168 h), and for temperature, from 0.57 (40 us 37 "C) to 0.96 (37 'us 36 "C). Differences were also seen when plates were incubated in anaerobe jars as opposed to an anaerobic work station (r = 0.75). It is concluded that it is essential to standardize growth parameters, and to use an anaerobe jar or an anaerobe work station, but not both.