If they have gone bad, oyster mushrooms can make you feel sick. You can identify an oyster mushroom that has gone bad by looking for changes in its color, texture, and smell, and most of these changes can be avoided by consuming your oyster mushrooms soon after they were purchased.
A less likely, but still possible option is that oyster mushrooms are making you sick due to an oyster mushroom allergy, or a mushroom allergy more broadly.
It is possible that oyster mushrooms could make you sick even if you do not have the same reaction to other mushrooms, and vice versa, and this allergy can develop at any point in your life.
However, the most likely reason oyster mushrooms are making you sick is that they are not fresh enough.
How To Tell If Oyster Mushrooms Will Make You Ill
1. If They Are Discolored
Pay attention to the color your oyster mushrooms are when you first purchase them. Oyster mushrooms can vary lots in color, with some varieties being more pinkish, but most are a white and grey or a pale brown mushroom.
One way of telling if an oyster mushroom has gone bad, and therefore would make you sick if you ate it, is if the color has changed. Oyster mushrooms can become darker in color or have darkened, discolored spots on them as they age.
If this is the case for your oyster mushrooms, I would recommend playing it safe and throwing them away, as they are past their best and could make you sick.
Depending on how fresh your oyster mushrooms were when you purchased them, this could take up to a fortnight to occur. To avoid any risk of oyster mushrooms making you sick, however, eat them as soon as possible after buying.
2. If They Are Damp or Slimy
Another way of identifying if an oyster mushroom will make you sick is by examining the texture of the mushroom.
Much like with the color, if the texture has changed significantly since they were purchased, it might be that the mushrooms have gone bad, and therefore could make you sick.
Oyster mushrooms should be quite dry, with a rubbery, smooth feel to them. If your oyster mushrooms are beginning to feel slimy or damp, they are probably past their best.
3. If They Feel Hard or Brittle
On the other end of the scale, if your oyster mushrooms have become hard and brittle, they also have the potential to make you sick.
When feeling the skin of oyster mushrooms, they should be firm, but with some give, as the meat of the mushroom should be soft and spongy.
If your oyster mushrooms have dried out, it is likely that they are not remarkably fresh, and they could make you feel unwell.
4. If They Smell Bad
You perhaps don’t need me to tell you that if your food is smelling off, it should not be consumed, as it could make you ill.
However, oyster mushrooms have a particular smell they will emit when they are past their best, and identifying this could save you from an unpleasant sickness.
If oyster mushrooms could make you sick, they might give off a smell similar to ammonia. A fresh oyster mushroom should smell earthy but should not have this strong aroma at all.
Therefore, if your oysters smell too strong, they could make you sick.
How To Avoid Oyster Mushrooms Making You Sick
The best way to stop any of these changes in your oyster mushrooms, and therefore stop them from making you ill, is to ensure that you are storing your oyster mushrooms properly.
Too much moisture will make your oyster mushrooms spoil, which you will see as they become damper, more slimy and darker in color. To keep your oyster mushrooms safe to eat for longer, store them in a paper bag, and place in the fridge.
If you want to keep your mushrooms for more than a week, you can dehydrate them, and they will stay fresh for up to 3 months. To do this, put them in a dehydrator or your oven at a really low temperature.
You cannot freeze mushrooms usually, but once they have been dried like this, they can be frozen and rehydrated when you’re ready to use them.
Keeping oyster mushrooms in this way should not make you sick, but when you rehydrate the mushrooms, do check for any of the warning signs mentioned above.
Can You Be Allergic To Oyster Mushrooms?
Though they are not a particularly common allergen, it is worth considering whether the reason oyster mushrooms are making you sick is because you have a mushroom allergy.
If you are have felt sick repeatedly after consuming oyster mushrooms, or any other kind of mushroom, it might be that the mushrooms have not gone bad, but that your body does not react well to them regardless.
Mushroom allergies can develop at any age, so even if you are used to eating mushrooms all of the time, mushrooms can begin to make you feel sick.
Some of the first signs of a mushroom allergy include watery eyes, skin irritation and rashes. If oyster mushrooms are making you sick, watch out for any of these other symptoms to tell if you are having an allergic reaction.
You might not be expecting to be allergic to oyster mushrooms since you eat other types of mushrooms all the time. However, It is possible to be allergic to some varieties and not others.
Unfortunately, it is difficult to tell whether you will feel unwell after a particular type of mushroom as a result of an allergy. If you are concerned about this, it might be worth taking a mushroom allergy test.
Currently, the only way to manage any mushroom allergy is to avoid the consumption of mushrooms.
You can take some comfort in the fact that mushroom allergies are pretty rare, so it’s more likely that the oyster mushroom that is making you feel sick is a one-off.