Abstract: Microbiological examination of foods involves sample preparation and subsequent homogenization. This paper addresses the effectiveness of Stomacher™, Pulsifier™, Bagmixer™ and Smasher™ instruments in terms of: 1) viable cell counts/g for 10 kinds of foods, 2) noise level of four instruments associated with human operation and decibel meter at 5 ft from each instrument, 3) convenience for cleaning instruments after use, and 4) ergonomics. Aliquots of 25 g for 10 kinds of foods were placed individually in a sample bag containing 224.5 mL of 0.1% peptone water plus 0.5 mL of Escherichia coli inoculum. Each food was homogenized for 60 s. Ease of cleaning and ergonomics when using Stomacher™ were determined as a reference. All 4 instruments revealed a similar performance regarding viable cell counts. As for noise level, Smasher™ and Bagmixer™ were the quietest, followed by Stomacher™ and Pulsifier™. Smasher™ ranked highest in ease of cleaning and ergonomics, followed by Bagmixer™, Stomacher™, and Pulsifier™.

Key words: noise level, decibels, ergonomics, viable cell count