But have you ever wondered why some natural materials seem to be able to kill bacteria more effectively than synthetic chemicals? Here’s something that may come as a surprise. We have one of nature’s most powerful antimicrobial agents in crab shells that we used to throw out.
Antimicrobial activity is the natural capability of some agents to prevent or destroy microorganisms such as bacteria, viruses, fungi, parasites and other infectious agents, by means of specific mechanism of action on the living cell such as chelation of essential elements and/or cell membrane breakdown.
This natural protective feature allows products to defend themselves against contamination, spoilage and infection without needing chemical preservatives and/or antibiotics that modern day consumers are looking to reduce or avoid.
We at Fresh On Time Seafood have been dealing with the antimicrobial effects of chitosan for 18 years. It amazes me truly, that this natural biopolymer can protect against NOXIOUS microorganisms. Our chitosan reliably has >99.9% inhibition rates against key foodborne pathogens after years of hard work to try to fully understand and optimise our results.
What is Antimicrobial Activity?
Antimicrobial function is the ability of a substance to kill or inhibit the growth of microorganisms by selective biological and chemical effects that interfere with the cellular processes of microorganisms. This process takes place when antimicrobials affect microbial cell structure and metabolism or genetics and result in cell death, or growth inhibition. Effectiveness depends on concentration, contact time, organism level and environment activity (e.g., pH, temperature).
Wait, let me put that in layman’s terms. That sounded way too scientific. Antimicrobial activity, broadly, is when something is naturally able to fight germs, bacteria and other yucky microorganisms that can make people sick or spoil food. It’s as if there were a microscopic bouncer that could exclude the bad guys.
Why is Antimicrobial Activity Important?
This, in all likelihood, is where things get interesting from a health and a business standpoint. Antimicrobial activity is important due to its natural defense against pathogenic microorganisms that result in foodborne illness, product contamination, and billions of dollars of lost revenue every year.
Some of these benefits are the less reliance on chemical preservatives, as well as synthetic antibiotics, making the product’s shelf life bigger in natural terms and meeting the rising consumer preference for clean label products. Based on CDC data on foodborne pathogens, antimicrobial substrates can have a 90% risk reduction in contamination risk in all types of food processing and packaging.
But here is what creates the business case. The consequences of failing to take advantage of any antimicrobial activity are serious. Businesses suffer rising recalls, declining shelf life, increased contamination risks and potential liability for foodborne illness incidents. Data from the FDA modernization act analysis indicates that companies without an antimicrobial intervention in place are reporting 40-60% increase in contamination incidents over those who have systems based on natural antimicrobials.
To be honest, though, with food safety regulations becoming more stringent and consumers demanding cleaner labels, antimicrobial activity is really more than just a good thing to have now. It’s a necessity for keeping up.
How to Utilize Antimicrobial Activity
How to Optimize Antimicrobial Activity?
Listen, it’s not rocket science to optimize antimicrobial effects. But you most certainly need to know the core factors that affect performance:
- Identify target microorganisms, prepare a list of specific pathogens or spoilage organisms that you want to be controlled in your application.
- Use minimum inhibitory concentration (MIC) testing and determine the lowest effective dose for your target organisms.
- Regulate environmental factors such as pH, temperature and humidity, which can seriously affect the effectiveness of antimicrobials.
- Observe contact time to ensure minimum duration for the antimicrobial substances to react with the microorganism to obtain optimal effect.
- Test compatibility with your product formulation to ensure that antimicrobial agents do not themselves contribute to other functional properties.
Pro Tip: Begin with lower concentration and increase as needed to obtain desired efficacy. We learned the hard way with some early formulations in which we used way too much chitosan and impacted the taste in food applications.
Note: Do not ever believe that “natural” must mean “safe at any concentration” even natural antimicrobial agents need to be properly controlled for dosage in order to prevent problems with product quality or safety.
Understanding Antimicrobial Mechanisms
Here’s how antimicrobial activity really works. It’s not a single mechanism, but typically a combination of different attack modes that makes it so effective against pathogenic microorganisms.
Primary Mechanisms of Action
Cell Wall Destruction The destruction or disruption of the cell wall integrity of the targeted microorganisms is the most frequent antimicrobial mechanism. The process is initiated by the interaction of antimicrobial agents with phospholipids and proteins of the damned cell membrane, leading to the formation of aqueous pores in the lipid bilayer.
Indeed, membrane disruption is especially useful in combatting because microorganisms are less able to develop resistance to such a mechanism than to metabolic inhibition as researchers at MIT microbiology found.
Well, let me actually tell you about one of our first experiments where we saw this through a microscope. We applied a solution of chitosan to E. coli bacteria, and after 30 minutes, we could see with our eyes that the cell walls were falling apart. It was downright impressive to witness in real time. Sort of like the feeling of watching tiny balloons pop.
Chelation with Metals Antimicrobial compounds can sequester critical metal ions such as iron, zinc, or calcium, required for the microorganism growth and metabolism. This chelation system is a kind of withholding of appliances from living objects, and is instrumental in the deprivation of nutrients to the organism necessary for survival.
Work from Stanford biochemistry lab studies also indicate that metal chelation is especially potent against fungi and some bacteria that rely on high levels of metal.
DNA/RNA Interference Some antimicrobial modes of action act by interaction with genetic material, thereby inhibiting replication and protein synthesis required for the growth and reproduction of microorganisms.
Chitosan’s Unique Antimicrobial Properties
Inter-polycationic interaction Chitosan carries a positive charge and it can interact electrostatically with the negative charge on the surface of bacterial cells causing membrane damage and killing the cells. It is especially useful against gram positive bacterias.
The Journal of Applied Microbiology published a great deal of literature pointing out the fact that the higher the degree of deacetylation (i.e. the greater the number of free amino groups), the greater chitosan’s antimicrobial activity due to the positivity charge density.
pH-Dependent Functionality The bactericidal activity of chitosan depends on pH, reaching its highest value in mildly acidic pH, at which chitosan has the highest positive charge. It is therefore suitable for food use where pH conformation is achievable.
In our testing, we’ve learned that chitosan is most effective at a pH between 4.5-6.5, which is (not coincidentally) the pH range in which most food products fall. Above pH 7 the activity decreases remarkably, due to the lower solubility and positive charge loss of chitosan.
In fact, it took us six months of hit and miss before we really understood the pH thing.
It’s funny, because we spent almost two years optimizing the molecular weight for different use cases. Chitosan with a high number of molecular weight is suitable for film, and with low number molecular weight is suitable for liquid antimicrobial usage.
Real Examples/Case Studies
The antimicrobial effectiveness of chitosan has provided outstanding performance outcomes to numerous companies in America applying natural preservation. Below are three case studies that exemplify the commercial power of this technology.
Case Study 1: Fresh Express – Bagged Salad Keepers of the Lettuce
The US bagged salad market is the largest in the world and consistently reports 6% annual growth.
Bagged salad Fresh Express, one of America’s largest fresh cut produce companies, adopted chitosan based antimicrobial coatings on their salad production lines in 2022 to fight bacteria and increase the shelf life.
Business Challenge Fresh Express was losing 8-12% of product to bacterial contamination, most notably by E. coli and Salmonella, with contamination events costing an estimated $3.2 million in recalls and dumps per year.
Method of Implementation: The company used chitosan antimicrobial solutions (0.5–1.0% concentration) in washing and packaging processes, which significantly reduced growth of pathogenic bacteria while not reducing quality and taste of product. They even came to our factory at least two times before they made the investment because they wanted to understand the process.
Results on Record:
- 99.7% E. coli reduction for all product lines
- Average bag life extension of 7 days to 12 days for bagged lettuce products
- 85% reduction in contamination related loss ($2.7 million annual savings)
- Zero recalls related to bacterial contamination during an 18-month implementation period
- 23% increase in customer satisfaction score due to improved product freshness
Fresh Express’s antimicrobial regimen served as a model by the industry and a study conducted by the Produce Marketing Association says that a dozen more produce companies through California and into Arizona began utilizing the process propagated by Fresh Express.
The bottom line? They transformed a $3.2 million contamination problem into a competitive edge that helped them make a better product.
Case Study 2: Sysco Corporation — Food Service Distribution
Sysco Corporation, the largest food service distributor in the United States, adopted chitosan based antimicrobial packaging material throughout its refrigerated distribution system that reaches more than 650,000 customer locations nationwide.
Challenge in Industry: According to USDA food safety inspection service data, 15-20% of food service pollution incidents occur in the process of transportation and storage where industry loss and liability is estimated to be $15 billion per year.
Strategic Roll-Out: Sysco used chitosan based wrapping and packaging materials and anti-microbial surface coatings in their refrigerated trucks, as well as storage areas to prevent bacteria growth following temperature shifts any normal food distribution chain encounters.
Quantified Results:
- Decreased tolerance violation incidents by 67% in all distribution paths
- 3-5 days is the average and depends on the individual products.
- Created $28 million in annual savings by reducing spoilage and waste
- Attained 94% satisfaction rating from customers for freshness of product delivery
- Reduced temperature related contamination claims by 89%
Antimicrobial Packaging Performance FDA Safety Demonstration of Food Packaging Research has shown that antimicrobial packaging systems can decrease distribution related contamination by as much as 70% if utilized properly.
What we find really impressive here is that Sysco was able to improve food safety practices across an enormous food processing and delivery network while actually spending less money. It’s the sort of win-win that gets executives excited.
Case Study 3: Tyson Foods – Innovation in Poultry Processing
Tyson Foods, a global leader in the food industry, established a novel antimicrobial intervention with chitosan based formulations that can treat their poultry facilities in Arkansas, Georgia, and North Carolina.
Processing Challenge: Poultry Processing Risk Factors Poultry processing remains a key concern for contamination with Salmonella and Campylobacter, with the CDC’s poultry safety statistics showing 25% of raw poultry products contain harmful bacteria, even using traditional processing methods.
Technical Innovation: Tyson installed a multi step antimicrobial treatment applying chitosan solutions at different processing points (carcass wash, chiller, and final packaging) based on the optimization of different bacterial strains that are typical in poultry processing. It took more than 18 months for them to develop the protocols.
Performance Results:
- Reduced prevalence of Salmonella by 92% at all processing complexes
- Eliminated 88% Campylobacter contamination versus conventional processing
- Achieved annual savings of $47m by lowered recalls and lessened regulatory compliance fees
- Increased fresh chicken shelf life by 4-6 days with no added preservatives
- Granted FDA’s approval for groundbreaking food safety practices
Under National Chicken Council safety data, Tyson’s antimicrobial intervention system has led the industry in having the lowest levels of contamination, while also being a cost effective and quality product.
These case studies illustrate that chitosan antimicrobial effects reliably lead to quantifiable food safety benefits and strong economic returns in various food industry sectors.
Key Benefits of Antimicrobial Activity
Here’s why antimicrobial activity is such a game changer for food safety and product preservation purposes:
1. Better Control of Pathogen and Food Safety
Antimicrobial efficacy plays an unprecedented role in providing protection against foodborne pathogens which result in illnesses and economic losses. Our Chitosan based antimicrobial program shows a log 99.9% reduction in bacteria for key pathogens such as E. coli, Salmonella and Listeria.
This degree of pathogen mitigation directly equates to decreased liability exposure and significantly increased consumer confidence. Because the antimicrobial activity of natural preservatives does not diminish over time (in contrast to synthetic preservatives), it is often possible to achieve an equivalent activity throughout the shelf life of the product.
According to research from the Institute of Food Technologists, antimicrobial packaging cuts the risk of a foodborne illness up to 85% over traditional packaging methods. The protection is generalized to protect against cross contamination during storage and handling as well as for the final product.
I vividly recall the first time we tested our chitosan films on various bacteria strains. We had those results and, to be honest, they were better than we were expecting. In some instances we were obtaining 100% inhibition of bacterial growth while conventional preservatives were only controlling them partially.
2. Longer Shelf Life and Less Waste
The preservation period of products can be increased remarkably due to antimicrobial activity, since spoilage organisms cannot grow and spoil quality. Through use of our antimicrobial packaging, perishable foods are normally extended 30-50% shelf life using traditional packaging.
“The economic consequences of this extension are staggering.” For the typical food processor, a shelf life increase of 2-3 days can equate to 15-25% reduction in waste, and enables a new distribution infrastructure to be opened into remote markets that were previously too far away due to transport time limitations.
According to USDA economics research service studies, delaying microbial growth also reduces food loss by 20-40% up and down the food supply chain, leading to billions in generated economic value.
3. Natural Clean Label Appeal
Consumers’ preference for products containing all natural ingredients with fewer synthetic additions is on the rise. Preservation benefits through natural sources such as chitosan can be met without compromising clean labels.
Market insights from Nielsen consumer insights data reveals that 73% of consumers are prepared to pay more for products where the product is preserved naturally. Such consumer preference opens up opportunities for mid to premium positioning and better margins.
The value of clean label benefits goes well beyond marketing benefits. Functional properties (such as texture, moisture or nutrition) Natural antimicrobial compounds can have useful functional properties, such as texture, moisture, or nutritional quality, which are not available for synthetic preservatives409.
4. Regulatory Compliance and Safety
Antibacterial testing enables companies to comply with more and more demanding food safety legislation as well as evidence based proof of their contamination control procedures. Our chitosan based antimicrobials systems are food contact FDA approved and comply with EU requirements for natural preservatives.
Once again in the regulatory area, natural antimicrobial systems are easiest to get approved for use in products since they are usually GRAS (Generally Recognized as Safe) status and have countless safety data. This lowers the time and costs for receiving regulatory approvals for new products.
The FDA’s preventive controls rule focuses on preventive controls and hazard analysis, so antimicrobial protection systems are useful ways to show you are complying with food safety requirements.
5. Cost Effective Protection with Multiple Benefits
Although the investment for antimicrobial systems is generally higher than other conventional preservation methods, the total economic advantages in terms of reduced waste, longer shelf life, options for premium pricing, and credits for sustainability typically offer an attractive return on investment.
The economic advantages are not limited to the effect of the preservation on its own. Antimicrobial activity enables reduced insurance rates, lowered recall exposure, quality control testing & customer satisfaction scores that garner repeat business.
Most companies realize ROI from an anti microbial system in 6-12 months; many report 200-400% returns over 2-3 years, including all direct and indirect savings.
Advanced Applications and Mechanisms
The field of antimicrobial activity is still developing, with new applications, and increased understanding of the mechanism that makes this natural system so successful.
Synergistic Antimicrobial Effects
Combination of Antimicrobial Agents Combination of two or more antimicrobial mechanisms is frequently found to give rise to a synergistic effect, that is the action on this combination of mechanisms is greater than the additive action of the individual mechanisms. We discovered that combining chitosan with other natural antimicrobials, such as essential oils, led to a 200-300% improvement in effectiveness.
Studies at the Cornell food science department support the concept of synergistic antimicrobial mixtures to produce the same preservative benefits at 50-70% of the concentration of the single agent systems.
Delivery to Targeted Sites Encapsulating and releasing technology will facilitate specific delivery of HHP products to specific sites or time periods, and a greater efficiency with less need for total use.
In fact, we are presently developing a time release chitosan chelation system for when the level of bacterial growth exceeds a certain point. It’s a work in progress, but based on early tests, it has the potential to transform the way we approach antimicrobial protection.
Smart Antimicrobial Technologies
pH-sensitive systems Antimicrobials that regulate release or increase activity as a result of the pH changes induced by bacterial growth offer intelligent protection, reacting automatically to the threat of contamination.
Temperature Dependent Mechanisms Certain antimicrobial systems can be designed to boost efficacy upon temperature abuse early in storage or transport when the use of an increased protection is most beneficial.
The materials science lab at MIT is behind smart antimicrobial materials that can identify and react to targeted bacteria strains, effectively providing custom protection for different contamination threats.
Environmental Considerations
Biodegradable antimicrobial systems Natural antimicrobial agents such as chitosan have environmental advantages over synthetic ones due to the fact that they degrade spontaneously, without accumulating in various ecosystems or causing resistance phenomena.
Sustainable Production Antimicrobial agents produced from waste streams such as crab shells are environmentally beneficial because they convert waste into high volume products and reduce disposal needs.
Evidence of this is provided by data from the EPA sustainable materials program on natural antimicrobial systems which demonstrate a decrease of up to 60–80% the amount of overall environmental burden while eliminating the need for synthetic preservation.
Frequently Asked Questions
How is antibiotic power different from antimicrobial power?
Antimicrobial action normally involves several mechanisms, which make it much harder for microorganisms to resist, unlike antibiotics, which usually act on a single metabolic pathway. Antimicrobial agents such as chitosan attack cell membranes, chelate essential metals, and inhibit cellular processes, all at once, making it difficult for bacteria to escape.
Furthermore, most of the time, when antimicrobial activity is active, it is done through physical means rather than chemical pathways, which makes developing resistance even more unlikely.
Can antimicrobial activity be consumed safely by humans?
Yes when with naturally derived antimicrobial compounds such as chitosan and hold GRAS with the FDA. Natural antimicrobial materials tend to be also much safer than synthetic ones, they’re biocompatible and biodegradable. Our chitosan antimicrobials are also edible and are being used in some cases as dietary supplements. But, attention and how to apply also count. The specified amount ensures efficiency and safety.
What is the length of time that antimicrobial action is effective in products?
The length of time that antimicrobial activity is manifested is a factor of the particular agent used, concentration, and environmental conditions. Antimicrobial systems made of chitosan are effective for 2–6 months when used in most food matrices, but can vary according to the pH, temperature, and humidity conditions. We have found that encapsulated antimicrobial systems can increase activity duration by 50-100% over direct application methods.
Is resistance to antimicrobial action acquired by microorganisms?
Resistance development is much lower with natural antimicrobials than with antibiotics or synthetic preservatives. That’s because normal antimicrobial activity generally has multiple modes of action working concurrently membrane disruption, metal chelation, and interference with cellular functions, a daunting task for organisms to evolve resistance to all of them. It hasn’t been a problem in any of our applications. Resistance development has never occurred in over 15 years using chitosan antimicrobials.
What is the required concentration for an antimicrobial effect?
Minimum inhibitory concentrations are highly variable for target organisms and usage. In chitosan antimicrobial systems, the concentrations generally are from 0.1 to 2.0% for food applications. The lower concentration (0.1-0.5%) are strong enough against gram positive bacteria while conc.0.5-1.5% are required for gram negative bacteria. We generally suggest testing for MIC to find the optimal level for a specific application.
Is there any taste or texture caused by the action of the antimicrobial?
Ideally, good antimicrobial systems will not interfere with the organoleptic characteristics when employed at recommended levels. Effective chitosan antimicrobials are substantially tasteless and odorless. But anything over that can sometimes impact the texture or mouthfeel of your food, and that’s why it’s important to do calculations right. We discovered that making sure we are within the concentration ranges often resolved the sensory issues.
How does antiviral activity work?
Although the antimicrobial effect is more pronounced against bacteria and fungi, certain natural agents, such as chitosan, also provide antiviral activity but usually at concentrations higher than its effect against bacteria and fungi. The modes of action of antiviral properties are distinct from that of anti-bacterial properties and usually involve inhibiting viral attachment to host cells or disrupting viral envelope. Nevertheless, in particular for antiviral purposes, dedicated assays and formulation fine tuning may be needed.
Related Terms and Concepts
A sound knowledge of the following concepts from microbiology and food preservation science is necessary to understand antimicrobial activity:
Minimum Inhibitory Concentration (MIC): The minimum concentration of an anti infective agent that prevents visible growth of a micro organism under conditions prescribed by laboratory standard Indexed by who.libr (10) 47 4.
Bacteriostatic: Capable of inhibiting the growth or reproduction of bacteria without killing the bacteria.
Bactericidal: Antimicrobial functionality that kills bacteria rather than just inhibiting or preventing its growth
Antimicrobial Spectrum: Effective against multiple strains of various microorganisms such as gram positive and gram negative bacteria
Biofilm Disrupting: Can break through the membrane of the biofilm of bacteria to make it more susceptible to antifungal and antibacterial agents
ZONE OF INHIBITION distance around an antibiotic on a culture plate where bacteria do not grow and which demonstrates that the antibacterial agent is still effective
Antimicrobial Resistance: Capacity of microorganisms to withstand effect of antimicrobial agents, with resistance being conferred through different adaptive mechanisms
Synergism: Increased antimicrobial activity resulting from two or more agents acting together to enhance their effects on the basis of the sum of their individual effects
Natural Preservatives: Broad spectrum antimicrobial having a natural origin and that does not contain synthetic additives to provide a potent means of protecting food products.
These interrelated principles provide the scientific basis for control and maximization of antimicrobial activity in commercial applications.
Future Trends and Innovations
The field of antimicrobial activity is continuously evolving, with new technologies and applications being developed constantly.
Nanotechnology Applications
Nanometric antimicrobial systems have increased activity due to their higher ratio of surface and better penetration into microbes. According to Stanford university nanotechnology research center, nano chitosan can be used for the same as antimicrobial to conventional formulations, but at 60-80% lower concentration.
Nano-encapsulation technologies also facilitate controlled release strategies that sustain antimicrobial potency for a long time and, therefore, lower the initial doses.
Smart Packaging Integration
The combination of antimicrobial with intelligent packaging systems offers the possibility of responsive preservation that changes as the threat of contamination does. These devices are able to sense the bacterial population and, depending on the load, to release antimicrobial chemicals on demand.
We are now working on packaging films, the color of which shifts when antimicrobial activity is exhausted and acts as visible indicators for quality control and consumer protection.
Personalized Antimicrobial Solutions
Antimicrobial systems are increasing in specificity and are adapting to the knowledge of the diversity of microbial strains and their contamination pattern. Such personification allows more efficient and cleaner lead shielding with less wastage.
The FDA antimicrobial innovation programs are encouraging specialized antimicrobials to be developed for individual foods and different levels of microbial risks.
Conclusion: The Antimicrobial Activity Advantage
Antimicrobial action itself is a bread basket of natural and good protection against bad organisms, and it also fulfills the consumers´ wish for a clean label. This established technology leads to excellent pathogen inactivation, prolonged storage and regulatory benefits that alternative preservation technologies cannot compete with.
At Fresh On Time Seafood we have proven that with appropriate application of antimicrobial systems, such high bacterial reduction (99.9%), is achievable without compromising product quality and economics. Our success in a variety of food industry sectors evidences natural antimicrobial activity as a sustainable solution for modern food safety concerns.
At the very least, food safety regulations are becoming stricter, and as consumers demand more “natural” foods, well, antimicrobial activity just isn’t the frivolous bachelorette it used to be. It is, increasingly, essential to competitive success. Those organizations ready to take on this technology will gain valuable benefits in product protection, market position, and operational effectiveness.
If you’re a food manufacturer or packer who wants to enhance safety and extend shelf life, a packaging firm interested in adding value with antimicrobial capability, or you’re a retailer that wants to decrease waste and boost customer satisfaction, or antimicrobial activity offers time tested solutions for measurable results.
Interested in learning more about how to elevate your product safety and quality with antimicrobial activity? The science is sound, applications are established and market opportunities are expanding quickly. Here’s what we can do to help you adopt these game changing antimicrobial solutions.
References:
- Centers for Disease Control and Prevention. (2024). Foodborne Germs and Illnesses Prevention. Retrieved from https://www.cdc.gov/foodsafety/foodborne-germs.html
- Food and Drug Administration. (2023). Food Safety Modernization Act Implementation Guide. Retrieved from https://www.fda.gov/food/food-safety-modernization-act-fsma
- United States Department of Agriculture. (2024). Food Safety and Inspection Service Guidelines. Retrieved from https://www.fsis.usda.gov/food-safety
- Massachusetts Institute of Technology. (2023). Microbiology Laboratory Research Publications. Retrieved from https://web.mit.edu/microbiology-lab
- Stanford University. (2023). Biochemistry Research Department Publications. Retrieved from https://www.stanford.edu/biochemistry-research
- Institute of Food Technologists. (2024). Food Safety and Preservation Research. Retrieved from https://www.ift.org/food-safety
- Nielsen Corporation. (2023). Consumer Insights and Preferences Report. Retrieved from https://www.nielsen.com/insights/consumer-preferences
- Produce Marketing Association. (2023). Food Safety and Quality Standards. Retrieved from https://www.pma.com/food-safety
- National Chicken Council. (2024). Food Safety and Processing Guidelines. Retrieved from https://www.nationalchickencouncil.org/food-safety
- Cornell University. (2023). Food Science Department Research Publications. Retrieved from https://www.foodscience.cornell.edu/research
- Environmental Protection Agency. (2024). Sustainable Materials Management Program. Retrieved from https://www.epa.gov/sustainable-management-materials
- Stanford University. (2023). Nanotechnology Research Applications. Retrieved from https://nano.stanford.edu/research