Comparing Thermal Pasteurization And UV Disinfection Of Water In Cheese & Dairy Process Applications

November 15, 2021 00:00 | Posted in News

Using Ultraviolet light (UV) to treat incoming plant process water as a firewall to deactivate waterborne bacteria and organisms is a common application for the technology. This application strategy enables deactivation of free-floating bacteria cells that enter the plant through process water pipes. Destruction of these bacteria with Thermal (HTST) Pasteurization for critical process water applications is well understood. By comparison De-activation of these bacteria with UV Technology is not as clear but can easily provide higher log reductions of Psychrotrophs and Pseudomonas bacteria among other target organisms compared to Thermal Pasteurization.



Thermal Pasteurization for Water Disinfection


Thermal pasteurization with a typical HTST achieves 5 log destruction of many harmful waterborne organisms and is widely used in Dairy and Cheese Production. This usually involves batching water through the HTST (after CIPing the HTST) to be stored in a water tank for future plant use. This effectively ties up the HTST making safer water instead of processing milk.


Most psychrotrophs are destroyed by pasteurization temperatures, however, some like Pseudomonas fluorescens, Pseudomonas fragi can produce proteolytic and lipolytic extracellular enzymes (creating biofilms) which are heat stable and capable of causing spoilage. Some species and strains of Bacillus, Clostridium, Cornebacterium, Arthrobacter, Lactobacillus, Microbacterium, Micrococcus, and Streptococcus can survive pasteurization and grow at refrigeration temperatures which can cause spoilage problems.


UV Disinfection for Pasteurized Equivalent Water


UV Water Disinfection breaks the DNA bonds of the target organisms which prevents them from reproducing. This approach provides higher levels of organism reduction than thermal pasteurization. For example a pasteurized equivalent dose of 120 mJ or and EPA water dose of 60 mJ of UV light provides infinitely higher log reductions of many common spoilage organisms. Only 8 mJ of UV energy is required to provide 5 log reduction of Listeria. 6 mJ of UV energy is enough to deactivate Pseudomonas to five log reduction.



You can see that UV Disinfection is highly effective at deactivating organisms of concern. UV also works on Thermophilic bacteria that are activated by thermal pasteurization. Thermal pasteurization is a much more energy intensive process when compared to UV Water Disinfection. Some potential applications to consider using UV treated water include:


  • Replacing HTST Pasteurized Water with PEW (UV Treated) Water
  • Water used to wash curd in washed curd cheeses
  • Water used to hydrate powders used as an ingredient used to make cheese
  • Water used to wash Cottage Cheese
  • Water used in production in Culture Rooms
  • Product Cooling and Packaging Water for fresh Mozzarella
  • Water used to make and make-up brine
  • Treated Clean Wastewater before discharge
  • After Carbon Beds
  • Before and/or after filtration systems depending on the application.


Microbial contaminants in water supplies can cause microbial growth in the process pipes and ultimately in the final product. Ultraviolet Disinfection provides a proven and safer way to deactivate water borne pathogens, spores, biofilms, and spoilage organisms that come into the plant through the municipal or well water supply.


UV is a proven and reliable technology for the disinfection of water. It is safe, free from chemicals, and cost efficient.


Book an application discussion with Valcour today to discuss your potential application(s) for utilizing the latest UV water disinfection technology.


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