy ring commonly known as the 12,13-epoxytrichothecene. This toxin is rapidly absorbed from the gastrointestinal tract. The mechanism of toxicity again involves inhibition of protein and DNA synthesis. They also produce general cytotoxicity by inhibiting the mitochondrial electron transport system (1).
It should be kept in mind that you only see part of the mold on the surface of food, for instance, gray fur on bologna that is kept outside, or small velvety spheres on fruits. It may seem less to you, but in reality, it could have penetrated the entire food deeply.
When a food exhibits substantial mold growth, the mold threads have undoubtedly penetrated it intensely. In deadly molds, toxic substances are often present in and throughout these threads. In some situations, poisons may have dispersed completely in the food.
So, even if you see slight mold growth on mushrooms, discard them right away.
Common mold found on mushrooms
Trichoderma is the most common mold found on mushrooms. It is a green mold but can also appear yellow with a white leading end and green center. It is fast-growing and survives best at temperatures between 25 to 30℃. So, you are more likely to find it in summers and it can invade your mushrooms before they have had a chance to grow.
Trichoderma initially produces a dense pure white mycelium which resembles mushroom mycelium therefore they are very difficult to distinguish. Mycelial mat on the casing layer gradually turns to a green color because of the heavy sporulation of the causal agent producing a characteristic symptom of the disease. Trichoderma colonized in mushroom compost competes with mushroom mycelium for space and nutrients and results in large areas of the growing beds not producing mushroom fruit bodies. Green mold is characterized by large areas of dense green sporulation on the compost and casing surface resulting in a dramatic reduction in mushroom yield (2).
How to know if the mushrooms have gone bad?
While some mushrooms grow mold when they are rotting, there is one symptom that clearly indicates spoiled mushrooms i.e., a slimy film that develops when the mushrooms have spoiled.
Molds may develop after 3 days and have green, dark green or yellowish green color. They usually produce brownish lesions and spots on the developing fruiting bodies, which later join and completely cover the mushroom fruiting bodies. Contamination in mushrooms that spreads mainly due to contaminated air or by a worker can be easily identified from the outside, as the contamination is green to dark green, black, yellowish green, or red in color due to the spores (3).
Every so often, if it is too soon and the mushrooms are not extremely slimy, they can still be prepared and consumed. But, if the mushrooms have become soft and are extremely slimy, then they have probably surpassed their shelf-life.
It is perpetually a helpful approach to get mushrooms only when you intend to eat them to avoid throwing away the mushrooms. Moreover, remember when buying that whole mushrooms remain fresh for longer.
How long can mushrooms be safe to eat?
Mushrooms are one of the most perishable products and tend to lose quality right after harvest: usually their shelf life is 1–3 days at ambient temperature under usual shipping and marketing conditions, mainly because they have no cuticle to protect them from physical or microbial attack and water loss; 3-8 days in modified atmosphere (2–5% O2 and 3–8% CO2) at 3°C 4 and a maximum of 14 days at 2°C in controlled atmosphere (5% O2 and 10% CO2).5 They are very sensitive to humidity levels, as high water levels favor microbial growth and discoloration; conversely, low water levels lead to loss of weight (and thus economic value) and undesirable textural changes (5).
Based on the variety of mushrooms you have, the period of time they can be safe to eat differs.
Many whole mushrooms and also cooked mushrooms will remain fresh in the fridge for around seven to ten days.
Sliced mushrooms remain fresh for less time, which is usually 5 days to 1 week.
Dried mushrooms last for the longest time. They can remain safe for 2 to 3 years.
Ways to minimize mold growth
Cleanliness is the primary step in regulating mold growth. Mold spores from contaminated mushrooms or other food products can accumulate in the fridge, dishcloths, and other cleaning tools. Follow the steps below to minimize mold growth (4):
- Clean the inside of the fridge after a few months with one tbsp of baking soda mixed in one-quarter of water.
- Clean with water and dry.
- Scrape any visible mold on rubber casings using three tsp of bleach in one-quarter of water.
- Keep dishcloths, napkins, sponges, and dusters clean and fresh. A musty smell indicates they are growing mold around. Discard items you can not clean or wash.
- Maintain the humidity level in the house under 40 per cent.
Safe handling of mushrooms with mold on it
Purchasing small amounts and using mushrooms soon can help prevent mold growth. However, when you see mold on your mushrooms:
- Do not smell the moldy mushrooms. This can lead to respiratory problems.
- If mushrooms are covered with mold, discard them. Put them into a small paper bag or wrap them in plastic and dispose of them in a covered garbage can, far away from your children and animals.
- Clean the fridge or cupboard at the spot where the mushrooms were stored.
- Examine nearby items the moldy mushrooms might have come in contact with. Mold grows quickly in fruits and vegetables. ·
Can molds cause mushroom poisoning?
No, mushroom poisoning occurs because of the toxin secreted by the fungi, which are in the same family as molds.
It basically occurs by consuming raw or cooked mushrooms. The toxins that induce mushroom poisoning are secreted naturally by the fungi. Mushroom poisoning, such as ergotism, poisoning can cause convulsions and hallucinatory effects (1).
Most mushrooms that produce mushroom poisoning can not be turned harmless either by cooking, preserving, freezing, or whatever other treatment. The only approach to prevent poisoning is not to eat toxic mushrooms.
However, molds that contaminate mushrooms can produce toxins and these toxins, called mycotoxins, are toxic, as mentioned earlier.
Other FAQs about Mushrooms that you may be interested in.
Can you eat the gills of a portobello mushroom?
Can you eat elephant ear mushrooms?
How long do mushroom spores last?
In this brief article, we have provided an answer to the question, “Can you eat moldy mushrooms?”. We have also elaborated on some common molds that grow on mushrooms, and different ways to minimize their growth along with the safe handling of mushrooms with mold on it.
(1) Fung, Frederick, and Richard F. Clark. Health effects of mycotoxins: a toxicological overview. J Toxicol Clin Toxicol, 2004, 42, 217-234.
(2) Choi, In-Young, et al. Physiological characteristics of green mold (Trichoderma spp.) isolated from oyster mushroom (Pleurotus spp.). Microbiol, 2003, 31, 139-144.
(3) Choi, In-Young, et al. Isolation and identification of mushroom pathogens from Agrocybe aegerita. Mycobiol, 2010, 38, 310-315.
(4) Hart, J. Moldy Food – what should I do? 2014. Michigan State University.
(5) Singh, Preeti, et al. Recent advances in extending the shelf life of fresh Agaricus mushrooms: a review. J Sci Food Agri, 2010, 90, 1393-1402.