Recently, the World Health Organisation published the “WHO fungal priority pathogens list to guide research, development and public health action,” which listed critical fungal pathogens in order of criticality to public health. This list has gotten the attention of regulatory agencies and manufacturing industries. Everyone should take fungi seriously.
Over the last five years, there has been an increasing number of product recalls due to fungal contamination. This contamination of home, personal care, and cosmetic products poses risks to both the product, like spoilage, and the consumer. Formulations can be altered by the fungi which ruin the product and make it undesirable to consumers by changing the appearance or smell. Fungal contamination can also result in infections or sickness, either directly or through fungal toxins.
Fungal contamination can originate from essentially anywhere. Fungi are not an issue that is specific to just a laboratory since fungi are a natural part of the environment. Fungi thrive in old manufacturing buildings, humid environments, air ventilation systems, and cardboard boxes. When manufacturing a product, anytime the preservative system is compromised, whether it’s due to formulation or to manufacturing defects, fungi can grow. Mold spores are microscopic, can be transported via air and have the ability to flourish and alter formula texture and efficacy.
What are Fungi?
What comes to mind when you think of fungi? Maybe it’s the mushrooms that you eat or spoiled bread that has green fuzzy mold on it, but there is so much more to fungi. Fungi includes mushrooms, mold, and yeast. Fungi are an extremely large and diverse group of organisms that come in every color of the rainbow and have complex structures. One of the most common, and time-consuming, ways to identify fungi is by simply looking at it macroscopically and via a microscope. Scientists examine the shape and visual characteristics of the spore and the colors of the colony. This process is inherently subjective and error prone. Does that look like a hyphae (long branched structures on mold spores) or is that a scratch on the microscope slide? Is the puffy white colony Chaetomium or Mucor? It can be difficult to tell.
The physical structures of fungi are very different than bacteria; however, they share some things in common. Both can grow in a variety of harsh environments and can be highly resistant to eradication. Some fungi like colder climates, and Cladosporium may find your refrigerated storeroom a cozy place to live. Other molds are more minimalist and prefer less food and moisture to survive and can even grow quite fast in that sparse habitat. Just one mold can create millions of spores in your lab, manufacturing plant, and even ride along in your distribution vehicles.
Unsurprisingly, almost every facility already has mold growing in it. Mold, and specifically spores, can move and thrive easily in the right conditions. Think about how easily pollen can irritate your nose. It doesn't need much, it just floated into your workspace through the open window. Mold spores can do the same thing. You have a manufacturing plant that constantly opens its receiving doors throughout the day and people walking in from outside. Are those same shoes traipsing through a manufacturing skid or lab? Is that door opening right near your filling station? Well, then you could have mold. You don’t normally see mold until you have a lot of it. You just need that small amount transported through spores floating in the air, just like that pollen tickling your nose, to settle in your product and pose a contamination risk.
While this is a scary proposition, if you know the entry point, if you know which mold is coming in, then you will be able to protect your critical areas and your product and kill it as soon as you can. Rarely can we visually see mold growing on walls, except when there are conditions for it to grow like a water leak for example. Spores can be transported through personnel, air flows, material flows, and waste flows. If you know the entry point, then you can better protect your products.
Many companies have global footprints with manufacturing plants of various ages and in need of structural improvement. Old buildings have a higher threat of fungal invasion. There can be many different types of mold infringing on these sites and for many different reasons. The everyday wear and tear on a building creates new nooks and crannies for a mold spore to reside. Cracks and water leaks can provide just the right habitat for mold to grow with the right temperature and a steady supply of food. These places can be hard to reach so you can’t easily remediate once you know it’s there. To properly clean and disinfect the mold source, you need to know what kind of mold it is to start and then investigate until you reach the source. Preventing the mold from entering your building and choosing the correct disinfectant or sporicidal agent, will give you more control over your manufacturing environment.
Mold can have different types of spores, some that are easy to get rid of and others that are more difficult. Think of it in terms of a criminal investigation, the CSI investigators are going to try and find the fingerprints or the DNA evidence to get to the culprit. Would you feel comfortable with a guilty verdict if the only evidence was the person’s first name? That’s the degree of confidence you have if you only have a genus level identification. Knowing that you have Aspergillus in your plant isn’t good enough. Is it Aspergillus brasiliensis or Aspergillus fumigatus? Aspergillus brasiliensis is less harmful and the other, Aspergillus fumigatus, is known to cause significant respiratory infections. What's in your facility? You can’t fully investigate and resolve fungal contamination without knowing the species, just like you can’t link the suspect unless you have the fingerprints or DNA. An accurate and reliable identification gives you the necessary information to make the right decisions and determine the next steps.
Accurate fungal identifications to the species level are also critical for comprehensive facility monitoring and quality risk management. For example, knowing the fungal species can give you information about how easy or difficult it is to get rid of it. Cladosporium sphaerospermum, a close relative to the molds you may find in homes, is a fungus that is resistant to cold temperatures and has been known to survive extreme radiation. It has even been found growing inside the Chernobyl reactor and a study has shown that it can utilise radiation as an energy source. UV light won’t be able to kill those fungi.
There are many ways to identify microorganisms and the method impacts accuracy and reproducibility. The most accurate identifier of all organisms is DNA. The deeper you dive into a microorganism’s family tree the more information you will learn about it. However, proteins can also be used to identify microorganisms. These identifications are generated by Matrix-Assisted Laser Desorption/Ionization–Time Of Flight mass spectrometry, also known as MALDI-TOF. The resulting protein spectrum is compared to a library of protein spectra from known microorganisms, kind of like a fingerprint at a crime scene. It is not as accurate as DNA, but it is less labor intensive for the lab and the results are substantially quicker.
A challenge within all industries is tracking molds and establishing good prevention and remediation procedures. Accurate fungal identifications to the species level will allow you to track and trend what you find so you can adequately assess risk to your manufacturing process and final product. It is important to accurately track the fungi in your facility to understand seasonal shifts (molds usually like warm, moist environments – so hey there summer) and determine whether you have a new isolate or a resistant fungal tenant you have a never seen before. Tracking fungal trends will demonstrate that the facility is operating with awareness and control in planning and performing appropriate and effective cleaning and sanitisation measures to reduce and prevent risk of product contamination.
There is real value in having a validated microbiological monitoring program to establish a baseline understanding of your entire manufacturing environmental conditions. Environmental monitoring gives you the power to easily identify areas for quality improvement, respond quickly and proactively to changes in the microorganisms of your environment, and maintain an overall contamination control strategy. Regulatory agencies recommend routine monitoring and data trending as best practices. Good Manufacturing Practice (GMP) compliance is a proven strategy for contamination risk mitigation for home, personal care, and cosmetic product manufacturers.
Manufacturers are not really thinking about mold; however, everyone should take fungi seriously. There are more product recalls due to microbial contamination including yeast and mold with one recent recall stating “Product may contain high levels of yeast” in a lotion. You need a process to identify fungi properly and accurately and have systems in place to monitor its presence in your facility to keep your products safe. Do you know if your microbiology lab has a testing specification for mold, are they looking for it?
