title: Short communication: Evaluation of a sol-gel-based stainless steel surface modification to reduce fouling and biofilm formation during pasteurization of milk.
abstract: Milk fouling and biofilms are common problems in the dairy industry across many types of processing equipment. One way to reduce milk fouling and biofilms is to modify the characteristics of milk contact surfaces. This study examines the viability of using Thermolon (Porcelain Industries Inc., Dickson, TN), a sol-gel-based surface modification of stainless steel, during thermal processing of milk. We used stainless steel 316L (control) and sol-gel-modified coupons in this study to evaluate fouling behavior and bacterial adhesion. The surface roughness as measured by an optical profiler indicated that the control coupons had a slightly smoother finish. Contact angle measurements showed that the modified surface led to a higher water contact angle, suggesting a more hydrophobic surface. The modified surface also had a lower surface energy (32.4 ± 1.4 mN/m) than the control surface (41.36 ± 2.7 mN/m). We evaluated the susceptibility of control and modified stainless steel coupons to fouling in a benchtop plate heat exchanger. We observed a significant reduction in the amount of fouled layer on modified surfaces. We found an average fouling weight of 19.21 mg/cm2and 0.37 mg/cm2on the control and modified stainless steel coupons, respectively. We also examined the adhesion of Bacillus and biofilm formation, and observed that the modified stainless steel surface offered greater resistance to biofilm formation. Overall, the Thermolon-modified surface showed potential in the thermal processing of milk, offering significantly lower fouling and bacterial attachment than the control surface.
authors.affiliation: Department of Animal Sciences and Industry/Food Sciences Institute, Kansas State University, Manhattan 66506.
authors.forename: Dylan Zhe
authors.initials: DZ
authors.lastname: Liu
authors.affiliation: Midwest Dairy Foods Research Center, Dairy and Food Science Department, South Dakota State University, Brookings 57007.
authors.forename: Shivali
authors.initials: S
authors.lastname: Jindal
authors.affiliation: Department of Animal Sciences and Industry/Food Sciences Institute, Kansas State University, Manhattan 66506. Electronic address: Jayendra@ksu.edu.
authors.forename: Jayendra
authors.initials: J
authors.lastname: Amamcharla
authors.affiliation: Midwest Dairy Foods Research Center, Dairy and Food Science Department, South Dakota State University, Brookings 57007.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Anand
authors.affiliation: Midwest Dairy Foods Research Center, Dairy and Food Science Department, South Dakota State University, Brookings 57007.
authors.forename: Lloyd
authors.initials: L
authors.lastname: Metzger
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D018441:Biofilms; D008892:Milk; D061352:Pasteurization; D013193:Stainless Steel / Q000737:chemistry*
chemical_list: D013193:Stainless Steel
keywords: bacterial attachment; milk deposit; surface treatment; thermal processing