Dry heat inactivation of <i>Bacillus cereus</i> in rice
2008
Houška, M. | Kýhos, K. | Landfeld, A. | Průchová, J. | Schlemmerová, L. | Šmuhařová, H. | Špelina, V. | Novotná, P.
The aim of this work was to validate the method of decontamination of rice at the temperature of 120°C (determined as optimal in previous experiments). <i>Bacillus cereus</i> was selected as the marker micro-organism for the monitoring of decontamination. The spores of <i>Bacillus cereus</i> are moderately heat resistant. In order to show the efficacy of our decontamination process, we artificially contaminated the rice under study with <i>B. cereus</i>. Decontamination was carried out in a homogenising steriliser about 20 h after contamination. The sample was first heated to 90°C and held at this temperature for 70 minutes. Then the temperature was increased to 120°C and held for 3 hours. Five samples were taken for microbiological analyses as follows: before the experiment, on reaching 120°C, and then after 1, 2, and 3 h of decontamination. Decontamination of rice from vegetative forms and spores of <i>B. cereus</i> present at the level of 400 CFU/ml was effected by heating to 120°C and holding for 1 hour.
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