Table 10.
Growth kinetic parameters of L. monocytogenes inoculated in vegetables (corn and green peas), frozena and thawedb and stored at different temperatures
| Parameter | Frozen–thawed corn | Frozen–thawed green peas | ||||||
|---|---|---|---|---|---|---|---|---|
| 4°C | 8°C | 12°C | 20°C | 4°C | 8°C | 12°C | 20°C | |
| Lag time (h) | 13.2 | 7.0 | 2.9 | 0.5 | 12.2 | 6.8 | 3.5 | 3.4 |
| EGR (log10/h) | 0.017 | 0.039 | 0.070 | 0.16 | 0.012 | 0.039 | 0.083 | 0.219 |
| Growth potential after 24 h (c),(d) (log10 units) | 0.4 | 0.9 | 1.7 | 3.8 | 0.3 | 0.9 | 2.0 | 5.3 |
| Growth potential after 48 h (c),(d) (log10 units) | 0.8 | 1.9 | 3.3 | 7.6 | 0.6 | 1.9 | 4.0 | 10.5 |
| Time to 0.5 log 10 increase c (h) | 30 | 13 | 7 | 3 | 43 | 13 | 6 | 2 |
| Time to 2 log 10 increase c (h) | 119 | 52 | 29 | 13 | 172 | 51 | 24 | 9 |
Note: Predicted lag time and exponential growth rate (EGR) according to the models developed by Kataoka et al. (2017) for a 12‐strain cocktail.
Individually quick frozen, kept at −18°C before and during inoculation and during 7 days before thawing to monitor L. monocytogenes growth.
Inoculated frozen vegetables (25 g portion) were transferred to the target temperatures and L. monocytogenes was monitored during thawing and storage (not at the time the vegetable reached the target temperature).
Log10 increase of concentration after 24 h and at 48 h of storage at the corresponding temperature.
The lag time was not considered for the calculation.