The consumption of fresh produce is steadily increasing and chlorine washing is the most commonly used method of disinfecting fresh produce. However, chlorine washing possesses a potential risk. Hence, this study used ozone microbubble (OMB) water to disinfect Salmonella Enteritidis, S. Typhimurium, Staphylococcus aureus, and Escherichia coli on tomatoes. After injecting ozone into the microbubble generator, OMB was fulfilled in a 10 L tank for 10 or 20 min. The inoculated tomatoes were washed for 30 or 60 s. Control groups included unwashed, water-washed, microbubble-only, and ozone-only. The microbial populations were significantly lower on the OMB-treated tomatoes than controls (p < 0.05), but not between various fulfilling or treatment time (p > 0.05). When tomatoes were treated with OMB with 10 min fulfilling and 30-s washing, the differences of tested bacteria and water washing, ozone-only, and microbubble-only were: S. Enteritidis: 4.11, 3.37, 2.54 log CFU/tomato; S. Typhimurium: 4.83, 4.50, 2.78 log CFU/tomato; E. coli: 4.31, 4.08, 2.09 log CFU/tomato; S. aureus: 4.12, 3.93, 2.82 log CFU/tomato. In addition, significant higher ozone concentrations and conductivity were detected in OMB water than other groups (p < 0.05). Color, texture, and sensory characteristics of the OMB-treated tomatoes were not significantly different from other groups (p > 0.05). This study demonstrated that OMB effectively inactivated bacteria on tomatoes and did not affect the physical and sensory characteristics of tomatoes.

In this paper, a plasma-induced hemi-wicking phenomenon observed on hydrophobic sanded polymer surfaces, polypropylene (PP), polyethylene terephthalate (PET) and polyethylene (PE) is reported. An atmospheric-pressure argon plasma jet was used to treat a limited area of the carefully sanded polymer surfaces to induce the hemi-wicking phenomenon. Such hemi-wicking triggered by the plasma activation is different from the traditional type, which is achieved purely by the surface topography. Surface analyses by X-ray photoelectron spectroscopy (XPS) and water contact analysis (WCA) show that the combination of sanding and plasma treatment increased the oxygen-to-carbon ratio, which is highly beneficial for surface hydrophilicity. The shear stress tests show that the combination of sanding and plasma treatment can enhance the shear stress by 125%, 95%, and 296% on PP, PET, and PE, respectively. The study shows that the newly developed technique by combining the sanding and plasma processing for polymers could be a potentially useful method in future industry applications.

Microbial contamination is the main safety concern of sprouts and seeds are the major source. High concentrations of sanitizers (>10,000 mg/kg) are recommended for effective sanitation. Microbubble (MB) was reported to elevate sanitizer efficacy. Hence, MBs combined with disinfectants, chlorine dioxide (ClO₂, 500 ppm), and slightly acidic electrolyzed water (SAEW, 250 ppm), were used to inactivate Salmonella Typhimurium on alfalfa seeds. After fulfilling MBs for 10 min, alfalfa seeds were washed in 10 L of water for 10, 20, or 30 min. Compared with untreated seeds, S. Typhimurium reductions obtained by SAEW-MBs (SMBs) and ClO₂-MBs (CMBs) for 20 min were 3.8 and 3.3 log CFU/g, respectively. Conversely, the 20 min treatments of SAEW and ClO₂ only obtained reductions of 0.9 and 1.1 log CFU/g, respectively. More surface ruptures on the seeds treated with CMBs were observed under a scanning electron microscope compared with the ones treated by water and ClO₂ only. No adverse effects on the seed germination rate and the weight yield of sprouts were observed when treated with CMBs for 20 min. An MB device with capacity of 100 L was assembled and achieved reductions of 3.9 and 3.2 log CFU/g of natural microbes and S. Typhimurium, respectively, after 20 min CMB washing. Additionally, an MB device at 250 L was assembled and achieved 3.0 log CFU/g reduction in natural microbes. This study demonstrated that MBs enhanced the efficacy of disinfectants and could be applied in industrial-scale operations.

Microbial contamination is the main safety concern of sprouts and seeds are the major source. High concentrations of sanitizers (>10,000 mg/kg) are recommended for effective sanitation. Microbubble (MB) was reported to elevate the sanitizer efficacy. Hence, MB combined with disinfectants, chlorine dioxide (ClO2, 500 ppm) and slightly acidic electrolyzed water (SAEW, 250 ppm), was used to inactivate Salmonella Typhimurium on alfalfa seeds. After fulfilling MB for 10 min, alfalfa seeds were washed in 10 L of water for 10, 20, or 30 min. Compared with untreated seeds, S. Typhimurium reductions obtained by SAEW-MB (SMB) and ClO2-MB (CMB) for 20 min were 3.8 and 3.3 log CFU/g, respectively. Conversely, the 20-min treatments of SAEW and ClO2 only obtained reductions of 0.9 and 1.1 log CFU/g, respectively. More surface ruptures on the seeds treated with CMB were observed under a scanning electron microscope compared with the ones treated by water and ClO2 only. No adverse effects on the seed germination rate and the weight yield of sprouts were observed when treated with CMB for 20 min. A MB device with capacity of 100 L was assembled and achieved reductions of 3.9 and 3.2 log CFU/g of natural microbes and S. Typhimurium, respectively, after 20-min CMB washing. Additionally, a MB device at 250 L was assembled and achieved 3.0 log CFU/g reduction of natural microbes. This study demonstrated that MB enhanced the efficacy of disinfectants and could be applied for industrial-scale operation.