Table 3. Distribution of minimum inhibitory concentrations (MIC) values of 20 C. jejuni and ten C. coli isolates for ten organic acids at pH 6.0 and 7.3 using the broth microdilution method.
| Number of isolates with MIC (mmol/L) value of | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Organic acid | Species | pH | 0.03 | 0.06 | 0.13 | 0.25 | 0.5 | 1 | 2 | 4 | 8 | 16 | 32 | 64 | 128 | 256 | 512 | MIC50 | MIC90 |
| Caprylic acid | C. jejuni | 6.0 | 0 | 0 | 0 | 1 | 11 | 8 | 0 | 0 | 0 | 0 | 0 | 0.5 | 1 | ||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 4 | 16 | 0 | 0 | 0 | 0 | 2 | 2 | ||||||
| C. coli | 6.0 | 0 | 0 | 0 | 2 | 6 | 2 | 0 | 0 | 0 | 0 | 0 | 0.5 | 1 | |||||
| 7.3 | 0 | 0 | 0 | 0 | 1 | 3 | 6 | 0 | 0 | 0 | 0 | 2 | 2 | ||||||
| Sorbic acid | C. jejuni | 6.0 | 0 | 0 | 0 | 15 | 5 | 0 | 0 | 0 | 0 | 0 | 0 | 0.5 | 1 | ||||
| 7.3 | 0 | 0 | 0 | 0 | 2 | 15 | 3 | 0 | 0 | 0 | 0 | 2 | 4 | ||||||
| C. coli | 6.0 | 0 | 0 | 2 | 5 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0.5 | 1 | |||||
| 7.3 | 0 | 0 | 0 | 0 | 3 | 5 | 2 | 0 | 0 | 0 | 0 | 2 | 4 | ||||||
| Caproic acid | C. jejuni | 6.0 | 0 | 0 | 0 | 6 | 10 | 3 | 1 | 0 | 0 | 0 | 0 | 1 | 2 | ||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 4 | 15 | 1 | 0 | 0 | 0 | 4 | 4 | ||||||
| C. coli | 6.0 | 0 | 0 | 0 | 5 | 3 | 2 | 0 | 0 | 0 | 0 | 0 | 0.5 | 2 | |||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 2 | 6 | 2 | 0 | 0 | 0 | 4 | 8 | ||||||
| Ascorbic acid | C. jejuni | 6.0 | 0 | 0 | 0 | 0 | 2 | 7 | 9 | 2 | 0 | 0 | 0 | 2 | 2 | ||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 6 | 8 | 3 | 0 | 8 | 16 | ||||||
| C. coli | 6.0 | 0 | 0 | 0 | 0 | 1 | 3 | 5 | 1 | 0 | 0 | 0 | 2 | 2 | |||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 5 | 4 | 1 | 0 | 4 | 8 | ||||||
| Benzoic acid | C. jejuni | 6.0 | 0 | 0 | 0 | 0 | 2 | 16 | 2 | 0 | 0 | 0 | 0 | 2 | 2 | ||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 17 | 2 | 0 | 0 | 8 | 8 | ||||||
| C. coli | 6.0 | 0 | 0 | 0 | 0 | 0 | 5 | 4 | 1 | 0 | 0 | 0 | 2 | 4 | |||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 4 | 6 | 0 | 0 | 16 | 16 | ||||||
| Propionic acid | C. jejuni | 6.0 | 0 | 0 | 4 | 10 | 4 | 2 | 0 | 0 | 0 | 0 | 0 | 4 | 8 | ||||
| 7.3 | 0 | 0 | 0 | 0 | 5 | 7 | 6 | 2 | 0 | 0 | 0 | 16 | 32 | ||||||
| C. coli | 6.0 | 0 | 0 | 0 | 2 | 4 | 4 | 0 | 0 | 0 | 0 | 0 | 8 | 16 | |||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 3 | 5 | 2 | 0 | 0 | 0 | 32 | 64 | ||||||
| Acetic acid | C. jejuni | 6.0 | 0 | 0 | 1 | 4 | 9 | 5 | 1 | 0 | 0 | 0 | 0 | 8 | 16 | ||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 4 | 10 | 4 | 2 | 0 | 0 | 32 | 64 | ||||||
| C. coli | 6.0 | 0 | 0 | 1 | 2 | 4 | 3 | 0 | 0 | 0 | 0 | 0 | 8 | 16 | |||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 2 | 6 | 1 | 1 | 0 | 0 | 32 | 64 | ||||||
| Formic acid | C. jejuni | 6.0 | 0 | 0 | 0 | 2 | 7 | 9 | 2 | 0 | 0 | 0 | 0 | 16 | 16 | ||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 13 | 4 | 0 | 0 | 64 | 128 | ||||||
| C. coli | 6.0 | 0 | 0 | 0 | 1 | 4 | 4 | 1 | 0 | 0 | 0 | 0 | 8 | 16 | |||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 0 | 6 | 3 | 1 | 0 | 0 | 32 | 64 | ||||||
| Tartaric acid | C. jejuni | 6.0 | 0 | 0 | 0 | 0 | 2 | 3 | 6 | 4 | 5 | 0 | 0 | 32 | 128 | ||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 2 | 2 | 4 | 7 | 5 | 0 | 128 | 256 | ||||||
| C. coli | 6.0 | 0 | 0 | 0 | 0 | 5 | 0 | 4 | 1 | 0 | 0 | 0 | 8 | 32 | |||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 4 | 1 | 2 | 2 | 1 | 0 | 32 | 128 | ||||||
| Fumaric acid | C. jejuni | 6.0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 13 | 6 | 0 | 128 | 256 | ||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 18 | 0 | 256 | 256 | ||||||
| C. coli | 6.0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 7 | 3 | 0 | 128 | 256 | |||||
| 7.3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 7 | 0 | 256 | 256 | ||||||
The white areas represent the tested range of organic acids.