ISO 8914:1990

Determination of the presence or absence of these microorganisms in food products or animal feeding products in three successive phases. Inoculation of the test portion into two selective enrichment media and incubation at 35 ° centigrade or 37 ° centigrade for 7 h or 8 h. Inoculation of the two selective solid media, thiosulfate citrate bile sucrose agar (TCBS) and triphenyltetrazolium chloride soya tryptone agar (TSAT) from the cultures thus obtained, incubation at 35 ° centigrade or 37 ° centigrade and then examination after 18 h, 24 h or 48 h (depending on the medium) for the presence of colonies by their visible characteristics. Confirmation by microscopical examination and biochemical analyses.