Non-fouling Stainless Steel for Dairy Processing

Fouling of dairy components (e.g. protein, minerals) onto stainless steel surfaces during processing reduces operating efficiency, shortens run times, and increases the likelihood of biofilm formation. Fouling and bacterial biofilm formation is a particular issue in heat exchangers where the heat transfer process increases foulant deposits and provides growth opportunity for thermoduric and thermophilic spoilage microorganisms. Pieces of biofilm can transfer into finished product, giving them high microbial loads and reduced product quality and acceptance. In addition, a fouled heat exchanger requires higher steam temperatures for operation, which increases the number of scorched particles and cooked flavor in the milk product. The ability to prevent biofilm formation and fouling will significantly improve the quality of milk powders by reducing or eliminating spores and scorched particles, and improving flavor. </P>The researcher proposes a practical method of rendering stainless steel food processing surfaces to resist fouling by food components and bacterial spores. The new process incorporates fluoropolymer particles in a plated metal matrix. These coatings will be highly resistant to biofilm formation and fouling by bacteria and food components and will be stable against commonly used cleaning solutions, heat, and abrasion. The proposed nonfouling stainless steel coating can be prepared inexpensively, would be compliant with current FDA regulations, and readily adopted by the dairy industry.