You could have what is called a 'mold allergy'. Mold is very common in sour breads, such as pumpernickel.
Here is some information on mold allergies:
Mold
Mold is a simple organism that is present is most places, outdoors and indoors. Mold is a type of fungus that works to break down dead material and return nutrients to the environment. Mold grows by digesting plant or animal matter, such as leaves, wood, paper, dirt and food. Mold spreads by releasing tiny, lightweight spores that travel through the air. Mold grows quickly in moist dark spaces, such as basements, garbage cans and piles of rotting leaves.
On food, mold often is visible on the food’s surface, such as the fuzzy green spots that appear on bread. However, molds also have branches and roots. As it grows, the mold’s roots can penetrate deep inside the food, where it cannot be seen.
All of us are exposed to some mold every day with no bad effects. We may breathe in mold spores that are present in the air or eat foods in which mold has begun to grow. People with mold allergies, however, may have a reaction if exposed to too much of the fungus. Symptoms of a mold reaction are those typical of many other allergies. They include wheezing; trouble breathing; stuffy or runny nose; itchy, watery eyes; and a rash or hives on the skin.
If you have a mold allergy, avoiding all exposure to mold may not be possible. However, you can reduce your risk of a reaction by choosing your foods carefully. Check all foods for signs of mold before you eat it. In addition, you can avoid foods that are more likely to contain mold or other fungi (mushrooms and yeast).
Common food sources of mold
- Cheese
- Mushrooms
- Vinegar and foods containing vinegar, such as salad dressing, catsup and pickles
- Sour cream, sour milk and buttermilk
- Beer and wine
- Meat or fish more than 24 hours old
- Sour breads, such as pumpernickel, and other food made with a lot of yeast
- Sauerkraut
- Pickled and smoked meats and fish
- Dried fruits such as dates, prunes, figs and raisins
