# Micro-Nanobubble Technology in Surface Cleaning and Defouling
## 3 Advanced Applications of NBs in Precision Surface Cleaning
### Food Industry and Pathogen Control  
The food sector has found that NBs are useful for improving food safety and infection control [78]. Their capacity to work in concert with other technologies and antimicrobial compounds provides novel approaches for lowering foodborne pathogens, such as _Listeria monocytogenes_ (LM) and _E. coli_ O157:H7, on food surfaces and under microbial growth conditions. [PERSON] et al. [79] investigated the effect of surfactants on enhancing the efficiency of NBs in eliminating _E. coli_ O157:H7 and _Listeria innocua_ (_L. innocua_) from spinach leaves (Figure 12). They also examined how effectively NBs and ultrasound worked together to inactivate pathogens in cell suspensions. After 15 min, the data demonstrated that neither the ultrasound nor NBs significantly decreased the number of germs in the cell solution. However, after 10 and 15 min, the combination of NBs with ultrasound produced a 7-log reduction in _E. coli_ and a more than 6-log reduction in _L. innocua_. Compared with significantly fewer reductions with ultrasound alone, NBs combined with ultrasound also improved the eradication of germs from spinach surfaces, achieving more than 2- and 4-log reductions in _L. innocua_ and _E. coli_, respectively. The addition of food-grade surfactants (0.1% SDS and 0.1% Tween 20) did not significantly increase the effectiveness of the ultrasound or NBs in removing microorganisms. The study concluded that although ultrasound and NBs are both successful at removing pathogens, further investigation is required to determine how surfactants affect the stability and characteristics of NBs. [PERSON] et al. [78] examined the efficacy of forced aeration and chlorinated water at removing pathogens from produce surfaces. After being inoculated with _L. innocua_, _E. coli_ O157:H7, and _Salmonella enterica_, cucumbers and bell peppers were rinsed with 100 ppm chlorinated and/or aerated water. Pathogen levels were considerably decreased by washing with chlorinated water, either with or without aeration. The most substantial decreases in _Salmonella_ and _Listeria_ were observed when both treatments were combined. Although non-chlorinated water was less effective against _Listeria_, which adheres more securely to produce surfaces, it also lowered _Salmonella_ levels. Pathogen levels in the chlorinated water were below detectable limits following treatment. According to the findings, sanitizer effectiveness, pathogen elimination, and cross-contamination improved when chlorine and forced aeration were combined. However, further investigation is required to evaluate this strategy for other produce varieties and larger-scale operations. [PERSON] et al. [80] examined the effects of adding MNBs to conventional food antimicrobials to improve their efficacy against LM and _E. coli_ O157:H7 (EC). MNBs were produced in municipal water using air, carbon dioxide (CO\({}_{2}\)), and nitrogen (N\({}_{2}\)), and the bacterial  
Figure 12: (**a**) _L. innocua_ and (**b**) _E. coli_ counts in NBs (NB), ultrasound (US), and NBs with ultrasound (NB + US) treated samples at different exposure times. (**c**) _L. innocua_ and (**d**) _E. coli_ reduction in ultrasound (US) and NBs with ultrasound (NB + US) treated spinach leaves at different exposure times. Capital letters indicate the significant differences among the treatments at given time, lower-case letters indicate the significant differences of specific treatment at different times, and the asterisk means “not detectable”. Reproduced with permission from [79], CC-BY 4.0 license, Copyright © 2021, the authors. Licensee MDPI, Basel, Switzerland. inocula were combined with antimicrobial solutions (with or without). The findings demonstrated that Cl\({}_{2}\)-CO\({}_{2}\) solutions resulted in a considerably higher log reduction (5.2-log) against EC than Cl\({}_{2}\) alone (3.8-log), whereas PAA-CO\({}_{2}\) solutions produced a significantly greater log reduction (4.4-log) against LM than PAA alone (1.7-log).