What Is Antimicrobial?
In the United States, antimicrobials are regulated by two organizations: The Environmental Protection Agency (EPA) regulates them as a pesticide, and the U.S. Food and Drug Administration (FDA) regulates them as drugs and antiseptics. The regulating body is dependent on what the antimicrobial is used for; when used to treat or prevent disease on living things (humans, pets, animals), the FDA is the regulating body, and when an antimicrobial is used to treat surfaces, the EPA is the regulating body. According to the EPA, an antimicrobial is "... intended to disinfect, sanitize, reduce or mitigate growth or development of microbiological organisms or protect inanimate objects, industrial processes or systems, surfaces, water, or other chemical substances from contamination, fouling, or deterioration caused by bacteria, viruses, fungi, protozoa, algae, or slime." In short, antimicrobials protect you or a surface from potentially harmful microorganisms by stunting or stopping the microorganism's growth.
Antimicrobial agents are important to use in a variety of settings, and they are found in non-public and public health settings. They are used in a non-public health setting on or within objects that can spoil or rot, such as fuel, wood materials and paper products. They are used in public health settings that may contain microorganisms that cause sickness to people, such as bathrooms, hospitals and restaurants. Antimicrobial agents help ensure that areas like your kitchen or a hospital room stay microorganism-free, providing you with a safe and healthy environment. Without the use of antimicrobials, damage to or loss of property and potential damage to your health could occur.
How Do Antimicrobials Work?
Before jumping into a discussion of different types of antimicrobials, it may be illustrative to understand how antimicrobials work. Antimicrobials work on a cellular level by causing physical damage to or destroying the microbial, or by impeding its ability to thrive. David Hooper from the Division of Infectious Diseases for Massachusetts General Hospital suggests that there are five ways in which antimicrobials combat bacterial targets: disrupting cell wall synthesis, disrupting protein synthesis, disrupting ribonucleic acid synthesis, disrupting deoxyribonucleic acid synthesis and disrupting intermediary metabolism. Affecting any of these targets results in the destruction or irreproducibility of the microorganism. While this example was exclusive to bacteria, these methods also affect other microorganisms.
An example of a common antimicrobial is chlorine bleach. Bleach's active ingredient is sodium hypochlorite. When the concentration of sodium hypochlorite is high enough, as it typically is in store-bought bleach, the hypochlorite causes the proteins within the bacteria to clump together and lose their three-dimensional structure, which means the bacteria can no longer grow and the threat of the bacteria or microorganism is effectively removed.
What Are Natural Antimicrobials?
Not surprisingly, nature has provided us with many antimicrobials. Naturally occurring materials that act as antimicrobials are "natural antimicrobials." One such example would be lemon juice. The acidity of lemon juice, which is due to the citric acid content, is capable of breaking down the cellular membranes of bacteria. This is one of the five properties described by Hooper as an indicator of antimicrobial activity. According to Medical News Today, a list of the top seven safe and consumable natural antimicrobials are garlic, honey, ginger, echinacea, goldenseal, clove and oregano.
Recent research by Irkin and Esmer looked into natural antimicrobial agents for food packaging systems, and these can be broadly broken into five categories: plant-based volatiles and extracts, polysaccharides, proteins/enzymes, lipid-based coatings and chelating agents. Incorporation of these or other materials into packaging or a coating provides a natural alternative to harsh chemicals for antimicrobial action.
Antimicrobials in Public Health Settings
Developing coatings and protectants is important for home or commercial use, as these are the products that are used to protect you from the environment or a surface. Sanitizers, disinfectants and sterilizers are three types of antimicrobial treatments that are used in public health settings. Sanitizers are generally effective against 99.9% of bacteria and are the only type that can potentially be used on food contact surfaces. An antimicrobial disinfectant is 100% effective against bacteria, fungi and certain viruses and is generally available in many different forms. An antimicrobial disinfectant may be used in the house or in a medical setting. Antimicrobial sterilizers are 100% effective against bacteria, fungi, viruses and spores. These are the most restricted for use and are usually found in research and used with medical instruments.
In general, an antimicrobial treatment with a disinfectant takes approximately 10 minutes of contact time to ensure effectiveness. This implies that the surface or object won't be used during that time. Simple coatings that maintain surface contact can aid in the reduction and availability of the microorganisms to spread.
Safety Considerations When Using Antimicrobials
In all cases, when using natural antimicrobials or not, the antimicrobials are acting upon a microorganism to break it down and destroy it. Therefore, utilizing personal protective equipment (PPE) is essential so that you do not unnecessarily put yourself in harm's way. PPE such as gloves or a face shield are necessary if handling or potentially spraying an antimicrobial. It is imperative that when using these materials in your kitchen or your commercial establishment, you place your safety and the safety of others above all else. Using just enough of the material to disinfect helps ensure that it is not ingested by you or anyone else.
If using a liquid or gel as an antimicrobial, it is usually important to let the material dry naturally. Wiping the material away or forcing it to dry faster may not allow the antimicrobial to interact with all the microorganisms for the required amount of time to ensure an effective treatment of the surface. If the antimicrobial material is solid, you may be able to leave it for an extended period. Some wrappings have antimicrobial agents embedded within the solid material and act as an external barrier, protecting the product from outside microorganisms.
Antimicrobials exist in both natural and synthetic products. Antimicrobials can exist in many different forms, such as gels, liquids, coatings or gasses. Whether utilizing a spray-on or solid-film antimicrobial coating, these materials are best used in a household or medical setting. Using antimicrobial agents is a sure way to keep you and others around you healthy and safe from microorganisms.
References and Resources:
- David C. Hooper, Mechanisms of Action of Antimicrobials: Focus on Fluoroquinolones, Clinical Infectious Diseases, Volume 32, Issue Supplement_1, March 2001, Pages S9–S15, https://doi.org/10.1086/319370
- Irkin, R., & Esmer, O. K. (2015). Novel food packaging systems with natural antimicrobial agents. Journal of food science and technology, 52(10), 6095–6111. https://doi.org/10.1007/s13197-015-1780-9