Filtration is a method used to separate substances based on specific criteria, such as physical or chemical properties. Sterile filtration is a process designed to remove microorganisms from a fluid, rendering it sterile.
In this blog, we will explain what sterile filtration is, how to filter microorganisms with sterilizing filters, which are the prefilters used for sterile filtration & its industrial applications in detail.
Sterile filtration is a critical process in industries like pharmaceuticals and food production, ensuring product safety by removing microorganisms from liquids and gas without altering their properties. This method relies on filters with extremely small pores (typically 0.2 microns) to trap contaminants, including bacteria, yeast, and molds.
Sterile filtration operates by physically trapping microorganisms within the filter or on its surface. The process is non-destructive, preserving the integrity of the filtered substance. With an efficiency rate of 99.99999%, this method ensures the removal of nearly all microorganisms. To prevent contamination, sterilizing filters are treated using methods like autoclaving or steam-in-place sterilization. These procedures ensure the filters themselves remain sterile throughout the process, providing consistent and reliable results.
The sterile filtration process uses a sterilizing filter to remove microorganisms from liquids, ensuring product safety and purity. Here’s how the step-by-step process works:
Depending on the application, different types of pre-filtration options are available. Spun PP or reusable stainless steel filters can be used to remove the bulk of the suspended particulate matter above 5 microns.
Then, pleated PP filters can be used to further clarify the fluid and remove the particles above 1 micron. It is important to remove the bulk of the suspended matter before using pleated PP filters otherwise their clogging frequency will be quite high, leading to large OPEX.
Finally, membrane filters are used to eliminate all micro-organisms from the fluid. Different membranes are available for different fluids, and the choice has to be thoughtfully made.
Before filtration begins, the system is meticulously cleaned and sanitized. This step ensures that no external contaminants compromise the process and that the sterile filter is ready for optimal performance. The system and piping will be sterilized with sterile steam between 120-140 C, to kill any micro-organisms left after the cleaning process. PP filters cannot be steam sterilized, so one has to be careful.
Sterilizing filters trap microorganisms on their surface or within the filter matrix. The tiny pore sizes prevent bacteria, yeasts, molds, and other contaminants from passing through, delivering a sterile final product while preserving the liquid's properties.
Ongoing testing and validation ensure that the sterile filter is performing as expected. This includes monitoring the process to confirm that the filter consistently removes the targeted microorganisms and maintains sterility standards. After every batch, the sterilizing filter is integrity tested. If it passes, the batch is deemed sterile. If not, the batch will have to be refiltered through a new membrane filter.
We specialize in designing high-performancemembrane filtersdesigned to meet diverse sterile filtration needs, including injectables like vaccines, medicated syrups, medicines for pets, etc. before further processing like bottling and packaging.
Prefilters play a crucial role in the sterile filtration process by removing larger particles and debris before the liquid reaches the final sterile filter. This step helps prolong the life of the sterile filter, prevent clogging, and improve overall filtration efficiency. By pre-filtering the liquid, ensuring it can effectively remove microorganisms, bacteria, and viruses.
Polypropylene (PP) pleated filter cartridges are commonly used in sterile filtration because they are highly efficient and compatible with many chemicals. Their pleated design provides a large surface area, making them effective at trapping microorganisms and particles while allowing liquids to flow easily. These filters can be used as the pre-final step in sterile filtration, where they remove larger particles to protect other downstream membrane filters. Their strong and reliable construction makes them ideal for use in industries like pharmaceuticals and biotechnology, where clean and safe filtration is essential.
Sintered powder filter cartridges are a strong option for sterile pre-filtration. Made from materials like stainless steel or titanium, they resist rust and can handle high pressure. They are easy to clean and reuse through backwashing, which helps reduce waste and save costs. Their strength and versatility make them useful for many industries. Additionally, they can be steam sterilized for an infinite number of times. Reusable powder sintered filters can be given for pre-filtration even to 0.2 microns (nominal), which would leave only a minute fraction of micro-organisms as the workload for the membrane filter, which would largely prolong its life.
Sterilizing injectable medicines, vaccines, and eye drops. Filtering IV fluids and nutrient solutions. Keeping cell culture media and biological products germ-free. Sterilizing cleaning solutions and disinfectants. Preparing sterile water for medical use.
Filtering growth media and protein solutions for research and production. Removing bacteria and particles from sensitive materials.
Sterilizing liquids like milk, wine, beer, and juices to make them last longer. Keeping the taste and quality while making them safe to consume.
Sterile filtration is important for keeping liquids and gases clean and safe in industries like pharmaceuticals, food, and chemicals. Kumar Filter offers best solutions like PP Pleated Filter Cartridges for efficient filtration and Sintered Powder Filter Cartridges for durable solutions.
A sterile filter should be sterilized after every production run. The steam sterilization temperature must be between 110°C and 140°C with the sterilization times being between 10 and 30 minutes, subject to steam temperature.
Filter materials typically used in the sterilization of liquids include PTFE, polyvinylidene fluoride (membrane), and polyethersulfone (PES), amongst others. These filter materials differ in their protein retention, flow rate, and the presence of leachable materials.
The filtration sterilization process uses porous membrane filters. The pores in the membranes are of differing sizes that prevent any substance larger than the size of the pore from passing through. Large pores will allow larger items to pass through, while smaller pores will allow only small items to pass through.