Prevalence of Listeria in soil.

One hundred thirty soil samples from agricultural fields and animal-inhabited areas were examined for the presence of Listeria. The microorganism was identified in 23 (17.7%) samples. L. monocytogenes was detected in 7 samples (5.4%), L. ivanovii in 2 (1.5%), L. innocua in 10 (7.7%) and L. welshimeri in 4 samples (3.1%). Prevalence of Listeria in soil from agricultural fields (17.5%) did not differ considerably from that in the soil and animal-inhabited area (18.0%), but L. ivanovii was isolated only from the latter source. Frequency of occurrence of different species of Listeria differed from place to place.