Process and apparatus for indicating the presence of contaminating microorganisms

摘要

A bacteria-containing food in a liquid state is mixed with a predetermined quantity of a nutrient medium containing a colour indicator in vessel 1 which has an outlet connection open towards the bottom. Where the subsequent cultivation of the bacteria is accompanied by formation of gas, equivalent measurable quantities of the mixture of nutrient medium and bacteria suspension flow out of vessel 1. Turbidity and colour changes in the nutrient medium containing the colour indicator also provide information about the bacteria. The apparatus comprises cultivation vessel 1 with a glass tip 2 which can be broken off by means of a "breaking-off ring" 7 and a canula 3 communicating with the inside of the vessel 1 through the tip 2. The canula 3 constitutes a suction intake for liquid food to be tested and an outlet connection for nutrient medium and bacteria suspension displaced from the vessel 1 upon formation of gas during cultivation.