MESSAI.iO

AI summary

75% confidence

This study compared the effectiveness of three surfactants in foam cleaning for removing Bacillus subtilis spores from stainless steel surfaces, with sodium dodecyl sulfate (SDS) achieving the highest spore removal. The surfactant type significantly influenced foam structure and cleaning performance. The findings have implications for the development of more efficient and environmentally friendly cleaning-in-place (CIP) processes.

Generated by MESSAI extraction pipeline · review against source PDF

Extraction

Reported parameters

2 extracted values

View extracted values

No 3D model is mapped to this paper yet. Parameter ranges above still place reported values on the literature distribution.

Abstract

Foam cleaning represents an environmentally and economically attractive alternative to conventional cleaning-in-place (CIP) processes for removing microbial contamination in food and bioprocessing industries. This study systematically compared three surfactants, sodium dodecyl sulfate (SDS), Ammonyx® LO, and Capstone® FS-30, to understand how surfactant type influences foam structure and cleaning performance. Stainless steel coupons contaminated with Bacillus subtilis 98/7 spores were cleaned under identical flow conditions using foam generated at a nominal air fraction of 0.5 and a mean velocity of 1.8 cm s -1 . SDS achieved the highest spore removal (1.9 log 10 reduction after 20 min), with superior kinetic detachment (K 1 = 114.75 s -1 ; f = 98.2%), while Ammonyx® LO (0.83 log 10 ) and Capstone® FS-30 (0.55 log 10 ) performed significantly worse. These differences were attributed to foam structural properties: SDS produced fine, stable bubbles persisting for 24 h, while Ammonyx® LO and Capstone® FS-30 collapsed after 8 and 3 h, respectively. Image analysis revealed local air fractions of 0.88 (SDS), 0.79 (Ammonyx), and 0.96 (Capstone) in the test section, confirming dry foam behavior. Theoretical analysis using Bretherton’s model and microscopic observations showed that SDS’s low capillary number promotes strong Marangoni stabilization and thin lamellae, generating sustained wall shear stress fluctuations essential for spore detachment. This study demonstrates that foam cleaning efficiency is primarily determined by surfactant-controlled variations in bubble size, foam stability, and interfacial properties. SDS provides the optimal balance for achieving efficient and sustainable foam-based cleaning.

Key findings

  • SDS achieved a 1.9 log10 reduction in spore removal after 20 minutes
  • Ammonyx LO and Capstone FS-30 performed significantly worse with 0.83 and 0.55 log10 reductions respectively
  • The kinetic detachment of SDS was superior with a K1 value of 114.75 s⁻¹ and a f value of 98.2%

Keywords

Pulmonary surfactantSodium dodecyl sulfateBubbleEndosporeBacillus subtilisBioprocess

Identifiers

DOI
10.3389/frsfm.2026.1750630
Journal
Frontiers in Soft Matter
Year
2026