Rapid non-microbiological methods for detecting microorganisms in foods

Pishawikar, M.S.; Kulkarni, P. R.

doi:10.1016/0924-2244(92)90179-z

Cited by 9 publications

(2 citation statements)

References 38 publications

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“…Although traditional methods such as pH measurements are still used for contamination detection in some industries, new technologies are changing the industrial microbiological quality control scenario. A great variety of new methods, for example, electric impedance measurements, ATP luminescence-based measurement, colorimetry, flow cytometry, epifluorescence, microcalorimetry, nucleic acid technologies, has been developed during the previous decades [1][2][3]. The reason for such diversity is the specific requirements, and the human and equipment resources available in each case.…”

Section: Introductionmentioning

confidence: 99%

“…The initial decrease rate of the absorbance characterizes the enzymatic activity. Following the suppliers' recommendations [11], the formula used to calculate the activity is [11,12] 34.5 Enzyme (units ml ) (2) t is the time in minutes required for the absorbance at 240 nm to decrease from 0.45 to 0.40 units which corresponds to a change in concentration from 10.3 to 9.2 mM.…”

Section: Catatase Activity Characterizationmentioning

confidence: 99%

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A new ultrasonic signal amplification method for detection of bacteria

Shukla¹,

López²,

Sánchez³

et al. 2012

Meas. Sci. Technol.

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A new method is presented that increases the sensitivity of ultrasound-based techniques for detection of bacteria. The technique was developed for the detection of catalase-positive microorganisms. It uses a bubble trapping medium containing hydrogen peroxide that is mixed with the sample for microbiological evaluation. The enzyme catalase is present in catalase-positive bacteria, which induces a rapid hydrolysis of hydrogen peroxide, forming bubbles which remain in the medium. This reaction results in the amplification of the mechanical changes that the microorganisms produce in the medium. The effect can be detected by means of ultrasonic wave amplitude continuous measurement since the bubbles increase the ultrasonic attenuation significantly. It is shown that microorganism concentrations of the order of 10 5 cells ml -1 can be detected using this method. This allows an improvement of three orders of magnitude in the ultrasonic detection threshold of microorganisms in conventional culture media, and is competitive with modern rapid microbiological methods. It can also be used for the characterization of the enzymatic activity.

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Section: Introductionmentioning

confidence: 99%

Section: Catatase Activity Characterizationmentioning

confidence: 99%