Table 1.
Different parameters used during the production of rakfisk in this study. (The temperatures were measured and given by the individual manufacturers).
| Producer ID | Fish Species/Origin b | Temperature °C | NaCl % (w/v) d | Sugar Addition | Starter Culture Addition g | Salting Method i | Sampling k |
|---|---|---|---|---|---|---|---|
| 1 a | Char/A | 3.5/4.5 c | 5.8/5.7 | No | No | Dry | Complete |
| 2 | Char/B | 5.0 | 3.5/4.0 | Yes e | No h | Brine | Complete |
| 3 | Trout/C | 7.0 | 4.9/4.2 | No | No | Dry | Complete |
| 4 | Trout/C | 7.0 | 4.8/5.1 | Yes f | Yes | Dry | Year 2+ |
| 5 | Trout/D | 7.5 | 4.9/3.9 | No | No | Dry | Year 2+ |
| 6 | Trout/E | 6.0 | 6.9/7.4 | No | No | Dry | Year 2+ m |
a Producer 1 applied higher ripening temperature (7 °C) and lower salinity (4.3% NaCl) in an additional experiment the second year. b A, ocean-based (brackish water), farmed arctic char; B, Land-based, farmed arctic char; C, land-based, farmed trout; D, wild-caught trout (lake in Western Norway); E, wild-caught trout (mountain lake in Southern Norway). c The ripening temperature given by the producer was 3.5 °C the first year and 4.5 °C the second year. d Mean values of the NaCl concentration (% w/v) calculated from end-point samples (middle layer). The values represent the 1st and 2nd year, respectively. Standard deviation were in all cases less than 0.01. e 0.33% sucrose; f 0.4% fructose; g T-RM-53 containing Lactobacillus sakei and Staphylococcus carnosus (Chr. Hansen, Hørsholm, Denmark); h This producer was claiming to use the T-RM-53 starter culture. However, the microbiological analyses (both culture-dependent and culture-independent) suggested this was not the case, or the level of starter addition was below detection due to errors by the producer. i Refers to how the salt was added to the fish during preparation. After the first 24 h, productions with dry salted fish were also completely covered in brine, either from natural formation, or topped up with brine holding the appropriate salinity. k “Complete” refers to full sampling series (days: 0, 3, 7, 14, 28, 42, 63, and 91) for two consecutive years; “Year 2+” refers to full sampling the second year and end-point (day 91 or 63) sample collected the 1st year. m Sample collection ended on day 63 for Producer 6.