1.Optimisation of topical antibacterial preparation from Malaysian kelulut honey by using xanthan gum as polymeric agent
Mohd-Aspar, M.A. ; Edros, R. ; Hamzah, N.A.
Tropical Biomedicine 2021;38(No.3):226-238
The study aims to formulate and optimise topical antibacterial preparation by using Malaysian kelulut honey as the active ingredient and xanthan gum as the polymeric agent. Response surface methodology was used to optimise the preparation. The acidity, honey concentration and xanthan gum concentration were the independent variables. The zone of inhibitions on S. aureus ATCC6538 and E. coli ATCC8739 were the response variables. The optimal preparation was evaluated on its physicochemical properties, viscosity, antibacterial efficacy and stability. The antibacterial efficacy of the optimal preparation was compared to the commercially antibacterial gel (MediHoney™, Comvita). The optimal preparation was formulated at pH of 3.5, honey concentration of 90% (w/v) and xanthan gum concentration of 1.5% (w/v) with the inhibition zones measured on S. aureus ATCC6538 was 16.2 mm and E. coli ATCC8739 was 15.8 mm respectively. The factors of acidity and honey concentration have significantly influenced the inhibition zone on S. aureus ATCC6538 and E. coli ATCC8739. The utilisation of xanthan gum as the polymeric agent was fit for the preparation which showed by adequate physicochemical properties and retained of the antibacterial effects. This was supported by constant viscosity and efficacy of the preparation within the six months of stability study indicating stable and reliable preparation. Xanthan gum is a potential polymeric agent due to its effective use in preparing stable preparation with effective antibacterial properties.
2.Survival of antibiotic resistant Escherichia coli in vacuum-packed keropok lekor: Food safety alert among SME keropok lekor producers
Wan-Hamat, H. ; Lani, M.N. ; Hamzah, Y. ; Alias, R. ; Hassan, Z. ; Mahat, N.A.
Tropical Biomedicine 2020;37(No.1):103-115
The microbiological quality of thirty ready-to-eat (RTE) keropok lekor (a sausage shape Malaysian fish product) was evaluated in comparison to microbiological guidelines for ready to eat foods. The two E. coli isolates were subjected to DNA sequencing, identified and tested for their resistance towards fifteen different antibiotics. The survival and growth of the isolated E. coli strains inoculated in keropok lekor at atmospheric air and vacuum packaging were also evaluated. Results revealed that four samples (13.33%) contained Enterobacteriaceae counts that exceeded the recommended allowable counts of 4.0 log10 CFU/g. Unsatisfactory level of coliforms (> 1.7 log10 CFU/g) was also observed in ten of the samples; two of which contained E. coli (2.1 ± 0.17 and 3.7 ± 0.02 log10 CFU/g), suggesting of poor hygiene and sanitation practices. While the ‘Possible E10’ E. coli strain was observably resistant towards Nalidixic acid (30µg) alone, B10 E. coli isolate was worryingly resistant towards Ampicillin (10µg), Ceftazidime (30µg), Ciprofloxacin (5µg), Ceftriaxone (30µg), Nalidixic acid (30µg) and Tetracycline (30µg). This study also revealed that the growth and survival of the ‘Possible E10’ and B10 E. coli strains were not significantly affected by vacuum packaging when stored at both 4°C and 28°C. Therefore, intervention programmes to alert and educate smallmedium enterprisers (SMEs) of keropok lekor producers on food safety as well as potential health risks that can be associated due to inappropriate handling procedures of such product, merits consideration.