Developing an air impingement dry cleaning device and investigating the factors affecting nonfat dry milk residue removal from stainless steel surfaces

Zhipeng Liu; Yu Liu; Jincheng Ma; Woo-Ju Kim; Long Chen

doi:10.3168/jds.2025-26826

Developing an air impingement dry cleaning device and investigating the factors affecting nonfat dry milk residue removal from stainless steel surfaces

J Dairy Sci. 2025 Jul 9:S0022-0302(25)00518-1. doi: 10.3168/jds.2025-26826. Online ahead of print.

Authors

Zhipeng Liu¹, Yu Liu¹, Jincheng Ma¹, Woo-Ju Kim², Long Chen³

Affiliations

¹ College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China.
² Department of Food Science and Biotechnology, Seoul National University of Science and Technology, Seoul, 01811, South Korea.
³ College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China; Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, NE 68588. Electronic address: long.chen@nwafu.edu.cn.

PMID: 40645494
DOI: 10.3168/jds.2025-26826

Abstract

Dry cleaning has been identified as one method for controlling allergen cross-contact/pathogen cross-contamination in low-moisture food (LMF) environments without introducing moisture. Therefore, an air impingement cleaning device was custom-designed and explored as a dry cleaning method to remove nonfat dry milk (NFDM) residue on stainless steel (SS) surfaces. We investigated the effects of water activity (a_w) of NFDM, residue thickness (THK), nozzle diameter (D), nozzle height to the SS surfaces/nozzle diameter (H/D), and air pressure (P) on the NFDM residue removal. During dry cleaning, the maximum wall shear stress (WSS) induced by airflow on SS surfaces was measured using the oil film interferometry method. The experimental results showed significant effects of all investigated factors on the removal time of NFDM residue and maximum WSS. The time to remove NFDM residue from SS surfaces increased with the increases of a_w, D, and H/D, and decreased with the rise of P. The maximum WSS decreased with the increases of D and H/D and increased with the rise of P. The developed air impingement device and obtained experimental results could help facilitate the practical application of dry cleaning technology to prevent cross-contact and cross-contamination in dry food manufacturing environments and improve LMF safety.

Keywords: cross-contact; cross-contamination; dry food processing environments; low-moisture foods; wall shear stress.

The Authors. Published by Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).