Rapid Detection and Counting of Viable Bacteria in Vegetables and Environmental Water Using a Photon-Counting TV Camera

Abstract

A bioluminescence assay carried out with a photon-counting TV camera was evaluated for rapid enumeration of viable bacterial counts. The test sample was filtered through a membrane filter, and the membrane filter retaining bacteria was incubated at 37 degrees C for 6 h on a filter paper soaked with nutrient broth supplemented with 0.5% NaCl. The membrane filter was then subjected to a bioluminescence reaction, and the intensity of light and numbers of light emission points on the filter were measured with a photon-counting TV camera. The light intensity measured on seven different bacteria correlated with initial viable counts; the correlation coefficient was calculated to be 0.89. The number of light emission points measured on Escherichia coli also correlated with the initial viable counts (r = 0.81) in a range from 1 to 100 CFU. Presumptive bacterial counts by the present bioluminescence assay determined on 79 samples of vegetables and 122 samples of environmental water correlated well with the viable counts obtained by the conventional plating method, with correlation coefficients of 0.87 and 0.82, respectively.

New Estimation Methods of Bacterial Concentration by Measuring ATP Changes during Incubation.

“…(iii) The kinetic methods did not need sophisticated apparatus. Miyamoto et al 21) reported a method for bacterial cell counts with a photon-counting TV camera, which was based on firefly bioluminescence. There is also a commercially available system of microbial cell counting with a similar camera system (MicroStar TM -RMDS, Millipore Corp.).…”

Isolation and characterization of proteolytic microorganisms from fresh and fermented cabbage

“…Microbes represent an excellent source proteases due to their broad biochemical diversity (Godfrey & West,1996), their rapid growth, the limited space and the low cost that growing substrates required for their cultivation (Gupta et al, 2002). Vegetables are renewable raw materials associated with diverse microbial populations (Gó mez, Muñ oz, de Ancos, & Cano, 2002;Miyamoto et al, 1998;Ponce, Moreira, del Valle, & Roura, 2008), therefore they could be an interesting and cheap source of proteolytic bacteria. Among vegetables cabbage (Brassica oleracea var capitata) is a biennial sturdy and inexpensive leafy plant.…”

Rapid Enumeration of Microbial Cells in Solubilized Soymilk Using an Automatic Cell Counting System with LED Illumination

“…Therefore, a simple, rapid, and accurate detection method is desirable. Several non-culture methods have been used for the rapid detection of bacteria in food (Fujikawa and Morozuki, 2003;Gracias and Mckillip, 2004;Kawasaki et al, 2004;Kawasaki et al, 2007;Masuda-Nishimura et al, 2000;Miyamoto et al, 1998). PCR is a useful technique because of its high sensitivity.…”