The penicillin molecule is a product of the penicillin mold

Many people believe they are allergic to penicillin — it’s the most common perceived drug allergy — but several studies have shown that most folks who think they are allergic are not. Perhaps they once were, but when people who thought they were allergic were tested, virtually none showed allergic reaction. In a test of 146, presumably allergic patients at McMaster University, only two had their penicillin allergy confirmed; 98.6% of the patients tested negative. A similar study at the Mayo Clinic tested 384 pre-surgical patients with a history of penicillin allergy; 94% tested negative. They were given clearance to receive penicillin antibiotics before, during, and after surgery. Read a summary here.

Orange showing three different strains of the penicillin mold; some of these are toxic.

This is very good news. Penicillin is a low-cost, low side-effect antibiotic, effective against many diseases including salmonella, botulism, gonorrhea, and scarlet fever. The penicillin molecule is a common product of nature, produced by a variety of molds, e.g. on the orange at right, and in cheese. It is thus something people have been exposed to, whether they realize it or not.

Penicillin allergy is a deadly danger for the few who really are allergic, and it’s worthwhile to find out if that means you. The good news: that penicillin is found in common cheeses suggests, to me, a simple test for penicillin allergy. Anyone who suspects penicillin allergy and does not have a general dairy allergy can try eating appropriate cheese: brie, blue, camembert, or Stilton. That is any of the cheeses made with penicillin molds. If you don’t break out in a rash or suffer stomach cramps, you’re very likely not allergic to penicillin.

There is some difference between cheeses, so if you have problems with Roquefort, but not brie or camembert, there’s still a good chance you’re not allergic to penicillin. Brie and camembert have a white fuzzy mold coat of Penicillium camemberti. This mold exudes penicillin — not in enough quantity to cure gonorrhea, but enough to give taste and avoid spoilage, and enough to test for allergy. Danish blue and Roquefort, shown below, have a different look and a sharper flavor . They’re made with blue-green, Penicillium roqueforti. This mold produces penicillin, but also a small amount of neurotoxin, roquefortine C. It’s not enough to harm most people, but it could cause an allergic reaction to folks who are not allergic to penicillin. Don’t eat a moldy orange, by the way; some forms of the mold produce a lot of neurotoxin.

For people who are not allergic, a thought I had is that one could, perhaps treat heartburn or ulcers with cheese; perhaps even cancer? H-Pylori, the bacteria associated with heartburn, is effectively treated by amoxicillin, a penicillin variant. If a penicillin variant kills the bacteria, it seems plausible that penicillin cheese might too. And since amoxicillin, is found to reduce the risk of gastric cancer, it’s reasonable to expect that penicillin or penicillin cheese might be cancer-protective. To my knowledge, this has never been studied, but it seems worth considering. The other, standard treatment for heartburn, pantoprazole / Protonix, is known to cause osteoporosis, and increase the risk of cancer, and it doesn’t taste as good as cheese.

The blue in blue cheese is Penicillium roqueforti. Most people are not allergic.

Penicillin was discovered by Alexander Fleming, who noticed that a single spore of the mold killed the bacteria near it on a Petrie dish. He tried to produce significant quantities of the drug from the mold with limited success, but was able to halt disease in patients, and was able to interest others who had more skill in large-scale fungus growing. Kids looking for a good science fair project, might consider penicillin growing, penicillin allergy, treatment of stomach ailments using cheese, or anything else related to the drug. Three Swedish journals declared that penicillin was the most important discovery of the last 1000 years. It would be cool if the dilute form, the one available in your supermarket, could be shown to treat heartburn and/or cancer. Another drug you could study is Lysozyme, a chemical found in tears, in saliva, and in human milk (but not in cow milk). Alexander Fleming found that tears killed bacteria, as did penicillin. Lysozyme, the active ingredient, is currently used to treat animals, but not humans.

Robert Buxbaum, November 9, 2017. Since starting work on this essay I’ve been eating blue cheese. It tastes good and seems to cure heartburn. As a personal note: my first science fair project (4th grade) involved growing molds on moistened bread. For an incubator, I used the underside of our home radiator. The location kept my mom from finding the experiment and throwing it out.