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Page No. : 31-34

ABSTRACT

A study was undertaken to determine the minimal inhibitory concentration (MIC) of stabilized hydrogen peroxide with colloidal silver in the ratio of 50 g/l and 0.0355 g/l, respectively for selected standard strains of microorganisms of food safety importance viz., Staphylococcus aureus, Escherichia coli, Aspergillus niger and Bacillus subtilis as per the technique of Rideal-Walker. Different concentrations were used for the study (50 ppm to 5000 ppm) with the contact time of 2.5 min to 60 min. The results revealed that S. aureus was inhibited at 800 ppm, E. coli at 200 ppm, A. niger at 3000 ppm concentration in 1 h and B. subtilis was inhibited at 2000 ppm in 10 min. As far as shortest contact time is considered, E. coli and B. subtilis were inhibited at 2000 ppm concentration in 10 min, S. aureus at 5000 ppm concentration in 10 min and A. niger was inhibited at 5000 ppm concentration in 30 min contact time. Thus, it can be concluded that E. coli was highly sensitive to hydrogen peroxide, followed by S. aureus and A. niger.

Keywords: Huwa-San, minimal inhibitory concentration (MIC), Rideal-Walker test