The increase of foodborne listeriosis outbreaks in recent years prompted more frequent investigation into various foods. In this study toe occurence and significance of L.m. in meat and meat products is discussed. Field research in Berlin medium sized meat processing plants was carried out. The operating areas were monitored for the presence of listeriae in swab samples, liquid from floor drains and on different steps of processing. Based on the resulting data, hygienic classification was established. Routine food samples from 1990-1992 were incorporated in this evaluation. Food samples were analysed using the official isolation method for L.m. as agreed on in February 1990 by the AfLMU (Ausschuss fur Lebensmitteluberwachung der Arbeitsgemeinschaft der Leitenden Veterinarbeamten der Lander). Modifications of this method are thus presented, in order to avoid time- and material-consuming laboratory diagnostics.