Table III.
pH and L. monocytogenes growth during ripening on the surfaces of trial cheeses inoculated with 34 complex consortia collected from cheese surfaces in the Saint-Nectaire area.
| Group | Trial cheese |
L. monocytogenes log CFU·cm−2 |
pH |
||||
|---|---|---|---|---|---|---|---|
| Day 11 | Day 81 | Day 18 | Day 28 | Day 18 | Day 28 | ||
| G1 | TR15.1 | 1.48 | < 1 | 3.33 | 4.05 | 6.42 | 7.12 |
| TR15.2 | < 1 | 1.48 | 3.34 | 4.11 | 7.17 | 7.83 | |
| TR15.3 | < 1 | 1.18 | 2.01 | 3.32 | 7.27 | 7.71 | |
| TR11 | < 1 | < 1 | 3.18 | 4.00 | 7.15 | 8.04 | |
| TR26 | < 1 | < 1 | 3.26 | 4.13 | 6.72 | 6.75 | |
| TR19 | < 1 | < 1 | 4.21 | 4.84 | 7.11 | 7.21 | |
| TR13 | < 1 | 1.78 | 4.01 | 4.86 | 7.10 | 6.84 | |
| TR9 | < 1 | 1.48 | 3.48 | 4.91 | 6.41 | 6.20 | |
| TR22 | < 1 | 1.96 | 3.74 | 4.93 | 6.74 | 6.73 | |
| TR30 | 1.78 | 1.78 | 3.82 | 4.97 | 6.60 | 7.15 | |
| TR24 | 1.48 | < 1 | 3.18 | 5.04 | 6.63 | 6.93 | |
| TR25 | < 1 | 1.48 | 4.23 | 5.05 | 7.41 | 8.47 | |
| G2 | TR23 | < 1 | 1.96 | 4.33 | 5.26 | 7.10 | 5.94 |
| TR12 | < 1 | 1.48 | 4.36 | 5.27 | 7.47 | 8.00 | |
| TR29 | < 1 | 1.48 | 3.52 | 5.27 | 6.35 | 7.00 | |
| TR6 | < 1 | < 1 | 4.38 | 5.34 | 7.17 | 8.18 | |
| TR8 | < 1 | < 1 | 4.17 | 5.39 | 7.14 | 8.06 | |
| TR34 | < 1 | 1.48 | 4.03 | 5.44 | 6.98 | 6.70 | |
| TR20 | 1.48 | 1.96 | 4.47 | 5.45 | 6.92 | 6.10 | |
| TR28 | 1.96 | < 1 | 4.24 | 5.52 | 7.34 | 8.26 | |
| TR16 | < 1 | 2.44 | 3.94 | 5.63 | 7.05 | 8.21 | |
| TR32 | 1.48 | 2.08 | 4.66 | 5.66 | 6.28 | 6.85 | |
| TR2 | < 1 | < 1 | 4.48 | 5.69 | 7.34 | 7.85 | |
| TR17 | 1.48 | 1.78 | 3.76 | 5.74 | 6.48 | 6.87 | |
| TR1 | 1.78 | < 1 | 4.09 | 5.93 | 6.21 | 7.03 | |
| TR31 | 2.52 | 2.88 | 4.52 | 5.96 | 7.05 | 7.96 | |
| TR35 | < 1 | < 1 | 4.27 | 5.96 | 6.97 | 7.06 | |
| G3 | TR27 | < 1 | < 1 | 4.08 | 6.03 | 6.31 | 6.95 |
| TR3 | 1.48 | < 1 | 4.29 | 6.08 | 7.14 | 6.82 | |
| TR14 | < 1 | 2.08 | 4.01 | 6.14 | 6.93 | 5.80 | |
| Control 2 | < 1 | 1.48 | 4.15 | 6.13 | 6.67 | 7.61 | |
| Control 1 | 1.48 | < 1 | 4.41 | 6.21 | 7.52 | 6.70 | |
| TR33 | < 1 | < 1 | 4.23 | 6.23 | 7.14 | 5.96 | |
| TR18 | < 1 | < 1 | 4.90 | 6.25 | 7.07 | 7.66 | |
| TR10 | 1.96 | 2.33 | 5.45 | 6.34 | 6.42 | 6.97 | |
| TR5 | 1.48 | < 1 | 4.26 | 6.36 | 6.45 | 6.94 | |
| TR4 | < 1 | < 1 | 4.71 | 6.40 | 6.67 | 5.91 | |
| TR7 | < 1 | 1.78 | 5.34 | 6.42 | 6.35 | 6.95 | |
| Control 3 | 1.48 | 3.33 | 4.63 | 7.66 | 7.29 | 7.70 | |
Trial cheese, TRx = complex cheese surface consortium prepared as described in Section 2.1; Control = commercial ripening culture.
Groups = Trial cheeses according to L. monocytogenes counts at 28 days of ripening: G1 = < 5 log CFU·cm−2, G2 = < 6 log CFU·cm−2 and G3 = > 6 log CFU·cm−2. TR15.1 = 1st challenge test using complex cheese surface consortium TR15. Control 2 and Control 3 = commercial ripening culture from the 2nd and 3rd challenge tests, TR15.2 = 2nd challenge test using TR15 after 3 months of storage at −20 °C, TR15.3 = 3rd challenge test using TR15 after 24 months of storage at −20 °C.