J A Vázquez Boland

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Because the hemolysis produced by Listeria monocytogenes and Listeria seeligeri on blood agar is frequently difficult to interpret, we developed a microplate technique for the routine determination of hemolytic activity with erythrocyte suspensions. This microtechnique is a simple and reliable test for distinguishing clearly between hemolytic and(More)
The survival of Listeria monocytogenes in raw milk treated in a pilot plant size pasteurizer was investigated. Raw milk was inoculated with different initial concentrations of L. monocytogenes and heated at temperatures ranging from 69 degrees to 73 degrees C. Listerias were not isolated from any of the milk samples immediately after thermal treatment. They(More)
Refrigerated mixtures of raw milk provided by a dairy which was supplied by farms from west and central Spain were tested for the presence of Listeria microorganisms. A total of 95 samples were taken at regular intervals over a 16-month period. Listeria grayi was isolated from 89.5% of the samples, Listeria monocytogenes s. str. from 45.3%, Listeria innocua(More)
An haemolytic Listeria monocytogenes strain pathogenic to mice was isolated from 6 out of 28 (21.4%) pasteurized milk samples (3.2% fat milk treated at 78 degrees C for 15 s) marketed by a Madrid processing plant. Listeria grayi was recovered from 25 of the samples (89.2%) and L. innocua from 3 samples (10.7%). One milk sample was contaminated with L.(More)
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