A serpentine path coiled tube UV-C system for non-thermal microbial inactivation in opaque and scattering fluids

Background

The field of non-thermal microbial inactivation has gained significant attention in recent years, particularly in the food and biopharmaceutical industries where maintaining product quality and safety is paramount. Traditional thermal pasteurization and sterilization methods, while effective at eliminating pathogens, often degrade sensitive nutrients, flavors, and bioactive compounds. As consumer demand grows for minimally processed, nutrient-rich products, there is a pressing need for alternative technologies that can ensure microbial safety without compromising quality. Ultraviolet (UV) light, especially in the UV-C range, has emerged as a promising non-thermal solution due to its proven germicidal properties and potential for energy efficiency. However, the application of UV-C treatment to highly opaque and UV-absorbing fluids—such as whole milk, plant-based beverages, and certain biopharmaceuticals—remains a significant challenge due to the poor penetration of UV light in these media.

Current approaches to UV-C treatment are largely limited by the inability of conventional reactor designs to deliver sufficient UV dose throughout opaque and scattering fluids. Standard UV systems rely on direct line-of-sight exposure, which is effective for clear liquids but fails to inactivate pathogens uniformly in turbid or colored products. This results in uneven treatment, leaving portions of the fluid insufficiently processed and potentially unsafe. Furthermore, accurately measuring and verifying the UV dose delivered to all parts of an opaque fluid is technically complex, as traditional sensors only capture local intensity and do not account for the dynamic mixing and light scattering within the system. These limitations have prevented the widespread adoption of UV-C technology for many high-value applications, highlighting the need for innovative solutions that can overcome the inherent optical challenges of treating opaque and scattering fluids.

Technology

This technology is a serpentine path coiled tube UV-C system designed for the germicidal treatment of highly opaque, UV-absorbing, and scattering fluids such as milk, plant-based beverages, and vaccines. Utilizing UV-C light in the 253.7 nm to 280 nm range from low-pressure mercury lamps or LEDs, the system inactivates a broad spectrum of microorganisms—including vegetative cells, endospores, and viruses—by delivering either a pasteurized or sterilized equivalent dose. The serpentine, coiled tube reactor maximizes fluid exposure to UV-C light by inducing secondary (Dean) flow and maintaining turbulent conditions, ensuring all portions of the fluid are effectively treated despite high absorption and scattering properties. The system also integrates advanced tools for dose prediction and verification, including a proprietary fluence prediction algorithm, biodosimetry with microbial surrogates, and genomic modeling to estimate UV sensitivity of viruses, ensuring robust and regulatory-compliant operation.

What differentiates this technology is its ability to overcome the fundamental limitations of conventional UV systems, which struggle to treat opaque and scattering fluids due to poor light penetration. By leveraging a unique reactor geometry and advanced mixing dynamics, it ensures uniform and effective UV exposure throughout the entire fluid volume. The inclusion of sophisticated dose modeling and validation methods—such as the use of genomic markers for surrogate selection and real-time fluence prediction—provides a level of process control and safety assurance not found in traditional systems. Additionally, the system offers significant commercial advantages: it preserves product quality by minimizing heat-induced nutrient loss, reduces energy and water consumption, and is designed for seamless integration and scalability within existing industrial processes. This positions the technology as a disruptive, non-thermal alternative for microbial stabilization in food, beverage, and biopharmaceutical applications, addressing a critical gap in the treatment of challenging fluid matrices.

Benefits

• Effective germicidal treatment of highly opaque, UV-C absorbing, and scattering fluids
• Non-thermal pasteurization and sterilization preserving nutrients, flavors, and bioactive compounds
• Enhanced UV exposure through serpentine coiled tube design inducing turbulent mixing
• Validated inactivation of a broad spectrum of microorganisms including bacteria, spores, and viruses
• Advanced predictive algorithms and biodosimetry for accurate UV dose delivery and process validation
• Energy and water efficient compared to traditional thermal pasteurization methods
• Continuous, high-throughput processing with scalable commercial models
• Integration capability with existing production lines for food, beverage, and biopharmaceutical sterilization

Applications

• Dairy and milk pasteurization
• Plant-based beverage sterilization
• Vaccine and biopharmaceutical sterilization
• Juice and liquid food processing

Additional info

This system is a serpentine coiled tube UV-C reactor for germicidal treatment of opaque, UV-absorbing fluids. It utilizes 253.7-280 nm UV-C light, with the serpentine path maximizing fluid exposure and inducing turbulent mixing to overcome penetration challenges. It inactivates microorganisms, delivering pasteurized or sterilized equivalent doses, and incorporates a novel algorithm for UV fluence prediction and verification.