TABLE 4.
Isolation of L. monocytogenes (Lm) from mixed culture with L. innocua ARL-Ln-010 after 48 h of enrichment of artificially inoculated guacamole on various selective and/or differential media
| No. of Lm-postive enrichment cultures and colonies/no. testeda | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
|
|||||||||||
| Culture type | Lm-001 | Lm-002 | Lm-003 | Lm-004 | Lm-006 | Lm-010 | Lm-027 | Lm-039 | Lm-051 | Lm-077 | Total |
| Chromogenic agar |
|||||||||||
| Enrichments | 1/3 | 0/3 | 0/3 | 0/3 | 0/3 | 0/3 | 3/3 | 2/3 | 3/3 | 3/3 | 12/30 |
| Colonies | 1/30 | 0/30 | 0/30 | 0/30 | 0/30 | 0/30 | 17/30 | 2/30 | 8/30 | 6/30 | 34/300 |
| PALCAM agar | |||||||||||
| Enrichments | 1/3 | 2/3 | 3/3 | 1/3 | 2/3 | 3/3 | 3/3 | 1/3 | 3/3 | 3/3 | 22/30 |
| Colonies | 1/30 | 2/30 | 4/30 | 1/30 | 3/30 | 6/30 | 23/30 | 2/30 | 10/30 | 9/30 | 61/300 |
| Oxford agar | |||||||||||
| Enrichments | 0/3 | 0/3 | 0/3 | 0/3 | 0/3 | 3/3 | 3/3 | 2/3 | 3/3 | 3/3 | 14/30 |
| Colonies | 0/30 | 0/30 | 0/30 | 0/30 | 0/30 | 5/30 | 24/30 | 3/30 | 13/30 | 12/30 | 57/300 |
| Total | |||||||||||
| Enrichments | 2/9 | 2/9 | 3/9 | 1/9 | 2/9 | 6/9 | 9/9 | 4/9 | 9/9 | 9/9 | |
| Colonies | 2/90 | 2/90 | 4/90 | 1/90 | 3/90 | 11/90 | 64/90 | 7/90 | 31/90 | 27/90 | |
a
Three enrichment cultures per isolate pair were tested. Ten colonies per enrichment culture were selected for confirmation, for a total of 30 colonies tested.