Polyhexamethylene guanidine hydrochloride (PHMGH), an antimicrobial biocide of the guanidine family, was tested for efficacy against quality-control strains of Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella choleraesuis, meticillin-resistant S. aureus (MRSA) and Escherichia coli. Bactericidal activity against S. aureus, P. aeruginosa and Salmonella choleraesuis was determined using the official methods of analysis of the Association of Official Analytical Chemists, with modifications as recommended by the Canadian General Standards Board. For MRSA and E. coli, the MIC and minimal bactericidal concentration were determined using the broth dilution technique. The experiments were carried out at 20 6C under a range of conditions including varying PHMGH concentration (0.001-0.1 %), contact time (0.5-10 min) and water type (distilled, tap and hard water). The phenol coefficient values determined with S. aureus, Salmonella choleraesuis and P. aeruginosa were 7.5, 6.1 and 5, respectively. No matter what type of water was used to make the dilutions, PHMGH killed MRSA and E. coli at concentrations as low as 0.04 and 0.005 % (w/v), respectively, within 1.5 min. The mode of action of PHMGH was elucidated by transmission electron microscopy: the cell envelope was broken, resulting in cell content leakage into the medium. The ultimate aim of this study was to show that PHMGH can be used as an odourless, colourless, non-corrosive and harmless disinfectant for hospital and household facilities.

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Mushrooms (Agaricus bisporus) were packaged in 4-liter modified atmosphere (MA) containers, and a steady-state atmosphere of 5% and 10% was maintained at 4 °C. Temperature was fluctuated from 4 °C to 20 °C during 12-d storage period in cycles: 2 d at 4 °C followed by 2 d at 20 °C. Temperature increase during fluctuations caused anoxic atmospheres both in O 2 (1.5%) and CO 2 (22% to 10%). The quality of mushrooms stored under temperature fluctuating regime was severely affected as indicated by extensive browning, loss of firmness, and the level of ethanol in the tissue compared to mushrooms stored at constant temperature. It was clear that temperature fluctuation, even if it should occur once, can seriously compromise the benefits of MA packaging and safety of the packaged produce.

Papaya (Carica papaya) is a common tropical fruit used for nutrition as well as medicinal purposes. Apart from fruit, seed, latex and other plant parts of papaya tree have been shown to have medicinal properties. Since, no systematic study has been performed on nutritional analysis of papaya (Carica papaya L. var solo 8) peels. In this study, the proximate composition, mineral element profile and phytochemical composition of papaya (Carica papaya L. var solo 8) peels were investigated. The peels were harvested fresh, dried in an oven at 45°C for 48 hours, ground and analyzed according to standard procedures. Proximate analysis showed high level of proteins (11.67 ± 0.04 %), crude fibre (32.51 ± 0.03 %), carbohydrate (47.33 ± 0.08 %), ash (5.98 ± 0.03 %) 0.03 %) and fat (2.51 ± 0.13 %). Mineral analysis indicated the papaya (Carica papaya L. var solo 8) peels were specifically rich in potassium and phosphorus. Potassium was found to be the most abundant mineral present in the peels (516.33 ± 0.82 mg/100g). Phytochemical composition showed high level of total phenolic (65.48 ± 0.39 mg (GAE)/100 g DW), flavonoids (5.58 ± 0.83 mg (QE)/100 g DW) and tannins (10.51 ± 0.93 mg (TAE)/100 g DW). The methanolic extracts of the papaya (Carica papaya L. var solo 8) peels exhibited the high DPPH radical scavenging activities (81.89 ± 0.14 %).These data indicated that this papaya (Carica papaya L. var solo 8) peels could constitute a potential good source of natural antioxidant for local population.