After pre-enrichment, raise the temperature in the water bath or move to a 42°C incubator. If analyzing for C. fetus, keep the temperature at 37°C, even if a thermotolerant strain (growth at 42°C) was associated with the sample. Incubate shaking enrichments 23-24 h, except shellfish samples, which are incubated an extra 4 h. Dairy samples are incubated 48 hrs total.Incubate non-shaking enrichments 28-29 h, except shellfish, which are incubated 48 h. Incubate samples for C. fetus at 48 h(shaking) or 52 h (non-shaking).