[Presence of E. coli bacteria in raw and pasteurized cow's milk]

Investigated for the presence of E. coli-bacteria belonging to the O-groups of dispeptic strains, are 85 samples of raw and 212 pasteurized milk, taken from subsequent departments of the milk-producing industry. Dispeptic E. coli are detected in 11.76 per cent of the samples of raw milk studied, and in 5.18 per cent in those of the pasteurized milk. No coli forms are established in samples, taken directly from the pasteurizing equipment. The secondary infection with E. coli results from the use of vessels and equipment in the course of the technological process. E. coli-bacteria, belonging to the O-groups of dispeptic strains, are demonstrated in samples both with the aid of a coli-titre, in conformity with standard requirements, and in samples that are not standard, according to this indice. The 21 strains of E. coli-bacteria isolated are referred to the following O-groups: 06, 025, 026, 055, 078, 086, 0111, 0119, 0124, 0125 and 0127. Some of the strains isolated manifest an atypical behaviour to lactose and sucrose in comparison with the properties, indicated in the scheme by Kauffmann.