White Bread Mold Explained (Different Types and How To Identify Them)

So you’ve left your bread for who knows how long, and now it seems like you are one step closer to becoming a microbiologist. Congrats, you just (accidentally) cultured your first batch of microorganisms. 

White bread mold can get quite problematic sometimes, and it can cause the bread to taste and smell funky. So what are white bread molds, are there any safe-to-eat ones, and is bread edible at first sight of mold?

Molds are fungi, and they feed on things that break down over time. Most molds are unsafe to eat, and experts do not recommend eating them for any particular justification. There are five common molds on bread and they are the Penicillium, Fusarium, Rhizopus, Mucor, and the Aspergillus. 

So what is mold, what are the types that grow on white bread, and can you eat certain types of it? This article will help you answer all that. 

Identifying Flour Vs. Mold

Mold grows almost anywhere, and one cannot limit its growth to cooked food. White bread mold can grow on the flour itself. When this situation happens, it can quite become problematic, as moldy flour can get cooked, and at that point, it will be hard to spot which bread is mold-infested and which is not.

The scenario above is why the first thing you should consider when trying to bake for many people is to check the integrity of your flour. So, how do you differentiate flour versus white bread mold?

Critical Tips For Knowing Which Is Flour And Which Is Mold

• Use your senses. Visual artifacts are effortless to spot and generally the most evident difference when flour turns moldy. Flour is typically white, and if you spot some dark fuzzy spots, especially green patches, it might be time to let your flour (the entire batch, not only a portion) retire. 
• Smelling flour can also be an excellent tip for identifying mold from bread. Mold-infested flour can have an earthy, dirt-like smell, and when flour starts to smell odd, double-check for molds.
• There is an apparent reason why eating molds isn’t popular, even though its effects upon ingestion vary from body to body. When molds start to take hold of food and start using them as a source of energy, these products tend to taste horrible. Take note of the taste to identify which is flour and which is white bread mold. (source)

Types Of Mold That Grow On Bread

Although we exclusively represent mold as a particular species, it is helpful to know that molds are a classification of fungi and have different characteristics. Below, we identify the types of mold that grow on white bread.

What Are The Molds That Grow On White Bread?

• Penicillium
• Fusarium
• Rhizopus
• Mucor
• Aspergillus

Penicillium

Penicillium is a naturally-occurring type of mold, meaning that this type of mold does not necessarily need cultivation to appear. In bread, the appearance of such molds is a natural part of food spoilage. Because mold signifies spoilage, this implies that it’s game over for your bread if white bread mold appears. 

Penicillium is not exclusively a part of food spoilage either. Specific genera are responsible for single-handedly revolutionizing pharmacology into what we know it today. For example, the drug penicillin is from this white bread mold (Kirk et al., 2008, “Dictionary of the Fungi”).

It revolutionized the industry because this mold inhibits the growth of certain bacteria and can even kill them. Sometimes, this mold is integral for cheesemaking. However, do not take this as a sign to eat Penicillium-infused white bread.

Fusarium

Commonly associated with soil and plants, since it primarily resides in those areas, Fusarium is perfectly harmless in some of its variations. However, it can affect human health when ingested, especially since it releases toxins on certain subspecific groups.

Rhizopus

Most Rhizopus can be in many organic substances, such as jellies, bread, leather, peanuts, and tobacco, including “mature fruits and vegetables.” A majority of its subspecific species are opportunistic human pathogens, and they can cause Mucormycosis or black fungus. (Zheng et al., 2007, “A monograph of Rhizopus”)

Black fungus is a severe fungal infection in immunocompromised people (those with weak immune systems, generally due to the presence of other pathogens, illnesses, and diseases) and can be fatal. Some symptoms that indicate black fungus are headache, fever, blurred vision, bulging or displacement of the eye (proptosis), tissue death, pain, and one-sided facial swelling. (Chandler, J., 2018, “26. Mucormycosis”)

Mucor

Like Fusarium, Mucor is also commonly found in soil. They are a fast-growing variety of mold and can grow as tall as a few centimeters. They are also present in rotten vegetables and certain cheeses like the Tomme de Savoie.

Aspergillus

Aspergillus is a white bread mold that is both a thorn and a blessing to the medical industry. Certain species of Aspergillus are known to cause infections in both humans and animals.

On the other hand, certain species are responsible for the fermentation of the Japanese alcoholic drink called sake. Meanwhile, one lauds the Aspergillus for their antibacterial and, ironically, antifungal properties. (source)

Identifying Mold Types On Bread

Although the kind of mold certainly does not matter in determining whether bread is edible or not, it may be helpful to identify the types of molds for the sake of knowledge. Below, we differentiate the five major white bread molds from each other. 

Differentiating The Five Kinds Of Bread Molds

• Penicillium – is easy to identify as it has a bushy, green appearance. They form in clusters, like a bush, and can have a pompous appearance, as they make themselves well-spotted due to their height. 
• Fusarium – this white bread mold tends to be black. If not black, they tend to appear darker than other molds. 
• Rhizopus – despite being associated with black fungus infection, rhizopus is white. However, in a cluster, they form black bases and heads. They are also extremely tall and can even be taller than Penicillium.
• Mucor – looks similar to Rhizopus, and it has a white body and a black head. However, while the cap (head) of the Rhizopus isn’t as dominant, Mucor has large black caps. 
• Aspergillus – looks similar to Penicillium. Like Penicillium, the Aspergillus white bread mold has a dark green to black color. However, it is not as bushy in appearance as the Penicillium. 

Safe Molds Vs. Hazardous Molds

It is tempting to eat moldy bread, especially when it is the middle of the night and you have nothing else in the house to eat. Sure, some genus of Penicillium is helpful for the creation of penicillin and some cheeses. 

Meanwhile, Aspergillus can be antibacterial and antifungal, while some genera are used for the fermentation of Japanese sake.

However, when you are contemplating whether your bread is safe to eat or not based on the appearance of the molds on the surface, then let us tell you this: do not eat moldy bread. SOME of the white bread molds have genera helpful for food. Still, ALL of them have genera that are seriously illness-inducing and some potentially fatal. 

We condone the eating of moldy bread. It is not for you to determine whether a mold is safe enough for eating or not. That’s for a microbiologist job and certainly not the job of someone who’s out for a midnight snack. 

• While researching this for the article, we found that some people tried to replace penicillin as medicine with moldy bread, which (spoiler alert) is not safe. 
• Also, when molds grow on something, they make sure that you or any other curious lad are not to eat them. When molds grow on white bread, it makes them taste and smell funny.

Do not eat moldy bread; buy a new loaf and eat safely. Eating white bread molds may cost more than just a loaf, especially if you do not have health insurance! However, for the sake of knowledge, we list some helpful molds.

Some Life-Changing Molds

• Aspergillus oryzae or koji-kin is an integral part of fermenting Japanese sake. Especially the yellow koji-kin, ancient Chinese, Japanese, and Koreans use this mold for fermenting rice to make alcohol. Meanwhile, koji-kin is also in use to ferment soybeans. (source)
• Penicillium rubens is the specific genus that was revolutionary enough to change the medical field. It stands as the first derived antibiotic and, until now, is the most used antibiotic. (source)
• Have you tried (or heard of) stinky cheese or blue cheese? This type of cheese is known for its appearance of mold and has a sharp, salty taste of the semi-soft cheese variety. It contains the Penicillium roqueforti mold. 
• The white bread mold Mucor lanceolatus is responsible for infusing the unique flavors of Tomme de Savoie. This mold works hand-in-hand to form complex taste palettes that make this cheese inherently unique. (Wilhelm M., 2018, “The Cheese Does Not Stand Alone: How Fungi And Bacteria Team Up For A Tastier Rind”)

Can You Eat Mold-Infested Bread?

“What a waste to throw away such perfectly good bread”, is an often-heard argument when one tries to dispose of mold-infested bread. “You can just scrape off the moldy parts,” they say incredibly nonchalantly. So, can you scrape off white bread molds and call it a day?

Can I Scrape Off The Mold And Eat The Rest?

Many people think that molds are only there when they are visible and that when you remove the visibly infected part of the bread, the rest is safe to eat. Unfortunately, although visual artifacts indeed help identify the presence of mold, the stage of their “actual” propagation starts before that. The white bread is often already in late-stage rotting when mold shows up. 

You cannot salvage bread with molds. Because when you see the molds, their roots have extended thoroughly already. That is because molds multiply by spreading their spores, and these can travel incredibly fast. Moreover, even if you remove the mold-infested bread section, these white bread molds’ roots are deep-rooted. 

According to the USDA, when molds are visible, they already have an extensive root system encompassing the rest of the bread. And when we say “bread,” we do not mean a single slice of white bread. When you see a part of your bread rotting, throw the entire loaf, not just the infected piece. (source)

So again, if your bread has grown mold or smells weird, through it out…..or compost it!

If you insist on eating mold-infested bread, there is a chance of you developing life-threatening diseases. Some molds destroy the probiotics in your gut. Some can even be poisonous.

How Do I Keep My Bread Away From Molds?

White bread molds are problematic due to their health risks and because it is so pervasive. At room temperature, bread can only last up to fourteen days before mold will start gnawing its way through your bread. So how can we resolve this? 

Preventing Mold Growth

• One thing you can do to slow this process down is to freeze it, as the cold temperature inhibits mold growth. 
• Buy vacuum-sealed bread. Molds need oxygen to propagate.
• Most fungi grow well in moist environments. Make sure you do not place your bread in humid spaces. Keep your bread dry.
• Try making sourdough bread. Because of its acids, sourdough bread is relatively mold-resistant.
• Make sure to buy enough bread for one session. Once the bread is exposed to open air, mold will surely grow sooner or later.
• By simply covering your bread, you can mitigate mold growth.
• Molds love moisture. For this reason, gluten-free bread typically displays characteristics of high moisture content which mold loves. Always keep gluten-free bread frozen. Similarly, gluten-free bread often contains fewer preservatives than traditional mass-produced bread.
• Learn about the bread expiration date.

Summary

White bread mold is one of bread’s primary arch enemies as it promotes spoilage. The first place to look for when examining bread integrity is to investigate how your flour is free of molds. One may use visual, tactile, and olfactory senses to differentiate flour from mold. There are five primary molds in bread: the Penicillium, Fusarium, Rhizopus, Mucor, and Aspergillus. Penicillium is integral for penicillin and the fermentation of some cheeses. Meanwhile, Aspergillus is responsible for Japanese sake, while it can also cause some infections in both animals and humans.

Penicillium and Aspergillus look similar to each other. Meanwhile, Mucor and Rhizopus are similar in color. 

There are no safe bread molds, as all white bread molds have the potential to cause harm to your body. Do not eat mold-infested bread, even if you scrape off the visibly infected parts. Molds have an extensive root system that can cause you illness even if you remove the discolored sections of the bread.