Antimicrobial Treatment of Escherichia coli and Staphylococcus aureus in Herbal Tea Using Low-Temperature Plasma.

A low-pressure capacitively coupled discharge was used to study antimicrobial treatment in herbal tea. Ambient air with a relative humidity of 40% was used as a precursor gas and fed into the chamber via a perforated power electrode. An electrical discharge plasma was produced at a radio frequency of 10 kHz and power of 80 W. The operating pressure during treatment was kept constant at 260 Pa. The target microorganisms, Escherichia coli and Staphylococcus aureus, isolated from the herbal tea were inoculated on nutrient agar petri dishes and exposed to the plasma for 0.5, 1.0, 1.5, and 2.0 min. All treatments were carried out in triplicate for different exposure times to calculate the D-value by the enumeration method. D-values of 0.73 and 0.67 min were obtained corresponding to E. coli and S. aureus reduction, respectively.

Consumption of Bifidobacterium lactis Bi-07 by healthy elderly adults enhances phagocytic activity of monocytes and granulocytes.

Elderly adults have alterations in their gut microbiota and immune functions that are associated with higher susceptibility to infections and metabolic disorders. Probiotics and prebiotics, and their synbiotic combinations are food supplements that have been shown to improve both gut and immune function. The objective of this randomised, double-blind, placebo-controlled, cross-over human clinical trial was to study immune function and the gut microbiota in healthy elderly adults. Volunteers (n 37) consumed prebiotic galacto-oligosaccharides (GOS; 8 g/d), probiotic Bifidobacterium lactis Bi-07 (Bi-07; 10(9) colony-forming units/d), their combination (Bi-07 + GOS) and maltodextrin control (8 g/d) in four 3-week periods separated by 4-week wash-out periods. Immune function was analysed by determining the phagocytic and oxidative burst activity of monocytes and granulocytes, whole-blood response to lipopolysaccharide, plasma chemokine concentrations and salivary IgA levels. Gut microbiota composition and faecal SCFA content were determined using 16S ribosomal RNA fluorescence in situ hybridisation and HPLC, respectively. Primary statistical analyses indicated the presence of carry-over effects and thus measurements from only the first supplementation period were considered valid. Subsequent statistical analysis showed that consumption of Bi-07 improved the phagocytic activity of monocytes (P < 0·001) and granulocytes (P = 0·02). Other parameters were unchanged. We have for the first time shown that the probiotic Bi-07 may provide health benefits to elderly individuals by improving the phagocytic activity of monocytes and granulocytes. The present results also suggest that in the elderly, the effects of some probiotics and prebiotics may last longer than in adults.

Antimicrobial activity of Blumea balsamifera (Lin.) DC. extracts and essential oil.

Leaves of Blumea balsamifera (Lin.) DC. are used in traditional Thai and Chinese medicine for the treatment of septic wounds and other infections. In this study, the essential oil, hexane, dichloromethane and methanol extracts of these leaves were evaluated for antibacterial and antifungal activities using the disc diffusion assay and agar microdilution method. The essential oil was the most potent, with a minimum inhibitory concentration (MIC) of 150 µg mL⁻¹ against Bacillus cereus and an MIC of 1.2 mg mL⁻¹ against Staphylococcus aureus and Candida albicans. Activity was also detected from the hexane extract against Enterobacter cloacae and S. aureus. Minimum bactericidal and fungicidal concentrations were typically equal to or two-fold higher than the MICs for both extracts, indicating microbicidal activity. The present data show that B. balsamifera extracts have activity against various infectious and toxin-producing microorganisms. This plant's active constituents could potentially be developed for use in the treatment and/or prevention of microbial disease.