ISOLATION OF COLIFORM BACTERIA USING A SY NTHETIC LIQUID-MEDIUM

A synthetic medium was developed and isolation of coliform bacteria fr om the food was investigated. Selectivity of the new medium (X-broth) was tested by the inoculation of Escherichia coli, Klebsiella pneumoni ae, Enterobacter cloaceae bacteria, as well as by pure cultures of mic robes of Proteus, Pseudomonas, Bacillus and Staphylococcus genera. Sui tability of the new medium for the isolation of coliform bacteria was tested by a nation-wide round test (with the participation of 15 labor atories) in quick-frozen tomato paprika samples where the synthetic me dium proved to be suitable on the basis of reproducibility and compara tiveness. It was found that the selectivity of X-broth was significant ly better than the brillantgreen-lactose-bile (BBL)-broth specified in the standard. Based on the results of round tests (Figure), the new m edium proved to be suitable also from the point of view of reproducibi lity (r) and comparativeness (R) (Table). Its main advantages are the freedom from inhibitor matters, standard composition, liability, good keeping quality and low price. On the basis of the studies carried out , the composition of the new medium was patented and commercialized.