| 摘要 |
<p>A sample of gas is withdrawn from the interior of a cheese. The sample is analysed to detect the presence of hydrogen or other gas or volatile arising from the fermentation. Pref. a tubular probe is pushed into the cheese and connected to the suction side of a pump via a transparent tube contg. a reagent which changes colour in the presence of hydrogen. The indicating reagent is pref. downstream of a catalyst which produces combustion of the hydrogen in the presence of air contained in the sample. The resulting water is used to react with the indicator. The sample gas is pref. passed through a dessicant before it reaches the catalyst. The gas sample is pref. always of constant volume by virtue of being withdrawn by a volumetric pump. The transparent indicator tube will then have a longitudinal scale with graduations indicating the concn. of hydrogen gas in the sample. The indication is related directly to the generation of hydrogen gas arising from butyric fermentation. The result is instantly available, rather than having to wait several days for analysis of butyric spores, which, in any case, is not direct evidence.</p> |
